partly preserved in an Arabic translation.<fnref n="274" /> Alexander's source text was probably the above-mentioned Galenic treatise.<fnref n="275" /> A Greek fragment of the same critique of Aristotle's argument, attributed to Galen (and possibly going back to the same source), is cited in Simplicius' commentary on the *Physics*.<fnref n="276" /> All this would hardly be worth mentioning here, did we not have a testimony from Ps-Ğābir ibn Ḥayyān that Galen examined the first mover in *Dem.* as well, arguing that "in moving what it moves, [the first mover] should necessarily be endowed with a movement of its own".<fnref n="277" /> Since we know that Galen discussed Aristotle's views on natural philosophy in books eight and nine, and book eight was not known to Arabic readers, the argument about the first mover could have been addressed in book nine. It is tempting to believe that Galen rehearsed some of the same objections against Aristotle as those reported by Alexander and Simplicius.<fnref n="278" />

## Books IX to XII

In book nine, Galen began the exposition of the syllogistic theory. The context of the critique reported by Abū al-‘Alā’ (E5) was a discussion of the pairs of categorical premisses. In the *Inst. log.*, Galen tells us that he dealt with categorical syllogisms in *Dem.*, showing that the number of syllogistic figures was exactly three (F2). A parallel in Ibn al-Ṣalāḥ

<footnote n="274">274 See above, p. 5. For a detailed reconstruction of Galen's argument, see O. Harari, "Alexander Against Galen on Motion: A Merely Logical Debate?" *Oxford Studies in Ancient Philosophy* 50 (2016), pp. 201–236.</footnote>

<footnote n="275">275 See *Alexander against Galen on motion*, Part A, the Carullah manuscript, 67a: "But a certain man [namely Galen] blamed Aristotle concerning this proof ... and wrote a book about it." Trans. al-Dimashqi, in: N. Rescher and M. E. Marmura, *The Refutation by Alexander of Aphrodisias of Galen's Treatise on the Theory of Motion* (Islamabad: Islamic Research Institute 1965), p. 18.</footnote>

<footnote n="276">276 Simplicius, *In Phys.* VII.1 (1039,13–15 Diels): ταύτην τὴν ἀπόδειξιν αἰτιᾶται μὲν καὶ ὁ φυλολογώτατος Γαληνός, αἰτιῶνται δὲ καὶ ἄλλοι ὡς ἀδυνάτω χρωμένην ὑποθέσει τῇ λεγούσῃ τοῦ ΑΒ πρώτως καὶ καθ' αὐτὸ κινουμένου τὸ ΓΒ μὴ κινεῖσθαι. ("The most scholarly Galen criticizes this demonstration, and others criticize it too, on the grounds that it uses an impossible hypothesis, [namely,] the one claiming that, though ΑΒ is moving primarily and in its own right, CB is not moving"); trans. C. Hagen, *Simplicius: On Aristotle's Physics* 7 [London: Duckworth 1994], p. 14). Simplicius probably draws on Alexander, whose response to the critique is mentioned in the following sentence. Here again, the reference is possibly to Galen's treatise mentioned in *Lib. prop.* 17.1; although it cannot be ruled out that, in his commentary on *Physics*, Alexander's background text was *Dem.*, just as it was, presumably, in his response to Galen's critique of Aristotle's definitions of time and place.</footnote>

<footnote n="277">277 Ps.-Ğābir ibn Ḥayyān, *Selected Texts*, p. 517 Kraus = E7. This testimonium was unknown to Galenic scholars until now; nonetheless, some have suspected that the argument about the first mover could have been developed in *Dem.* too; see Chiaradonna, "Le traité," pp. 45–46 n. 18; Havrda, "The Purpose," p. 280 n. 63.</footnote>

<footnote n="278">278 As mentioned above, there was a significant overlap between *Dem.* XIII and *PHP* VII; there was also some overlap between *Dem.* XIII and *Hipp. elem.*; between *Dem.* V and *PHP* VII; and probably also between *Dem.* III and *PHP* II. Possibly, then, there was also an overlap between some part of *Dem.* (book IX?) and Galen's treatise on the prime mover.</footnote>
allows us to locate this discussion in book nine.<fnref n="279" /> The next reference to a specific book concerns book eleven. There, Ibn Buḥṭīšū tells us, Galen, “after explaining [the propositions] used by Aristotle in syllogisms of the third figure,” discussed a particular issue in Plato.<fnref n="280" /> This indicates that Galen continued his analysis of categorical syllogisms, a topic introduced in book nine, in the subsequent two books, perhaps explaining each of the three Aristotelian figures in turn. Having concluded the topic in book eleven, he turned to Plato. The Platonic issue mentioned by Buḥṭīšū is a curious one: Galen argues that Plato “imposes no constraints on most people as to the use of sex which follows its natural course”; on the other hand, he wishes to restrain those who suffer from love-sickness, arguing that they should only be allowed a moderate use of sex. It is not clear which passage in Plato Galen is referring to, but the context of the discussion in *Dem.* seems to be revealed by the anonymous treatise *All the kinds of syllogism* from the Alexandrian Neoplatonist school.<fnref n="281" /> There we learn that Galen distinguished between simple and compound syllogisms, the former being standard Aristotelian syllogisms composed of three terms, whereas the latter were four-term syllogisms, of which Galen “found many examples in Plato’s dialogues” (F4).<fnref n="282" /> The treatise then analyses several examples of the compound syllogism, mostly (or solely) from Plato’s dialogues. One of these, from the third book of the *Republic*, runs as follows:

> All correct passions come about through moderation.

> All sexual activities come about through excessive pleasure.

> No excessive pleasures come about through moderation.

> Therefore, no correct passions come about through sexual activities.<fnref n="283" />

This example recalls the passage from Buḥṭīšū, insofar as both texts (a) deal with sexual desire and activities, contrasting excess and moderation in that regard; (b) do so in the course of a discussion about syllogisms; and (c) refer to Plato. They differ from each other in that each attributes to Plato a different attitude towards sex. Whereas according to Buḥṭīšū, Plato imposes no constraints on sexual activities he considers to be natural, according the *All the kinds*, Plato speaks disparagingly of sexual activity as such. However, it is quite possible that Buḥṭīšū reflects Galen's gloss on this very example, which, like other examples from Plato cited in *All the kinds*, is probably taken from *Dem*.<fnref n="284" /> Having analysed Plato's argument about sexual activity in the *Republic*,

<footnote n="279">279 Ibn al-Ṣalāḥ, *On the fourth figure of the categorical syllogism*, 122b18–20, ed. in N. Rescher, *Galen and the Syllogism* (Pittsburgh: Pittsburgh University Press 1966), p. 76 = F1.</footnote>

<footnote n="280">280 Ibn Bukhtīšū', ed. F. Klein-Franke, *Abū Sa'id 'Ubaydallah ibn Buḥṭīšū': Über die Heilung der Krankheiten der Seele und des Körpers* (Beirut: Dar El-Machreq 1978), p. 48,11–21 = F3.</footnote>

<footnote n="281">281 See above, p. 8.</footnote>

<footnote n="282">282 *Omn. syllog.* x,30 Wallies, trans. Barnes and Morison, forthcoming.</footnote>

<footnote n="283">283 *Omn. syllog.* x,16–19 Wallies, trans. Barnes and Morison.</footnote>

<footnote n="284">284 See above, p. 8.</footnote>
Galen may have recalled the same philosophers's distinction between natural and unnatural sex, and argue that a moderate use of sex is acceptable for Plato.<fnref n="285" /> But even if Butišū' refers to a different Platonic passage, it seems safe to assume that the context of the reference is the discussion of compound syllogisms. If this is correct, it follows that Galen discussed compound syllogisms in book eleven.

Rāżī tells us that in book twelve, Galen dealt with necessary consequence. His example was one season following upon another (F7). A parallel in Ps-Ġābir ibn Hayyān suggests that Galen regarded this consequence as “one of the first premissed in the mind” (F8); this presumably means that it is primitive and need not be proved. We do not know the context in which Galen dealt with this issue, but a reasonable guess is that in book twelve Galen discussed the modality of syllogistic premisses and conclusions. In *SMT* Galen recalls “a certain logical theorem pointed out in the books *On demonstration*,” which concerns this issue. According to this theorem, “of demonstrations, some conclude that this holds of that of necessity, whereas others that it is possible [for this] to hold [of that]. Some of these latter change into [this] holding [of that] of necessity, whenever they follow necessary principles” (F9).<fnref n="286" /> This passage, analysed in detail by Jonathan Barnes, shows that Galen was interested in modality and examined this issue in *Dem*.<fnref n="287" /> And even though, according to another source, he thought that “the theory of the possible and the syllogisms that are generated from it are superfluous” (F12, see also F10), he did concede a positive role to the possible demonstrations within scientific method. As F9 indicates, this role is one of tentative conclusions, which are to be confirmed by showing why they are necessarily true. These and related issues were probably dealt with in book twelve.<fnref n="288" />

<footnote n="285">285 See, e.g., Plat. *Leg*. I, 636c3–5 and V, 733e6–734a9.</footnote>

<footnote n="286">286 *SMT* III.25 (XI.612–613 K).</footnote>

<footnote n="287">287 For a discussion of Galen's attitude to modal syllogistic, including a detailed commentary on our testimonia F9 and F12, see J. Barnes, *Truth, etc.* (Oxford: Oxford University Press 2007), pp. 465–487. See also R. Chiaradonna, “Galen on What is Persuasive (*pithanon*) and What Approximates to Truth,” in P. Adamson, R. Hansberger, and J. Wilberding (eds.), *Philosophical Themes in Galen* (London: Institute of Classical Studies 2014), pp. 61–88, here pp. 83–87.</footnote>

<footnote n="288">288 Some of these issues were developed in Galen's treatise *On the possible*, mentioned in A9(3). A short fragment is preserved in an Arabic translation; see N. Rescher and M. E. Marmura, *The Refutation by Alexander of Aphrodisias of Galen's Treatise on the Theory of Motion* (Islamabad: Islamic Research Institute 1965), pp. 69–70. In that fragment, Galen criticizes Theophrastus for distinguishing between two meanings of “necessity”, one in statements about eternal things (“the sun illuminates of necessity”), and the other about things perishable (“man is endowed with speech of necessity”). Galen regards this distinction as pointless, as in both cases the expression refers to the same thing, namely to the fact of inseparable existence of one thing in another. As Chiaradonna points out, this passage displays a “similar attitude” as Fārābī's testimonium F11 about the double meaning of the word “possible”: “for in both cases, modal distinctions (contingency vs. necessity and the various senses of the term ‘necessity’) are ultimately regarded as useless and unfounded” (Chiaradonna, “Galen on what is Persuasive,” p. 86). For the Arabic reception, see further below, pp. 85–87.</footnote>
Somewhere within the span of books IX to XII, Galen also probably introduced
"a third species" of syllogisms – besides the categorical and hypothetical – which he
describes as coming about κατὰ τὸ πρός τι ("based on relation").<sup>289</sup> One example is the
following argument: "Theo is equal to Dio; Philo is equal to the same Dio; therefore,
Theo is equal to Philo."<sup>290</sup> The issue of relational syllogisms is complex and controver-
sial and cannot adequately be covered within the confines of this overview.<sup>291</sup> The little
we do know about it comes from Galen's *Introduction to logic*, a badly preserved trea-
tise written late in Galen's career. In one passage (our testimonium F6) Galen tells us
that he discussed relational syllogisms in two works, both of which have been lost: *On
demonstration* and *On the number of syllogisms*.<sup>292</sup> The text is corrupt, but Galen seems
to be saying that in both of these works he explored two aspects of relational syllo-
gisms, namely, their σύστασις and their πίστις, and found that they have their σύστασις
because of the πίστις of the axioms to which they are subordinated. The word πίστις
is probably used in the same sense as in the definition of demonstration in B6*[4],<sup>293</sup>
i.e., as credence, which is supplied from something that has been agreed to something
that is in dispute; in the case of demonstration in the proper sense, the "thing agreed"
is agreed to because it is evident or credible in virtue of itself (see B6*[8–9]; B7*[11];
A12; A16). Relational syllogisms, then, obtain their credence from axioms, defined as
propositions "credible in virtue of themselves".<sup>294</sup> In the example mentioned above,
the axiom is this: "Items equal to the same are also equal to one another."<sup>295</sup> By furnish-
ing their credence to them, axioms in turn endow relational syllogisms with σύστασις,
which is probably to be interpreted in the sense of "guarantee" or "confirmation".<sup>296</sup> In

<footnote n="289">289 Galen, *Inst. log.* 16.1 (38,13–14 Kalbfleisch). We are using the forthcoming edition of Jonathan Barnes and Ben Morison, and are grateful to them for sharing it with us prior to publication.</footnote>

<footnote n="290">290 *Inst. log.* 1.2 (3,12–4,1 Kalbfleisch).</footnote>

<footnote n="291">291 The best contributions include: I. Mueller, “Greek Mathematics and Greek Logic,” in J. Corcoran (ed.), *Ancient Logic and Its Modern Interpretations* (Dordrecht/Boston: Reidel 1974), pp. 35–70, here pp. 61–64; J. Barnes, “Proofs and Syllogisms in Galen,” in J. Barnes and J. Jouanna (eds.), *Galien et la philosophie* (Geneva: Fondation Hardt 2003), pp. 1–24, here pp. 16–24; Morison, “Logic,” pp. 105–115; idem, “Late Antiquity,” in L. Castagnoli and P. Fait (eds.), *Cambridge Companion to Ancient Logic* (Cambridge: Cambridge University Press 2023), pp. 82–105, here pp. 87–96.</footnote>

<footnote n="292">292 Galen, *Inst. log.* 17.1 (42,10–11 Kalbfleisch). *On the number of syllogisms* is mentioned in A9, among the works “providing a broader treatment of what was discussed concisely in [Dem.].”</footnote>

<footnote n="293">293 Clement of Alexandria, *Lib. log.* (= *Strom*. VIII) 3.5.1 (82,12–14 Stählin–Havrda).</footnote>

<footnote n="294">294 See e.g. *Inst. log.* 17.7 (44,13–14 Kalbfleisch): τὸν γὰρ ἐξ αὐτοῦ πιστὸν λόγον οὕτως (*scil*. ἀξίωμα) ὀνομάζειν ὑπεθέμεθα κατά τήν προκειμένην διδασκαλίαν.</footnote>

<footnote n="295">295 *Inst. log.* 1.2–3 (3,12–4,7 Kalbfleisch). See Galen, *MM I.4.10* and 14 (48,2–3 and 50,13–14 Lorusso / X.34 and 36 K); the second passage, which refers to *Dem.*, is listed as A15.</footnote>

<footnote n="296">296 This meaning of σύστασις is arguably derived from συνίστημι in the sense of “guarantee” or “make firm” (LSJ, s.v., IV.2 and V); see also ibid. s.v. σύστασις, II. For a detailed commentary on *Inst. log.* 17.1 (= F6), see Barnes, *Truth, etc.*, pp. 419–444.</footnote>
*Dem.*, Galen was concerned with showing that relational syllogisms obtain their confirmation in precisely this way: by the force of the axiom under which they fall.<fnref n="297" />

## Book XIII

Book thirteen fortunately attracted the attention of Rāzī, and so we possess a wealth of information about its contents, both from Rāzī and his opponent Abū al-‘Alā’ ibn Zuhr. This is complemented by Galen’s own evidence, which indicates that Galen dealt mainly with two topics in this book: the elements and the causes of vision. Galen’s discussion was partly polemical, especially in relation to corpuscular theories; but he also argued in favour of alternative theories, presenting arguments he regarded as demonstrative. This latter feature – the presence of positive views about issues in natural philosophy, supported by demonstrations – seems to distinguish the thirteenth book from books IV, VIII, and IX, where natural-philosophical arguments were exposed as undemonstrative or false but with no fully-fledged positive arguments to replace them.

Galen must have devoted a significant part of the thirteenth book to a polemic against Asclepiades and his corpuscular theory of the elements:

> For this reason we will no longer mention Asclepiades in this account, having demonstrated that his elements are false, namely in the thirteenth book of *On demonstration* and in the treatise on *The doctrines of Asclepiades*, in which the fifth and sixth book contain refutations of his elements. (G1)<fnref n="298" />

A discussion of the same topic is preserved in Galen's *Elements according to Hippocrates (Hipp. elem.)*. However, Galen tells us that in that treatise he only presented the arguments that Hippocrates himself used. “For the most complete scientific knowledge about the elements of the body,” he adds, “one should read the discussion in the thirteenth book *On demonstration* and in the fifth and sixth book of *The opinions of Asclepiades*” (G2).<fnref n="299" /> *The opinions of Asclepiades* is lost and Galen tells us next to nothing about the relevant part of *Dem*. XIII. Yet, Arabic sources give us at least a glimpse of the argument. Even though they never mention Asclepiades or the theory of the elements, some of their evidence for book XIII fits neatly into this framework.

Besides the causes of vision (on which more below), three issues are addressed in the Arabic sources for *Dem*. XIII: (1) “the primary body”, also described as “the substratum of generation and corruption” and as “substance”; (2) void; and (3) time. In relation

<footnote n="297">297 See *Inst. log.* 16.5–13 and 18.1–8 (39,5–42,6 and 45,6–47,17 Kalbfleisch). According to Galen (*Inst. log.* 18.8, 47,16–17 Kalbfleisch), Posidonius of Apamea called these arguments (or some of them) “conclusive by virtue of an axiom” (συνακτικοῦς κατὰ δύναμιν ἀξιώματος).</footnote>

<footnote n="298">298 Galen, *Cur. rat. ven. sect.* 3 (XI.257 K).</footnote>

<footnote n="299">299 Galen, *Ord. lib. prop.* 2.8 (93,9–15 Boudon-Millot / XIX.55 K).</footnote>
to the first issue, Galen is concerned with showing that the primary body is devoid of shape (G3–G5). Void and time then both seem to be treated as parts of the same argument concerning the separability of quantity from an incorporeal substance (G6–G7). In addition, Galen produced arguments against the existence of void (G8–G9).<fnref n="300" />

The testimonia about the primary body are unfortunately somewhat confused. Rāzī reports Galen as saying that “substance is the primary body and substratum of all generation and all corruption, which is in itself devoid of quality” (G3). In Galen’s other writings, the predicate “devoid of quality” (ἀποιος) is said of the matter underlying the elementary bodies (fire, water, earth, and air), which does not exist in itself, but can be separated from the primary qualities (the hot, the cold, the dry, and the wet) by thought (κατ' ἐπίνοιαν).<fnref n="301" /> Galen never describes this abstract matter as “the primary body” or as “substance”. In fact, according to Abū al-‘Alā’, “in this book [i.e., *On demonstration*] by ‘primary substance’ [Galen] does not mean the substance as being devoid of the sensible, but as the first sensible [thing]” (G5). Whatever is meant by the phrase “the first sensible thing”, it surely does not refer to the abstract “unqualified matter”.<fnref n="302" />

It seems, however, that when Galen speaks of the primary body as being devoid of qualities, he does not present his *own* doctrine; rather he articulates the position of his opponents. In his *Commentary on Hippocrates’ Nature of man*, Galen summarizes the view of the atomists and other corpuscularists regarding the elements as follows:

> For what really exists is one in form according to these people too. Thus the primary body is called ungenerated and indestructible, since everything else derives its generation by way of composition out of it.<fnref n="303" />

Now, as Galen reports elsewhere, the primary bodies, according to his opponents, are devoid of qualities in the sense that they have none of the primary sensible qualities such as colour, taste or temperature:

<footnote n="300">300 Rāzī’s testimonium G8 (*Doubts* 4.2, 20,7–9 Koetschet) is discussed by Adamson, “Galen on Void,” pp. 208–211.</footnote>

<footnote n="301">301 See *Hipp. elem.* 6.38 (114,16–21 De Lacy / I.469 K); *QAM* 3 (36,21–37,2 von Müller / IV.773 K); *PHP* IX.9.44 (608,19–21 De Lacy / V.804 K).</footnote>

<footnote n="302">302 Galen uses the phrase “the first and simplest sensible elements” in reference to the homoeomerous parts; see *Hipp. elem.* 8.11 (126,1–2 De Lacy / I.479 K); see also *Nat. Fac.* I.6 (109,18–19 Helmreich / II.12 K); *Opt. med.* 3.6 (290,13–14 Boudon-Millot / IV.60 K).</footnote>

<footnote n="303">303 *HNH* I.7 (21,12–15 Mewaldt / XV.36–37 K), trans. R. J. Hankinson: ἐν γὰρ τῷ εἶδει καὶ κατὰ τούτους ἐστὶ τὸ ὄντως ὄν. Οἴτω δὲ καὶ �ώνόμασται τὸ πρῶτον σώμα τὸ ἀγέννητόν τε καὶ ἄφθαρτον, ἐπειδή τᾶλλα πάντα τὴν γένεσιν ἐκ τῆς ἑκείνου συνθέσεως λαμβάνει. We are grateful to Jim Hankinson for providing his unpublished translation to us.</footnote>
It is posited by all of them that the first element is without qualities; it does not have inherent whiteness or blackness or any colour whatever; it does not have sweetness or bitterness or heat or cold; and it has no other quality at all.<fnref n="304" />

It is true that the corpuscules have shape, hardness, and weight; but these are not regarded as qualities by these thinkers.<fnref n="305" /> Galen, then, in response to these views, seems to have argued that the primary bodies – in the sense of the elements of sensible bodies – are *not* without qualities, but *are* devoid of shape.

Further, according to G4, Galen seems to have argued dialectically that if the primary body were without qualities (as his opponents believe), it would be without shape; and if shape were added to it, it would become a mathematical body (rather than an element of sensible things). According to G5, Galen argued that, since the first substance is susceptible to change in nature, which extends to all its parts, it is a body devoid of shape. The claim that the first substance of sensible things is susceptible to an alteration “through-and-through” (δι' ὁλων) is defended at length in *Hipp. elem.* and was probably defended already in *Dem.*<fnref n="306" /> The conclusion that such a substance does not have a shape of its own follows from this premiss.

Possibly in the same connection Galen also appears to have argued that quantity cannot be separated from the first substance. This – namely *That quantity is inseparable from the first substance* – was the title of one of the works mentioned in A9, “which provide a broader treatment of what was discussed concisely in [*On demonstration*]”.<fnref n="307" /> Rāzī and Abū al-‘Alā’ give us a hint as to the context of this discussion in *Dem*. According to Rāzī, Galen says: “Void is not sensible and it is not clear whether it exists or not, whereas time exists without any doubt and quantity is inseparable from it even if it [i.e., time] is not corporeal.”<fnref n="308" /> It is unclear at first glance what the point of these statements was. Rāzī is intrigued by the part which mentions quantity as being inseparable from time and concludes that, according to Galen, “time is a substance because it is the subject of quantity”.<fnref n="309" /> Abū al-‘Alā’ objects that Galen’s statement does not imply that time is a substance, since quantity is predicated also of other things than substances, such as speech and number. And he continues: “Moreover, when Galen says about this substance [i.e. time] that there is something inseparable from it that characterizes it and that obviously differentiates it from other sensible things, and that this is quantity,

<footnote n="304">304 *Hipp. elem.* 2.11 (60,5–8 De Lacy / 1.417 K).</footnote>

<footnote n="305">305 See CAM 7.4 (74,3–8 Fortuna / 1.246–247 K); D. Leith, “The Qualitative Status of the Onkoi in Asclepiades’ Theory of Matter,” *Oxford Studies in Ancient Philosophy* 36 (2009), pp. 283–320; for Galen, see pp. 292–294.</footnote>

<footnote n="306">306 Cf. *Hipp. elem.* 9.12–17 (130,11–132,13 De Lacy / 1.484–485 K).</footnote>

<footnote n="307">307 *Lib. prop.* 14.23 (169,8 Boudon-Millot / 12, XIX.45 K).</footnote>

<footnote n="308">308 Rāzī, *Doubts* 4.1 (20,1–6 Koetschet) = G6.</footnote>

<footnote n="309">309 Rāzī, *Doubts* 4.1 (20,1–6 Koetschet) = G6. See further below, p. 78.</footnote>
he tells us nothing except that [time] is sensible.”<fnref n="310" /> Abū al-‘Alā’, then, denies that in this passage Galen discussed the question of whether time is a substance or not. Rather, he says, Galen singled out one feature of time that “characterizes it and obviously differentiates it from other sensible things”, describing this feature as quantity. If this is correct, Galen must have meant a peculiar quantity belonging to time – perhaps duration, as discussed above. By pointing out that some such quantity is inseparable from time, Galen, according to Abū al-‘Alā’, “tells us nothing except that [time] is sensible”. This perhaps indicates that for Galen duration is that by which time is sensible and distinguishable from other sensible things.

According to the testimonia, Galen further drew a contrast between time and void. The contrast can be outlined as follows: whereas void is not sensible and it is not clear whether it exists or not, time exists without any doubt and (even though it is incorporeal) it is sensible through a peculiar quantity which is inseparable from it.<fnref n="311" /> Now void, of course, was postulated by the corpuscularist as one of the principles of the universe; and the notion of time as incorporeal, although commonly associated with the Stoics, is also attested among the Epicureans.<fnref n="312" /> Galen apparently argued from the assumptions of his opponents. What did he argue about? According to Abū al-‘Alā’, Galen said: “I only did this for void and time.”<fnref n="313" /> Discussions of both topics, then, must have shared a common point, and maybe that point was this: neither void nor time can be conceived of without quantity. Time is an incorporeal but sensible substance and what characterizes it as such is a peculiar quantity (duration). Void, irrespective of whether it exists or not, is thought of as “place suitable for the movement of the bodies in it” (G7). Galen presumably argued that void too in this sense cannot be thought of without quantity, specifically extension. As Rāzī reports, “by the word ‘void’ [Galen] means place” (that is, place unoccupied by any body), and place, as we have seen above, was probably interpreted by Galen as extension.<fnref n="314" /> Taking up the issues discussed already in book eight (and possibly nine), Galen showed that neither void nor time can be conceived of without quantity.<fnref n="315" /> Many details elude us, but the discussion of void and time in book thirteen could have formed part of an argument about the first substance of sensible bodies and the view that quantity (just like quality) is inseparable from it.

<footnote n="310">310 Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, fol. 5b, ll. 10–11 Koetschet–Rajab = G7.</footnote>

<footnote n="311">311 Rāzī, *Doubts* 4.1 (20, 1–6 Koetschet = G6), the last part (regarding the peculiar quantity) being interpreted in light of Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, fol. 5b, ll. 7–16, Koetschet–Rajab = G7.</footnote>

<footnote n="312">312 See Sextus Empiricus, *M. X.227*.</footnote>

<footnote n="313">313 *Solution to the Doubts about Galen*, fol. 5b, ll. 7–16, Koetschet–Rajab = G7.</footnote>

<footnote n="314">314 Rāzī, *Doubts* 4.1 (20,1–6 Koetschet) = G6.</footnote>

<footnote n="315">315 The existence of void was postulated only for the sake of the argument. Galen went on to demonstrate, no doubt against his corpuscularist opponents, that void does not exist. See G8–G9.</footnote>
The same book also included a discussion of the causes of vision, which is largely paralleled in *PHP* VII.<fnref n="316" /> We cannot be sure about the order in which Galen dealt with these issues. However, our arrangement follows the order of Rāzī's references, where the primary body, void and time come first, and vision second, followed by a quotation from “the end of this [i.e., thirteenth] book” (G28).

Why did Galen discuss vision in *Dem.*? In *PHP* VII, the starting point is the role of pneuma in the functioning of the ruling part of the soul.<fnref n="317" /> In *Dem.*, the topic may have emerged in the wake of the preceding polemic against the corpuscular theory of the elements, which also extends to the explanation of vision. According to Abū al-‘Alā’, “Galen’s purpose in this part of his book is to do away with the belief of those who say that vision occurs through images of visible things streaming towards the eye or that small bodies enter the pupil of the eye” (G15).<fnref n="318" /> As in the case of the elements, Galen presented arguments in favour of a different view, according to which vision arises due to the optic pneuma emanating from the eye, which alters the quality of the illuminated air and uses the air – modified by the twofold impact of the optic pneuma and the light from the Sun – as the instrument of vision. He provided five signs to the effect that the pneuma emanates from the eye; at the same time, he refuted what he apparently considered to be an exhaustive list of alternative explanations of vision, both extramissionist and intromissionist, exploring them each separately (see esp. G17).<fnref n="319" />

Towards the end of the book, Galen returned to the question of the primary body. Perhaps by way of summarizing the main conclusions of the argument as a whole, he set down a proposition according to which the primary body is neither generated nor corruptible. He further argued that this proposition is universally accepted, because it follows from “two first principles evident to all people, namely that nothing is created out of that which does not exist at all; and nothing is corrupted in such a way as to become that which does not exist” (G28).<fnref n="320" />

## The last two books

We know nothing about the fifteenth book and next to nothing about the fourteenth. According to Rāzī, somewhere in the fourteenth book Galen discussed digestion and

<footnote n="316">316 Galen, *PHP* VII.4.1–8.14 (448,4–478,8 De Lacy / V.611–647 K); for discussion, see H. von Staden, “La théorie de la vision chez Galien: la colonne qui saute et autres énigmes,” *Philosophie Antique* 12 (2012), pp. 115–156; K. Ierodiakonou, “On Galen’s Theory of Vision,” in P. Adamson, R. Hansberger, and J. Wilberding (eds.), *Philosophical Themes in Galen* (London: Institute for Classical Studies 2014), pp. 235–247.</footnote>

<footnote n="317">317 Cf. *PHP* VII.4.1 (448,4–14 De Lacy / V.611–612 K).</footnote>

<footnote n="318">318 Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, fol. 7a, ll. 27–28 (Koetschet–Rajab).</footnote>

<footnote n="319">319 Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, fol. 9a, ll. 3–26 (Koetschet–Rajab).</footnote>

<footnote n="320">320 *Doubts* 6.1 (36,2–5 Koetschet). Cf. Galen, *MM* I.4.14 (50,16–17 Lorusso / X.36–37 K) = A15.</footnote>
the question of how long food remains in the stomach (G30–G31).<fnref n="321" /> This might indicate that after discussing the elements Galen’s intention was to show how the methods expounded in *Dem*. could be used in dealing with topics of immediate interest to doctors.

