bluuebunny/crossref_metadata_2025_split huggingface dataset:
Democritus (mid 5th–4th century BC)
Authors: Taylor C.C.W. 
Published: September 2018

A co-founder with Leucippus of the theory of atomism, The Greek Philosopher Democritus developed it into a universal system, embracing physics, cosmology, epistemology, psychology and theology. He is also reported to have written on a wide range of topics, including mathematics, ethics, literary criticism and theory of language. His works are lost, except for a substantial number of quotations, mostly on ethics, whose authenticity is disputed. Our knowledge of his principal doctrines depends primarily on Aristotle’s critical discussions, and secondarily on reports by historians of philosophy whose work derives from that of Aristotle and his school.
The atomists attempted to reconcile the observable data of plurality, motion and change with Parmenides’ denial of the possibility of coming to be or ceasing to be. They postulated an infinite number of unchangeable primary substances, characterized by a minimum range of explanatory properties (shape, size, spatial ordering and orientation within a given arrangement). All observable bodies are aggregates of these basic substances, and what appears as generation and corruption is in fact the formation and dissolution of these aggregates. The basic substances are physically indivisible (whence the term atomon, literally ‘uncuttable’) not merely in fact but in principle; (1) because (as Democritus argued) if it were theoretically possible to divide a material thing ad infinitum, the division would reduce the thing to nothing; and (2) because physical division presupposes that the thing divided contains gaps. Atoms are in eternal motion in empty space, the motion caused by an infinite series of prior atomic ‘collisions’. (There is reason to believe, however, although the point is disputed, that atoms cannot collide, since they must always be separated by void, however small; hence impact is only apparent, and all action is at a distance.) The void is necessary for motion, but is characterized as ‘what-is-not’, thus violating the Eleatic principle that what-is-not cannot be.
Democritus seems to have been the first thinker to recognize the observer-dependence of the secondary qualities. He argued from the distinction between appearance and reality to the unreliability of the senses, but it is disputed whether he embraced scepticism, or maintained that theory could make good the deficiency of the senses. He maintained a materialistic account of the mind, explaining thought and perception by the physical impact of images emitted by external objects. This theory gave rise to a naturalistic theology; he held that the gods are a special kind of images, endowed with life and intelligence, intervening in human affairs. The ethical fragments (if genuine) show that he maintained a conservative social philosophy on the basis of a form of enlightened hedonism.
Empedocles (c.495–c.435 BC)
Authors: Schofield Malcolm 
Published: September 2018

Empedocles, born in the Sicilian city of Acragas (modern Agrigento), was a major Greek philosopher of the Presocratic period. Numerous fragments survive from his two major works, poems in epic verse known later in antiquity as On Nature and Purifications.
On Nature sets out a vision of reality as a theatre of ceaseless change, whose invariable pattern consists in the repetition of the two processes of harmonization into unity followed by dissolution into plurality. The force unifying the four elements from which all else is created – earth, air, fire and water – is called Love, and Strife is the force dissolving them once again into plurality. The cycle is most apparent in the rhythms of plant and animal life, but Empedocles’ main objective is to tell the history of the universe itself as an exemplification of the pattern.
The basic structure of the world is the outcome of disruption of a total blending of the elements into main masses which eventually develop into the earth, the sea, the air and the fiery heaven. Life, however, emerged not from separation but by mixture of elements, and Empedocles elaborates an account of the evolution of living forms of increasing complexity and capacity for survival, culminating in the creation of species as they are at present. There followed a detailed treatment of a whole range of biological phenomena, from reproduction to the comparative morphology of the parts of animals and the physiology of sense perception and thinking.
The idea of a cycle involving the fracture and restoration of harmony bears a clear relation to the Pythagorean belief in the cycle of reincarnations which the guilty soul must undergo before it can recover heavenly bliss. Empedocles avows his allegiance to this belief, and identifies the primal sin requiring the punishment of reincarnation as an act of bloodshed committed through ‘trust in raving strife’. Purifications accordingly attacked the practice of animal sacrifice, and proclaimed prohibition against killing animals to be a law of nature.
Empedocles’ four elements survived as the basis of physics for 2,000 years. Aristotle was fascinated by On Nature; his biology probably owes a good deal to its comparative morphology. Empedocles’ cosmic cycle attracted the interest of the early Stoics. Lucretius found in him the model of a philosophical poet. Philosophical attacks on animal sacrifice made later in antiquity appealed to him as an authority.
Melissus (mid or late 5th century BC)
Authors: Sedley David 
Published: September 2018

