[ca] L'objectiu de la tesi doctoral és estudiar la figura del matemàtic Claudiu Ptolemeu en el context social i intel•lectual del seu temps i del seu ambient, és a dir, l'Alexandria romana del segle II dC. La tesi argumenta que Ptolemeu no va ser aliè al clima general de competició de coneixements que es dóna en aquesta època, ben estudiat en la bibliografia recent en el cas de Galè. Ptolemeu, en contrast amb aquest autor, no proporciona en la seva obra dades evidents sobre el seu entorn, però això és habitual en els textos matemàtics grecs, on l'estil està molt fixat i on les digressions com les que trobem en Galè gairebé no hi tenen cabuda. Així doncs, la metodologia usada en aquest estudi és indirecta, consistent en cercar possibles indicadors de la relació entre Ptolemeu i els seus contemporanis. La primera part de la tesi analitza en profunditat aspectes d'aquest tipus presents en les tres obres de Ptolemeu considerades més primerenques, la Inscripció de Canopus, els Harmònics, i Sobre el criteri i la facultat prinicipal. En cadascuna d'aquestes obres s'observa una secció final en la qual Ptolemeu tracta d'integrar la recerca científica de la part principal dins de tradicions platòniques ja testimoniades en autors anteriors, derivades sobretot de desenvolupaments de l'anomenat Platonisme mitjà alexandrí (especialment Eudor d'Alexandria) a partir del Timeu. Es podria dir que Ptolemeu fa servir aquest platonisme pitagòric per crear una màscara filosòfica en aquests tres textos, una personificació que és possible trobar, més deslligada de la investigació principal, també en l'Almagest. La curiosa divisió dels textos que es pot observar en vàries obres, especialment en les tres primerenques, podria tenir a veure amb aquesta escenificació. En general aquest actitud es pot comparar amb les pràctiques retòriques de l'època, en les quals la imitació i l'aparença externa són importants elements estratègics. Ptolemeu podria haver usat aquestes eines per presentar la matemàtica com a coneixement imprescindible, com la 'veritable' filosofia, dins de la paideia grecoromana. Un altre aspecte important del context de Ptolemeu és el seu dedicatari Syrus, per al qual proposo una identificació amb un individu de l'elit romana, testimoniat en vàries fonts, que hauria exercit de protector per a Ptolemeu.

[en] The main objective of this dissertation is to study the relationship between the mathematician Claudius Ptolemy and his social and intellectual context in the Roman Alexandria of the second century CE. Against the communis opinio (and the much more common silence) on this issue, my main conclusion is that Ptolemy consciously engaged in the competition for gaining a place in the paideia of his time, both by using techniques related to the rhetorical practices of his time, and by seeking the support of a powerful patron. Indeed, I argue that the dedicatee of many of Ptolemy's works, a certain Syrus, may be indentified with a powerful Roman with links to Alexandria and with probable mathematical interests. Unlike Galen, an author for whom such a scenario has been shown and studied in modern bibliography, Ptolemy does not offer us direct insights on his writing context. However, this is normal in Greek mathematical authors, who tend to write in a highly formulaic style specific of this kind of texts, providing very few biographical evidence. In consequence, the methodology I use in this study is based on indirect strategies, basically consisting in analyzing parts of Ptolemy's works which may show the author's concern for self-presentation and for the external projection of his work. The first chapters deal with the works which are considered to be earlier in Ptolemy's production, the Canobic Inscription, Harmonics, and On the Criterion and the Ruling Principle. In these three works a main scientific topic (astronomy, harmonics, and knowledge theory) is followed by a non-argumentative section linking the main part with Platonic traditions attested in earlier writers, mainly Middle Platonic developments inspired in the Timaeus. The Pythagorizing Platonist Eudorus of Alexandria could have been an important source for Ptolemy in this aspect, since there are many parallels between material drawn from his work by Plutarch and some passages in the last parts of Ptolemy's inscription and the Harmonics. As regards the text on knowledge theory, it is interesting that, although concomitant with the topic of mathematics, and overlapping with the epistemology developed in the Harmonics (of Stoic, Aristotelian, and Platonic tradition, in the line of Antiochus of Ascalon), mathematics is not even alluded in there. In the same manner as in the preface of the Almagest, where mathematics appears only very late in the text, Ptolemy seems to present himself mainly as a philosopher. Another telling feature of the text on the criterion is its style: it is neither didactic nor 'seriously' philosophical. I mean that the text does not present the clarity of a manual kind of work, but neither the deep engagement with philosophical issues of a genuine philosophical text: Ptolemy does not cite authors or works, and he does not develop long arguments. At the same time, the text presents throughout many verbal echoes of the Timaeus. Imitation of the Timaeus could be related to rhetorical practice, which Ptolemy probably received to some degree as every educated citizen in the empire. I also analyze an external feature of some of Ptolemy's works, especially prominent in the three earlier ones: in such treatises the text appears divided in nearly equally long portions, perhaps related to harmonic intervals. Comparing with rhetors, this could be interpreted as the voice and the gesture, the external qualities which must reflect a harmony suitable to the contents of the discourse. It seems that Ptolemy gradually frees himself from such formal concerns in later works, perhaps because he had acquired by then a more stable position: already in the Almagest the impersonation of a Pythagorean and Platonic philosopher appears only as an introduction restricted to the preface and the epigram, rather than as a development of the main scientific part.