## Conclusion

According to our reconstruction, the structure of *Dem*. was roughly as follows. After inviting his readers to the study of demonstration in the first book, Galen introduced the concept of demonstration as such. Next he outlined, by means of specific examples, the method for dealing with problems. He started, possibly in the second book, with the question of whether the embryo is an animal or not, using it to illustrate how to “recognize the problems” and to define the object of investigation. Another question taken up probably in the third book concerned the bodily location of the ruling part of the soul. Again, Galen used it as a didactic example to show how to distinguish between different sorts of premisses and to identify those appropriate to the problem. The same line of thought was followed in the fourth book, where the question of whether the world is generated or not served to familiarize the reader with the distinction between scientific and merely persuasive premisses. The fifth book, where the proper objects of individual senses were discussed, was arguably the beginning of a systematic exposition of the theory of demonstration, starting with the natural criteria of knowledge. There are certain indications that the context of this discussion might have been a polemic against scepticism; and it could have been followed – somewhere between books V and VIII – by the treatment of the rational criteria of knowledge, and the capacities and methods corresponding to them, such as the capacity to distinguish the same and the different, and the methods of division and composition. As our tentative remarks indicate, the last sentence rests upon relatively meagre evidence or reasonable but unprovable hypotheses. Yet, given the sheer darkness at this point in our journey – especially when it comes to books VI–VII – we gratefully snatch at any glimmer of light, however dim it may be. Later, in books VIII and IX, Galen presented a critical discussion of issues in Aristotle’s natural philosophy: certainly his definition of time, and probably also place and the prime mover. The context might have been the exposition of rational methods, such as definition. And Aristotle’s argument about the prime mover could have been taken up as an example of a failed proof, giving students the satisfaction of being able, with the knowledge they had acquired so far, to discover the flaws in the great philosopher’s reasoning. Book IX also marks the beginning of an exposition of the syllogistic theory. Within the span of book IX and book XII, Galen discussed the three Aristotelian figures, the so-called compound four-term syllogisms identified in Plato (XI), the difference between possible and necessary syllogisms (XII), and probably

<footnote n="321">321 Răzî, *The comprehensive book of medicine*, 5.45 and 5.95 Hyderabad (G30–G31).</footnote>
also relational syllogisms. In Book XIII there was a critique of the corpuscularist theories of the elements and of vision, and arguments in favour of the particular views that Galen himself held about these matters. Perhaps, after explaining the theory of demonstrative argument in all its complexity, and training his readers to become experts in this area, Galen thought it fitting to test their demonstrative skills by tackling issues of prime importance for natural philosophy. In the final books he may have continued along similar lines, showing how the theory and practice of demonstration is useful for inquiry about particular issues relevant to medicine.
# 5 The Arabic *On demonstration*: Transmission, translation, and interpretation

Given the sheer number of Galenic works that were translated into Arabic and so can still be read today in their Arabic translation, the loss of *Dem.*, in both Greek and Arabic, is certainly one of the most regrettable casualties in the history of texts. The loss is particularly acute because of the wide influence that this treatise – and more generally Galenic logic – had on Arabic philosophers.

This chapter will discuss three different aspects of the Arabic *Dem*. The complex historical transmission of the text itself will first be examined. Arabic testimonia are crucial for our access to *Dem.*, but the Arabic *Dem.* was unfortunately always lacunose to some extent. The second section will stress the importance of shifting our perspective from transmission to reception. In doing so, I wish to stress that fully understanding the Arabic testimonia requires not only utilizing them as a means to restoring the (lost) Greek text, but also appreciating them in their own linguistic and intellectual context.<fnref n="322" /> Finally, I will focus on the interpretation of *Dem*. The Arabic reception of *Dem*. bears testimony to the evolution of Arabic philosophy itself: while the formative period of Arabic philosophy, in the 9th and beginning of the 10th century, is characterized by the predominance of Galen, his authority as a philosopher and logician became a target for criticism in the wake of the growing influence of Aristotelian logic, and the privileged status accorded to *Dem.* as a logical treatise was undermined.

## (i) The transmission of *Dem*.

The translation of *Dem.* formed part of the herculean program of translating Galenic writings undertaken by Ḩunayn and his circle. By the middle of the 9th century, almost all of Galen's treatises were available in high-quality translations. In this period Galen was the Greek author whose writings were most extensively translated into Arabic – a fact that would remain true even after the 10th century. In addition to making Galen's treatises readily accessible to his fellow Arab physicians, the Arabic translations also extended Galen's influence beyond the realm of medicine. *Dem.*, Galen's most important work on logic, was largely responsible for his reputation as a first-class philosopher in the Islamic world.

The transmission of *Dem.* in Arabic was always marred by lacunae, as Ḩunayn explains in his *Epistle* (see A2). Nine books were available in Arabic, at least in part:

<figure><img src="image_13.png" /></figure>

<footnote n="322">322 On the need for this change of perspective, see R. Rashed, “Greek into Arabic. Transmission and Translation,” in J. E. Montgomery (ed.), *Arabic Theology, Arabic Philosophy. From the Many to the One* (Leuven/Paris/Dudley: Peeters), pp. 157–196. See also R. Rashed (ed.), *Lexique historique de la langue scientifique arabe* (Hildesheim/Zurich/New York: Georg Olms 2017).</footnote>
book II (a small part), book III (most of it), IV (the first half), IX (with a lacuna at the beginning), XII, XIII, XIV, XV (with a lacuna at the end). Ḩunayn first translated this material into Syriac, and his circle then translated the Syriac version into Arabic.

Abū al-ʻAlā' ibn Zuhr, one of our main sources on the Arabic *Dem*. and the author of most of the new material gathered in this collection, was well aware of the complex transmission of the Galenic treatise. In his *Solution to the Doubts about Galen*, he comments on a passage from the *Doubts* (C15a). In this passage, according to Rāzī, Galen claims in book IV that it is possible to show that the circle of the zodiac is the cause of the generation of the animals and of the plants, and that he made that clear in his *Use of the Parts*, among other references. Rāzī then moves on to condemn this claim as preposterous, as nowhere in *UP* does Galen provide such proof. Abū al-ʻAlāʼs response illustrates the caution that should accompany the interpretation of *Dem*.

> How [would the obscurities be absent] in such a book, which Ḩunayn collected with difficulty, and only by guessing about the parts that had been lost? So he put it back together piece by piece, but the elements needed to make the expression perfect and the understanding excellent remained missing.<fnref n="323" />

Despite this lacunose transmission, Arabic fragments play a key role in the reconstruc-
tion of *Dem*. Around sixty testimonia – of variable size – come from Arabic sources. They
form the bulk of the available material on books IV and XIII, while book XII is solely
referred to in Arabic sources. In addition to this, a large proportion of these Arabic tes-
timonia are direct quotations from *Dem*.<fnref n="324" />

In some cases, the missing passages of the Arabic *Dem*. could be supplemented by
the indirect tradition. For example, even though book VIII did not reach Arabic philoso-
phers, they knew about the discussions on time that this book contained through Greek
sources, such as Alexander of Aphrodisias. In the case of book IV, our collection shows
that the Arabic tradition was more complete than previously thought. Until now, in addi-
tion to Galen, our evidence for book IV, and specifically the question of the eternity of
the world, came from Philoponus and Rāzī. Rāzī seems to have missed the double inter-
pretation of eternity outlined in book IV, when he attributes to Galen the following argu-
ment: 1) the world is not subject to corruption; 2) what is not subject to corruption is not
generated; 3) the world is not generated. Rāzī's account follows Aristotle's *De caelo* but
ignores the reference to Plato's account of the creation of the world in the *Timaeus* and,
in particular, the argument based on the double interpretation of the adjective "eternal"
as ungenerated and incorruptible. Yet his argument forms the core of the fragment from
Philoponus' *De aeternitate mundi* – to which we should add Galen's own reference in

<footnote n="323">323 Abū al-ʻAlā' ibn Zuhr, *Solution to the Doubts about Galen*, ed. Koetschet-Rajab (forthcoming), MS Āstān Quds Riḍawī 13997, fol. 4b, ll. 18–20.</footnote>

<footnote n="324">324 In addition to the quotations found in Arab authors' writings, the Arabic *Dem.* also included the numerous references to *Dem.* that Galen himself made in his other treatises, all of them translated into Arabic, as well as references in Greek in treatises later translated into Arabic.</footnote>
*On decay*.<fnref n="325" /> We have therefore up until now been left with a significant discrepancy between the Greek and the Arabic versions of book IV of *Dem*. What was responsible – Rāzī’s misrepresentation of Galen’s argument or the lacunose state of book IV in Arabic?

Abū al-‘Alā’ s account now shows that the reference to the *Timaeus* was indeed known in Arabic. When commenting on section 2 of the *Doubts*, which contains Rāzī’s response to book IV, Abū al-‘Alā’ explains that Galen explicitly says that the proposition that what is not corrupted is not generated can only be correct “after we have made determinations (*taḥdīd*) and distinctions (*tamīz*)” (C10). This expression echoes Philoponus’ report that “the proposition that everything that is incorruptible is also necessarily ungenerated requires a distinction for us to readily accept it” (C4). Further on in the *Solution*, when commenting upon the passage C1 from *On decay*, Abū al-‘Alā’’s text is even closer to Philoponus and leaves us in no doubt that he did indeed have access to the same source. We may compare both passages:

C3. Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, ed. Koetschet–Rajab (forthcoming), fol. 72b, 1. 27– fol. 73a, 1. 9.

What Galen says, that the proposition that every gener-
ated thing will be corrupted is not true by all means but
it is <persuasive>, is correct. He explained it clearly in
the fourth book of his treatise *On demonstration*: there
may be a generated being that is corruptible **because
it obtained immortality by way of restoration and
was forbidden to receive death.** In turn, what the
Sophist claims, that what Galen says – the proposition
that every generated thing will be corrupted is not true
by all means but is persuasive – contradicts the result
that he obtained in his treatise *On demonstration*, that
is, everything that is not corruptible, is not generated,
is a lie. Indeed, Galen does not say that, but he says:
**what we said about everything incorruptible, that
it must necessarily be ungenerated, requires deter-
minations and distinctions for us to readily accept
it. The distinction and the determination consist in
considering the ways in which a particular thing
is conceded to be incorruptible, because it can be
(incorruptible) either because it does not admit cor-
ruption at all, like what is unique, perfectly simple
and unaffected, either because it obtained immor-
tality by way of restoration and was forbidden to
receive death.**

C4. Philoponus, *Aet. mund*. XVII.5 (599,17–601,20 Rabe):

Nevertheless, [the proposition] that everything that is incorruptible is also necessarily ungenerated requires a distinction for us to readily accept it. What distinction is it? [It consists] in setting apart the ways in which a particular thing is conceded to be incorruptible, whether in the sense of not admitting the account of corruption at all, like what is perfectly simple and unaffected, or in the sense of having obtained immortality by restoration, like something Plato, too, seems to say about the gods in the *Timaeus*, in which he makes the first god discourse with them. The speech goes as follows: ‘Since you have been generated, you are not immortal nor completely indissoluble. And yet you will not be dissolved nor will you meet a fate of death, having obtained a bond of my will that is even greater and more authoritative than those by which you were bound together when you came to be’.

<footnote n="325">325 On the discussion on the eternity of the world in book IV, see above, pp. 40–45.</footnote>
It is conceivable that the Arabic version of *Dem.* did not include this passage and that Abū al-‘Alā’ quoted it directly from Philoponus’ *On the eternity of the world against Proclus*. This treatise was translated into Arabic, although only a few quotations from it are known today.<fnref n="326" /> However, this hypothesis seems unlikely to us. First, this is not the only passage where Abū al-‘Alā’ quotes passages from *Dem.* that are absent from the *Doubts*, indicating that Abū al-‘Alā’ had direct access to *Dem.* which he used to correct Rāzī’s account. This method is in line with Abū al-‘Alā’’s usual approach in the *Solution*. This method is in line with Abū al-‘Alā’’s usual approach in the *Solution*, where he constantly confronts Rāzī’s account of a Galenic passage with direct quotations of the corresponding passages in the Arabic translation. Second, to our knowledge, Abū ‘Alā does not refer to or draw upon any source other than Rāzī’s *Doubts* and Galen’s writings. Finally, at the beginning of his commentary on book IV of *Dem.*, Abū al-‘Alā’ mentions both Plato and Aristotle, whereas Philoponus only mentions Plato. This suggests that he had access to the whole of Galen’s argument, including his discussion of Aristotle’s *De caelo* and Plato’s *Timaeus*.

(ii) **Translating Dem.**

As was the case for all translations from Greek into Arabic, the translation process of
*Dem.* created a space where the Arabic text was in contact not only with its Greek orig-
inal but also with the philosophical and theological debates that formed the context of
the production and reception of this translation. Recent research has begun to investi-
gate how the translations may have been adapted with a view to the target audience.
For example, Elvira Wakelnig has shown that in the Arabic translation of Galen’s trea-
tise *On diseases and symptoms*, produced by Hunayn or his nephew Hubayš, the trans-
lator sometimes omits to translate “phusis” in the case of the Galenic demiurgic nature
and uses expressions such as “wisdom and kindness”.<fnref n="327" /> Although we cannot, in the
limited scope of this chapter, analyze the translation of *Dem.* in detail, it is important to
indicate how the reception context contributes to our understanding of the testimonia.
Indeed, the Arabic translation of *Dem.* was read in relation to other texts that belonged

<footnote n="326">326 On the Arabic translation of Philoponus' treatise, see: E. Giannakis, "The Quotations from John Philoponus' *De Aeternitate Mundi Contra Proclum* in al-Bīrūnī's India," *Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften* 15 (2002–2003), pp. 185–195; E. Wakelnig, "The Other Arabic Version of Proclus' *De Aeternitate mundi*. The Surviving First Eight Arguments," *Oriens*, 40 (2012), pp. 51–95; M. Rashed, "Nouveaux fragments anti-procliens de Philopon en version arabe et le problème des origines de la théorie de l'instauration" (hudūth), in G. Federici-Vescovini and A. Hasnawi (eds.), *La circolazione dei saperi nel Mediterraneo: filosofia e scienze (secoli IX–XVII)*. Florence: Cadmo 2013), pp. 323–360.</footnote>

<footnote n="327">327 E. Wakelnig, "Translation as Interpretation: Translating Galen's Polysemous Term *Physis* into Arabic," *Medieval Worlds* 11 (2020), pp. 60–116.</footnote>
to the same intellectual context, texts sometimes written by the same author who pre-
served the testimonium.

Let us turn for example to C15. According to this report by Abū al-‘Alā’ ibn Zuhr, Galen’s attempt to show how to acquire demonstrative premisses involves the examination of four questions related to the eternity of the world: Is there an eternal substance in the world? Is this substance sentient? Is it knowledgeable (*habīr*)? Is it skillful (*hakīm*)? Only for the second question is it impossible to discover appropriate premisses (*al-muqaddimāt al-mulā’ima lahu*). The appropriate premisses to the first question are provided by “the arguments above”, i.e. probably Aristotle’s in *De caelo*.<fnref n="328" /> Abū al-‘Alā’ adds that for Galen these premisses belong to the category of possible premisses, not of necessary premisses.<fnref n="329" />

How should we understand the adjectives ḥabīr and hakīm here and in C15a? A few lines further on, Abū al-‘Alā’ continues to discuss Galen’s attempt to find the premisses appropriate to the question of the eternity of the world, in a passage that might be either a paraphrase of *Dem.*, or Abū al-‘Alā’s commentary. It explains how the science of the stars and zoology provide premisses that establish that the celestial spheres are uncorruptible and that we may find scientific proof of providence in the world. In this regard, this passage is very close to UP XVII.

Thus, the objects of creation serve as a sign that they have a Creator; the substances that always subsist and are far from all corruption, such as the celestial sphere and the planets, serve as a sign that their Creator is eternal, that nothing precedes Him, and that no corruption nor change affects Him. Indeed, if exemption from corruption exists among the objects of His creation, then He (i.e. the Creator) is [even] more worthy [of being eternal] and this is more appropriate to Him. Furthermore, the agreement between the disposition of the celestial sphere and the change that occurs in the world wherever the planets follow their course, and the fact that we find that [this agreement] is particularly important when the astral associations move from the triangles is a sign that their inventor and creator is extremely skillful to the utmost degree (*hikma laysa ba’dahā nihāya*); in the same way, the fact that we see the parts of animals being arranged in such perfect agreement that it is not possible to imagine a better disposition, and the bad and foul humours being transformed into pure, living, rational and thinking bodies, [all] this serves as a sign to us that the creator is knowledgeable (*habīr*) and skillful (*hakīm*). This is Galen’s objective.<fnref n="330" />

The two words of ḥabīr and ḥakīm strike a theological note for the 9th-century (and later) reader from the Islamic world. Both of them are attributes of God in the Koran, and they are often associated (for example 6.18, 6.73, 34.1).

Proving not only the existence, but also the knowledge and skill of God based on
the arrangement of the cosmos and of the human body is a commonplace in antiq-
uity. In *Laws* X, Plato establishes a connection between the existence and nature of god

<footnote n="328">328 See above, p. 44.</footnote>

<footnote n="329">329 See further below, p. 85–87.</footnote>

<footnote n="330">330 Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, fol. 4b, ll. 20–29.</footnote>
and the fact that the cosmos is intelligible arithmetically. As for the arrangement of the human body, Galen himself had prominently developed this line of argument in *The use of parts*.

Going back to *Laws* X, one of Galen's possible sources, might help us understand the meaning of the two attributes of the Creator, “knowledgeable” and “skillful”.<fnref n="331" /> Like Galen's discussion in *Dem.*, book 10 focuses on the demonstration of the existence of the nature of the gods. This discussion is prompted by the circulation of impious ideas in a city – that the gods do not exist, or that they exist but pay no attention to humans, or that they do pay attention to humans, but can simply be won over by sacrifices and prayers (888c). Clinias' first answer relies on “the evidence of the earth, the sun, the stars, and all the universe, and the beautiful ordering of the seasons, marked out by years and months; and then there is the further fact that all Greeks and barbarians believe in the existence of gods”. Beyond this belief, it is necessary to provide “adequate proofs” that “the gods exist and that they are good and honor justice more than do men” (X, 887b). One of these proofs is the orderly motion of the stars and all the other things under the control of reason (*nous*), which has organized the universe (XII, 967b). The intellectual component of the nature of the gods is further developed in the *Timaeus*, which Galen epitomized.

*The use of parts* is the second obvious source. Here, we are fortunate enough to be able to study its Arabic reception. Ḥabīr and ḥakīm are also used here to describe the action of the Creator in this context. Starting from the 9th century, *UP* became a central point of reference for philosophers and theologians as a theological treatise that offered proof of the Creator's wisdom based on the arrangement of the human body. Elvira Wakelnig has demonstrated that this theological interpretation was facilitated by a peculiarity of the translation of *UP*, namely that personified Nature is no longer featured, and is instead completely replaced by the praise of the Creator.<fnref n="332" /> Her article provides several examples of the semantic field in which ḥabīr and ḥakīm operate.

Ḥabīr, an attribute of God, refers more specifically to the fact that a fundamental attribute of God is His possession of knowledge. For example, in a treatise attributed to

<footnote n="331">331 No extant Arabic translation of the *Laws* came down to us. Ibn al-Nadim mentions two translations, one by Ḥunayn and one by Yaḥyā ibn ‘Adī, but their existence has been questioned (Ibn al-Nadīm, *Kitāb al-Fihrist*, ed. Flügel, p. 246). Al-Fārābī wrote a *Compendium* of the *Laws*, but it does not cover books X–XII. On the existing Arabic tradition of the *Laws*, see D. Gutas, “Galen’s *Synopsis* of Plato’s *Laws* and Fārābī’s *Talkhīṣ*,” in *The Ancient Tradition in Christian and Islamic Hellenism: Studies on the Transmission of Greek Philosophy and Sciences, Dedicated to H.J. Drossaart Lulofs on his Ninetieth Birthday* (Leiden: Brill 1997), pp. 101–119; reprint in D. Gutas, *Greek Philosophers in the Arabic Tradition* (London/ New York: Routledge 2020).</footnote>

<footnote n="332">332 E. Wakelnig, “Medical Knowledge as Proof of the Creator’s Wisdom and the Arabic Reception of Galen’s *On the Usefulness of the Parts*,” in P. Bouras-Vallianatos and S. Xenophontos (eds.), *Greek Medical Literature and its Readers: From Hippocrates to Islam and Byzantium* (Abingdon/New York: Routledge 2018), pp. 131–149.</footnote>
the renowned Muslim scholar al-Ġāḥiẓ, based on Galen's *UP*, the author speaks about the dissection of the head. He explains that the cranium acts as a protective helmet and adds:

> So who, do you think, has endowed the brain with this fortification and has decreed it this way, if not the Kind (al-Laṭīf) and the Knowledgeable (al-Ḥabīr)?<fnref n="333" />

The word *ḥikma*, referring to providence, is often used in the Arabic *UP* in relation to the application of God's knowledge through art (ṣināʻa). For example, in the Arabic translation of the epilogue, the translator speaks of “the traces (āṭār) of the Creator's wisdom (*ḥikma*) and of his power (*qudra*)” offered through dissection.<fnref n="334" /> This wisdom is first and foremost practical, as it is associated with art.

This interpretation of providence, that underlies the use of two adjectives *habīr* and *ḥakīm*, echoes the understanding of how God acts in the world in the 9th-century *kalām* theology. According to the *Mu'tazila*, one of the qualifications of God is that He is capable of acting in a skillful way - *fi'l muḥkam* -, the adjective *muḥkam* being formed from the same root as *ḥakīm* and *ḥikma*. This skillful act may be used as a proof that God is knowledgeable ('ālim).<fnref n="335" /> In turn, the proof that God acts in a skillful way is provided by the creation of the animals and the “marvels” ('ağā'ib) displayed by them, as well as by the revolutions of the stars and their combination. Thereby, the fact that the world is an artefact is crucial to prove the existence of God, and science itself is understood as a skillful act.

This intertextuality can occur on a second level, when the translation displays parallels in the philosophical ideas of the author who quotes it. An example of this phenomenon is the use of the term *ğawhar*, “substance”, by Rāzī in G3:

> [Galen] says in the thirteenth book of [Dem.] that substance (*ğawhar*) is the primary body (al-ġīsm al-awwal) and substratum of all generation and all corruption, which is in itself devoid of quality. He therefore states that matter (*hayūlā*) is a body without making [the statement] clear in this work or referring to a passage where he had already made it clear, as if it were a part of primary knowledge.<fnref n="336" />

This passage can be read in the context of the discussions between *kalām* theologians and *falsafa* philosophers on matter in Rāzī's time, in which he took part.<fnref n="337" /> Here, Rāzī identifies substance (*ğawhar*) with matter (*hayūlā*). “Substance” (*ğawhar*) is of course a

<footnote n="333">333 (Ps.?)al-Ġāḥiẓ, *Book of examples and their study*, p. 87 Idris; trans. (slightly modified) by E. Wakelnig, “Medical Knowledge as Proof of the Creator’s Wisdom,” p. 135.</footnote>

<footnote n="334">334 Galen, *UP* XVII, MS Paris 2853, fol. 295a16.</footnote>

<footnote n="335">335 See 'Abd al-Ġabbār, *Explanation of the Book of the Five Principles (by Al-Mānkadīm)*, ed. İlyas Çelebi, Istanbul: Türkiye Yazma Eserler Kurumu Başkanlığı, 2013, p. 253-255.</footnote>

<footnote n="336">336 Rāzī, *Doubts* 3.1 (18,9–16 Koetschet).</footnote>

<footnote n="337">337 On *kalām* atomism, see M. Rashed, “Natural Philosophy,” in P. Adamson (ed.), *The Cambridge Com-*)</footnote>
very polysemic term in Arabic philosophy. However, it is rarely associated with “matter” (hayūlā, from the Greek ὕλη) by falsafa philosophers. For example, in his treatise *On the definitions and descriptions of things*, al-Kindī distinguishes between matter (hayūlā), “a potentiality that is the subject for the predication of forms, and is passive”<fnref n="338" />, and substance (*ğawhar*): “what subsists through itself. It is the bearer for the accidents, and its essence does not undergo alteration.”<fnref n="339" /> On the other hand, *ğawhar* is frequently used in the sense of matter by kalām theologians, many of whom espoused an atomistic conception of matter (see below).

This association between *ğawhar* and hayūlā dovetails with another passage from Rāzī's writings: in his treatise *On absolute matter*, Rāzī is said by Nāşir-e Khusraw to have used the word *ğawhar* as a synonym for matter (hayūlā).<fnref n="340" />

This form of intertextuality between the translation of *Dem.* and the emerging philosophical systems can also infuse the translation with more distant echoes. These echoes are nonetheless essential for grasping how Arab authors read this translation. An example can be found in E3. In this fragment, Ibn al-Mawşīlī, in his correspondence with Yaḥyā ibn ‘Adī, recalls Galen’s account on time in book VIII of *Dem*.

> For Galen held that time is subsistent through itself and has no need for motion in its existence, and he said that Plato was of the same opinion on this topic, that is, that he held that time is a substance, by which he [i.e. Plato] meant ‘duration’ (*mudda*), and motion merely measures and determines it.<fnref n="341" />

The close relation between Galen’s criticism of the Aristotelian definition of time in *Dem*. and Rāzī’s own conception of time has already been examined by Peter Adamson, and need not detain us here.<fnref n="342" /> My focus is on how G3, through the Timaeic reference to *mudda*, resonates with Rāzī’s conception of time, based on the duality between absolute duration (*mudda*), and time determined by number (*zamān*), *mudda* being also unmeasured, and existing independently from motion.

<footnote>panion to Arabic Philosophy (Cambridge: Cambridge University Press 2005), pp. 287–307. On Rāzī’s conception of matter, see P. Adamson, *Al-Rāzī* (Oxford: Oxford University Press 2021), pp. 71–98.</footnote>

<footnote n="338">338 Kindī, *On the definitions and descriptions of things*, in *The Philosophical Works of Al-Kindī*, ed. and trans. P. Adamson and P. E. Pormann, pp. 297–311, here p. 300.</footnote>

<footnote n="339">339 Kindī, *On the definitions and descriptions of things*, trans. Adamson and Pormann, p. 301.</footnote>

<footnote n="340">340 Rāzī, *On absolute matter*, p. 224 Kraus.</footnote>

<footnote n="341">341 Ibn Abī Sā’īd al-Mawṣīlī, in Yaḥyā ibn ‘Adī, *The Philosophical Treatises* (318,6–319,3 Khalifat).</footnote>

<footnote n="342">342 See P. Adamson, “Galen and al-Rāzī on Time,” in R. Hansberger, M. Afifi al-Haytham, and C. Burnett (eds.), *Medieval Arabic Thought: Essays in Honour of Fritz Zimmermann* (London: Warburg Institute 2012), pp. 1–14.</footnote>
(iii) Dem. in the formative period of Arabic philosophy

In the formative period of Arabic philosophy, the work of Ḩunayn secured a central
place for Galen's writings well beyond the medical sphere. As far as logic went, Dem.
was not the only treatise by Galen translated into Arabic by Ḩunayn and his associates:
Ḥunayn's *Epistle* also mentions the *Institutio logica* as well as a short treatise *On the
number of syllogisms*.<fnref n="343" />

The central role played by Dem. is best shown in the writings of Abū Bakr al-Rāzī,
who calls it “the most precious and useful book after the sacred books”, in his *Doubts
about Galen*. Most of the fragments found in this text focus on philosophical topics: the
eternity of the world (book IV, book XII), time and place (book XIII), the primary body
/book XIII), and vision<fnref n="344" /> (book XIII). Rāzī emphasizes the methodological purpose of
the treatise on several occasions.