Melissus was a Greek philosopher from the island of Samos. A second-generation representative of Eleatic metaphysics, he published one work, entitled On Nature or On That-Which-Is, which has been partially reconstructed by editors. It defends a version of Parmenides’ monism, but recast with terminology and arguments directly accessible to a readership schooled in the eastern Greek (Ionian) style of physical speculation, as distinct from Parmenides’ western Greek background. Although it is uncertain how important Melissus was to his own contemporaries, his prosaic but clear presentation of Eleatic concepts was more widely adopted by later writers than the enigmatic pronouncements of Parmenides.
Melissus argues that that-which-is is: (1) omnitemporal; (2) infinite in extent; (3) one; (4) homogeneous; (5) changeless, that is, without (a) reordering, (b) pain, (c) grief or (d) motion; (6) indivisible; and (7) bodiless. Here (1) – ‘it always was what it was, and always will be’ – is a departure from Parmenides, who had outlawed past and future in favour of a static present. Likewise (2) contrasts with Parmenides’ defence of spatially finite being. The remaining predicates are consonant with Parmenides, although (5) b–c suggest that the being Melissus has in mind is a living one, presumably a deity – an aspect not brought out by Parmenides. Melissus wrote ‘If there were many things, they ought to be such as I say the One is’ – a remark sometimes thought to have inspired his contemporaries the atomists.
Parmenides (early to mid 5th century BC)
Authors: Sedley David 
Published: September 2018

Parmenides of Elea, a revolutionary and enigmatic Greek philosophical poet, was the earliest defender of Eleatic metaphysics. He argued for the essential homogeneity and changelessness of being, rejecting as spurious the world’s apparent variation over space and time. His one poem, whose first half largely survives, opens with the allegory of an intellectual journey by which Parmenides has succeeded in standing back from the empirical world. He learns, from the mouth of an unnamed goddess, a dramatically new perspective on being. The goddess’s disquisition, which fills the remainder of the poem, is divided into two parts; the Way of Truth and the Way of Seeming.
The Way of Truth is the earliest known passage of sustained argument in Western philosophy. First a purportedly exhaustive choice is offered between two ‘paths’ – that of being, and that of not-being. Next the not-being path is closed off: the predicate expression ‘… is not’ could never be supplied with a subject, since only that-which-is can be spoken of and thought of. Nor, on pain of self-contradiction, can a third path be entertained, one which would conflate being with not-being – despite the fact that just such a path is implicit in the ordinary human acceptance of an empirical world bearing a variety of shifting predicates. All references, open or covert, to not-being must be outlawed. Only ‘… is’ (or perhaps ‘… is…’) can be coherently said of anything.
The next move is to seek the characteristics of that-which-is. The total exclusion of not-being leaves us with something radically unlike the empirical world. It must lack generation, destruction, change, distinct parts, movement and an asymmetric shape, all of which would require some not-being to occur. That-which-is must, in short, be a changeless and undifferentiated sphere.
In the second part of the poem the goddess offers a cosmology – a physical explanation of the very world which the first half of the poem has banished as incoherent. This is based on a pair of ultimate principles or elements, the one light and fiery, the other heavy and dark. It is presented as conveying the ‘opinions of mortals’. It is deceitful, but the goddess nevertheless recommends learning it, ‘so that no opinion of mortals may outstrip you’.
The motive for the radical split between the two halves of the poem has been much debated in modern times. In antiquity the Way of Truth was taken by some as a challenge to the notion of change, which physics must answer, by others as the statement of a profound metaphysical truth, while the Way of Seeming was widely treated as in some sense Parmenides’ own bona fide physical system.
Philo of Alexandria (c.15 BC–c. AD 50)
Authors: Runia David T. 
Published: September 2018

Philo of Alexandria is the leading representative of Hellenistic-Jewish thought. Despite an unwavering loyalty to the religious and cultural traditions of his Jewish community, he was also strongly attracted to Greek philosophy, in which he received a thorough training. His copious writings – in Greek – are primarily exegetical, expounding the books of Moses. This reflects his apologetic strategy of presenting the Jewish lawgiver Moses as the sage and philosopher par excellence, recipient of divine inspiration, but not at the expense of his human rational faculties. In his commentaries Philo makes extensive use of the allegorical method earlier developed by the Stoics. Of contemporary philosophical movements, Philo is most strongly attracted to Platonism. His method is basically eclectic, but with a clear rationale focused on the figure of Moses.
Philo’s thought is strongly theocentric. God is conceived in terms of being. God’s essence is unreachable for human knowledge (negative theology), but his existence should be patent to all (natural theology). Knowledge of God is attained through his powers and, above all, through his Logos (‘Word’ or ‘Reason’), by means of which he stands in relation to what comes after him. In his doctrine of creation Philo leans heavily on Platonist conceptions drawn from reflection on Plato’s Timaeus. The conception of a creation ex nihilo (‘from nothing’) is not yet consciously worked out. Philo’s doctrine of human nature favours the two anthropological texts in Genesis 1–2, interpreting creation ‘according to the image’ in relation to the human intellect. With regard to ethics, both Stoic concepts and peculiarly Jewish themes emerge in Philo’s beliefs. Ethical ideals are prominent in the allegorical interpretation of the biblical patriarchs.
Philo’s influence was almost totally confined to the Christian tradition, which preserved his writings. He was unknown to medieval Jewish thinkers such as Maimonides.
Pneuma
Authors: Stead Christopher 
Published: September 2018