Rāzī’s interest in these passages was both epistemological as well as metaphysi-
cal and physical. I have shown elsewhere how Rāzī’s discussion of these topics helps
us understand his philosophical system, otherwise known mainly through fragments
transmitted in a polemical context.<fnref n="345" /> In what follows, I will focus on the intertextual-
ity between Rāzī’s interpretation of Dem. in the *Doubts* and other passages by him on
matter and on demonstration.

Matter and the elements were discussed in book XIII of *Dem.* as the Arabic frag-
ments show. These passages were of great interest to Rāzī, who endorsed atomism, an
unusual position among Islamic philosophers. On this topic, he engaged with *Dem.* in
the third section of the *Doubts.* Along with section 15, where Rāzī responds to the Galenic
criticism of atomism in *UP*, section 3 (18,9–16 Koetschet) sheds light on Rāzī’s conception
of matter and its Greek pedigree. In the third section of the *Doubts*, immediately after
the discussion of the eternity of the world, Rāzī turns to the primary matter in *Dem.*, as
“a body devoid of quality” and “the substratum of all of generation and corruption”. He
argues that if the substratum is a body, it is necessarily endowed with tridimensionality,
and bears at least one quality, namely shape (šakl). Through this critique, Rāzī lays the
foundations of his own interpretation of “absolute matter” (*hayūlā mutlaqa*), that he
will develop in other treatises, such as *On matter*. In section 15.1 (108,1–2 Koetschet) of
the *Doubts*, he explains that, according to the atomists, the elements are composed of
“small bodies” (*ağsām şuğār*), which they call “primary bodies” or “indivisible bodies”.
From that point on, the “first body” is no longer the Aristotelian-Stoic substratum

<footnote n="343">343 *Epistle on what was translated* 126–127 (51 Bergsträsser).</footnote>

<footnote n="344">344 On Rāzī's theory of vision and how it relates to *Dem.*, see P. Koetschet, "Abū Bakr al-Rāzī on Vision," in P. Adamson and P. E. Pormann (eds.), *Philosophy and Medicine in the Formative Period of Islam* (London: Warburg Institute 2017), pp. 170–189.</footnote>

<footnote n="345">345 P. Koetschet, *Abū Bakr al-Rāzī: Doutes sur Galien. Introduction, édition et commentaire* (Berlin/Boston: de Gruyter 2019).</footnote>
defended by Galen. The first level of matter, i.e. absolute matter, is constituted by the
atoms, that underlie the Aristotelian elements. The debate on the tridimensionality of
atoms extends beyond the specific polemical context of the *Doubts*. It takes place within
the framework of the disagreement between Rāzī and the *kalām* theologians. Indeed,
while both Rāzī and the *kalām* theologians endorse an atomistic conception of matter,
the *Doubts* show that Rāzī’s atomism draws on the corpuscular theories of ancient
atomism. By contrast, *kalām* theologians such as Abū ‘Alī al-Ġubbāī and Abū al-Qāsim
al-Balḥī (contemporaries of al-Rāzī) identify the atom with the Euclidian points and
deny that it has extension.<fnref n="346" /> Rāzī’s atoms, on the other hand, are ultimately conceptu-
alized in terms of their role in the composition of the bodies, and not as positions.

Turning to Rāzī’s analysis of demonstration, I would like to reflect on Rāzī’s recep-
tion of *Dem*. in the wider context of his logical writings. Rāzī wrote several treatises on
logic, unfortunately lost today, but referred to by Bīrūnī in his *Epistle on Rāzī’s writings*.
In addition to a book *On demonstration (Kitāb al-Burhān)*, we find the following titles:
*Introduction to logic (al-Madḥal ilā al-manṭiq)*, *Summaries of the Categories, the De inter-
pretatione, and the Analytics (Ġawāmi‘ Qāṭīġūrīyās wa-Bārīrimīnīyās wa-Anālūṭīqā)*, *On
logic in the expressions of Muslim theologians (Fī al-manṭiq bi-alfāẓ mutakallimī al-is-
lām)*, *On how sign works (Kayfīyat al-istidlāl)*, and *On expression and how to rely on it
and what indicates that it is correctly attributed (Fī al-ḥabar kayfa yuskanu ilayhi wa-mā
‘alāma al-muḥaqqaq minhu)*.<fnref n="347" />

According to Ḩunayn, Galen’s main objective in *Dem*. was “to explain the method of establishing what is [capable of being] established necessarily. This was also Aristotle’s objective in the fourth book of the *Organon*,” which corresponds to the *Posterior analytics*. At least two of Rāzī’s logical writings are related to the *Posterior analytics*: his summary of the treatise, and his own book *On demonstration*.

Very few fragments are known of Rāzī’s logical treatises, which makes it impos-
sible to reconstruct Rāzī’s theory of demonstration based on his logical writings. For
this reason, the critiques of Galen in the *Doubts* on topics related to demonstration are
especially valuable. Analysis of this material – passages from his logical writings and
the *Doubts* – suggests that Rāzī endorsed a strong conception of demonstration, similar
to Galen’s, and illustrates the specific attention he gave to inductive arguments.

In the only reference that we know of to his treatise *On demonstration*, Rāzī stresses
the importance of “intellectual knowledge” (‘ulūmunā al-‘aqlīya). This reference may
be found in Book I of Rāzī’s *Abridgement of Galen’s Therapeutic method*. In Book III of
*The therapeutic method*, Galen underlines the limits of the treatment of hollow wounds
by empiricist physicians. He explains that, having acquired a thorough knowledge of
the nature of the disease, he was able to put in place a treatment that combined two

<footnote n="346">346 See A. Dhanani, *The Physical Theory of Kalām: Atoms, Space, and Void in Basrian Mu‘tazilite Cosmology* (Leiden/New York/Köln: Brill 1994), pp. 90–140. M. Rashed, “Natural Philosophy,” pp. 290–293.</footnote>

<footnote n="347">347 Al-Bīrūnī, *Epistle on the writings of Abū Bakr al-Rāzī*, p. 14 Kraus.</footnote>
substances which, separately, are harmful. Based solely on their experience, the Empir-
icists were unable to come up with such treatment. Rāzī seizes upon this passage to
recall the importance of theoretical knowledge in medical methodology.

If I weren't reluctant to go on [about it], I would have spoken more fully on the subject. I have shown that our noblest knowledge is intellectual [knowledge], not sensory [knowledge], but on this subject, I have tended to abbreviate, also because this treatise is not the place to have this discussion, and that moreover, I have examined this subject in depth in the second book of the treatise *On demonstration*.<fnref n="348" />

A fragment that I have identified as probably coming from Rāzī's *On demonstration*, found in Ps.-Gābir's *Book of morphology*, provides us with a glimpse of Rāzī's conception of sign-inference.<fnref n="349" /> This passage is closely related to Galen's *Dem.*, from which it includes two quotations. The author announces that he will study how sign inference (*al-istidlāl*) and deduction (*al-istinbāṭ*) proceed from the manifest (*al-šāhid*) to the hidden (*al-ġāʾib*). He distinguishes three categories of sign inference: “homogeneity (*al-muğānasa*),” equivalent to the paradigm, the “course of habit” (*mağrā al-ʿāda*), which refers to induction, and traces (*al-āṭār*). According to the text, the first two categories only achieve persuasive rather than demonstrative knowledge.<fnref n="350" /> The section on traces is unfortunately missing.

The influence of Galen's *Dem.* is explicit in the case of the second category, where
the author turns to two passages from *Dem.* as examples.

This is why, despite his capacity for science and his experience in theoretical matters, Galen adopted such premisses as if they were [first] principles and he used them to illustrate [his thesis], so much so that he says in his book *On demonstration*: "One of the first premisses in the mind is the following: if it is true that summer must undoubtedly be followed by autumn, this can only take place after spring has passed." For my part, I think that this premiss is not correct unless it has been [previously] established that [the alternation] of the seasons has always taken place and will always take place in the same way as it is taking place [now]. If this is not established, the possibility is not excluded that [in the future] there may be a summer that is not followed by an autumn and not preceded by a spring. I have studied this example well in my book *On sign inference*, thoroughly and according to the doctrines of the logicians.

(...)

[Galen] also uses this [inference based on induction] in his book entitled *On demonstration*. Indeed, what he says is misleading, even if he is unaware of it. He says: "We must come to know that this noble part – I mean the part that corresponds to the heavens – is not generated from the fact that our fathers and all the ancients have always observed it to be one and the same, and astronomers have made observations for thousands of years, and have seen that its dimensions and movements

<footnote n="348">348 Abū Bakr al-Rāzī, *Abridgment of Galen’s Therapeutic method*, ed. N. Deif, I. Hamed, and P. Koetschet (forthcoming), MS Escorial 801, fol. 4b, ll. 17–19.</footnote>

<footnote n="349">349 P. Koetschet, “Abū Bakr al-Rāzī et le signe. Fragment retrouvé d’un traité logique perdu,” *Arabic Sciences and Philosophy* 27 (2017), pp. 75–114.</footnote>

<footnote n="350">350 Koetschet, “Abū Bakr al-Rāzī et le signe,” p. 80.</footnote>
are one and the same.” He spent time on this and expanded his remarks, and he established a con-
nection based on this sign and what results from it.<fnref n="351" />

The two first categories of sign-inference, and Rāzī's approach to them as non-demon-
strative, are echoed in the *Doubts*, when Rāzī discusses the different kinds of premisses
in relation to *Dem*. In section 14, Rāzī engages with Galen's discussion of the attractive
faculties in the organs in *On the natural faculties*. Rāzī objects to an inductive argument
by which Galen intends to apply the same explanation to the path of all liquids in the
body. For Galen – according to Rāzī's account – if it is validated that urine is secreted
because the kidneys attract it due to a natural power within them, then it must also be
the case that the distribution of food in the organs takes place in the same way. Rāzī
then refers to *Dem.*, where he learnt to be wary of such inductive arguments:

Did he (i.e. Galen) not himself teach us to avoid this type of criteria in his treatise *On demonstration*,
and in many other treatises, showing the greatest skill and the most thorough examination? So
why, I would like to know, is he satisfied with it here and using it, if not because he is excessively
inclined to validate this opinion and because he leans towards it at the expense of others? And
why, I'd like to know, does it follow necessarily from the fact that urine doesn't move to the kidneys
by the necessary force of the vacuum, that the journey of the blood in the body cannot be caused
by the necessitating force of the vacuum either, if not because he (i.e. Galen) breaks away here
from the demonstrative method (*tarīq al-burhān*) and takes the one used by the rhetoricians (*mā
yusta'miluhu al-ḥutabā*), i.e. the syllogism by examples (*al-qiyās bi-al-miẓāl*), or [the one used by]
dialecticians ([*mā yusta'miluhu* al-ğadalīyūn), i.e. the inductive syllogism (*al-qiyās bi-al-istiqrā*)?<fnref n="352" />

Rāzī’s critical approach to inductive arguments appears in different places of the
*Doubts*, where he dismisses induction as a scientific tool, following Galen’s position (see
A27, A28).<fnref n="353" /> In this respect, Rāzī’s approach to the question of the eternity of the world
(which raises the question of his access to book IV) can be understood as a further cri-
tique of induction, with Rāzī turning Galen’s reluctance against him. When discussing
Galen’s argument in this book, Rāzī addresses the claim that it is an unmistakable truth
confirmed by observations that the world is unperishable. Whatever may have been
Rāzī’s knowledge of the overall discussion in *Dem.*, his main objection here is directed
against the first premiss of this syllogism, which is reached through a sign inference
based on observations: according to these observations, the world is not subject to
change. This statement, according to Rāzī, is merely based on an inductive sign infer-
ence, which cannot rule out the possibility of sudden destruction. Nor can the observa-
tions made by astronomers eliminate the approximation of their results. In the conclu-

<footnote n="351">351 Ps.-Ğābir ibn Hayyān, *Book of morphology*, pp. 420–421 Kraus. French translation in Koetschet, “Abū Bakr al-Rāzī et le signe,” p. 84.</footnote>

<footnote n="352">352 Rāzī, *Doubts* 14.16 (104,4–9 Koetschet).</footnote>

<footnote n="353">353 On the critique of induction in the *Doubts*, see P. Koetschet, *Abū Bakr al-Rāzī: Doutes sur Galien*, pp. cii–cxii.</footnote>
sion of this discussion, Rāzī points out that the justification that Galen's objective was to
demonstrate where the premisses could be drawn from does not hold, since, he "used
principles that were not principles and consequents that are not necessarily attached
to their antecedents."<fnref n="354" />

Because of the limits of induction, the best that Galen can get to, according to Rāzī,
is a hypothetical syllogism where the first premiss must be construed as a conditional
proposition:

Now, the implication of this consequent by this antecedent is validated if we add a condition (*šart*) to [this antecedent], so that [this implication] can be stated as follows: "If the world was subject to corruption by decay, then the bodies in it would not remain in one and the same state", or another antecedent, so that it becomes clear that nothing is ever corrupted except by decay.<fnref n="355" />

The syllogism obtained can be outlined as follows: 1. If the world were subject to corruption by decay, then the bodies in it would not remain in one and the same state. 2. The bodies in the world remain in one and the same state. 3. So the world is not subject to corruption by decay. It reminds us of the second of the five Stoic indemonstrables: If the first, then the second; but not the second; therefore not the first.<fnref n="356" />

According to Rāzī, the first premiss remains defective – even in its hypothetical
form – since the substances can be subject to a dissolution that is so slow that it could
never be observed and made evident. Moreover, even if this premiss held, the world
could always be subject to another form of corruption.

On another occasion, Rāzī suggests transforming the first premiss into a condi-
tional proposition (F7):

Now, I do not consider that this antecedent (i.e. if it happens to be winter) necessarily implies this
consequent (i.e. it was necessarily preceded by autumn, and summer will necessarily follow it), as
long as we haven't added a condition (*šart*) to it, so that [the argument] can be stated as follows:
if the [alternation] of the seasons has always taken place and will continue to take place in the
manner that it does at the moment, and we are in winter, then this [season] necessarily follows
autumn, which necessarily precedes it; similarly, if [the season] happens to be summer, autumn
will necessarily follow it.<fnref n="357" />

Adding a condition (*šart*) is equivalent to transforming an inductive argument into a
merely conditional connection. In this case, the two premisses are construed as condi-
tions.

<footnote n="354">354 Rāzī, *Doubts* 2.6 (14,8 Koetschet).</footnote>

<footnote n="355">355 Rāzī, *Doubts* 2.3 (10,10–13 Koetschet).</footnote>

<footnote n="356">356 See for example S. Bobzien, "Demonstration and Indemonstrability of the Stoic Indemonstrables," *Phronesis* 55/3 (2020), pp. 355–371.</footnote>

<footnote n="357">357 Rāzī, *Doubts* 2.8 (16,16–19 Koetschet).</footnote>
(iv) Galen under siege: the Aristotelian movement

In Rāzī's own time, Galen's influence as a philosopher was starting to be challenged. Rāzī himself mentions the growing criticism against Galen from one Aristotelian whom he describes as “an eminent man in Baghdad, supporter of Aristotle”.<sup>358</sup> When recalling Galen's exposition of vision in *On the use of parts* and Galen's lengthy explanation of geometrical notions, he mentions the suggestion made by this eminent man that Galen would sometimes attempt to “kill the dead”, in other words, explaining what is already clear.<sup>359</sup>

These attacks on Galen initially stemmed from the Baghdad school led by Mattā ibn Yūnus, the teacher of both Yaḥyā ibn ‘Adī and Fārābī. Their criticism was based on a strict demarcation between the contributions of Galen as a physician on the one hand and as a philosopher and a logician on the other. They could find an ally in their critical evaluation in Alexander of Aphrodisias, whose work was also being translated into Arabic.

Al-Siğistānī (d. ca. 985), who belonged to the circle of Yaḥyā ibn ‘Adī in Baghdad, disparages *Dem*. in his doxographical work (*Ṣiwān al-Ḥikma*).

Galen wrote on logic; but expert logicians disapprove of his *On demonstration*, which they say does not bear witness to his competence in the subject. An exception is Ḩunayn ibn Isḥāq who has shown excessive partiality for this book... A similar verdict applies to what we know of Galen's attempts to establish the principles of his discipline (i.e. medicine), such as prime matter, form, or active cause – in other words, the physical concepts it presupposes. When, at the end of his life, he wrote on his personal beliefs, he acknowledged his ignorance and confessed himself defeated by the problems which exercise the philosophers. This caused Alexander of Aphrodisias to remark that Galen had spent eighty years of his life to come to the conclusion that he did not know, notwithstanding the contributions his efforts had made to his own discipline... for the benefit of mankind, a benefit so great that there was no one in the world who did not owe him a debt of gratitude.<sup>360</sup>

One of the most important representatives of this Aristotelian turn was Fārābī, who demoted medicine in favour of philosophy in order to elevate Aristotle's authority over Galen's. In his extant treatises, Fārābī often scornfully refers to Galen as "the doctor Galen" and puts medicine, as a practical science concerned with quotidian matters, on a par with agriculture. This is the line taken in his *Long commentary on De interpretati-one*, as well as in his *Short treatise* on the same Aristotelian work. F. Zimmermann has observed that, until the gap had narrowed between the Arabic reception of Galen and

<footnote n="358">358 Rāzī, *Doubts* 16.11 (152,1 Koetschet).</footnote>

<footnote n="359">359 Rāzī, *Doubts* 8.6 (58,8 Koetschet).</footnote>

<footnote n="360">360 Abū Sulaymān al-Siğistānī, Ṣiwān al-Ḥikma, p. 86 Badawī. Translated by F. Zimmermann, *Al-Farabi's Commentary and Short Treatise on Aristotle's De Interpretatione* (London: Oxford University Press 1981), p. lxxxi, note 2 (slightly modified).</footnote>
that of Aristotle, one or two generations after Ḩunayn's death, "Galen, as a philosopher and logician, enjoyed an ascendency over Aristotle apt to scandalize Aristotelians. The Aristotelian movement of al-Fārābī's day set out to redress the balance".<fnref n="361" />

This critical position certainly does not mean that Fārābī did not study Galen's logical treatises intensively. In the *Doubts*, it is possible that the mysterious Aristotelian from Baghdad reading Galen alongside Rāzī might be Fārābī. Fārābī does in fact quote Galen on several occasions.<fnref n="362" /> As far as *Dem.* is concerned, in Fārābī's remaining treatises, only the abovementioned two direct references may be found, in the *Long commentary on De interpretatione* and in the *Short treatise on De interpretatione*. In addition to these, two indirect references in Ibn Rušd and Maimonides ultimately go back to Fārābī. In the *Short treatise*, Fārābī discusses the difference between contradictions about possibilities that are unknown by nature, not just in relation to us, and contradictions about necessities that are unknown in relation to us, but not by nature. He complains that Galen in *Dem.* ignored this difference and considered that what is possible by nature is the same as what is possible to our minds (see F11).<fnref n="363" /> This criticism is matched by the additional reference in Fārābī's *Long commentary*, where Galen is said to claim that Aristotle, in talking at length about possible and hyperctic affairs, has wasted his time on useless things.<fnref n="364" /> Even though the polemical context of these two quotations might not do justice to Galen's approach to possible syllogisms in *Dem.*, they indicate that Galen considered modal syllogistic as superfluous, and focused on hyperctic syllogisms.

Abū al-‘Alā’ ibn Zuhr drew on this distinction between the possible and the necessary. When addressing Galen’s discussion of the eternity of the world in *Dem.* IV, Abū al-‘Alā’ quotes Rāzī as saying that, according to Galen, “it is possible, concering something like the circle of the zodiac, to show that it is the cause of the generation of animals, plants, and of the arts found in them” (C15, quoting C15a). Here the word “possible” indicates that premisses for this conclusion can be discovered, without specifying the nature of these premisses. The rest of the testimonium, which we have already discussed above, helps us to answer this question.<fnref n="365" /> Abū al-‘Alā’ mentions four epistemological questions raised by Galen in book IV: (1) Is there an eternal substance in the world? (2) Is this substance sentient? (3) Is it knowledgeable? (4) Is it skillful? According to Abū al-‘Alā’, Galen states that it is “likely impossible to discover the appropriate

<footnote n="361">361 F. Zimmermann, *Al-Farabi's Commentary*, p. lxxxvi. This section on Fārābī draws heavily on Zimmermann's analysis in this introduction.</footnote>

<footnote n="362">362 F. Zimmermann, “Al-Fārābī und die philosophische Kritik an Galen von Alexander zu Averroes,” in A. Dietrich (ed.), *Akten des VII. Kongresses fur Arabistik und Islamwissenschaft, Göttingen, 15. bis 22. August 1974* (Göttingen: Vandenhoeck & Ruprecht 1976), pp. 401–414, here p. 407.</footnote>

<footnote n="363">363 Fārābī, *Treatise*, p. 82 Kutsch/Marrow; trans. in Zimmermann, *Al-Farabi's Commentary*, p. 246.</footnote>

<footnote n="364">364 Fārābī, *Long commentary*, p. 193 Kutsch/Marrow; trans. in Zimmermann, *Al-Farabi's Commentary*, p. 186.</footnote>

<footnote n="365">365 For other aspects of the testimonium, see above, pp. 75–78.</footnote>
(mulā’ima) premisses” for (2), but he thinks that it is possible to discover these premises for (1), (3), and (4). Since appropriateness is the characteristic feature of scientific premisses,<fnref n="366" /> the premisses to (1), (3), and (4) are probably considered to be scientific by Galen. However, after repeating that “it is possible, in the case of the circle of the zodiac, to show that it is the cause of the generation of animals and plants,” Abū al-‘Alā’ continues:

> Galen does not take this [inference] beyond the realm of the possible (*unşur al-imkān*). Now, this Sophist (i.e. Rāzī) transforms [the course of] the possible into the course of the necessary (*unşur al-iğāb*).<fnref n="367" />

In this passage, the word “possible” has a different meaning than in the preceding sentence attributed to Galen. Whereas Galen states that it is possible to demonstrate a causal connection between the zodiac and the generation of animals and plants, Abū al-‘Alā’ interprets him as saying that *this causal connection* is merely possible. In this sense, the conclusions based on the premisses found in astronomy and the study of animals would be only tentative, not demonstrative. It seems, therefore, that Abū al-‘Alā’ confuses different sorts of questions addressed by Galen: on the one hand, the questions about the existence, wisdom, and skill of the eternal substance, which, according to Galen, can be solved scientifically, by means of appropriate premisses (C15); and, on the other, the question of whether the world is generated or not, which can be solved at most in a dialectical or plausible manner, as shown by Abū al-‘Alā’ (C13) as well as Galen himself (C1).

In his article “Galen on What is Persuasive”, Riccardo Chiaradonna convincingly argues that, from the Galenic perspective, “possible” does not refer to an ontological category, but rather constitutes an epistemic category based on the limitations of our knowledge. As opposed to Alexander of Aphrodisias, who distinguishes the status of medicine along with the other stochastic arts from that of rigorous sciences on the basis of the ontological status of their objects, Galen strives to establish a medical methodology that integrates stochastic as well as axiomatic principles,<fnref n="368" /> and even compares medicine to geometry. Fārābī’s criticism in F10, F11, and F12 should be understood against the backdrop of these views on the epistemic status of medicine, according to Zimmermann<fnref n="369" /> and Chiaradonna. In this context, “possible” and “necessary” are merely epistemic concepts: they point to the current limitations of our knowledge, while remaining open to the possibility that these boundaries might be extended some day.

<footnote n="366">366 See above, pp. 39 and 44.</footnote>

<footnote n="367">367 Abū al-‘Alā’ ibn Zuhr, *Solution to the Doubts about Galen*, ed. Koetschet-Rajab (forthcoming), MS Āstān Quds Riḍawī 13997, fol. 4a, ll. 16–17.</footnote>

<footnote n="368">368 On this (very large) topic, one can refer to M. Havrda and R. J. Hankinson, “Introduction,” in M. Havrda and R. J. Hankinson (eds.), *Galen’s Epistemology* (Cambridge: Cambridge University Press 2022), pp. 1–12.</footnote>

<footnote n="369">369 F. Zimmermann, *Al-Farabi’s Commentary*, p. Ixxxii.</footnote>
One debate relating to Galen's presentation of Aristotelian syllogistic takes place mainly in the Arabic tradition: whether Galen did or not invent a fourth figure of syllogisms. Benjamin Morison has surveyed the available material on this debate.<fnref n="370" /> While various Arabic philosophers, such as Ibn Sīnā and Ibn Rušd, attributed such invention to Galen, and while Ibn al-Ṣalāḥ wrote a treatise called *On the fourth figure of the categorical syllogism attributed to Galen*, there is also evidence to the contrary. In F1, the same Ibn al-Ṣalāḥ says that in *Dem*. and *On the number of the syllogisms*, Galen divided the categorical figures into three only. According to Morison, it is probable that the attributions to Galen of the fourth figure are based on a misunderstanding of the discovery by Galen of four figures of compound syllogisms (see F4).

Much work remains to be done on the influence that Galen's *Dem*. had on Arabic philosophy. It must unfortunately be carried out through the refracted history of lost texts: *Dem*. of course, but also all of Rāzī's logical treatises, as well as a great part of Fārābī's commentaries on Aristotle's *Organon*. However, it is sufficiently clear that Galen was central to the formative period of Arabic philosophy not only as a physician and a philosopher but also as a logician.

<footnote n="370">370 B. Morison, “Logic,” in R. J. Hankinson (ed.), *Cambridge Companion to Galen* (Cambridge: Cambridge University Press 2008), pp. 66–115, here pp. 85–91. See also N. Rescher, *Galen and the Syllogism* (Pittsburgh: Pittsburgh University Press 1966).</footnote>
<figure><img src="image_14.png" /></figure>
Part II The testimonia
<figure><img src="image_15.png" /></figure>
# Introduction to the edition of the testimonia

## 1. Criteria for inclusion

We have selected passages from ancient and medieval sources that meet some of the following criteria:

a) They mention Galen's *Dem.*, referring to it either by its original name, or by a paraphrase of this name, or by a more general description.<fnref n="1" />

b) They mention Galen and refer to or quote a passage from *Dem.*, as can be inferred from the context or from parallels with passages mentioning *Dem*.

c) They refer to or quote from *Dem.*, as can be inferred from their content.

Thus passages selected according to the first criterion, while referring to *Dem.*, do not necessarily refer to it by name.<fnref n="2" /> Those selected according to the second criterion, while mentioning Galen, do not mention *Dem*.<fnref n="3" /> And those selected according to the third criterion do not even mention Galen. While the inclusion of the last group of passages is based on careful consideration, it is nevertheless conjectural. We call them “presumed testimonia” and designate them with an asterisk.<fnref n="4" />

## 2. Quotations, indirect references, and context

Direct quotations from *Dem.* are marked with quotation marks, just as any quotations in our selected passages. We do not distinguish passages containing direct quotations as “fragments” as opposed to “testimonia”, which merely refer to, or paraphrase, the source text indirectly. We regard all the selected passages as testimonia, in the sense that they bear witness to the reconstructed text. We include as much surrounding material as we consider useful for understanding the context in which *Dem.* is quoted, paraphrased, or mentioned.

<footnote n="1">1 For various paraphrases of the title, see above, p. 24. When passages are excerpted from a larger discussion concerning *Dem.*, we take such expressions as “the same book”, “this treatise” as equivalent to direct references.</footnote>

<footnote n="2">2 See A7 (“the demonstrative methods”) and A23 (“the study of reasoning”). A20 is a borderline case.</footnote>

<footnote n="3">3 Easy cases are passages quoted in a larger context where *Dem.* is discussed (especially those preserved by Abū Bakr al-Rāzī and Abū al-'Alā' ibn Zuhr) or those with verbatim parallels in other passages where *Dem.* is mentioned (A30, E1, E1b); more difficult are those whose inclusion is based on thematic relevance rather than verbatim parallels, coupled with other considerations about the likely source of the quoted material (E3, E4, E6, E6a).</footnote>

<footnote n="4">4 B6*, B7*, E9*, E10*, and E11*.</footnote>
3. Edition

The testimonia from Abū Bakr al-Rāzī's *Doubts about Galen* are quoted according to the edition by Pauline Koetschet, *Abū Bakr al-Rāzī: Doutes sur Galien. Introduction, édition et commentaire*, Berlin/Boston: de Gruyter 2019.<fnref n="5" /> Passages from Abū al-'Alā' ibn Zuhr's *Solution to the Doubts about Galen* are printed here for the first time, based on the forthcoming edition of MS Rīḍawī 13997 by Pauline Koetschet and Iktimal Rajab.

The remaining Arabic texts as well as all Greek and Latin texts are quoted on the basis of modern editions, with manuscripts being consulted selectively.<fnref n="6" /> Information about the emendations proposed by other editors also draws on these editions. Emendations proposed by the editors of this volume are printed here for the first time. Readings proposed by Jonathan Barnes and Benjamin Morison come from their forthcoming edition of Galen's *Institutio logica*. In all cases, the chosen reading is the responsibility of the editors, Pauline Koetschet for the Arabic, and Matyáš Havrda for the Greek and Latin.

All deviations from the manuscripts are marked in the apparatus, but the differences in manuscript readings are given only selectively. The list of editions used is in the Bibliography section. Manuscripts mentioned in the apparatus include:

Ambrosianus graecus 659⁷

British Library, IO Islamic 1296⁸

Hamilton 270⁹

Laurentianus 74.3¹⁰

Laurentianus Pluteus 5.3 (also referred to as “ms.” in section B)<fnref n="11" />

Mosquensis 467¹²

Marcianus 236¹³

<footnote n="5">5 See the textual introduction in Koetschet, *Abū Bakr al-Rāzī: Doutes sur Galien. Introduction, édition et commentaire* (Berlin/Boston: de Gruyter 2019), pp. cxxxiii–cxxxviii.</footnote>

<footnote n="6">6 E.g. in A12 and F6. For all quotations from Galen's *Institutio logica*, we are grateful to Jonathan Barnes and Benjamin Morison for sharing their forthcoming edition with us.</footnote>

<footnote n="7">7 For Galen, *Lib. prop.* and *Ord. lib. prop.* The manuscript is described in V. Boudon-Millot, *Galien I: Introduction générale, Sur l'ordre de ses propres livres, Sur ses propres livres, Que l'excellent médecin est aussi philosophe* (Paris: Les Belles Lettres 2007), pp. 35–42.</footnote>

<footnote n="8">8 For *al-Ṭabarī* (C5).</footnote>

<footnote n="9">9 For Galen, *PHP*; described in P. De Lacy, “Introduction,” in *Galeni De placitis Hippocratis et Platonis I–V* (Berlin: Akademie Verlag 2005), pp. 12–60, here pp. 12–18.</footnote>

<footnote n="10">10 For Galen, *Opt. doct.*; cf. A. Barigazzi, *Galeni De optimo docendi genere, Exhortatio ad medicinam (Protrepticus)* (Berlin: Akademie-Verlag 1991), pp. 39–46.</footnote>

<footnote n="11">11 For Clement of Alexandria, *Liber logicus*; described in O. Stählin, *Clemens Alexandrinus II: Stromata Buch I-VI* (Berlin: Akademie-Verlag 1985), pp. vii–viii.</footnote>

<footnote n="12">12 For Galen, *PHP*; cf. De Lacy, “Introduction,” pp. 19–21.</footnote>

<footnote n="13">13 For Philoponus, *Aet. mund.*; cf. H. Rabe, *Ioannes Philoponus, De aeternitate mundi contra Proclum* (Leipzig: Teubner 1899), pp. iii-vii.</footnote>
Marcianus 284<sup>14</sup>

Parisinus graecus 635<sup>15</sup>

Parisinus graecus 2058<sup>16</sup>

Parisinus graecus 2064<sup>17</sup>

Riḍawī 13997<sup>18</sup>

Vlatadon 14<sup>19</sup>

### 4. Translation

The majority of the Arabic material has been translated by Pauline Koetschet (Ko) with the collaboration of Sean Coughlin (C) and Matyáš Havrda (H). In most cases, Koetschet produced a draft translation from Arabic into French, which was then translated into English by Coughlin, and the draft English translation was then revised in view of the Arabic original and Greek parallels during a series of online meetings attended by all three collaborators. Other testimonia were translated into English directly by Pauline Koetschet. The majority of the Greek material has been translated by Sean Coughlin and/or Matyáš Havrda. Texts marked (C-H) are based on translations originally drafted by Coughlin, which were more or less substantially revised by Havrda.

In some cases we have adopted existing translations, sometimes with modifications. They include:

> Peter Adamson, "Galen and al-Rāżī on Time." In Rotraud Hansberger, M. Afifi al-Haytham and Charles Burnett (eds.), *Medieval Arabic Thought: Essays in Honour of Fritz Zimmermann* (London: Warburg Institute 2012), pp. 1-14, here p. 5 (for E3 and E4)

> Jonathan Barnes and Benjamin Morison, "On All the Kinds of Syllogism: Edition, translation, and commentary," Annex to Galen, *Introduction to Logic*, edition, translation, and commentary, forthcoming with Oxford University Press (for F4)

> Aileen Das and Pauline Koetschet, "Galen: *Compendium of Plato's Timaeus*". In Aileen Das, Pauline Koetschet, and Mark Shiefsky, *Galen: Writings on Plato's Timaeus. Compendium of the Timaeus. Commentary of the Medical Statements in the Timaeus*, forthcoming with Cambridge University Press (for G10)

<footnote n="14"><sup>14</sup> For Galen, *PHP*; cf. De Lacy, "Introduction," pp. 18-19.</footnote>

<footnote n="15"><sup>15</sup> For Galen, *Inst. log.*; cf. K. Kalbfleisch, *Galeni Institutio logica* (Leipzig: Teubner 1896), p. vi.</footnote>

<footnote n="16"><sup>16</sup> For Philoponus, *Aet. mund.*; cf. Rabe, *Ioannes Philoponus, De aeternitate mundi*, pp. vii-viii.</footnote>

<footnote n="17"><sup>17</sup> For Anonymus, *Omn. syllog.*; cf. M. Wallies, *Ammonii in Aristotelis analyticorum priorum librum 1 commentarium* (Berlin: Reimer 1899), pp. v-viii.</footnote>

<footnote n="18"><sup>18</sup> For Abū al-‘Alā’ ibn Zuhr’s *Solution to the Doubts about Galen*; cf. Koetschet, *Abū Bakr al-Rāżī: Doutes sur Galien*, pp. cxxxv-cxxxvi.</footnote>

<footnote n="19"><sup>19</sup> For Galen, *Lib. prop.* and *Ord. lib. prop.*; cf. Boudon-Millot, *Galien* I, pp. 42-44.</footnote>
Matyáš Havrda, “The So-Called Eighth *Stromateus* (‘Liber Logicus’) by Clement of Alexandria: Greek Text, Translation, and Commentary.” In Matyáš Havrda, *The So-Called Eighth Stromateus by Clement of Alexandria: Early Christian Reception of Greek Scientific Methodology* (Leiden: Brill 2016), pp. 87–103 (for B6* and B7*)

Marwan Rashed, *Essentialisme. Alexandre d’Aphrodisse entre logique, physique et cosmologie* (Berlin/Boston: de Gruyter 2007), p. 271 (for C16)

Marwan Rashed (with Jonathan Barnes), Maimonides’ quotation from al-Fārābī’s *Commentary on the Prior analytics*, in Jonathan Barnes, *Truth, etc.: Six Lectures on Ancient Logic* (Oxford: Clarendon Press 2007), p. 465 (for F12)

Robert W. Sharples, “Alexander of Aphrodisias, *On Time*,” *Phronesis* 27 (1982), pp. 58–81, here pp. 60–61, 64, and 65–66 (for E9*–E11*)

Friedrich W. Zimmermann, *Al-Fārābī’s Commentary and Short Treatise on Aristotle’s De interpretatione* (London: Oxford University Press 1981), pp. 186 and 246 (for F10 and F11)

One testimonium (A29) was translated by Elvira Wakelnig for this book.

The names of the translators are given for each passage. Regardless of who authored the original translation, responsibility for all translations rests with the editors of this book.

**5. Arrangement**

The testimonia are divided into seven sections, called A-G. Section A contains those which cannot be located in a particular book or refer to *Dem*. in general. Starting from section B, the criterion of division is the presumed thematic structure of *Dem*. Thus, section B contains the material we believe was included in the first three books, section C the material discussed in book IV, etc. The rationale for the division is explained in the Introduction, Chapter 4 (“Reconstruction of the contents”).

**6. Cross-references**

Cross-references to testimonia include their designation (e.g. E1) and usually also the lines of the referenced passage. The reference lines in the edition notes are edition lines, while the reference lines in the translation notes are translation lines.
Text / Translation
A1. Galenus, *De libris propriis* 14.6–8 (165,11–23 Boudon-Millot / XIX.40–41 K)

κατὰ τοῦτο τοίνυν ἔτι καὶ μᾶλλον ἔγνων δεῖν ἀποστῆναι μὲν ὧν ἐκεῖνοι λέγουσι,
ἀκολουθῆσαι δὲ τῷ χαρακτῆρι τῶν γραμμικῶν ἀποδείξεων. ἀλλήλοις μὲν οὖν λέγω
διαφέρεσθαι τοὺς φιλοσόφους ἐν τῇ λογικῇ θεωρίᾳ, τοὺς Περιπατητικούς τε καὶ
Στωικούς καὶ Πλατωνικούς, καὶ αὐτοῖς δὲ πάλιν ἰδίᾳ τούς καθ' ἑκάστην αἴρεσιν· μικρὰ
μὲν δή πώς ἐστιν ἡ παρὰ τοῖς Περιπατητικοῖς διαφωνία, μεγάλη δὲ παρὰ τοῖς Στωικοῖς
καὶ Πλατωνικοῖς ἔσοι τοίνυν ἐθέλουσι κατὰ τὰς γραμμικὰς ἀποδείξεις ἀσκηθῆναι,
παιδευθῆναι μὲν [ἐν] αὐτοῖς ἐν ἐκείναις συμβουλεύω, μετ' ἐκείνας δὲ τὴν ἀναλέξασθαι
περὶ τῆς ἀποδείξεως πραγματείαν, ἦν ἐν πεντεκαίδεκα βιβλίοις ἐποιησάμην.

5

A2. Hunayn ibn Ishāq, *Epistle on what was translated* 115 (47–48 Bergsträsser)

هذا الكتاب جعله في خمس عشرة مقالة وغرضه فيه أن يبين كيف الطريق في تثبيت ما يبين
ضرورةً وذلك كان غرض أرسطوطالس في كتابه الرابع من المنطق. ولم يقع إلى هذه الغاية
أحد من أهل دهرنا لكتاب البرهان نسخة تامة باليونانية على أن جبريل قد كان عني بطلبه
عنية شديدة وطلبته أنا غاية الطلب وجُلْتُ في طلبه بلاد الجزيرة والشام كلها وفلسطين ومصر
إلى أن بلغت الإسكندرية فلم أجد منه شيئاً إلا بدمشق نحو من نصفه إلا أنها مقالات غير
متوالية ولا تامة وقد كان جبريل أيضاً وجد منه مقالات ليست كلها المقالات التي وجدت
بأعيانها وتترجم له أيوب ما وجد وأما أنا فلم تطب نفسي بترجمة شيء منها إلا باستكمال
قراءتها لِما هي عليه من النقصان والاختلال وللسمع وتشوق النفس إلى وجود تمام هذا الكتاب
ثم إني ترجمت ما وجدت إلى السريانية وهو جزء يسير من المقالة الثانية وأكثر المقالة الثالثة

5

<footnote>A1, 6 ἀσκηθῆναι Ambr. 659 : del. von Müller : non legitur Vlat. 14 A2, 3 ἀσκηθῆναι Bergsträsser : غُنِي</footnote>

<footnote n="4">4 والشام Bergsträsser : الشام</footnote>
# Section A: General and Unlocated Testimonia

## I. The Work

**A1. Galen, *His own books* 14.6–8**

This made me realize even more that I had to distance myself from the teachings of these [philosophers] and to follow the pattern of linear demonstrations. I mean that, as far as the study of reasoning is concerned, the philosophers differ from one another, the Peripatetic, the Stoic, and the Platonist; but they also differ among themselves individually within each school. (It is true that the disagreement is rather small among the Peripatetics, but considerable among the Stoics and the Platonists.) Therefore, I advise everyone who wants to be trained in linear demonstrations to educate themselves in them and after doing so to read my treatise *On demonstration*, which I composed in fifteen books. (H)

5

**A2. Hunayn ibn Ishāq, *Epistle on what was translated* 115**

This treatise is composed of fifteen books, and [Galen's] objective is to explain the method of establishing what is [capable of being] established necessarily. This was also Aristotle's objective in the fourth book of the *Organon*. No one has managed to obtain a complete Greek version of the treatise *On demonstration* in our time, although Ġibrīl has invested a lot into his research. I myself have searched a great deal [for this treatise], across Mesopotamia, all of Bilād al-Šām, Palestine and Egypt, all the way to Alexandria. I found nothing except in Damascus approximately half [of the treatise]. But they were neither books in consecutive order, nor were they complete. Ġibrīl also found some books, not all of which were the same books as the ones I had found. Ayyūb translated for him [Ġibrīl] that which he had found. For my part, I could not bring myself to translate anything before reading it completely, because of the gaps and corrupted passages, and because I always wanted and hoped to read a complete version of this treatise. Then I translated into Syriac what I had found, namely a small part of the second book, most of book three, about half of book four (from the

5

10

<footnote>A1, 2 linear] I.e., geometrical. On their role as models of philosophical arguments, see, e.g., Gal. *Foet. form.* 6.21 (100,3–9 Nickel / IV.695 K); *Aff. dig.* 8.5–6 (28,19–24 De Boer / V.42 K); *PHP VIII.*1.25–26 (486,10–16 De Lacy / V.656 K). 3 study of reasoning] λογικὴ θεωρία, “logic” in a broad sense, distinguished from the study of nature and ethics; cf. e.g. Sextus, *M VII.*12; Gal. *Opt. med.* 3.8 (290,19–291,5 Boudon-Millot / I.60–61 K); apart from other issues, such as entailment and incompatibility (see below, A14, 14–15), it includes the study of the criterion and the methods of solving problems; cf. e.g. Gal. *Thras.* 22 (59,7–21 Helmreich / V.842–843 K). A2, 3 fourth... *Organon*] I.e., *Posterior analytics.* 4 Ġibrīl Ġibrīl ibn Buḥṭīšū'. 6 Bilād al-Šām] A transliteration of the Arabic endonym for the Greater Syria region. It corresponds roughly to the modern countries of Syria, Lebanon, Israel, Jordan, and Palestine, as well as southern regions of modern Turkey.</footnote>
10

ونحو نصف المقالة الرابعة من أولها والمقالة التاسعة خلا شيئاً من أولها فإنه سقط وأما سائر المقالات الأخرى فوجدت إلى آخر الكتاب خلا المقالة الخامسة عشرة فإنَّ في آخرها نقصاناً [ترجم عيسى بن يحيى ما وجد من المقالة الثانية إلى المقالة الحادية عشرة وترجم إسحاق بن حنين من المقالة الثانية عشرة إلى المقالة الخامسة عشرة إلى العربية].

**A3. Abū Bakr al-Rāzī, Doubts about Galen** 2.1 (6,15–17 Koetschet)

فلنأخذ الآن في غرضنا الذي قصدنا ونبد أ من ذلك بكتاب البرهان إذ كان أجلَّ الكتب عندي وأنفعها بعد كتب الله المنزلة.

**A4. Galenus, De ordine librorum suorum** 1.11–2.1 (90,19–91,15 Boudon-Millot / XIX.52–53 K)

5

άλλα τῶν γε τοῖς φίλοις δοθέντων ἐκπεσόντων εἰς πολλοὺς ἐγράφη μὲν ἐξ ἀνάγκης δι’ ἐκεῖνα καὶ τὸ περὶ τῆς ἀρίστης αἰρέσεως, εἶρηται δ’ ἐν αὐτῷ καὶ ἡ τῆς γραφῆς αἰτία. ταῦτά τε οὖν εἴ τις ἀναγιγνώσκειν ἐθέλοι πρῶτα πάντων, ὀρθῶς ποιήσει, καὶ εἰ πεισθεὶς αὐτοῖς βουληθεῖν, πρὶν ἐπὶ τὴν μάθησίν τε καὶ κρίσιν ἤκειν ἀπασῶν τῶν αἰρέσεων, ἔχει πραγματείαν τὴν ὑφ’ ἡμῶν γεγραμμένην, τὴν περὶ ἀποδείξεως, ἔς ἐάν μὴ μόνας μάθη τὰς μεθόδους ἀλλὰ καν γυμνάσηται κατ’ αὐτάς, ἐπὶ πάσης ὕλης πραγμάτων ἐξευρήσει τὴν ἀλήθειαν, ἐάν γ’ ἐραστὴς ὑπάρχη καὶ μὴ κατὰ πάθος ἄλογον αἰρήσεται τις, καθάπερ οἱ περὶ τὰς διαφορὰς τῶν χρωμάτων ἐν ταῖς ἱπποδρομίαις ἐσπουδακότες· ὁ δ’ αὐτὸς οὖτος ἐπὶ τοῖς ἔμπροσθεν εἰρημένοις παραγενόμενος ἐξευρήσει τάληθῶς αὐτοῖς ἐγνωσμένα καὶ ψευδῶς ὑπειλημμένα. μία μὲν οὖν ἤδε τῶν ἡμετέρων ὑπομνημάτων ἐστὶν ἀρχὴ τῆς ἀναγνώσεως ἐκείνοις τῶν ἀνδρῶν, ὅσοι καὶ φύσει συνετοὶ καὶ ἀληθείας ἐταῖροι.

10

**A5. Galenus, De ordine librorum suorum** 2.18 (95,17–25 Boudon-Millot)

osοι δὲ διὰ τῆς ἀποδεικτικῆς πραγματείας ἀπασῶν πρώτης ἐπὶ τὰς ἄλλας ἔρχονται, τοῦτοις χρήσιμόν ἐστι καὶ τὸ πρότερον βιβλίον τῶν ἐπιγραφομένων περὶ τεχνῶν συστάσεως· ἔτι δὲ δὴ μᾶλλον ἐπόμενον τουτῷ βιβλίον ἔτερόν ἐστιν ὁ Πατρόφιλος

<footnote>A4, 6 ἐπὶ... πραγμάτων] Cf. A21, 2.</footnote>

<footnote n="11">11 **فَجَدَّتْ** Bergsträsser : **فَجَدَّتْ** A4, 1 **δοθέντων Cornarius** : ἐκπεσόντα Ambr. 659 **3 ποιήσει Aldina** : ποιήσοι Ambr. 659, Vlat. 14</footnote>
beginning), book nine, except for one passage from the beginning, because it was 15 missing. As for all the remaining books, they were found, up to the end of the treatise, apart from book fifteen, because at the end of this book there is a passage missing. ['Aysā ibn Yahyā translated what was available from book two to book eleven, and Ishāq ibn Hunayn translated from book twelve to book fifteen into Arabic.] (Ko [C])

**A3. Abū Bakr al-Rāzī, *Doubts about Galen* 2.1**

Let us now turn to the goal we are pursuing, starting with the book *On demonstration*, because it is, in my opinion, the noblest and most useful of books, next to those sent by God. (Ko)

**A4. Galen, *The order of his own books* 1.11–2.1**

However, since those writings which I had given to my friends had leaked out to the public, I was compelled for these reasons to write in addition the treatise *On the best school*, and the reason which made me write it is also set out in it. One will do well if he wishes to read these books first of all; and if, having been persuaded by them, he wants to become skilled in demonstration before embarking on the study of all the schools and making a judgement about them, then he has the treatise written by me, the one *On demonstration*. And if he not only learns its methods but also trains himself in them, he will discover the truth in every instance of the things [in hand]—if, at any rate, he is a lover [of truth] and not one who joins a school on account of an irrational affection, like the supporters of the different colours at the horse races. That one who attends to what was said before will discover which things are truly known by others and which are falsely assumed. And so this is one starting point for reading my works, for those men who are naturally intelligent and companions of truth. (C-H)

**A5. Galen, *The order of his own books* 2.18**

The first book of those called *On the constitution of the arts* is also useful to [the readers] who approach all my other treatises through the treatise *On demonstration*. And even more [useful for them] is another book, following upon the one [just mentioned], whose title is *Patrophilos* and deals with the constitution of the art of medicine. Of the

<footnote>A4, 2–3 On the best school] Not extant. 5 skilled in demonstration] Cf. B6*, 94. 7 trains himself] For the study of rational methods as training, see A1, 6–8; A6, 7; A7, 2–4; A13, 3; A16, 8–12; A17, 2; A18, 4; A24, 8–10; A26, 1–8; A28, 9. 9 lover of truth] See Plat. *Resp.* VI, 501d2; Gal. *At. bil.* 7.1 (84,31 De Boer / V.130 K), etc. 13 naturally... truth] Cf. *Pecc. dig.* 1.7 (43,5–6 De Boer / V.61 K); *MM* II.7.40 (198,9–10 Lorusso / X.145 K); *Opt. med.* 3.4 (290,5–8 Boudon-Millot / I.59 K), etc. A5, 1 On the constitution of the arts] Not extant. 4 *Patrophilos*] *CAM*, ed. Fortuna, CMG 5.1.3.</footnote>
5

ἐπιγέγραπται περὶ συστάσεως ἰατρικῆς ὑπάρχον. ἔστιν ἐκ ταύτοῦ γένους καὶ ὁ Θρασύ-
βουλος ἐν ᾧ ζητεῖται πότερον ἰατρικῆς ἡ γυμναστικῆς ἐστι μόριον τὸ ὑγιεινόν.

### A6. Galenus, *Ars medica* 37.13–14 (391,20–392,12 Boudon / I.411 K)

5

πάντων δὲ ἀναγκαιότατα πρὸς τὴν θεραπευτικὴν μέθοδον ἐστιν τό τε περὶ τῆς τῶν
νόσων διαφορᾶς, καὶ τὸ περὶ τῆς τῶν συμπτωμάτων, καὶ τρίτον ἐπ' αὐτοῖς, ἐν ᾧ τὰς
αιτίας τῶν νοσημάτων διέξιμεν, ἐφ' οἷς ἄλλα τρία, καθ' ἄ τὰς ἐν τοῖς συμπτώμασιν
αιτίας ἐξηγούμεθα, τὰ τε περὶ τῆς τῶν ἀπλῶν φαρμάκων δυνάμεώς ἐστιν, ὧν ἔμπροσθεν
ἐμνημόνευσα, καὶ τὰ περὶ συνθέσεως φαρμάκων, οἷς τὰ τῆς θεραπευτικῆς ἔπεται
μεθόδου γεγραμμένα ἡμῖν ἰδίᾳ, καὶ τῆς τῶν ὑγιεινῶν πραγματείας· ὅτι δὲ καὶ πρὸ
ἀπάντων τούτων ἐγγεγυμνάσθαι χρὴ τῇ περὶ τῆς ἀποδείξεως πραγματείᾳ τὸν μέλλοντα
λογικῶς μεταχειρίζεσθαι τὴν τέχνην, ἐν τῷ περὶ τῆς ἀρίστης αἰρέσεως ἐπιδέδεικται
γράμματι.

### A7. Galenus, *De simplicium medicamentorum facultatibus* I.13 (XI.403 K)

5

ταῦτα ἐπιστημονικὴν μὲν ἔχει τὴν ἀπόδειξιν, οὐ μὴν πίστιν γε τοῖς ἀγυμνάστοις περὶ τὰ
πρῶτα· χρὴ γὰρ κὰν τοῖς περὶ στοιχείων λογισμοῖς γεγυμνάσθαι καν ἦν τοῖς περὶ κράσεων
τε καὶ περὶ χρείας σφυγμῶν ὑπομνήμασιν καὶ πρὸ τούτων ἀπάντων ἐν ταῖς ἀποδεικτι-
καῖς ἡσκῆσθαι μεθόδοις.

### A8. Galenus, *De ordine librorum suorum* 4.2; 4.7 (99,13–18; 100,15–20 Boudon-Millot / XIX.58, 60 K)

5

ἔστι δ' ἐξ αὐτῶν σοι μέν, ὦ Εὐγενιανέ, καὶ ὅσοι τὴν ἰατρικὴν μόνην ἐσπουδάκατε, (τὰ)
περὶ τῆς ἀποδείξεως αὐτάρκη, τοῖς δ' ἄλλοις, ὅσοι φιλοσοφίᾳ σχολάζουσι, καὶ τᾶλλα,
πλὴν εἴ τις ἀμφοτέρας δύναιτο καλῶς μετέρχεσθαι τὰς θεωρίας ἰατρικῆς τε καὶ φιλοσο-
φίας. (...) τὰ γοῦν τῆς φιλοσόφου θεωρίας ἡμέτερα βιβλία μετὰ τὴν περὶ τῆς ἀποδείξεως
πραγματείαν ἀναγιγνώσκειν χρή· τίνες δ' αὐτῶν εἰσιν αἰ ὑποθέσεις καὶ πόσαι, καθ'
ἔκαστον αὐτῶν γέγραπται, δι' ἐκεῖνου δὲ δειχθήσεται τοῦ γράμματος, ἐν ᾧ τὴν γραφὴν
ποιήσομαι ἀπάντων τῶν ἐμῶν βιβλίων.

<footnote>A7, 1 πίστιν Havrda, cf. Gal. *Ut. resp.* 3.6 (18,11–12 Noll / IV.492 K); PHP VIII.1.45 (488,36–37 De Lacy / V.660 K) : πιστήν mss. A8, 1 τὰ *add.* von Müller</footnote>
same kind is also *Thrasyboulos*, which examines whether hygiene is the part of medicine or of gymnastics. (H)

**A6. Galen, *Art of medicine* 37.13–14**

Most necessary of all for the therapeutic method is the book *On the difference of diseases, On the difference of symptoms*, and a third after them in which we discuss *The causes of diseases*, after which there are three more in which we expound *The causes of symptoms*, and there are those *On the power of simple drugs*, which we mentioned before, and those *On the composition of drugs*, which are followed by those written by us specifically *On the therapeutic method*, and the treatise *On matters of health*. That one must, even before all these, be trained in the treatise *On demonstration* if one is going to practise the art in a rational way, has been shown in the book *On the best school*. (C-H)

**A7. Galen, *The power of simple drugs* I.13**

These things have scientific demonstration, but no credence to those untrained with regard to the first principles. For it is necessary to be trained also in the arguments about the elements and in the treatises *On mixtures* and *On the use of the pulse*, and before all these in the demonstrative methods. (H)

**A8. Galen, *The order of his own books* 4.2 and 4.7**

Of these [books], those *On demonstration* are sufficient for you, Eugenianus, and those of you who have only studied medicine, whereas the other books are for the others, who are engaged in philosophy—unless someone is able to do a good job pursuing both studies, medicine and philosophy. (...) At any rate, one should read our books pertaining to the philosophical study after the treatise *On demonstration*. What their subjects are and how many they are is written in each of them, but will be shown in the work in which I will make a list of all of my books. (C-H)

<footnote n="5">5 *Thrasyboulos*] *Thras.*, ed. Helmreich, SM 3, pp. 33–100. **A6, 1–6** The works mentioned are *Morb. diff.*, VI.836–880 K.; *Symp. diff.*, ed. Gundert, CMG 5.5.1; *Caus. morb.*, VII.1–41 K; *Caus. symp.*, VII.85–272 K; *SMT*, XI.379–892, XII.1–377 K; *Comp. med. gen.*, XIII.362–1058 K, and *Comp. med. loc.*, XII.378–1007 K, XIII.1–361 K; *MM*, ed. Lorusso (Libri I–II: Roma 2018; Libri III–IV: Roma 2021); and *San. tu.*, ed. Koch, CMG 5.4.2, pp. 3–198. **A7, 2–3** arguments...elements] See *Hipp. elem.*, ed. De Lacy, CMG 5.1.2. **3** On mixtures] *Temp.*, ed. Helmreich, Leipzig 1904. On the use of the pulse] *Us. puls.*, ed. Furley–Wilkie, Princeton 1984. **4** demonstrative methods] Probably a reference to *Dem.*; see A13, 3–5; A16, 1–2; A28, 8–10. **A8, 6–7** the work] I.e., *Lib. prop.*</footnote>
A9. Galenus, *De libris propriis* 14.17–23 (167,14–169,2 Boudon-Millot / XIX.43–45 K)

(1) ἀ δ' ἐγώ μετὰ τὴν περὶ τῆς ἀποδείξεως πραγματείαν ἔγραψα πλατύτερον ἐξειργασμένα τῶν ἐν ἐκείνη συντόμως εἰρημένων, ταῦτ' ἐστί· περὶ τῶν ἀναγκαίων εἰς τὰς ἀποδείξεις ἔν· περὶ τῶν παραλειπομένων προτάσεων ἐν τῇ λέξει τῶν ἀποδείξεων ἔν· περὶ τῶν ἰσοδυναμουσῶν προτάσεων ἔν· (2) περὶ τῶν κατὰ τὸ διότι ἀποδείξεων ἔν· περὶ τοῦ τῶν συλλογισμῶν ἀριθμοῦ ἔν· περὶ παραδείγματος δύο· περὶ ἐπαγωγῆς ἔν· περὶ εἰκόνος ἔν· περὶ ὀμοιότητος τρία· περὶ (τῶν) ἐξ ὑποθέσεων ἀρχῶν ἔν· (3) περὶ (τῶν) κατὰ τὸ γένος καὶ τὸ εἶδος καὶ τῶν συζυγούντων αὐτοῖς σημαινομένων ἡμῖν κατὰ τὴν αὐτόματον φωνὴν ἔν· περὶ τοῦ δυνατοῦ (ἐν)· περὶ τῶν πολλαχῶς λεγομένων τρία· περὶ τῶν ἐν ταῖς τέχναις κοινῶν καὶ ἰδίων ἔν· περὶ τῶν ἑαυτοὺς περιτρεπόντων λόγων ἔν· (4) περὶ τῶν ἐνδεχομένων προτάσεων ἔν· περὶ τῶν ἐκ μικτῶν προτάσεων [καὶ] συλλογισμῶν ἔν· ὅπως χρὴ διακρίνειν τὴν πραγματικὴν ἔζητησιν τῆς κατ' ὄνομα καὶ τὸ σημαινόμενον ἔν· περὶ Κλειτομάχου καὶ τῶν τῆς ἀποδείξεως αὐτοῦ λύσεων· περὶ τοῦ κοινοῦ λόγου δύο· (5) περὶ τῆς ἀρίστης διδασκαλίας πρὸς Φαβωρῖνον· ὑπέρ Ἐπικτήτου πρὸς Φαβωρῖνον ἔν· (...· περὶ χρείας συλλογισμῶν· περὶ χρείας τῶν εἰς τοὺς συλλογισμοὺς θεωρημάτων δύο· περὶ τῆς ἀρίστης αἰρέσεως ἔν· περὶ ὀνομάτων ὀρθότητος τρία· περὶ τοῦ τῶν ὄντων ἔκαστον ἐν τ' εἶναι καὶ πολλὰ· περὶ τοῦ ὅτι τοῖς ἀντικειμένοις ἔν καὶ ταὐτὸν ἐξ ἀνάγκης ἀκολουθεῖν ἀδύνατον ἐστιν ἔν· (6) περὶ τῆς ἀποδεικτικῆς εὐρέσεως ἔν· περὶ τῆς λογικῆς δυνάμεως καὶ θεωρίας ἐννέα· (...· διάλογοι πρὸς φιλόσοφον (...· (...· ἰδίως τοῦ κατὰ τὰς κοινὰς ἐννοίας (...· πρὸς τοὺς ἐπηρεαστικῶς ἀκούοντας τῶν ὀνομάτων ἔν· [περὶ τῶν ἰδίων καὶ κοινῶν ἐν ταῖς τέχναις]· περὶ τῆς τῶν τεχνῶν συστάσεως τρία· [περὶ τῶν σημαινομένων ἐκ τῆς (κατ') εἶδος καὶ γένος φωνῆς καὶ τῶν παρακειμένων αὐτοῖς· (7) σύνοψις τῆς ἀποδεικτικῆς θεωρίας, ἔν· περὶ τῆς κρίσεως τῶν διαφωνούντων ἐν τοῖς δόγμασιν· ὅτι τῆς πρώτης οὐσίας ἀχώριστος ἡ ποσότης ἔν· περὶ τοῦ προτέρου ἔν· περὶ

<footnote>A9, 2 ἐκείνη Vlat. 14 : ἐκείνοις Ambr. 659 5 εἰκόνος Ambr. 659, Vlat. 14 : εἰκότος Boudon-Millot (ref. ad K. Kalbfleisch, *Über Galens Einleitung*, p. 685, *sed non ibi invenitur*) : *post* περὶ εἰκόνος ἔν Chartier et Kühn περὶ εἰκότος ἔν interpolaverunt (*sic* von Müller) 6 τῶν¹ *add.* von Müller τῶν² *add.* Cornarius, Chartier 8 ἔν *add.* Cornarius *sec.* Fichardi vers. lat. (1531), Hunaini vers. arab. 10 ἐκ μικτῶν Vlat. 14, von Müller : ἐμμικτῶν Cornarius, Boudon-Millot *sec.* Hunaini vers. arab. : ἐν μικτῶν Ambr. 659, Aldina. Cf. e.g. Alex. Aphr. *In An. pr.* I.17 (219,21 Wallies). καὶ *del.* Cornarius, von Müller : *lect. ms. def.* Boudon-Millot 12 τῶν – λύσεων Chartier : τὰ ... αὐτῶν λύσις Ambr. 659, Vlat. 14 14 *lac. ind.* Boudon-Millot *sec.* Hunaini vers. arab. 14–15 περι² – δύο *secl.* von Müller, cf. *Lib. prop.* 18.2 (172,10–11 Boudon-Millot / XIX.47 K) : *lect. ms. def.* Boudon-Millot 15 δύο Boudon-Millot *sec.* Hunaini vers. arab. : α΄ καὶ β΄ Ambr. 659, Vlat. 14 αἰρέσεως Ambr. 659, Vlat. 14 : εὐρέσεως Boudon-Millot *sec.* Hunaini vers. arab. 17–18 περι² – ἐννέα *secl.* von Müller, cf. *Lib. prop.* 18.1 (172,7–8 Boudon-Millot, XIX.47 K) : *lect. ms. def.* Boudon-Millot 18 ἐννέα Boudon-Millot *sec.* Hunaini vers. arab. : ἔν Ambr. 659 *lac. ind.* Boudon-Millot *sec.* Hunaini vers. arab. 18–19 ἰδίως – ἐννοίας *ante* ἰδίως *lac. susp.* Havrda : *post* ἰδίως περὶ *add.* von Müller : *post* ἐννοίας *lac. susp.* Boudon-Millot 19 ἐπηρεαστικῶς Cornarius, Chartier : ἐπηρεαστικοῦς Ambr. 659, Vlat. 14 19–20 περὶ – τέχναις] *cf.* 8–9 (168,3–4 Boudon-Millot / XIX.44 K); *om.* Hunaini vers. arab., *secl.* von Müller, Boudon-Millot 20–21 περι² – αὐτοῖς] *cf.* 6–8 (167,23–168,2 Boudon-Millot / XIX.43 K); *om.* Hunaini vers. arab., *secl.* Boudon-Millot 21 κατ' *add.* Chartier, *om.* Ambr. 659, Vlat. 14</footnote>
A9. Galen, *His own books* 14.17–23

(1) There are also the [books] which I wrote after the treatise *On demonstration*, which provide a broader treatment of what was discussed concisely in that work: *On what is necessary for demonstration*, one book; *On premisses omitted in the expression of demonstrations*, one book; *On equivalent premisses*, one book; (2) *On demonstrations ‘because’*, one book; *On the number of syllogisms*, one book; *On example*, two books; *On induction*, one book; *On simile*, one book; *On similarity*, three books; *On principles from hypotheses*, one book; (3) *On what Is meant by “genus” and “species” and words connected to them in ordinary speech*, one book; *On the possible*, one book; *On what is said in many ways*, three books; *On the common and the peculiar in the arts*, one book; *On self-refuting arguments*, one book; (4) *On contingent premisses*, one book; *On syllogisms from mixed premisses*, one book; *How to discern inquiry into things from that into names and meanings*, one book; *On Clitomachus and his refutations of demonstration*; *On common reason*, two books; (5) *On the best teaching against Favorinus*; *In defence of Epictetus against Favorinus*, one book; (another book *On teaching for money*;) *On the use of syllogisms*, two books; *On the use of theorems for syllogisms*, two books; *On the best school*, one book; *On the correctness of names*, three books; *On each existing thing being both one and many*; *On the claim that it is impossible for one and the same thing to follow necessarily from contraries*, one book; (6) *On demonstrative discovery*, one book; *On the capacity and study of reasoning*, nine books; (one book *On the controversy regarding the apprehension of things*;) *Dialogues with (a man who does not consider the science of philosophy a science)*; (...) in particular of the (...) in accordance with common notions; *Against those who interpret names abusively*, one book; *On the constitution of the arts*, three books; (7) *Summary of the theory of demonstration*, one book; *On the judgment regarding disagreements in doctrines*; *That quantity is inseparable from the first substance*, one book; *On priority*, one book; *On demonstration through impossibil- 5*

<footnote>A9, 1–2 With one exception noted below (A9, 13), all treatises mentioned in this testimonium are lost.</footnote>

<footnote n="8">8 On the possible] For an Arabic fragment of the treatise, see Rescher–Marmura (eds.), *The Refutation by Alexander of Aphrodisias*, pp. 69–70; also partly edited and translated by Dmitry Gutas in Fortenbaugh *et al.* (eds.), *Theophrastus of Eresus*, I, pp. 188–189 (Theophrastus, fr. 100C). 13 On the best teaching] *Opt. doct.*, ed. Bariggazi, CMG 5.1.1. 14 another…money] This and the following inserted passages are supplied from Hunayn’s Arabic translation of *Lib. prop.*; see Boudon-Millot’s notes *ad loc*.</footnote>
25

τῆς δι' ἀδυνάτου ἀποδείξεως ἔν· περὶ τῶν ἔνεκά του γιγνομένων ἔν [περὶ τῶν πολλαχῶς λεγομένων δύο]· περὶ τῆς κατ' ὄνομα καὶ σημαινόμενον ζητήσεως.

**A10.** Al-Ruhāwī, *The physician's conduct*, chap. 16 (p. 259 ‘Asīrī)

وإنما أفردنا كتاب البهان فقط من جملة الستة عشر، لأنه لا يقوم بقراءته ولا يفهم جل ما فيه،
إلا من قد تفسف وقرأ المنطق والهندسة (...)

**A11.** Al-Ruhāwī, *The physician's conduct*, chap. 20 (p. 285 ‘Asīrī)

وأما إن علوت منزلة الأطباء، وأردت أن تكون طبيباً فاضلا فعليك بمقالته التي بيّن فيها أن
الطبيب الفاضل فيلسوف، ثم بكتابه في آراء بقراط وفلاطن ثم بكتابه في البهان كأنك تبلغ
المراد من آداب النفس ومصالحها.

**A12.** Galenus, *De optima doctrina* 5.2 (106,10–108,1 Barigazzi / I.51–52 K)

(1) Γελοῖος οὖν ἑστιν ὁ Φαβωρῖνος ἐπιτρέπων κρίνειν τοῖς μαθηταῖς ἄνευ τοῦ συγχωρῆ-
σαι τὴν πίστιν τοῖς κριτηρίοις· εἰ γὰρ οὐδέν ἑστιν ἐναργὴς τῷ νῷ ἤ πιστὸν ἐξ ἑαυτοῦ,
διέφθαρται πάντων ἡ κρίσις. εἰ δ' ἔστι μὲν, οἶδος περ ὁφθαλμὸς ἐν σώματι, τοιοῦτος ἐν
ψυχῇ νοῦς, οὐ μὴν ἄπασί γε ὁμοίως ὁξύς, ἐγχωρεῖ, καθάπερ (λο) βλέπων ὁξύτερον ἐπάγει
πρὸς τὸ θέαμα τὸν ἀμβλύτερον ὁρῶντα, κατὰ τὸν αὐτὸν τρόπον κἀπὶ τῶν νοημάτων
ὑπὸ τοῦ φθάσαντος ἰδεῖν ἐναργῶς τὸ νοητὸν ἐπάγεσθαι πρὸς τὴν θέαν αὐτοῦ τὸν
ἀμβλύτερον. (2) καὶ τοῦτ' ἑστιν ὁ διδάσκαλος, ὡς Πλάτων τέ φησι κάγω πείθομαι. καὶ
γέγραπταί γέ μοι περὶ τούτων ἐπὶ πλέον ἐν τῇ <περὶ> τῆς ἀποδείξεως πραγματείᾳ,
†τοιαύτη τις οὖσα τῇ πρὸς τὴν νόησιν ἐναργῶς ἡ διδασκαλία† γέγραπται δὲ καὶ ὅπως ἄν

5

<footnote n="24">24 ἔνεκά του Vlat. 14 *post corr.*, Prantl : ἔνεκ' αὐτοῦ Ambr. 659, Vlat. 14 *ante corr.* 24–25 περι'² – δύο] cf. 8 (168,3 Boudon-Millot / XIX.44 K), *secl.* von Müller, Boudon-Millot 25 σημαινόμενον Chartier : σημαινο-μένων Ambr. 659, Vlat. 14 **A12**, 2 ἑαυτοῦ Aldina : αὐτοῦ Laur. 74,3 : *eo* Nicolai vers. lat. (s. XIV) 4 ὁ ed. Basileensis (1538) 5 κἀπὶ Barigazzi : καὶ ἐπὶ Aldina : ὑπὸ Laur. 74,3 8 περι'² *add.* Havrda, cf. A1, 8; A6, 7; A8, 4; A9, 1; A17, 5; D1, 9; F6, 2–3; G26, 8. 9 τοιαύτη – διδασκαλία *secl.* Marquardt : *ante* τοιαύτη *add.* ὅτι Aldina (*quod* Nicolai vers. lat.) : *ante* τοιαύτη *lac. ind. et suppl.* ἑνθα (vel καὶ) δέδεικται Brinkmann : post πείθομαι (7) *transposuerit* Havrda τῇ Laur. 74,3 : ἦν Aldina : *del.* Barigazzi : ἡ *coni.* Havrda ἐναργῶς Barigazzi : ἑναρωως Laur. 74,3, f. 134v : ἐναργὴς Aldina : *evidens* Nicolai vers. lat. : ἐπάγουσα *coni.* Havrda (cf. 6: ἐπάγεσθαι) ἡ *del.* Havrda</footnote>
ity, one book; *On things that come-to-be for the sake of something*, one book; *On the inquiry by name and meaning*. (C-H)

**A10.** Al-Ruhāwī, *The physician's conduct*, chap. 16

We have singled out the book *On demonstration* only from the sixteen books, because only those who have learned philosophy, read logic and geometry can read it and understand the best part of it. (Ko)

**A11.** Al-Ruhāwī, *The physician's conduct*, chap. 20

If you have elevated yourself to the status of physician and want to be an excellent physician, you should read the treatise where he (i.e. Galen) explains that the excellent physician is also a philosopher, then his book *On the doctrines of Plato and Hippocrates*, then his treatise *On demonstration*. You would have reached the goal set for the knowledge of the soul and its benefits. (Ko)

5

## II. Tenets

### The Criteria

**A12.** Galen, *The best teaching* 5.2

(1) And so, it is ridiculous for Favorinos to refer the matter to his students to judge, without granting credence to the criteria. For if nothing is evident to the intellect or credible by virtue of itself, then the judgment of everything is destroyed. If it is the case, however, that intellect is in the soul like the eye is in the body, but not equally sharp in all people, it is possible that, just as the person who sees more sharply leads the one who sees more dimly to the object of vision, the same applies to thoughts: one who already sees the object of thought evidently leads the one who sees it more dimly to the vision of it. (2) And this is the teacher, as Plato says and as I am convinced. And in fact, I have written about these things at length in the treatise *On demonstration*;

5

<footnote>A12, 2 credence] See B6*, 19, with references. 3 credible...itself] See B6*, 62–63 and B6*, 68; Gal. *Inst. log.* 17.7 (44,13 Kalbfleisch), on axioms. 4 intellect...body] Plat. *Resp.* VII, 518c1; Arist. *Top.* I.17, 108a11; Philo Alex. *Opif.* 53, etc. 8 as Plato says] Cf. *Resp.* VII, 518d3–7. as I am convinced] This should possibly be followed by: “and such is the teaching that leads to intellectual insight” (a reconstruction based on the assumption that this part of the sentence was accidentally misplaced in the manuscript, and on several modifications; see apparatus). 9 *On demonstration*] In Greek, these words are followed by an unintelligible clause that may have entered the text from another place. We are omitting it in the translation (but see the previous note).</footnote>
10 τις ὁρμώμενος ἀπὸ τῶν ἐν ἐκάστῳ στοιχείων τε καὶ ἀρχῶν ἀποδεικνύοι μάλιστα πᾶν ὅσον ἀποδειχθῆναι δυνατόν.

**A13. Galenus, De simplicium medicamentorum facultatibus IV.4 (XI.632 K)**

os δὲ χρὴ πρότερον συμβουλεῦσαι τοῖς τὰ τοιαῦτα χωρὶς ἀλαζονείας σοφιστικῆς αὐτῆς ἔνεκεν τῆς ἀληθείας ἐπισκοπουμένοις, ἤδη μοι καιρὸς εἰπεῖν, ὡς οὐ χρὴ μόνῳ τῷ λόγῳ γεγυμνάσθαι δι’ ὧν ἀεὶ παρακελεύομαι μεθόδων λογικῶν, ἃς ἐν τοῖς περὶ τῶν ἀποδείξεων ὑπομνήμασιν εἶπον, ἀλλὰ καὶ τὴν αἰσθησιν τὴν γευστικὴν ἐπὶ τῶν χυμῶν γυμνάζειν ἐπιμελῶς, ἀρχομένους ἀπὸ τῶν ἐναργεστάτην ἐχόντων ἡντιναοῦν ποιότητα μίαν.

**A14. Galenus, De placitis Hippocratis et Platonis IX.1.10–13 (542,4–20 De Lacy / V.722–723 K)**

(1) δείξομεν οὖν ἤδη πῶς ἄν τις εὑρίσκοι τὴν ἀρχὴν τῆς τῶν ζητουμένων εὑρέσεως, ἀναμνήσαντες ἀ διὰ μακρῶν ἐν τε τῇ περὶ τῆς ἀποδείξεως πραγματεία λέλεκται καὶ κατ’ ἄλλας τινάς. εἰ μὲν γὰρ οὐδὲν ἡμῖν ἐστι φυσικὸν κριτήριον, οὐδὲ τεχνικὸν οὐδὲν εὑρεῖν δυνησόμεθα· φυσικὰ δ’ ἔχοντες εὖροιμεν ἄν τι καὶ τεχνικόν. (2) ἄρ’ οὖν ἔχομέν τινα φυσικὰ κριτήρια κοινὰ πάντες ἀνθρωποι; οὐδὲ γὰρ ἐνδέχεται φυσικὰ λέγειν [αὐτὰ] τὰ μὴ κοινὰ πάντων ὄντα· χρὴ γὰρ δήπου τὰ φυσικὰ πρὸς τῷ πάντων εἶναι κοινὰ καὶ τὴν φύσιν ἔχειν κοινήν. (3) ἐγώ μὲν ἔχειν φημὶ πάντας ὑμᾶς φυσικὰ κριτήρια καὶ τοῦτ’ ἀναμιμνήσκων οὐ διδάσκων οὐδ’ ἀποδεικνύς οὐδ’ ὡς αὐτὸς εἰρηκώς λέγω. (4) τίνα δὲ [ἐστὶ] ταῦτα; τοὺς κατὰ φύσιν ἔχοντας τῶν ὁφθαλμῶν ὁρῶντας τὰ ὁρατὰ καὶ (τὰ) κατὰ φύσιν ἔχοντα τῶν ὥτων ἀκούοντα τὰ ἀκουστὰ καὶ γλῶτταν γευομένην χυμῶν καὶ ῥῖνας ὁσμῶν καὶ σύμπαν τὸ δέρμα τῶν ἀπτῶν, ἐπὶ δὲ τούτοις τὴν γνώμην ἤ ἔννοιαν ἤ ὅ τί ποτ’ ἄν ἐθέλη τις ὀνομάζειν, ὦ διαγιγνώσκομεν ἀκόλουθόν τε καὶ μαχόμενον καὶ ἄλλα ἀ καταπέπτωκε τούτοις, ἐν οἷς ἐστι καὶ διαίρεσις καὶ σύνθεσις ὁμοιότης τε καὶ ἀνομοιότης, ἀφ’ ὧν ὁ παρῶν ὡρμήθη λόγος.

<footnote n="10">10 μάλιστα Aldina : κάλιστα Laur. 74,3 : κάλλιστα Barigazzi et al. **A14**, 1 δείξομεν Chartier : δείξω μὲν Ham. 270 : δείξωμεν Aldina 5 αὐτὰ *del*. von Müller, “Über Galens Werk,” p. 29 7 φύσιν Cornarius : φυσικὴν Ham. 270 9 ἐστὶ *del*. von Müller τὰ2 *add*. von Müller 10 ἔχοντα – ἀκούοντα von Müller : ἔχοντας ... ἀκούοντας Ham. 270 11 ἔννοιαν] διάνοιαν von Müller</footnote>
and I have also written there how, starting from the elements and principles in each case, one can best demonstrate everything that is capable of being demonstrated. (C-H) 10

**A13. Galen, *The power of simple drugs* IV.4**

It is now right time for me to say what advice needs to be given in advance to those who are inquiring into these things without sophistical pretension for the sake of the truth itself: that they must not be trained in reason alone, through those rational methods which I always encourage and which I discuss in the books on demonstrations, but must also carefully train the sense of taste using flavours, beginning from those that have some single quality that is especially evident. (C) 5

**A14. Galen, *The doctrines of Hippocrates and Plato* IX.1.10-13**

(1) So then, I will now show how someone can discover the starting point of the discovery of what is being sought, recalling the issues which I discussed at length both in the treatise *On demonstration* and in certain others. For if we possess no natural criterion, we will not be able to discover a technical one either. But if we have natural criteria, we could also discover a technical one. (2) So then, do all we human beings possess some common natural criteria? For it is not possible to call 'natural' those things which are not common to everyone; for surely what is natural must, in addition to being common to all, also have a common nature. (3) I declare that you all have natural criteria and I say this as one reminding you, not teaching it or demonstrating it or as making an assertion on my own authority. (4) What are they? Those who have eyes in accordance with nature that see visible objects, those who have ears in accordance with nature that hear audible objects, a tongue that tastes flavours, nostrils [that smell] scents, and the entire skin [that touches] the objects of touch; and besides these, mind or thought or whatever one wants to call it, by which we discern what is entailed and what is incompatible and other things that fall under these, among which are division, composition, and similarity and dissimilarity, which prompted the present discussion. (C-H) 10 15

<footnote>A14, 4-5 But...one] Cf. *Opt. doct.* 4.3-4 (104,6-15 Barigazzi / I.49-50 K); Clem. Alex. *Strom.* VII.16.93.2. 14-15 entailed...incompatible] Cf. B6*, 77.</footnote>
A15. Galenus, *De methodo medendi* I.4.14 (50,9–20 Lorusso / X.36–37 K)

οἱ δ' αὖ παλαιοὶ φιλόσοφοι διττὸν γένος εἶναι φασι τῶν φαινομένων, ἔν μὲν ὅπερ καὶ τοῖς ἐμπειρικοῖς ὁμολογεῖται, τῶν αἰσθήσει τινὶ διαγινωσκομένων οἶον λευκοῦ καὶ μέλανος καὶ σκληροῦ καὶ μαλακοῦ καὶ θερμοῦ καὶ ψυχροῦ καὶ τῶν ὁμοίων, ἔτερον δὲ τῶν ὑποπιπτόντων νοήσει κατὰ πρώτην ἐπιβολὴν ἀναπόδεικτον ὡς τὰ τῷ αὐτῷ ἵσα καὶ ἀλλήλοις ὑπάρχειν ἵσα καὶ ἐὰν ἰσοὶ ἵσα προστεθῆ, καὶ τὰ ὅλα ἵσα γίγνεσθαι, καὶ ἐὰν ἀπὸ ἰσων ἵσα ἀφαιρεθῆ, καὶ τὰ λοιπὰ ἵσα εἶναι. τοῦ τοιούτου γένους εἶναι φασι καὶ τὸ μηδὲν ἀναιτίως γίγνεσθαι καὶ πάντ' ἐξ ὄντος τινός, ἐκ δὲ τοῦ μηδόλως ὄντος οὐδέν· οὕτω δὲ καὶ τὸ φθείρεσθαι μηδὲν εἰς τὸ τελέως οὐκ ὃν καὶ τὸ περὶ παντὸς ἀναγκαῖον ἤ καταφάσκειν ἤ ἀποφάσκειν ἔτερά τε τοιαῦτα πολλὰ περὶ ὧν ἐν ταῖς λογικαῖς πραγματείαις ἐπισκέπτονται· καὶ ἡμῖν δ' εἰς ὅσον οἶον τε σαφέστατα διὰ τῶν ὑπέρ ἀποδείξεως ὑπομνημάτων εἴρηται περὶ τούτων.

A16. Galenus, *De methodo medendi* 1.5.1–4 (54,7–56,11 Lorusso / X.39–41 K)

(1) Καί σοι τὸν ἐξῆς λόγον ἤδη ἄπαντα ποιήσομαι χρώμενος ταῖς μεθόδοις ἃς ἐν τοῖς περὶ τῆς ἀποδείξεως ὑπομνήμασι κατεστησάμην· ὅτι τε γὰρ ἀρχαι πάσης ἀποδείξεως εἰσὶ τὰ πρὸς αἰσθησίν τε καὶ νόησιν ἐναργῶς φαινόμενα καὶ ὡς ἐπὶ πάντων τῶν ζητουμένων εἰς λόγον χρὴ μεταλαμβάνεσθαι τοῦνομα, δι' ἐκείνων ἀποδέδεικται· (2) νυνὶ δὲ ὅπως μὲν εὐρίσκειν ἡ ἀποδεικνύναι προσάκει, λέγειν οὐ πρόκειται, τοῖς δὲ ἤδη μεμαθηκόσι τε καὶ ἡσκηκόσιν ἄμα μὲν ἀποδοῦναι τινα καρπὸν τῶν πόνων εὐκαιρότατον ἐξευρόντας οὐ μικρὸν πρᾶγμα τὸ νῦν ἡμῖν προκείμενον, ἄμα δ' εἶ τινες ἐπιθυμηταὶ τῆς μεγίστης τέχνης εἰσὶν ἤ περὶ τὴν ψυχὴν τάνθρώπου καταγίνεται, προγυμνάσαι καὶ τούτους εὖλογον ἐν τοῖς μικροτέροις· τούτου γὰρ χρὴ μάλιστα κατὰ πάσας τὰς μεθόδους ἀντέχεσθαι, τοῦ γυμνάζεσθαι κατ' αὐτὰς ἐπὶ πολλῶν πολλάκις προβλημάτων μικροτέρων πρὶν ἐπιχειρεῖν τοῖς μείζοσιν. (3) ἤδ' οὖν ἡμῖν ἀρχὴ τῆς ἀληθοῦς ἔστω διδασκαλίας ἥν ἂν εὐθὺς ἀπ' ἀρχῆς ἐποιησάμεθα ζητοῦντες τε τὴν τέχνην αὐτοὶ καὶ ποδηγοῦντες ἐτέρους μηδέπω διεστραμμένους· ὥστ' ἐπειδή πρόκειται θεραπείαν ἐξευρεῖν ἀπάντων τῶν νοσημάτων, ἀναγκαῖον ἐπίστασθαι πρότερον ὁπόσα τὰ σύμπαντ' ἐστίν· ἀλλ' ἐπειδή μήτε διαφορὰς μήτ' εἶδη δυνατὸν ἐξευρεῖν γένους μηδενὸς ἄνευ τοῦ βεβαίως αὐτὸ τὸ τεμνόμενον ἐπίστασθαι, χρὴ δήπου καὶ νῦν ὅ τί ποτ' ἐστὶ νόσημα τῷ λόγῳ διελθεῖν ἵν' οὕτως ἐπιχειρήσωμεν ὁρθῶς αὐτοῦ τῇ διαιρέσει. (4) πῶς οὖν ἐξεύρω-

<footnote>A15, 4 κατὰ πρώτην ἐπιβολὴν] Cf. Clem. Alex. *Lib. log.* (= *Strom.* VIII) 8.23.6 (95,3 Stählin–Havrda); cf. *Havrda, The So-Called Eighth* Stromateus, p. 254; Chiaradonna, “Αθρόα ἐπιβολή”, pp. 109–118. **A16, 3 τὰ ...φαινόμενα**] Cf. B6*, 59. **4 εἰς ...τοῦνομα**] Cf. B6*, 19. **16–17 τῷ λόγῳ διελθεῖν**] cf. B6*, 2.</footnote>
The Starting Points

A15. Galen, *The therapeutic method* I.4.14

Now ancient philosophers claim that there are two kinds of manifest things: one kind, also acknowledged by the Empiricists, of those discerned by a particular sensation, such as pale, dark, hard, soft, warm, cold, and the like; and the other undemonstrated kind of things that present themselves immediately to intellection, for instance, that items equal to the same item are equal to one another; that when equal parts are added to equal parts, the wholes will also be equal; and when equals are subtracted from equals, the remainders will be equal too. That nothing happens without a cause, and everything comes to be from something existent and nothing comes to be from the wholly non-existent, is also, according to them, of the latter kind. Likewise, that nothing perishes into the completely non-existent, and that one must necessarily either affirm or deny about everything, and many other things of this sort discussed in logical treatises. We too have spoken about these things as clearly as possible in our books about demonstration. (H)

5

10

A16. Galen, *The therapeutic method* I.5.1–4

(1) It is for you that I will now make the whole subsequent argument using the methods I established in the books *On demonstration*. It was demonstrated in those books that the starting points of every demonstration are things evidently manifest to sense perception and intellection and that in every case of the things we seek we must change the name into an account. (2) At present, however, it is not our task to say how one should discover or demonstrate; rather, it is to give to those who have already learned and practised it a most timely fruit of their labour by discovering the thing which now lies before us and which is of some importance. At the same time, if anyone desires the greatest art, namely that concerned with the human soul, it is reasonable that he also train beforehand in less significant matters. For in all methods, one must keep to this especially, that one practise in accordance with them many times at many less significant problems, before attempting more important ones. (3) Let this, then, be a starting point for the true teaching, which we should have established straight from the start, as we were seeking the art ourselves and leading others who had not yet gone astray. So, since the task before us is to discover the therapy for all diseases, it is necessary to know how many they are in total. But since it is not possible to discover either the *differentiae* or the species of any genus at all without the object of division itself being firmly known, one must surely also now explain with an account what a disease is, so that we may thus properly attempt a division of it. (4) How then do we

5

10

15

<footnote>A15, 1 two...things] Cf. B6*, 71–72. 4 immediately] Lit. “at first application”; see references under the Greek text. A16, 3–4 evidently...intellection] Cf. B6*, 71–72 5 change...account] Cf. B6*, 22.</footnote>
μεν αὐτὸ ὁρθῶς μεθόδω; πῶς δ' ἄλλως ἤ ὡς ἐν τοῖς περὶ ἀποδείξεως ἐλέγετο; τῆς ἐννοίας πρότερον ὁμολογηθείσης ἧς χωρὶς οὐχ οἶον τ' ἐστὶν εὑρεθῆναι τὴν οὐσίαν τοῦ προκειμένου πράγματος· αὐτὴν δὲ τὴν ἔννοιαν ὁμολογουμένην ἄπασιν ἐλέγομεν χρῆναι λαμβάνειν ἤ οὐδ' ἄν ἀρχὴν δεόντως ὀνομάζεσθαι. τίς οὖν ὑπὸ πάντων ἐστὶν ἀνθρώπων ὁμολογουμένη περὶ τοῦ νοσεῖν ἔννοια; καὶ κατὰ τίνος μάλιστα φέρουσιν ὑποκειμένου πράγματος τουτὶ τὸ ῥῆμα τὸ νοσεῖν;

20

**A17. Galenus, De placitis Hippocratis et Platonis VII.1.21–23 (432,27–434,1 De Lacy / V.592–593 K)**

ὥσπερ οὖν ἐν τούτοις οὐκ ἐγὼ τοῦ μήκους τῶν λόγων αἴτιος, ἀλλ' ὅσοι μήτ' ἡσκήθησαν ἐν ἀποδεικτικῇ μεθόδῳ μήτ' ἀληθείας ἐρῶσιν, οὕτω κάπι τοῦ πλήθους τῶν ἀρετῶν ὁ μὲν ἐπιστημονικὸς λόγος ἐλάχιστος, οἱ δ' ἐξ ἁμαθίας τε καὶ φιλονεικίας ὁρμώμενοι πολλοί. τίς οὖν ὁ ἐπιστημονικὸς λόγος; ὁ ἄπ' αὐτῆς δηλόνοτι τῆς τοῦ πράγματος οὐσίας ὁρμώμενος, ὡς ἐν τῇ περὶ τῆς ἀποδείξεως ἐδείχθη πραγματεία. γρὴ γὰρ ἄρξασθαι μὲν ἀπὸ τῆς κατὰ τὴν ἀρετὴν ἐννοίας, μεταβήναι δ' ἐντεῦθεν ἐπὶ τὴν τῆς οὐσίας εὑρεσιν, ἐπισκοπούμενον εἴτε μία τῆς κατὰ ψυχὴν ἀρετῆς εἴτε πλείους εἰσὶν αἰ οὐσίαι, κατὰ τὸ κοινότατον τῶν σημαινομένων, ὡς ἐν τοῖς περὶ τῆς ἀποδείξεως εἴρηται βιβλίοις, ἀκουόντων ἡμῶν τοῦ τῆς οὐσίας ὀνόματος, ὅπερ ἐστὶν οἶον ὑπαρξις.

5

**A18. Galenus, Thrasybulus 1 (33,1–15 Helmreich / V.806–807 K)**

Οὐκ ἄλλα μέν, ὦ Θρασύβουλε, παραχρῆμα περὶ τοῦ προβληθέντος ὑπὸ σοῦ ζητήματος εἴπον, ἄλλα δὲ συγγράψασθαι τοῖσδε τοῖς ὑπομνήμασιν ἔχω· πάντως γὰρ που γιγνώ- σκεις ὡς αἰεὶ τε τὰ αὐτὰ περὶ τῶν αὐτῶν διεξέρχομαι καὶ ὡς εἰς οὐδὲν ἐπιχειρῶ λέγειν, ὦν οὐτε μέθοδον ἐμαθον οὐτ' ἐγυμνασάμην πω κατ' αὐτήν. ἀρχὴ τοίνυν εὑρέσεως οὐ τούτω μόνω τῷ νῦν προκειμένῳ σκέμματι τὸ γνῶναι τί ποτ' ἐστὶ τὸ ζητούμενον, ἀλλὰ καὶ τοῖς ἄλλοις ἄπασιν. αὐτὸ δὲ δὴ τοῦτο τὸ γνῶναι διττόν ἐστιν· ἤ γὰρ τὴν ἔννοιαν μόνην τοῦ πράγματος ἤ καὶ τὴν οὐσίαν γιγνώσκομεν. ὅτω δ' ἀλλήλων ταῦτα διαφέρει, γέγραπται μὲν ἐπὶ πλέον ἐν τοῖς περὶ ἀποδείξεως, ἵναπερ καὶ τὰς ἄλλας ἀπάσας μεθόδους ἐκτιθέμεθα, γένοιτο δ' ἄν καὶ νῦν δῆλον ἐξ αὐτῆς τῆς χρήσεως.

5

**A18a. Galenus, In Hippocratis Prorrheticum I commentaria I.4 (16,32–17,1 Diels / XVI.517 K)**

δέδεικται γὰρ ἐν τοῖς περὶ ἀποδείξεως ἀρίστη πάντων τῶν ῥηθήσεσθαι μελλόντων ἀρχὴ τοῦ ζητουμένου πράγματος ἡ ἔννοια.

<footnote n="20">20 ὁμολογουμένην ἄπασιν] Cf. B6*, 17</footnote>
discover this properly with a method? How else than as it was said in *On demonstration*? First, having agreed on the notion, without which it is not possible for the substance of the thing before us to be discovered. We said that one must get hold of a notion that is itself agreed on by everyone, or else it is not suitably called a starting point. What notion concerning being sick is agreed upon by all human beings? And to what underlying subject do they apply this verb, 'being sick'? (C-H)

**A17.** Galen, *The doctrines of Hippocrates and Plato* VII.1.21–23

And so, as in these matters it is not I who am responsible for the length of the discussion, but rather those who are neither practised in demonstrative method nor love truth, so too in the case of the number of virtues, the scientific account is very short, but those that begin from ignorance and contentiousness are many. What, then, is the scientific account? Obviously, the one that begins from the substance of the thing, as we have shown in the treatise *On demonstration*. For one must start from the notion of virtue and pass from there to the discovery of the substance, inquiring whether the substance of virtue in the soul is one or many, while we understand the word 'substance', as I said in the books *On demonstration*, in its most common meaning, which is roughly 'being.' (C-H)

**A18.** Galen, *Thrasybulus* 1

My arguments about the question you have proposed, Thrasyboulos, as I am going to write them in this treatise, are the same as when I was speaking offhand. For, as you surely know, when dealing with the same things, I give the same explanations; and I never attempt to speak on any subject unless I have learned and practised a method of dealing with it. Thus the starting point not only of this issue which lies before us, but also of all others, is to know what it is we seek. And this knowing is of two sorts: either we know solely the notion of the thing or we also know its substance. The difference between the two has been discussed at length in the books *On demonstration*, where we also set out all the other methods. And it should also become clear in the present writing from the way it is used. (H)

**A18a.** Galen, *Commentary on Hippocrates' Prorrhetic* I.4

For it has been shown in the books *On demonstration* that the best starting point of all that is to be said is the notion of the thing being sought. (C-H)

<footnote>21–22 having... discovered] Cf. B6*, 9–13.</footnote>
**A18b. Galenus, *In Hippocratis librum primum Epidemiarum commentarii* 1.1 (19,9–11 Wenkebach / XVIIa.28 K)**

τίνα τοίνυν οἰκεῖα στοιχεῖα τῶν καταστάσεών ἐστιν, ἰδωμεν ἀπὸ τοῦ πράγματος τῆς οὐσίας ὁρμηθέντες, ὡς ἐν τοῖς περὶ ἀποδείξεως ἐδιδάχθημεν.

**A18c. Galenus, *De temperamentis* II.2 (53,4–7 Helmreich / I.592–593 K)**

μακρὰν ἵσως σοι δόξω λέγειν τὴν ἐξέτασιν ἀλλ' ἀληθῆ γε παντὸς μᾶλλον ἐξ αὐτῆς τε τοῦ ζητουμένου τῆς οὐσίας λαμβανομένην, ὡς ἐν τοῖς ὑπὲρ ἀποδείξεως ἐλέγετο.

**A19. Galenus, *De constitutione artis medicae ad Patrophilum* 9.3 (82,23–25 Fortuna / I.255–256 K)**

ο διορισμὸς δ' ἀπὸ τῆς ἐννοίας ἐκατέρων τῶν πραγμάτων, ὡς ἐν τῷ περὶ ἀποδείξεως ἐδείκνυτο, τὴν πρώτην ἀρχὴν ἔξει.

**A20. Galenus, *De temperamentis* II.2 (49,11–21 Helmreich / I.586–587 K)**

ὥστε δι' ἀλλήλων καὶ ἐξ ἀλλήλων αὐτοῖς γίγνεσθαι τὰς ἀποδείξεις, ἐκ μὲν τῶν νῦν
ζητουμένων ὡς ἤδη γιγνωσκομένων, ἐπειδὰν ὑπὲρ τῶν ἐνεργειῶν διαλέγωνται καὶ τὴν
τῶν ἐδεσμάτων τε καὶ φαρμάκων ἐξευρίσκωσι δύναμιν ὕπων τε πέρι καὶ τῶν ἄλλων
τῶν τοιούτων ἐπισκέπτωνται. πάλιν δ' αὖ τὰ νῦν ἐνεστῶτα δι' ἐκείνων ὡς ἤδη προεγνω-
σμένων ἀποδεικνύουσιν. ἐγώ δ' οὐκ ἐπαινῶ τὰς τοιαύτας ἀποδείξεις, ἀλλ', εἰ χρὴ
τάληθès εἰπεῖν, οὐδ' ἀποδείξεις εἶναι νομίζω, καθάπερ ἐπὶ πλέον δι' ἐτέρων ἐδήλωσα,
καὶ βέλτιον εἶναί φημι κατὰ πᾶσαν διδασκαλίαν ὁρίσασθαι τὴν τάξιν τῶν νοημάτων.

**A21. Galenus, *De placitis Hippocratis et Platonis* II.5.46 (136,26–30 De Lacy / V.250 K)**

ἄπερ οὖν ἐν ταῖς περὶ τῆς ἀποδείξεως μεθόδοις ἐδιδάχθημεν καθόλου, ταῦθ' εὑρίσκεται
κατὰ μέρος ἐπὶ πάσης ὕλης πραγμάτων ἀληθεύοντα. χρὴ γὰρ οὐκ ἀπὸ πάντων τῶν
ὑπαρχόντων τῷ προκειμένῳ πράγματι τάληθες λαμβάνειν ἀλλ' ἀπὸ μόνου τοῦ συνημμέ-
νου τῷ προβλήματι.

<footnote>Α21, 2 ἐπὶ...πραγμάτων] Cf. A4, 6.</footnote>

<footnote>**A18b, 2** ἐδιδάχθημεν] δεδιδάχαμεν Wenkebach, *sed cf. infra*, A21, 1</footnote>
**A18b.** Galen, *Commentary on Hippocrates’ Epidemics* II.1.

Now we know what the proper elements of the conditions are when we have begun
from the substance of the thing, as we have been taught in the books *On demonstration*.
(C-H)

**A18c.** Galen, *Mixtures* II.2

You will perhaps think that the examination I am describing is long; but it is also true
above anything else, taken as it is from the very substance of the thing being sought, as
discussed in the books about demonstration. (H)

**A19.** Galen, *The constitution of the art of medicine* 9

The distinction will take its first starting point from the notion of each of these things,
as shown in *On demonstration*. (C-H)

**A20.** Galen, *Mixtures* II.2

And so their demonstrations are produced through each other and from each other. On
the one hand, [they are produced] from things being sought right now as if they were
already known, whenever they reason about activities and search for the power of
foods and drugs and inquire about sleep and other such things. And then again they
demonstrate the things currently under inquiry through those just mentioned, as if
they were already known. As for me, I do not approve of such demonstrations. Rather,
to tell the truth, I do not even regard them as demonstrations, as I have explained at
length in other [books], and I claim that in every teaching one should determine the
order of thoughts. (H)

5

## The Discovery of Premisses

**A21.** Galen, *The doctrines of Hippocrates and Plato* II.5.46

And so the [tenets] we have been taught in the inquiries *On demonstration* on a general level are discovered to be true on a particular level in each instance of the things [in hand]. For one should not take true [premisses] from all attributes of the thing before us, but only from that which is connected to the problem. (H)

<footnote>A19, 1 each of these things] I.e., of imbalanced mixture on the one hand, and illness on the other. A20, 8 in other books] Probably a reference to *Dem*.; see Singer-van der Eijk, *Galen: Works on Human Nature I*, p. 114 n. 55.</footnote>
A22. Galenus, *De methodo medendi* I.5.5–6 (56,23–58,7 Lorusso / X.41–42 K)

καὶ οὐδεὶς ὅλως Ἕλλην ὀῦτ' ὡνόμασεν ἄλλως οὐτ' ἐπ' ἄλλό τι πρᾶγμα φέρει τῶν εἰρημένων ὅνομάτων ἔκαστον ὡς ἐπὶ πλεῖστον ἐδείξαμεν ἐν τῇ τῶν ἰατρικῶν ὅνομάτων ἐξηγήσει. καὶ αὐτοῦ γε τούτου μέμνησό μοι διὰ παντὸς τοῦ λόγου μάλιστα, ὅτι τὰς μὲν τῶν ὅνομάτων ἐξηγήσεις ἐκ τῆς τῶν Ἕλλήνων συνηθείας ποιούμεθα καθότι κάν τοῖς περὶ τῆς ἀποδείξεως ὑπομνήμασιν ἐλέγετο, τὰς δὲ τῆς οὐσίας αὐτῆς τοῦ πράγματος εὑρέσεις τε καὶ ζητήσεις καὶ ἀποδείξεις οὐκέτ' ἐκ τῶν τοῖς πολλοῖς δοκούντων, ἀλλ' ἐκ τῶν ἐπιστημονικῶν λημμάτων ὑπὲρ ὧν τοῦ τρόπου τῆς εὑρέσεως ἐν ἐκείνοις εἴρηται.

5

A23. Galenus, *De methodo medendi* I.5.11–12 (60,17–62,12 Lorusso / X.44–45 K)

(1) εἴρηται δ' ὡς οἴσθα περὶ τῆς τῶν ὅνομάτων χρήσεως ἐπὶ πλέον ἐτέρωθι καὶ νῦν ὅσον ἀναγκαῖον εἰς τὸ προκείμενον δίειμι τοῦτ' ἐνδεικνύμενος μόνον, ὡς οὐ χρὴ περιέλκεσθαι τοῖς ὅνόμασιν οὐδὲ τοὺς ἐν τούτοις διαφερομένους ἤδη κάν τοῖς πράγμασιν αὐτοῖς ἡγεῖσθαι διαφέρεσθαι, καὶ τούτου δ' αὐτοῦ πάντας ὡς ἔπος εἰπεῖν ὁρᾶς ἀγυμνάστους, οὐ τοὺς ἰατροὺς μόνον τοὺς νῦν ὄντας, ἀλλὰ καὶ τῶν φιλοσόφων τοὺς πλείστους· ὀλίγοι γὰρ αὐτῶν ἵσασι διακρίνειν τὰς ἐν τοῖς ὅνόμασι διαφωνίας τῶν ἐν αὐτοῖς τοῖς πράγμασιν· ἀλλ' ἐδείχθη καὶ τούτου μέθοδος ἐν τῇ λογικῇ θεωρίᾳ, καὶ νῦν ἤκει καιρὸς αὐτῆς, εἴπερ ποτε καὶ ἀλλοτε. (2) τίς δ' ἦν ἡ μέθοδος; ἀπὸ τῆς τῶν πραγμάτων ἄρξασθαι διαφορᾶς, οὐκ ἀπὸ τῆς τῶν ὅνομάτων, καὶ δεῖξαι λόγου χάριν ἀλλήλοις παρακείμενα τέτταρα πράγματα, κᾶπειθ' ἐξῆς ἀποδείξει βεβαιώσασθαι τὸ μήτε πλείω τούτων εἶναι μήτ' ἐλάττω, τὰ κατὰ τὸ προκείμενον σκέμμα περιεχόμενα· μετὰ τοῦτο δ' ἤδη καθ' ἑκάστου τῶν πραγμάτων ἰδίον ὅνομα θέμενον οὕτω περαίνειν ἄπαντα τὸν ἐξῆς λόγον οὐκέτ' οὐδαμόσε μετατιθέντα καὶ μεταφέροντα τῶν ὅνομάτων οὐδὲν, ἀλλ' ἀκριβῶς διαφυλάττοντα καθ' ὅτουπερ ἀν αὐτὸς ἐξ ἀρχῆς ἐπιθῆται πράγματος. καὶ γὰρ σαφής οὕτως ἡ διδασκαλία γίνεται καὶ τῶν παρὰ τὰς ὁμωνυμίας σοφισμάτων ἐκτὸς καὶ ῥαδίως ἐξελέγχεται τὰ μάτην προσκείμενα καὶ διὰ ταχέων εὑρίσκεται τὰ λείποντα καὶ τὰ τε διαφωνούμενα καὶ τὰ συμφωνούμενα μάλιστα ἐν ταῖς τοιαύταις ἐρμηνείαις ἀκριβῶς γνωρίζεται.

5

10

15

A24. Galenus, *De placitis Hippocratis et Platonis* II.2.3–5 (102,20–104,5 De Lacy / V.212–213 K)

φημι δὴ τῶν λημμάτων ἀ ἔνεκα τοῦ συμπεράσματος λαμβάνουσιν, [ώς] τὰ μὲν ἄντικρυς εἶναι ψευδῆ, τὰ δὲ οὐκ οἰκεῖα τοῦ προκειμένου σκέμματος· ἄντικρυς μὲν ψευδῆ τὰ
**A22.** Galen, *The therapeutic method* 1.5.5–6

And no Greek at all would name [these things] otherwise or apply any of the names mentioned to any other thing, as we have shown at length in the explanation of medical names. At any rate, keep this point especially in mind throughout my whole argument that we make the explanation of names based on the customs of the Greeks, just as we said also in the books *On demonstration*. But the discoveries, inquiries, and demonstrations of the very substance of the thing [in question] are not based on the opinions of the many, but on the scientific premises, the manner of whose discovery has been described in these [books]. (C-H)

5

**A23.** Galen, *The therapeutic method* 1.5.11–12

(1) Elsewhere, as you know, I have spoken about the use of names at length. Now I will discuss it to the extent that is necessary for the task in hand, indicating only that one should not become distracted by names nor suppose that those who differ in the names [they use] already also differ in regard to the things themselves. In fact you see pretty much everyone untrained in this very thing, not only doctors living now, but also most of the philosophers. For few of them know how to distinguish disagreements with respect to names from those with respect to things. But the method for doing this too has been shown in the study of reasoning and now the right time for it has come, if ever there was one. (2) What is the method? To begin from the differences between things, not from those between names, and to show that there are, for the sake of argument, four things closely connected with one another (and then confirm by successive demonstration that there are neither more nor less than this number of them) which come into consideration in view of the problem in hand. After this, once we have given distinctive names to each of these things, the whole successive argument should be concluded accordingly, without any of the names being changed or transferred to anything else, but kept precisely for that thing to which it was given at the beginning. For in this way the teaching becomes clear and free of sophisms based on homonymy, and pointless additions are easily exposed and omissions quickly discovered. Also, the points of agreement and of disagreement are both recognized with precision especially when things are expressed in this way. (C-H)

5

10

15

20

**A24.** Galen, *The doctrines of Hippocrates and Plato* II.2.3–5

Now I claim that, of the premisses which they take for the sake of the conclusion, some are outright false, and others are inappropriate to the issue lying before us. Outright

<footnote>A22, 1-2 names mentioned] I.e. 'being sick' and 'being healthy'. 2-3 explanation...names] Med. nom.; the first book of the treatise is preserved in an Arabic translation, ed. Meyerhof-Schacht, *Über die medizinischen Namen*. 4 customs of the Greeks] Cf. B6*, 3. A23, 8 study of reasoning] A reference to Dem.; "too" (καί) links this passage with A16, 20-24. For "the study of reasoning", see A1, 3.</footnote>
τοιαῦτα, περὶ ὧν ἐν τῷ πρώτῳ βιβλίῳ διῆλθον ἐπὶ πλέον, ὅταν ἤτοι μηδὲν τῶν ἀλόγων
ζώων ἐπιθυμεῖν τις ἤ θυμοῦσθαι φάσκη, καθάπερ οἱ ἀπὸ τῆς Στοᾶς, ἤ πάλιν ἐκ καρδίας
πεφυκέναι τὰ νεῦρα· τὰ δὲ οὐκ οἰκεῖα τῶν λημμάτων ὁπόσα (καὶ ὁποῖα) τὴν φύσιν
ἐστίν, εἴρηται μὲν ἐπὶ πλεῖστον ἐν τοῖς περὶ ἀποδείξεως ὑπομνήμασιν, ἐν οἷς ἄπασαν
ἐδήλωσα τὴν ἀποδεικτικὴν μέθοδον ὁποία τίς ἐστιν παρεκάλουν τε διὰ τοῦ πρώτου
τῶνδε τῶν ὑπομνημάτων ἐν ἐκείνη γυμνάσασθαι πρότερον, ὅστις ὀτιοῦν ἀποδεικνύειν
ἐπιχείρει. γεγράφθαι δὲ λέγω ὑπέρ αὐτῆς ἄριστα τοῖς παλαιοῖς φιλοσόφοις τοῖς περὶ
Θεόφραστόν τε καὶ Ἀριστοτέλην κατὰ τὰ τῶν δευτέρων ἀναλυτικῶν βιβλία...

**A25. Galenus, De placitis Hippocratis et Platonis II.2.23–3.3** (108,16–31 De Lacy /
V.218–219 K)

(1) πάντ’ οὖν ὅσα τοιαῦτα τῶν ἐπιχειρημάτων ἐν τοῖς περὶ ἀποδείξεως ἐδείξαμεν οὐκ οἰκεῖα τῷ ζητουμένῳ πράγματι καὶ διὰ τοῦτο νῦν οὐ χρὴ μηκύνειν περὶ αὐτῶν, ὥσπερ οὐδ’ ἐπὶ τῶν ἐκ τῆς ἐτυμολογίας ὁρμωμένων· εἴρηται γὰρ καὶ περὶ ἐκείνων αὐτάρκως ἐν τοῖς περὶ ὀνομάτων ὁρθότητος. (2) ἀλλὰ τίνα χρὴ ζητεῖν λήμματα τῷ προκειμένῳ προβλήματι προσήκοντά τε καὶ οἰκεῖα; γέγραπται μὲν δήπου καὶ περὶ τούτων ἐπὶ πλεῖστον ἐν τοῖς περὶ ἀποδείξεως ὑπό τε τῶν παλαιῶν εἰρημένοις ἀσαφέστερόν τε καὶ συντομώτερον ὑπό τε ἡμῶν ἐξηγουμένων ἐκεῖνα σαφῶς τε ἄμα καὶ διὰ πολλῶν. ἀρκέσει δὲ νῦν ἐξ αὐτῶν τὸ κεφάλαιον ἀναμνήσαι μόνον ἐκείνῳ χρήσασθαι σκοπῷ εἰς τὴν τῶν κατὰ μέρος εὖρεσιν. (3) ἦν δὲ τὸ κεφάλαιον ὡς ἀπ’ αὐτῆς χρὴ τῆς οὐσίας τοῦ ζητουμένου πράγματος ἐξευρίσκειν τὰ προσήκοντά τε καὶ οἰκεῖα λήμματα, καθάπερ ἐν τούτοις ἐν οἷς Χρύσιππος ἐπισκοπεῖται περὶ τοῦ τῆς ψυχῆς ἡγεμονικοῦ τὸν τῆς οὐσίας λόγον εἰπόντας ὑπέρ οὖν ζητοῦμεν πράγματος ἐκείνῳ χρῆσθαι κανόνι τε καὶ σκοπῷ τῶν κατὰ μέρος ἀπάντων.

**A26. Galenus, De placitis Hippocratis et Platonis II.3.23–26** (114,22–116,5 De Lacy /
V.226 K)

(1) εἴ τις οὖν καλῶς ἤσκηται τὰς διαφορὰς τῶν λημμάτων ἐξευρίσκειν τε καί γνωρίζειν, οὐ δεήσομαι πρὸς αὐτὸν ἀντιλογίας μακροτέρας, ὥσπερ οὐδὲ πρὸς τοὺς ἐκ τοῦ Περιπτάτου. (2) κατὰ γὰρ τὰς ἰδίας αὐτῶν διδασκαλίας ὁ λόγος ἔσται μοι πρὸς αὐτοὺς ὑπέρ τοῦ τὴν τοῦ ἡγεμονικοῦ τῆς ψυχῆς ἀρχὴν ἐν ἐγκεφάλῳ περιέχεσθαι, τῆς δὲ θυμοειδοῦς ἐν καρδίᾳ, τῆς δ’ ἐπιθυμητικῆς ἐν ἥπατι. (3) πρὸς μέντοι τοὺς Στωϊκοὺς ἀναγκαῖον ἐστι μακρὸν ἀνύεσθαι λόγον, ἀνθρώπους ἐν μὲν τοῖς ἀχρήστοις τῆς λογικῆς θεωρίας ἱκανῶς

<footnote n="5">5 καὶ ὁποῖα add. Havrda **A25**, 6 ἀσαφέστερόν von Müller: ἀσφαλέστερόν mss.</footnote>
false are such as those I discussed at length in the first book [of the present treatise], when someone claims, as the Stoics do, that none of the irrational animals is desirous or angry, or again that the nerves grow out from the heart. As far as inappropriate 5 premisses are concerned, I have set out at great length how many they are (and what they are like) by nature in the books *On demonstration*, where I clarified what the demonstrative method is in its entirety and encouraged, though the first book of this treatise, anyone who attempts to give a demonstration of anything to train themselves in this method first. I say that the best account of it was given by the ancient philosophers Theophrastus and Aristotle in their books of the *Second analytics*. (C-H) 10

**A25.** Galen, *The doctrines of Hippocrates and Plato* II.2.23–3.3

(1) We have shown in *On demonstration* that all such arguments are inappropriate to the thing being sought and for this reason there is no need to speak at length about them, just as there is no need in the case of [arguments] that begin from etymology; for these have been discussed sufficiently in *On the correctness of names*. (2) But what premisses should one seek as suitable and appropriate to the problem before us? 5 Surely these have also been written about at length in the [books] on demonstration, both by the ancients speaking rather unclearly and briefly, and by us explaining their statements at once clearly and extensively. For now, it will be sufficient to recall from [these accounts] only the main point and use it as an objective for the discovery of particular [premisses]. (3) The main point was that the suitable and appropriate pre- 10 misses must be discovered from the very substance of the thing sought, just as in this case, when Chrysippus inquires about the ruling part of the soul, we should state the account of the substance of the thing with which our inquiry is concerned, and then use that as a standard and objective for [the discovery of] all particular [premisses]. (C-H) 15

**A26.** Galen, *The doctrines of Hippocrates and Plato* II.3.23–26

(1) If someone has been well practised in the discovery and recognition of the differences of premisses, I will not need a very long response to him, just as it is not needed in response to the Peripatetics. (2) For my argument against them will be in accordance with their own instructions, that the principle of the ruling part of the soul is enclosed in the brain, the spirited in the heart, and the appetitive in the liver. (3) Yet against the Stoics, it is necessary that a long argument be made, since they are people excessively trained in the useless parts of the study of reasoning, but completely untrained in the

<footnote>A24, 6–7 how...nature] See *PHP* II.3.10–11 (110,24–112,2 De Lacy / V.221–222 K); *PHP* II.4.3–4 (116,23–31 De Lacy / V.227–228 K), etc. A25, 1 all such arguments] I.e., such as Chrysippus’ cardiocentric argument from nodding. A26, 7 study of reasoning] Cf. A1, 3.</footnote>
γεγυμνασμένους, ἐν δὲ τοῖς χρησίμοις ἀγυμναστοτάτους τε ἄμα καὶ μοχθηραῖς ὁδοῖς ἐπιχειρημάτων ἐντεθραμμένους· ὥστε ἀναγκαῖον εἶναι μὴ μόνον διδάσκειν αὐτοὺς ὁσν χρηστὸν ἀλλὰ πολὺ πρότερον ἀποστῆσαι τοῦ μοχθηροῦ. (4) τοῦτο δὲ χαλεπῶς μὲν ἂν ἰσως, ἀνύσειν δ' ἡλπίσαμεν, εἴ τις αὐτῶν ὑπέμεινε τῇ περὶ ἀποδείξεως πραγματείᾳ ἀκολουθήσας ἐπὶ πλέον ἐν αὐτῇ δοῦναι τε καὶ λαβεῖν λόγον ἐν εὑμενέσιν ἐλέγχοις.

10

### A27. Galenus, *Thrasybulus* 5 (37,20–26 Helmreich / V.812–813 K)

δέδεικται δ' ἡμῖν ἐν τοῖς περὶ ἀποδείξεως, ὡς οὐ χρηστέον ἐπαγωγαῖς εἰς ἀποδείξεις ἐπιστημονικάς· ὥσθ' ὅστις ἐν ἐκείνοις ἐγυμνάσατο, καταφρονήσει μὲν τῆς τοιαύτης ὁδοῦ, ζητήσει δ' ἑτέραν βελτίω, ὁ μὴ γυμνασάμενος δὲ θάτερον τῶν μερῶν ἐλόμενος, ὁπότερον ἂν βουληθῆ, δι' ὅλης ἡμέρας ἐρίζειν ἔξει.

### A28. Galenus, *De simplicium medicamentorum facultatibus* II.4 (XI.470–471 K)

(1) τὸ γὰρ ἐκ παραδείγματος ἤ ἐκ παραδειγμάτων πιστοῦσθαί τι διαφέρει τοῦ δι' ἐπαγωγῆς πιστουμένου τῷ τὸν μὲν ἐκ παραδειγμάτων πιστούμενον ἐν μὲν ἤ δύο τῶν ὁμογενῶν λέγειν, ἤ πάντως γε ὁλίγα τὰ πλείω παραλείποντα, τὸν δ' ἔξ ἐπαγωγῆς ἄπαντα περιλαμβάνειν πειρᾶσθαι τὰ διὰ τῆς ἐμπειρίας ἐγνωσμένα, καὶ μηδὲν ὡς οἶόν τε παραλιπεῖν ὃ προφανές τε καὶ δῆλον τοῖς πολλοῖς, ἀλλὰ ἀποκεκρυμμένον τε καὶ ὀλίγοις γνωστόν. (2) ὅθεν καὶ βίαιός ἐστιν καὶ πείθει σφοδρῶς ἡ διὰ πάντων τῶν ἔξ ἐμπειρίας γινωσκομένων ἐπαγωγὴ καὶ μόνοις αὐτοῖς ἡ ἀλαζονεία κατάφωρος γίνεται τοῖς γεγυμνασμένοις ἐν ἀποδεικτικαῖς μεθόδοις. (3) καὶ διὰ τοῦθ' ἡμεῖς ἐπιπλέον ὑπέρ αὐτῆς ἐν τοῖς περὶ τῆς ἀποδείξεως ὑπομνήμασιν διήλθομεν. ἰσως δ' ἂν ποτε καὶ κατὰ μόνας ἐν ὑπέρ αὐτῆς ἰδίᾳ συνθείημεν γράμμα.

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### A29. Ibn al-Ṭayyib, *Commentary on the Categories* (p. 103 Ferrari)

(1) فطافة رابعة رئيسها جالينوس، زعمت أنّ أجناس الأجناس الشاملة لسائر الموجودات خمسة على ما ذكره رئيسها في البرهان. أما ثلاثة، فالجوهر والكمية والكيفية، وأما رابع

<footnote>A27, 4 ἔξει Chartier : ἔχει mss.</footnote>
useful parts while at the same time having been nurtured in unsound ways of reason-
ing. Therefore, it is necessary not only to teach them what is good, but much more
importantly to make them abandon what is bad. (4) This will be difficult to accomplish
perhaps, but we would have hoped to succeed if any of them, having followed the
treatise *On demonstration*, persevered by it at length in giving and taking an argument
in friendly scrutiny. (C-H)

10

Induction

A27. Galen, *Thrasybulus* 5

However, it has been shown in the [books] *On demonstration* that inductions should
not be used for scientific demonstrations. Thus everyone who has been trained by
these books will despise this method and look for another, better one; whereas those
who have not been trained can take one side, whichever they choose, and argue
contentiously all day. (H)

5

A28. Galen, *The power of simple drugs* II.4

(1) For to confirm something from an example or examples differs from confirming it
through induction in the following way: the person who confirms from examples
mentions one or two things of the same kind, at any rate a few, omitting the majority
of cases. In contrast, the person who confirms from induction attempts to include
everything that has been recognized through experience and to omit, as far as possible,
nothing which is obvious and clear to the many, but only that which is hidden and
known to a few. (2) For this reason, induction by all that has been recognized through
experience is forceful and persuades strongly, and their false pretension is detected
only by those trained in demonstrative methods. (3) And this is why we discussed it at
length in our books *On demonstration*. Perhaps at some point we might also compose a
separate single piece dealing specifically with it. (C-H)

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Categories

A29. Ibn al-Ṭayyib, *Commentary on Aristotle's Categories*

(1) A fourth group whose head is Galen believes that there are five highest genera that comprise all the beings in accordance with what their head mentions in *On demonstration*. As for three [of the highest general], they are substance, quantity, and quality, the

<footnote n="13">13 friendly scrutiny] Cf. Plat. *Epist*. VII, 344b5.</footnote>
5

فالأطراف التي تأخذ من الكيفية شيئا ما، فأما الخامس فالإضافة إلى شيء آخر. (2) وينبغي أن تعلم أنَّ هذا الفعل غير موافق للفلسفة، ولا لمن يجب علُّمها على الصحة. (3) أما أوَّلا فجنس الأطراف التي تأخذ من الكيفية، أمرٌ لا يقتدر على فهمه أحد أو يعرف معناه. (4) وأما ثانيا فمن قبل الغاية مقولات شديدة الظهور لا تذهب على أحد، بمنزلة متى وأين ويفعل وينفعل والموضوع وله. وإن ظنَّ أنَّ هذه كلها تدخل في المضاف، فيقبح به لأن المضافين ليس هما اللذين لأحدهما إلى الآخر نسبة حسب لكن اللذين ذات كل واحد منهما تقال بالقياس إلى الآخر.

A30. Elias, *In Aristotelis Categorias commentarium* 4 (160,20–23 Busse)

ἄλλοι διὰ τί μὴ πέντε αἱ κατηγορίαι, ὡς ὁ Γαληνός, οὐσία ποσὸν ποιὸν πρός τι πρός τί πως ἔχον. πρὸς ὁ φαμεν ὅτι οὐ δύναται τὸ πρός τί πως ἔχον γένος εἶναι τῶν λοιπῶν κατηγοριῶν.
fourth are terms that take something from quality, and the fifth is relation to something else. (2) You must know that doing this does not correspond to philosophy nor to him who affirms its knowledge correctly. (3) First, no one is able to understand the genus 'terms that take something from quality' or to know what it means. (4) Second, regarding the aim, clearly apparent categories do not escape anyone, such as when, where, acting, being acted upon, position, and having, even if one believes that all these are included in (the category of) the relative. However, one is wrong in that, because two relatives are not those of which only one has a link to the other, but the essence of each one of the two is said in reference to the other and is only completely understood through the other. (Wakelnig)

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**A30. Elias, *Commentary on Aristotle's Categories* 4**

Others suggest why not there be five categories, for instance Galen: substance, quantity, quality, relative, relative disposition. To this we say that relative disposition cannot be the genus of the remaining categories. (H)

<footnote>A29, 4 terms] The word *taraf* (pl. *atrāf*) means “extreme”, “limit”, and in the context of this discussion, “term” (W). terms... quality] The expression is unclear, as al-Ṭayyib notes (A29, 6–7), perhaps due to a mistranslation of the Greek source. 5 doing this] I.e., postulating five categories (W). 8 the aim] I.e., of the ten categories (W). 9–10 even...relative] A view attributed to Galen by al-Ṭayyib (W). 10 wrong in that] I.e., in the belief that the categories when, where etc. are included in the category of the relative (W). 11–13 two...other] In what follows, Ibn al-Ṭayyib gives several examples to explain the difference between the category of the relative and the other categories: “Substance and time are understood separately, but they are also the two terms (*tarafān*) of when. Substance and place are understood separately, but they are also the two terms of where. Property and possessor are understood separately, but they are also the two terms of having. Do understand our expression ‘separately’ to mean ‘not inasmuch as they are relatives’, unless these two terms are taken insofar as they are terms of a relation (*iḍāfa*), for (then) each one of the two is only understood in reference to (*bi-al-qiyās*) the other” (Ibn al-Ṭayyib, *Tafṣīr K. al-Maqūlāt*, ed. Ferrari, pp. 103–104, translated by Wakelnig). A30, 1 for instance Galen] Probably a reference to *Dem*.; see A29, 2–3. The doctrine is otherwise unattested.</footnote>
**B1.** (= A24 pars). Galenus, *De placitis Hippocratis et Platonis* II.2.3 (102,26–104,2 De Lacy / V.213 K)

... έν τοῖς περὶ ἀποδείξεως ὑπομνήμασιν, έν οἷς ἄπασαν ἐδήλωσα τὴν ἀποδεικτικὴν μέθοδον ὁποία τίς έστιν παρεκάλουν τε διὰ τοῦ πρώτου τῶνδε τῶν ὑπομνημάτων έν ἐκείνη γυμνάσασθαι πρότερον, ὅστις ὁτιοῦν ἀποδεικνύειν ἐπιχειρεῖ.

**B2.** Nemesius, *De natura hominis* 21 (82,5–18 Morani)

τῆς δὲ λύπης ὅργανον τὸ στόμα τῆς κοιλίας· τοῦτο γάρ έστι τὸ τῆς δῆξεως αἰσθανόμενον ἐν ταῖς λύπαις, ὡς ὁ Γαληνὸς ἐν τῷ τρίτῳ τῆς ἀποδεικτικῆς φησιν οὕτω πως· « τοῖς λυπουμένοις οὐκ ὁλίγον εἰς τὴν γαστέρα καταρρέιξανθῆς χολῆς, ὃ τὴν δῆξιν αὐτοῖς παρέχει, καὶ οὐ πρότερον παύονται λυπούμενοι καὶ δακνόμενοι πρὶν ἐξεμέσαι τὴν χολήν. γίνεται γὰρ ἡ δῆξις αὐτοῖς ὑποκάτω τοῦ κατὰ μέσα στέρνα χόνδρου τοῦ ξιφοειδοῦς ὀνομαζομένου. πολὺ δὲ ἀνωτέρω κεῖται ἡ καρδία· τοῦ γὰρ διαφράγματος ἡ μὲν γαστὴρ κατωτέρω έστίν, ἡ δὲ καρδία ἀνωτέρω. συνήθως δὲ οἱ παλαιοὶ καρδίαν καὶ τὸ στόμα τῆς γαστρὸς καλοῦσιν, ὡς Ἱπποκράτης καὶ θουκυδίδης ἐν τῷ λοιμῷ λέγων οὕτως· «οπότε εἰς τὴν καρδίαν στηρίξαι, ἀνέστρεφέν τε αὐτὴν καὶ ἀποκαθάρσεις χολῆς πᾶσαι, ὁπόσαι ἀπ' ἰατρῶν ὡνομασμέναι εἰσίν, ἐπήεσαν.» τὸ γὰρ ἀναστρεφόμενον τὸ στόμα τῆς γαστρός έστιν ἀναγκαζόμενον ἐμεῖν, οὐ τὸ σπλάγχνον ἡ καρδία.»

5

10

**B3.** Galenus, *De usu partium* XV.5 (II.357,24–28 Helmreich / IV.238–239 K)

περὶ δὲ τοῦ ζῷον ἤδη τὸ κατὰ γαστρὸς ὑπάρχειν, ὅταν γε διαπεπλασμένον ἄπασιν ἧ τοῖς μορίοις, ἔν τε τοῖς περὶ ἀποδείξεως ὑπομνήμασιν εἴρηται κάν τοῖς περὶ τῶν Ἱπποκράτους τε καὶ Πλάτωνος δογμάτων.

<figure><img src="image_16.png" /></figure>

<footnote>B2, 5–7 Cf. PHP II.8.6 (158,13–15 De Lacy / V.274 K). 7–8 Cf. PHP II.8.8 (158,20–21 De Lacy / V.274 K). 9–10 Thucydides II.49.3; cf. PHP II.8.11 (158,26–28 De Lacy / V.275 K). **B3, 1–2** διαπεπλασμένον... μορίοις] Cf. B7*, 60–61.</footnote>
# Section B: Books I–III and Related Testimonia

## Book I

**B1.** (= A24 pars). Galen, *The doctrines of Hippocrates and Plato* II.2.3

... in the books *On demonstration*, where I clarified what the demonstrative method is in its entirety and encouraged, though the first book of this treatise, anyone who attempts to give a demonstration of anything to train themselves in this method first. (C-H)

## Book III

**B2.** Nemesius, *The nature of man* 21

The mouth of the belly [i.e., the cardia] is the organ of distress. For this senses biting pain in distress, as Galen says in the third book of the *Apodeictics* in these words: "For those who are in distress, a large amount of yellow bile runs down into the stomach, which makes them feel biting pain, and they do not stop being distressed and feeling the pain until they vomit out the bile. For the biting pain is produced in these cases below the cartilage in the middle of the chest, which is called 'ensiform.' The heart is situated much higher up. For the stomach is lower than the diaphragm, while the heart is higher up. The ancients also customarily called the mouth of the stomach 'heart' (kardia), as did Hippocrates and Thucydides in [his account of] the plague, saying: 'When it settled in the heart, it upset it, and all the purging secretions of bile which have been named by the doctors followed after.' For the thing that is upset is the mouth of the stomach that is forced to vomit, not the internal part, the heart." (C-H)

## Issues Probably Discussed in Books II–III

**B3.** Galen, *The use of parts* XV.5

Of the [proposition] that the thing in the womb is already an animal, at least when it has been formed in all its parts, we have spoken in the books *On demonstration* and *On the doctrines of Hippocrates and Plato*. (C-H)

<footnote>**B2, 10-11** Thucydides II.49.3; cf. Gal. *PHP* II.8.11 (158,26-28 De Lacy). **B3, 2** formed...parts] Cf. B7*, 73-74.</footnote>
B4. Abū Bakr al-Rāzī, Doubts about Galen 13.1 (84,1–13 Koetschet)

(1) فأما في كتابه في القوى الطبيعية فقال: "لَمَا كان الحَسَنُ والحركة الإرادية خاصَّين بالحيوان والنمو والتَّغَذِي عامَّين للحيوان والنبات، صارت الأولى أفعالاً للنفس والثانية أفعالاً للطبيعة".

وقد كان ينبغي له أن يلحق بالحس أيضاً زيادةً وفضلاً كما الحقهما بالحركة، إذ كان هذا شيئاً قد إختلف فيه، لا سيما وقد قال هو في غير موضع إن للنبات حسًا ما. (2) فإنَّه قال في آرائه إنَّ

للنبات إحساساً بما خالفه وبما وافقه. وقال في كتاب الذبول إن الأجسام التي لها حياة ثلاثة: 5

الحيوان والنبات والبزور. وقال في الثانية من الأخلاق وأوجب أن يكون في النبات حس ولذة وكرامة. ثم أيضاً فإنَّه لم يقل في شيء من كتبه - فضلاً عن أن يبْتَنِ - أنَّه ليس للنبات شعور

بما ماسَه. وقال في كتاب البرهان (3): كل ما له شعور بما يمسه حيوان. فكيف يجوز مع هذا أن يأخذ شيئاً مُختلفًا فيه لم يتقدَّم منه فيه قول - فضلاً عن بيان - كالشيء المتفق عليه أو المُبَيِّن،

فيقول قولاً جمَّاً إنه لما كان الحَسَنُ والحركة الإرادية خاصَّين بالحيوان كأنَّه قد بين هذا وبرهنه، 10

لا كأنَّه قد كاد يحكم بصحة نقيضه؟

B5. Nemesius, De natura hominis 2 (23,24–24,4 Morani)

Γαληνὸς δὲ ἀποφαίνεται μὲν οὐδὲν, ἀλλὰ καὶ διαμαρτύρεται ἐν τοῖς ἀποδεικτικοῖς λόγοις ὡς οὐδὲν εἴη περὶ ψυχῆς ἀποφηνάμενος· ἔοικε δὲ, ἐξ ὧν λέγει, δοκιμάζειν μᾶλλον τὸ κρᾶσιν εἶναι τὴν ψυχήν (ταύτη γὰρ ἐπακολουθεῖν τὴν τῶν ἡθῶν διαφοράν),
**B4. Abū Bakr al-Rāzī, Doubts about Galen 13.1**

(1) In his treatise *On the natural faculties*, he [i.e., Galen] says: "Since sensation and voluntary motion are peculiar to animals, while growth and nutrition are common to animals and plants, the former are activities of the soul, and the latter are activities that belong to nature". He should have added to "the sensation" some other [word] to determine it, as he did for the motion, since this is a topic about which there is disagreement, and since he himself has said in several places that plants possessed a form of sensation. (2) Indeed, he says in *On his own opinions* that plants have a sensation of what is alien to them and of what agrees with them; in the treatise *On decay*, he says that bodies endowed with life are of three kinds: animals, plants, and seeds; in the second book of the treatise *On character traits*, he says in a decisive manner that plants possess sensation, pleasure and aversion. Then, in addition to this, at no time in his books does he say – and a fortiori clearly establishes – that plants do not feel what comes into contact with them. (3) Whereas, in his treatise *On demonstration*, he says: "Everything that feels what comes into contact with it, is an animal". How then, in spite of this, can he take up a subject about which there is disagreement, without having said anything about it beforehand, and a fortiori without having established it clearly, as [if it were] a clear notion or one on which there is agreement, and declare in a clear-cut manner that sensation and voluntary motion are peculiar to animals", as if he had established this proposition clearly and demonstrated it, and not as if he had already practically decided the contradictory [of this proposition] to be true. (Ko)

**B5. Nemesius, The nature of man 2**

Galen asserts nothing, and even attests in the accounts on demonstration that he would prefer not to assert anything about the soul. But it seems from what he says that he rather considers the soul to be a mixture (for the difference among character traits follows from mixture), his argument being based on those of Hippocrates. If this is the

<footnote>**B4, 1-4** *Nat. fac.* 1.1 (101,1-5 Helmreich / II.1 K). **7 Prop. plac.** 13.6 (Garofalo-Lami). **9-10 Marc.**, VII.666 K. **10 On character traits** [*De moribus*; the treatise survives only in an Arabic summary edited by Kraus, "Kitāb al-akhlāq li-Jālīnūs". This summary was translated into English by Mattock, "A translation of the Arabic epitome", and this translation was then revised by Davies (in *Galen. Psychological Writings*, ed. Singer, pp. 135-201). We haven't been able to locate an exact parallel to this passage. However, in the opening section of the second book, Galen does speak about plants, states that they too possess a desiderative soul, equivalent to the (Aristotelian) vegetative/nutritive part of the soul: "This is the vegetative soul, which nourishes our bodies, makes them grow, and preserves life in them, and generates seed in both animals and plants in order that propagation may continue" (*Mor.* 2 [35 Kraus / 151 Davies]). **18-19** sensation...animals] Cf. B7*, 47-48; B7*, 94. **B5, 2** not...soul] Cf. B7*, 126-127. **3-4** difference...mixture] Cf. Gal. *Mor.* 2 (38 Kraus, 155 Davies); *QAM* 2 (32,14-33,16 von Müller / IV.768-769 K). **4** Hippocrates] Probably a reference to Hipp. *Nat. hom.*, discussed by Galen in *Hipp. elem.* and *HNH*.</footnote>
ἐκ τῶν Ἰπποκράτους κατασκευάζων τὸν λόγον. εἰ δὲ τοῦτο, δῆλον ὅτι καὶ θνητὴν αὐτὴν εἶναι οἴεται, οὐ πᾶσαν δέ, ἀλλὰ τὴν ἄλογον μόνην ψυχὴν τοῦ ἀνθρώπου. περὶ δὲ τῆς λογικῆς ἀμφιβάλλει, λέγων οὕτως. (***)

5

**B6***. Clemens Alexandrinus, *Liber logicus* (= *Stromata VIII*) 2.3.1–3.8.3 (81,9–84,23 Stählin–Havrda)

(1) τίς ἂν οὖν ἄλλη βελτίων ἤ ἐναργεστέρα μέθοδος εἰς ἀρχὴν τῆς τοιᾶσδε εἴη ἂν διδασκαλίας ἤ τὸ προταθὲν ὅνομα λόγῳ διελθεῖν οὕτω σαφῶς ὡς πάντας ἀκολουθῆσαι τοὺς ὁμοφώνους; ἄρ' οὖν τοιοῦτόν ἐστι (τὸ) ὅνομα τῆς ἀποδείξεως οἰόν περ τὸ βλίτυρι, φωνὴ μόνον οὐδὲν σημαίνουσα; καὶ πῶς ο' ὁ φιλόσοφος ο ὁ ῥήτωρ, ἀλλ' οὐδέ ὁ δικαστὴς ὡς ἄσημον ὅνομα προφέρεται τὴν ἀπόδειξιν, οὕτε τις τῶν δικαζομένων ἀγνοεῖ τὸ σημαινόμενον ὅτι οὐχ ὑπάρχει; αὐτίκα ὡς ὑποστατὸν πορίζονται τὴν ἀπόδειξιν οἱ φιλόσοφοι, ἄλλος ἄλλως.

5

(2) περὶ παντὶς τοίνυν τοῦ ζητουμένου εἴ τις ὁρθῶς διαλαμβάνοι, οὐκ ἂν ἑφ' ἐτέραν ἀρχὴν ὁμολογούμένην μᾶλλον ἀναγάγοι τὸν λόγον ἤ τὸ πᾶσι τοῖς ὁμοεθνέσι τε καὶ ὁμοφώνοις ἐκ τῆς προσηγορίας ὁμολογούμενον σημαίνεσθαι. εἶτα ἐντεῦθεν ὁρμηθέντα ζητεῖν ἀνάγκη, εἰ ὑπάρχει τὸ σημαινόμενον τοῦτο περὶ οὖ ὁ λόγος εἴτε καὶ μή· ἑφεξῆς δέ, εἴπερ ὑπάρχειν δειχθείη, ζητητέον τούτου τὴν φύσιν ἀκριβῶς, ὁποία τίς ἐστιν, καὶ μή ποτε ὑπερβαίνειν τὴν δοθεῖσαν τάξιν. (3) εἰ δ' οὐκ ἀρκεῖ τοῦτο μόνον ἀπλῶς εἰπεῖν περὶ τοῦ ζητουμένου τὸ δόξαν (ἔξεστι γὰρ καὶ τὸν ἀντικαθιστάμενον ἐπ' ἵσης ἀνταπο- φήνασθαι ὃ βούλεται), ἀλλὰ πιστώσασθαι χρὴ τὸ λεχθέν, εἰ μὲν εἰς ὁμοίως ἀμφισβητού- μενον ἀναφέροιτο αὐτοῦ ἡ κρίσις κάκείνου πάλιν ὁμοίως εἰς ἀμφισβητούμενον ἔτερον,

10

15

<footnote>**B6***, 1–2 ἀρχὴν...διδασκαλίας] Cf. Gal. *MM I*.5.1 (54,20 Lorusso / X.40 K) = A16, 11–12. 2 προταθὲν ὅνομα] Cf. Gal. *Diff. puls*. II.3 (VIII.569,10–11 K). λόγῳ διελθεῖν] Cf. *MM I*.5.2 (56,4 Lorusso / X.40 K); cf. A16, 16–17. 3 ὁμοφώνους] Cf. *Diff. puls*. IV.2 (VIII.704,11–12 K). 13–14 ἀπλῶς...δόξαν] Cf. *Diff. puls*. IV.2 (VIII.708,15–16 K); *Tum. pr. nat*. 2 (VII.707,9–10 K). 15 πιστώσασθαι] Cf. *MM I*.3.17 (40,7 Lorusso / X.29 K).</footnote>

<footnote>**B5**, 6 *lac*. ind. Matthäi **B6***, 6 πορίζονται] ὁρίζονται Barnes, *sed cf*. Clem. Alex. *Strom*. VII.16.103.4: πορίζεσθαι ἀποδείξεις, Simpl. *In Cael*. II.8 (460,30 Heiberg) et al. 8–11 ζητουμένου – λόγος del. Morani : *lect. ms*. def. Sharples and van der Eijk, *Nemesius: On the Nature of Man*, p. 144 n. 728; cf. *Gal. PHP II*.8.11 (158,26–28 De Lacy / V.275 K). 8 βελτίων – ἐναργεστέρα Sylburg : βελτίω καὶ ἐναργεστάτη Laur. Plut. 5.3 (*a modo*: “ms.”) τοῦ¹ *add*. Stählin : ἐστιν ms. 11 περὶ οὖ Stählin : που ms. 13 ὑπερβαίνειν Havrda : ὑπερβαίνει ms.</footnote>
case, it is clear that he also thinks it is mortal, not completely, but only the irrational 5
soul of man. Concerning the rational, he is ambivalent, saying the following. (Text
missing) (C-H)

Presumed excerpts from Dem. in Liber logicus

B6*. Clemens Alexandrinus, *Liber logicus* 2.3.1–3.8.3

(1) What other method, then, of arriving at the starting-point of such a teaching could be better or more evident than to explain the proposed name with an account so clearly that all who speak the same language will follow? Now, is the name ‘demonstration’ of such a kind as ‘blituri’, a mere sound meaning nothing? But why, then, is it so that no philosopher, rhetor, or judge proposes ‘demonstration’ as a meaningless name and none of the litigants ignores the fact that the signified item exists? Philosophers, at any rate, furnish demonstration as something real, each in a different way.

(2) Indeed, it is true of everything sought that if one wants to argue correctly about it, he will refer the argument to an agreed starting-point, which is no other than what people of the same nation and language agree to be the meaning of the noun. Then, having started from there, one must inquire whether the signified item, with which the argument is concerned, exists or not. Next, if it is shown to exist, one must precisely investigate its nature, what it is like, and never transgress the given order. (3) And if it is not sufficient to say simply what seems to be the case about the thing sought (for an opponent can equally assert whatever he wants to the contrary), but it is necessary to confirm what has been said, then, if judgment about it is referred to something equally disputed, and judgment about the latter again to something else that is disputed as well, [the argument] will proceed to infinity and [what has been said] will be indemon-

<footnote>5–6 only...man] Cf. QAM 3 (36,16–19 Müller / IV.773 K). 6 ambivalent] Cf. QAM 3 (36,12–16 Müller / IV.772–773 K). 6–7 The missing passage is often believed to have been a quotation from QAM; see Sharples and van der Eijk, *Nemesius*, p. 61. However, the argument in QAM is not “based on those of Hippocrates”, and the only treatise mentioned by Nemesius is *Dem*. It cannot be ruled out, then, that the missing quotation was from *Dem*. B6*, 4 sound meaning nothing] Cf. Gal. MM II.7.38 (196,19–20 Lorusso / X.144 K). For ‘blituri’ see also Artemidorus, *Onir*. IV.2.47; DL VII.57; Sextus, *M* VIII.133. 6 that...exists] Cf. Sextus, *M* VIII.337 (an Epicurean argument), trans. Bett: “Either you understand what demonstration is, or you do not. And if you understand and have a conception (ëvvoia) of it, there is demonstration.” 9–10 what...noun] Cf. Gal. *Diff. puls*. IV.2 (VIII.704,5–706,3 K), on “notional definition”. See above, A16, 21–22. 11–12 whether...not] Cf. MM II.7.38 (196,20–21 Lorusso / X.144 K). For the distinction between the meaning of the proposed name and the existence of the signified object, see also *Diff. puls*. IV.2 (VIII.696,18–697,8 K). 13 the given order] Cf. Gal. *Opt. corp. const*. 1 (8,12–14 Helmreich / IV.738–739 K); MM I.4.6 (44,8–11 Lorusso / X.32 K); Simpl. *In Phys*. IV.10 (696,10–13 Diels). 15 assert...contrary] Cf. Sextus, *M* VIII.281–282. 18 proceed to infinity] Cf. Arist. *An. post*. I.3, 72b5–73a20; Sextus, *M* VIII.347; *PH* I.166; Aspasius, *In Eth. Nic*. III.5 (74,21–22 Heylbut).</footnote>
εἰς ἄπειρον προβήσεται καὶ ἀναπόδεικτον ἔσται, εἰ δ' εἰς ὁμολογούμενον ἄπασιν ἡ τοῦ (μὴ) ὁμολογουμένου πίστις ἀναφέροιτο, ἐκεῖνο τὴν ἀρχὴν τῆς διδασκαλίας ποιητέον.

(4) πᾶν οὖν τὸ προβληθὲν ὄνομα μεταλαμβάνειν χρὴ εἰς λόγον ὁμολογούμενὸν τε καὶ σαφῆ τοῖς κοινωνοῦσι τῆς σκέψεως, ἀρχὴ μὲν τῆς διδασκαλίας ἐσόμενον, ἐξηγησόμενον δὲ τὴν τῶν ζητουμένων εὑρεσιν. φέρε οὖν προβεβλήσθω ὁ ἥλιος τοῦνομα. φασὶν οὖν οἱ Στωτικοὶ τοῦτ' εἶναι « ἄναμμα νοερὸν ἐκ θαλαττίων ὑδάτων ». ἄρ' οὐκ ἁσαφέστερος ὁ λόγος αὐτοῦ τοῦ ὀνόματος, ἄλλης ἀποδείξεως δεόμενος εἰ ἀληθής ἐστιν; ἄμεινον οὖν εἰπεῖν κοινῷ καὶ σαφεῖ τῷ λόγῳ ἥλιον ὀνόμαζεσθαι « τὸ λαμπρότατον τῶν κατ' οὐρανὸν ἱόντων »· πιστότερος γὰρ, οἶμαι, καὶ σαφέστερος καὶ πᾶσιν ὁμοίως ὁμολογούμενος ὁ λόγος οὖτος. ὡσαύτως δὲ καὶ τὴν ἀπόδειξιν πάντες ἄνθρωποι ὁμολογήσαιεν ἀν λόγον εἶναι τοῖς ἀμφισβητουμένοις ἐκ τῶν ὁμολογουμένων ἐκπορίζοντα τὴν πίστιν.

(5) οὐ μόνον δὲ ἀπόδειξις καὶ πίστις καὶ γνῶσις, ἀλλὰ καὶ πρόγνωσις λέγεται διχῶς, ἤ μὲν ἐπιστημονική τε καὶ βεβαία, ἄλλη δὲ μόνον ἐλπιστική. κυριώτατα μὲν οὖν ἀπόδειξις λέγεται ἡ τὴν ἐπιστημονικὴν πίστιν ἐντιθεῖσα ταῖς τῶν μανθανόντων ψυχαῖς, δοξαστικὴ δὲ ἡ ἑτέρα, ὡς καὶ ἄνθρωπος ὁ μὲν ὄντως ἄνθρωπος ὁ τὰς κοινὰς φρένας κεκτημένος, ὁ δὲ ἄγριος καὶ θηριώδης. οὕτω τοι καὶ ὁ κωμικὸς ἔλεγεν· « ὡς χαρίεις ἐστὶν ἄνθρωπος, ἔστ' ἄν ἄνθρωπος ἥ». καὶ ἐπὶ βοὸς καὶ ἵπρου καὶ κυνὸς ὁ αὐτὸς λόγος παρὰ τὴν ἀρετὴν τοῦ ζώου ἡ κακίαν. εἰς γὰρ τὴν τοῦ γένους τελειότητα βλέποντες ἐπὶ τὰ κυριώτατα τῶν σημαινομένων ἐρχόμεθα. αὐτίκα ἰατρὸν νοοῦμεν ᾧ μηδὲν τῆς ἰατρικῆς δυνάμεως ἐνδεῖ, γνωστικὸν δὲ ὁ μηδὲν λείπει τῆς ἐπιστημονικῆς εἰδήσεως.

(6) καὶ διαφέρει ἐνδειξις συλλογισμοῦ ἥ τὸ μὲν ἐνδεικνύμενον ἐνός ἐστι δηλωτικὸν ἐν ὑπάρχον καὶ αὐτό, ὡς τοῦ μηκέτι εἶναι παρθένον ἔνδειξιν εἶναι τὸ κυεῖν φαμεν, τὸ δὲ

<footnote n="17">17 ὁμολογούμενον ἄπασιν] Cf. A16, 20. 19 μεταλαμβάνειν...λόγον] Cf. MM I.5.1 (54,10–11 Lorusso / X.39 K); A16, 4. 20–21 ἐξηγησόμενον...εὑρεσιν] Cf. Gal. UP II.7 (I.85,23–25 Helmreich / III.117 K). 27 λόγον...πίστιν] Cf. Clem. Alex. Strom. II.11.48.1: φήσαμεν δ' ἀν αὐτὴν (sc. τὴν ἀπόδειξιν) λόγον εἶναι τοῖς ἀμφισβητουμένοις ἐκ τῶν ὁμολογουμένων ἐκπορίζοντα τὴν πίστιν. ἐκπορίζοντα τὴν πίστιν] Cf. Arist. Rhet. I.2, 1356a1; Gal. Dig. puls. IV.3 (VIII.954,10 K). 28 ἀπόδειξις...διχᾶς] Cf. Clem. Alex. Strom. II.11.48.2: πίστεως δ' οὐσῆς διττῆς, τῆς μὲν ἐπιστημονικῆς, τῆς δὲ δοξαστικῆς, οὐδὲν κωλύει ἀπόδειξιν ὀνομάζειν διττήν, τὴν μὲν ἐπιστημονικήν, τὴν δὲ δοξαστικήν, ἐπεὶ καὶ ἡ γνῶσις καὶ ἡ πρόγνωσις διττὴ λέγεται, ἡ μὲν ἀπηκριβωμένην ἔχουσα τὴν ἑαυτῆς φύσιν, ἡ δὲ ἐλλιπῆ. 28–29 πρόγνωσις... ἐλπιστική] Cf. Gal. Hipp. Prog. I.4 (203,31–33 and 204,17–18 Heeg / XVIIIb.12–14 K); Hipp. Off. med. I.1 (XVIIIb.636,14–15 K). 30 ἡ...ψυχαῖς] Cf. Strom. II.11.49.3: ἡ γὰρ ἀνωτάτω ἀπόδειξις, ἤν ἡνιξάμεθα ἐπιστημονικήν, πίστιν ἐντίθησι ... ταῖς τῶν μανθάνειν ὁρεγομένων ψυχαῖς, ἡτίς ἀν εἶν ἡ γνῶσις. ἐπιστημονικήν πίστιν] Gal. Ut. resp. 3.6 (18,11 Noll / IV.492 K). ἐντιθεῖσα...ψυχαῖς] Gal. Hipp. Epid. III, I.4 (23,5–6 Wenkebach / XVIIa.517 K). 30–31 δοξαστικὴ δὲ ἡ ἑτέρα] Cf. Strom. II.11.49.2: ἡ δὲ δοξαστικὴ ἀπόδειξις ἀνθρωπική τε ἐστι καὶ πρὸς τῶν ῥητορικῶν γινομένη ἐπιχειρημάτων ἡ καὶ διαλεκτικῶν συλλογισμῶν. 34–35 τὰ κυριώτατα τῶν σημαινομένων] Cf. Gal. Hipp. Aph. III.2 (XVIIb.565,5–6 K); PHP VI.1.20 (364,28 De Lacy / V.511 K).</footnote>

<footnote n="18">18 μὴ add. Potter 21 δὲ Potter : τε ms. 26–27 ἀν λόγον Sylburg : εὐλογον ms. 27 ἐκπορίζοντα Sylburg : ἐμπορίζοντα ms. 32 χαρίεις Sylburg (cf. Menander Sent. 852 Pernigotti) : χαρίης ms.</footnote>
strable. Yet if credence concerning that on which there is no agreement is referred to something everyone agrees with, then the latter should be taken as the starting-point of teaching.

20

(4) Every proposed name, then, has to be changed into an account that is agreed and clear to those who participate in the research. This will be the starting-point of teaching, one that will show the way to the discovery of the things sought. For example, let us propose the name ‘sun’. The Stoics say that it is ‘intelligent ignited mass from the waters of the sea’. Is not such an account less clear than the name itself? Does it not need another proof to demonstrate if it is true? It is better to use a common and clear account and call the sun ‘the brightest thing traversing the sky’. This account, I think, is more credible, clear, and agreed to by all alike. In the same vein, all human beings will agree that demonstration is an argument that furnishes credence from something agreed to something disputed.

25

30

(5) However, not only demonstration, credence, and knowledge are spoken of in two ways, but foreknowledge, too: One is scientific and firm, and the other merely based on expectation. Now demonstration in the proper sense is the one that instils scientific credence into the souls of students, whereas the other is doxastic. Similarly, we call ‘human being’ the truly human being, i.e. the one equipped with common reason, but also the one that is savage and brutish. Thus the comic writer says: “How graceful the human being, if human being it is.” And the same is true of ox, horse, or dog, with respect to the virtue or vice of the animal in question. We have to look at what is perfect within a genus to arrive at the most proper meaning of names. For example, by ‘doctor’ we mean someone with a perfect capacity to heal and by ‘gnostic’ someone with flawless scientific knowledge.

35

40

(6) And indication differs from deduction in that the item which indicates something shows one thing while being itself one. For example, when a woman gives birth to a child we call it an indication that she is no longer a virgin. But when reached by deduction, one thing follows from more than one item. Thus, for instance, in the

45

<footnote n="19">19 credence] For the meaning of πίστις, see Havrda, *The So-Called Eighth Stromateus*, p. 154. Cf. A12, 2; B6*, 30–35; B6*, 67–70; C13, 13; F6, 1. 22 changed...account] Cf. A16, 5. 25–26 intelligent...sea] Cf. Aët. II.20.6 and 15, with Mansfeld–Runia, *Aetiana* V.2, pp. 987–991, for parallels. 28 brightest...sky] Cf. Plat. *Tht*. 208d; Arist. *Top*. V.3, 131b25–30, with Gal. *Diff. puls*. IV.2 (VIII.705,14–17 K), on the notional definition in terms of τὰ συμβεβηκότα ἰδίως. 30–31 demonstration...disputed] Cf. Cicero, *Ac*. II.8.26; DL VII.45; Sextus, *M* VIII.314 and 422–423. Cf. also Alex. Aphr. *In An. pr.* I.4 (44,14–15 Wallies), on deduction in general. 34 based on expectation] Possibly a hint to Arist. *Mem*. I, 449b12, describing divination as ἐπιστήμη τις ἐλπιστική. Cf. Gal. *CAM* 17.8 (116,1–2 Fortuna / I.292 K). 35 doxastic] I.e., based on, or producing, δόξα, opinion. 36–37 common reason] Cf. Plutarch, *Comm. not*. 37, 1077e4. 37–38 How...is¹] Menander, fr. 484 Koerte; cf. Gal. *Di. dec*. I.9 (IX.815,2–6 K). 38–39 ox...dog] Cf. Gal. *Temp*. I.6 and 9 (24,10–15 and 36,12–16 Helmreich / I.547 and 566 K). 41 doctor...heal] Cf. Arist. *Met*. Δ.16, 1021b14–17. 41–42 gnostic...knowledge] Probably Clement’s addition to his source. 43 indication...deduction] Cf. Gal. *Inst. log*. 11.1 (24,14–17 Kalbfleisch); *Dig. puls*. IV.1 (VIII.923,12–14 K). 44–45 when...virgin] Cf. Ps.-Gal. *Hist. phil*. 9 (*Doxographi Graeci*, ed. Diels, 605,15–18). For the example, cf. Arist. *Rhet*. I.2, 1357b15–16; *An. pr*. II.27, 70a6–16; Cicero, *Inv*. I.40.72: *si peperit, virgo non est*.</footnote>
συλλογισμῷ λαμβανόμενον ἐν ὑπάρχον ἔπεται πλείοσιν, ὡς τοῦ Πύθωνα προδιδόναι Βυζαντίους, εἰ οὕτως ἔτυχεν, οὐχ ἔν, ἀλλὰ πλείω λαμβάνεται τὰ διλωτικά.

(7) καὶ τὸ μὲν περαίνειν ἐξ ὁμολογουμένων συλλογίζεσθαι ἐστίν, τὸ δέ γε ἐξ ἀληθῶν τι περαίνειν ἀποδεικνύειν ἐστίν, ὥστ’ εἶναι σύνθετόν τινα τῆς ἀποδείξεως τὴν νόησιν ἔκ τε τοῦ τὰ λαμβανόμενα πρὸς τὰ ζητούμενα ἀληθῆ λαμβάνειν κάκ τοῦ τὸ συμπέρασμα αὐτοῖς ἀκόλουθον ἐπιφέρεσθαι. εἰ δ’ ἤτοι μὴ ὑπάρχοι τὸ πρότερον ἤ μὴ ἔποιτο αὐτῷ τὸ δεύτερον, οὐκ ἀπέδειξεν μέν, συνελογίσατο δέ. τὸ μὲν γὰρ οἰκεῖον ἐπενεγκεῖν συμπέρασμα τοῖς λήμμασιν συλλογίσασθαι μόνον ἐστίν, τὸ δὲ καὶ τῶν λημμάτων ἔκαστον ὑπάρχειν ἀληθὲς οὐ συλλογίσασθαι μόνον, ἀλλὰ καὶ ἀποδεδειχέναι. (8) περαίνειν δ’ ἐστίν, ὡς καὶ ἐκ τοῦ ὀνόματος δῆλον, τὸ ἄγειν ἐπὶ τὸ πέρας. ἔστι δὲ δήπου πέρας ἐν ἐκάστω λόγω τὸ ζητούμενον, ὃ δὴ καὶ συμπέρασμα καλεῖται. οὐδεὶς δὲ ἀπλοῦς καὶ πρῶτος λόγος ὀνομάζεται συλλογισμός, καν ἀληθὴς ἦ, ἀλλ’ ἔστι τούλάχιστον ἐκ τριῶν τοιούτων σύνθετος, δυσεῖν μὲν ὡς λημμάτων, ἐνὸς δὲ ὡς συμπεράσματος.

(9) ἤτοι δὲ πάντα ἀποδείξεως δεῖται ἤ καί τινα ἐξ αὐτῶν ἐστὶ πιστά. ἀλλ’ εἰ μὲν τὸ πρότερον, ἐκάστης ἀποδείξεως ἀπόδειξιν αἰτοῦντες εἰς ἄπειρον ἐκβησόμεθα καὶ οὕτως ἀνατραπήσεται ἡ ἀπόδειξις· εἰ δὲ τὸ δεύτερον, ταῦτα αὐτὰ τὰ ἐξ αὐτῶν πιστὰ τῶν ἀποδείξεων ἁρχαὶ γενήσονται. αὐτίκα οἱ φιλόσοφοι ἀναποδείκτους ὁμολογοῦσι τὰς τῶν ὅλων ἁρχάς. ὥστ’ εἴπερ ἐστὶν ἀπόδειξις, ἀνάγκη πᾶσα πρότερον εἶναί τι πιστὸν ἐξ ἑαυτοῦ, ὃ δὴ πρῶτον καὶ ἀναπόδεικτον λέγεται. ἐπὶ τὴν ἀναπόδεικτον ἄρα πίστιν ἡ πᾶσα ἀπόδειξις ἀνάγεται. (10) εἶεν δ’ ἂν καὶ ἀλλαι τῶν ἀποδείξεων ἁρχαὶ μετὰ τὴν ἐκ πίστεως πηγήν, τὰ πρὸς αἴσθησίν τε καὶ νόησιν ἐναργῶς φαινόμενα· τὰ μὲν γὰρ πρὸς αἰσθησιν σύμπαντα ἐστὶν ἀπλᾶ τε καὶ ἄλογα, τὰ δὲ πρὸς νόησιν ἀπλᾶ τε καὶ λογικὰ καὶ <ταῦτα μὲν> πρῶτα, τὰ δὲ ἐξ αὐτῶν γεννώμενα σύνθετα μέν, οὐδὲν δ’ ἦττον ἐναργῆ καὶ πιστὰ καὶ λογικώτερα τῶν πρώτων. (11) ἀκολούθου καὶ μαχομένου οὖν <διαγνωστική>

<footnote>45–46 οἰκεῖον... συμπέρασμα] Cf. Gal. *Hipp. elem.* 4.12 (90,5–6 De Lacy / I.445 K); *Ven. sect. Er. Rom.* 7 (XI.230,1–2 K); Alex. Aphr. *In Top.* I.1 (14,2–4 Wallies). 59 τὰ¹... φαινόμενα] Cf. *MM* I.5.1 (54,9–10 Lorusso / X.39 K); A16, 3.</footnote>

<footnote n="39">39 Πύθωνα Dindorf : Πύθωνος ms. 41 περαίνειν Potter : παραινεῖν ms. 42 νόησιν Pohlenz, cf. Gal. *Diff. puls.* I.27 (VIII.555,14 K); *Syn. puls.* 21 (IX.494,8–9 K); *MMG* II.1 (XI.77,6 K) : ὄνησιν ms. 44 δ’ ἤτοι Sylburg : δή τοι ms. 51 σύνθετος Barnes : σύνθετον ms. 60 σύμπαντα *corr. a secunda manu* ms. : συμβάντα ms. ἄλογα Barnes : ἄλυτα ms. 61 ταῦτα μὲν *add.* Barnes 62 διαγνωστική *add.* Havrda</footnote>
case of the claim that Pytho betrayed the people of Byzantium, we take into account
not one but many items to show it.

(7) Now, to conclude from agreed premisses is to deduce, but in order to demonstrate we must draw a conclusion from true premisses. Thus the notion of demonstration is a composite one consisting of two things: true assumptions are taken in view of the things sought and a conclusion following from these assumptions is drawn. If either the first does not obtain, or if it is not followed by the second, one has made a deduction, but not a demonstration. By drawing an appropriate conclusion from our premisses we only make a deduction; however, when each of our premisses is also true, we have not only deduced a conclusion, but also demonstrated it. (8) To conclude (perainein), as the word shows, is to bring something to an end (peras). Now the endpoint of every argument is the thing sought, and this is what we call ‘conclusion’. A simple and primary assertion, even if true, is never called a deduction, because the latter consists of at least three such assertions, two of which function as premisses and one as a conclusion.

(9) Either everything needs demonstration, or there are certain things credible by virtue of themselves. If the first, we will have an infinite regress by demanding demonstration of every demonstration and so demonstration will be refuted. If the second, these very things that are credible by virtue of themselves will become the principles of demonstration. For example, philosophers agree that the principles of the universe are not demonstrated. Thus if demonstration exists, it is absolutely necessary that it is preceded by something credible by virtue of itself, and this is called primary and undemonstrated. Every demonstration, therefore, is based on undemonstrated credence. (10) But there are supposed to be yet other principles of demonstrations beyond the source springing from credence, namely things evidently manifest to sense-perception and intellection. For those [evidently manifest] to sense-perception are all simple and irrational, while those [evidently manifest] to intellection are simple and rational, and (these are) primary, whereas the things generated from them are composite, but no less plain and credible, and more rational than the primary ones. (11) Now it is a peculiar capacity of reason, available to all of us by nature, to recognize

<footnote n="47">47 Pytho] of Byzantium, a pupil of Isocrates. Cf. Philostratus, *Vitae soph.* I.20 (II.27,16–26 Kayser). 48 from true premisses] Cf. Gal. *Inst. log.* 11.1 (24,16–17 Kalbfleisch). 49–54 one has made a deduction] This is both false and in conflict with B6*, 86–87. 59 simple…assertion] Cf. Arist. *Int.* 5, 17a20–21. 60 three…assertions] Cf. Arist. *An. pr.* I.14, 34a17–19, etc. 62–63 credible…themselves] Cf. Arist. *Top.* I.1, 100b18–21; Gal. *MM* I.4.9 (46,11 Lorusso / X.33 K); *Inst. log.* 17.7 (44,13 Kalbfleisch); above, A12, 3. 66–67 principles…demonstrated] Cf. Theophrastus, fr. 159 Fortenbaugh *et al.* 68–69 primary and undemonstrated] Cf. Arist. *An. post.* I.2, 71b27. 71 beyond…credence] This is probably Clement’s interpretation of his source. 71–72 evidently…intellection] Cf. A16, 3–4. 73 simple and irrational] Probably simple perceptible qualities; cf. A15, 2–3. 73–74 simple and rational] Presumably not the axioms, but elementary concepts; cf. *MM* II.7.54 (206,22–24 Lorusso / X.151–152 K).</footnote>
ἐστιν ἤνπερ ἰδίαν λόγου δύναμιν πεφυκυῖαν ἄπαντες ἔχομεν φύσει. ἑὰν οὖν τις εὑρεθῆ λόγος τοιοῦτος οἰος ἐκ τῶν ἤδη πιστῶν τοῖς οὐπω πιστοῖς ἐκπορίζεσθαι τὴν πίστιν δυνάμενος, αὐτὸν τοῦτον εἶναι φήσομεν οὐσίαν ἀποδείξεως.

65

(12) εἴρηται δὲ ὡς καὶ τὸ τῆς πίστεως καὶ τὸ τῆς ἀποδείξεως γένος διττόν, τὸ μὲν πειθὼ μόνον ταῖς ψυχαῖς τῶν ἀκουόντων, τὸ δὲ ἐπιστήμην ἀπεργαζόμενον. εἰ μὲν οὖν ἐκ τῶν πρὸς αἰσθησιν καὶ νόησιν ἐναργῶν ἄρξαιτό τις κάπειτα τὸ οἰκεῖον ἐπενέγκοι συμπέρασμα, ὄντως ἀποδείκνυσιν· εἰ δ' ἐξ ἐνδόξων μόνον, οὐ μὴν πρώτων γε, τουτέστιν οὕτε πρὸς αἰσθησιν οὐτε πρὸς νόησιν ἐναργῶν, εἰ μὲν οἰκεῖον ἐπιφέροι συμπέρασμα, συλλογιεῖται μέν, οὐ μὴν ἐπιστημονικήν γε ποιήσεται τὴν ἀπόδειξιν, εἰ δ' οὐκ οἰκεῖον, οὐδὲ συλλογιεῖται τὴν ἀρχήν.

70

(13) διαφέρει δ' ἀναλύσεως ἀπόδειξις· ἔκαστον μὲν γὰρ τῶν ἀποδεικνυμένων διά τινων ἀποδεικνυμένων ἀποδείκνυται, προαποδεδειγμένων κάκείνων ὑφ' ἐτέρων, ἄχρις ἂν εἰς τὰ ἐξ ἑαυτῶν πιστὰ ἀναδράμωμεν ἤ εἰς τὰ πρὸς αἰσθησίν τε καὶ νόησιν ἐναργῆ, ὅπερ ἀνάλυσις ὀνομάζεται· ἀπόδειξις δέ ἐστιν, ὅταν ἀπὸ τῶν πρώτων (τις εἰς) τὸ ζητούμενον ἀφικνῆται διὰ πάντων τῶν ἐν μέσῳ.

75

(14) χρὴ τοίνυν τὸν ἀποδεικτικὸν ἄνδρα τῆς μὲν ἀληθείας [ώς] τῶν λημμάτων πολλὴν ποιήσασθαι πρόνοιαν, τῶν δὲ ὀνομάτων ἀφροντιστεῖν, εἴτε ἀξιώματά τις ἐθέλοι καλεῖν εἴτε προτάσεις εἴτε λήμματα, ὁμοίως δὲ καὶ τοῦ τίνων ὑποκειμένων τί περαίνεται πολλὴν ὡσαύτως πεποιῆσθαι τὴν πρόνοιαν, εἴτε δὲ περαίνοντα λόγον εἴτε περαντικὸν εἴτε συλλογιστικὸν ἐθέλοι τις ὀνομάζειν αὐτόν, ἤκιστα φροντίζειν. δύο γὰρ ταῦτα ἐν ἄπασι χρῆναί φημι τὸν ἀποδεικτικὸν φυλάττειν, τὰ μὲν λήμματα ἀληθῆ λαμβάνειν, ἀκόλουθον δ' αὐτοῖς ἐπιφέρειν (τὸ) συμπέρασμα, ὅπερ τινὲς καὶ ἐπιφορὰν καλοῦσιν, τὸ ἐπιφερόμενον τοῖς λήμμασιν.

80

85

<footnote>73–75 ἔκαστον... ἀναδράμωμεν] Cf. *MM* I.4.9 (46,9–11 Lorusso / X.33 K): ἑκατέρα δὲ πάλιν τούτων ἐτέρων τινῶν εἰς ἀπόδειξιν ἑδεῖτο προτάσεων, εἴτ' ἐκεῖναι πάλιν ἐτέρων ἄχρι περ ἂν ἐπὶ τὰς πρώτας ἀνέλθωμεν αἱ οὐκέτ' ἐξ ἀλλων οὐδὲ δι' ἀποδείξεως, ἀλλ' ἐξ ἑαυτῶν ἔχουσι τὴν πίστιν. **78** χρὴ... ἄνδρα] Cf. Gal. *Sem.* II.6.27 (204,8–9 De Lacy / IV.649 K): τὸν δ' ἀποδεικτικὸν ἄνδρα ... προσήκει. **79–80** εἴτε... λήμματα] Cf. Gal. *SMT* I.13 (XI.401,18–402,1 K): εἰς τὴν ἀπόδειξιν ἀρχῶν, ἤ λημμάτων, ἤ ἀξιωμάτων, ἤ προτάσεων, ἡ ὅπως ἂν ἐθελήσῃς ὀνομάζειν.</footnote>

<footnote n="64">64 οὐπω Hervetius : οὐτω ms. 76 τις εἰς add. Stählin 78 ὡς del. Stählin 84 τὸ¹ add. Wilamowitz</footnote>
what is entailed and what is incompatible. So if an argument is found such that it will be able to furnish credence from things already credible to those not credible yet, we will describe this very argument as the essence of demonstration.

(12) However, as we have already said, there are two kinds of credence and demonstration: one producing mere persuasion in the souls of the auditors and one producing scientific knowledge. So if you start from things evident to sense-perception and intellection, and then infer an appropriate conclusion, you will truly demonstrate. But if you start from those that are merely reputable and not primary, i.e. not evident to sense-perception and intellection, then, should you draw an appropriate conclusion, you will make a deduction, but your demonstration will not be a scientific one. If the conclusion is not appropriate, it will not even be a deduction.

(13) Further, demonstration differs from analysis. Each of the things that are demonstrated is demonstrated by means of certain demonstrated premisses and these have been demonstrated by means of other premisses, until we ascend to premisses credible by virtue of themselves or those plain to sense-perception and intellection; and this is called 'analysis'. But when we reach the thing sought through all the intermediates, it is demonstration.

(14) Thus a man skilled in demonstration must be very careful about the truth of premisses, but he need not be concerned about names, whether one prefers to call them 'axioms', 'propositions', or 'premisses'. Likewise, he must be very careful about what conclusion is drawn from what suppositions, but not be at all concerned whether one prefers to call it a 'concluding argument', or a 'concluent', or a 'syllogistic' one. These, I claim, are two things that a man skilled in demonstration must always observe: he must take true premisses and infer a conclusion that follows from them, what some call an 'inference', that which is inferred from the premisses. (H)

<footnote n="77">77 entailed...incompatible] Cf. Gal. *PHP* III.5.13 (202,34–35 De Lacy / V.325 K); *PHP* IX.1.13 (542,17–18 De Lacy / V.723 K), etc. The description is of Stoic origin; see Cicero, *Leg*. I.16.45; *Ac*. II.7.22; Sextus, *M* VIII.276. Cf. A14, 14–15. 78 furnish credence] Cf. B6*, 19–21. 80 as...said] Cf. B6*, 32–33 with Clem. Alex. *Strom*. II.11.48.2, quoted under the Greek text. 81 one¹...auditors] Cf. B6*, 35, on doxastic demonstration. According to *Strom*. II.11.49.2, it includes both rhetorical and dialectical arguments. For the word ἀπόδειξις in this sense, see e.g. Arist. *Rhet*. I.1, 1355a4–7; Gal. *Sem*. II.6.10 (200,1 De Lacy / IV.644 K). 83 appropriate conclusion] Cf. B6*, 54. 84 reputable] ἔνδοξα, cf. Arist. *Top*. I.1, 100a27–30; for the role of *endoxa* in persuasion, cf. Gal. *PHP* II.3.11 (110,31 De Lacy / V.221 K). 92 analysis] For similar descriptions see *MM* I.4.9 (quoted under the Greek text) and *Pecc. dig*. 4.4 (54,9–11 De Boer / V.79 K). 94 skilled in demonstration] Cf. A4, 5. For other (mainly Galenic) parallels, see Havrda, *The So-Called Eighth* Stromateus, p. 173 n. 146. 96 axioms...premisses] Characteristically Galenic indifference; in addition to *SMT* I.13 (quoted under the Greek text), see *PHP* II.3.12 (112,4–5 De Lacy / V.222 K). Contrast Alex. Aphr. *In An. pr*. I.4 (44,16–23 Wallies). 98 concluding...syllogistic] For the Stoic classification of arguments, see DL VII.77–78 and Galen’s criticism thereof mentioned in *Inst. log*. 19.6 (49,1–5 Kalbfleisch). 101 some] The Stoics; cf. Ammonius, *In An. pr*. (68,13–14 Wallies).</footnote>