Pneuma, ‘spirit’, derives from the Greek verb pneo, which indicates blowing or breathing. Since breathing is necessary for life and consciousness, pneuma came to denote not only wind and breath but various vital functions, including sensation and thought, and was understood by some philosophers as a cosmological principle. It became especially important in Stoicism, which explained the world in terms of matter and the rational structure exhibited in all its forms; this is established by rhythmical variations in the tonos or ‘tension’ of the pneuma.
In Hebrew tradition, where Greek was used, pneuma stood for life, consciousness, and for invisible conscious agents, angels or demons. In Christian thought it denotes divine inspiration, in particular the Holy Spirit acknowledged as a divine Person. At John 4:24 it is used, unusually, to describe God himself.
Immortality in ancient philosophy
Authors: Brennan Tad 
Published: September 2018

In Greco-Roman philosophy immortality is discussed in two contexts: as an uncontroversial attribute of the gods and as a highly controversial attribute of human souls. Subdividing this latter topic, one may discern a more metaphysical question about whether every human soul as such is immortal in virtue of its nature or essence, and a more ethical topic about whether certain souls may enjoy a greater degree or share of immortality through adopting a certain mode of life. (This sub-topic is joined to the first main topic, to the extent that the virtuous agent’s approximation to immortality is part of their imitation of god or homoiōsis theōi).
Several Presocratic philosophers held that human souls are immortal, but it is Plato who first offers extensive arguments for this claim, as well as extensive reflections on the ethical import of personal immortality. Aristotle’s psychology leaves little room for the soul’s immortality, and it remains controversial whether he wished to leave any whatsoever. Discussions of immortality and its ethical consequences are similarly downplayed in surviving Stoic sources. The Epicureans gleefully argued the contrary view that a virtuous outlook depends on our conviction that we are irredeemably mortal. Only with the resurgence of Platonism in the Common Era does the soul’s immortality become once again a commonplace among philosophers. The connection between this and the Christian belief in resurrection is complicated. It is presumably due to the ascendancy of this double legacy that current popular usage counts it as nearly tautological that souls are immortal, but acknowledges a real question of whether human beings have souls, where ancient usage accepted as a near tautology that all living beings have souls, but admitted wide dispute over whether souls are immortal or not.
Buridan, John (c.1300–after 1358)
Authors: Zupko Jack 
Published: September 2018

Unlike most other important philosophers of the scholastic period, John Buridan never entered the theology faculty but spent his entire career as an arts master at the University of Paris. There he distinguished himself primarily as a logician who made numerous additions and refinements to the Parisian tradition of propositional logic. These included the development of a genuinely nominalist semantics, as well as techniques for analyzing propositions containing intentional verbs and paradoxes of self-reference. Even in his writings on metaphysics and natural philosophy, logic is Buridan’s preferred vehicle for his nominalistic and naturalistic vision.
Buridan’s nominalism is concerned not merely with denying the existence of real universals, but with a commitment to economize on entities, of which real universals are but one superfluous type. Likewise, his representationalist epistemology accounts for the difference between universal and singular cognition by focusing on how the intellect cognizes its object, rather than by looking for some difference in the objects themselves. He differs from other nominalists of the period, however, in his willingness to embrace realism about modes of things to explain certain kinds of physical change.
Underlying Buridan’s natural philosophy is his confidence that the world is knowable by us (although not with absolute certainty). His approach to natural science is empirical in the sense that it emphasizes the evidentness of appearances, the reliability of a posteriori modes of reasoning and the application of certain naturalistic models of explanation to a wide range of phenomena. In similar fashion, he locates the will’s freedom in our evident ability to defer choice in the face of alternatives whose goodness appears dubious or uncertain.
Byzantine philosophy
Authors: Benakis Phil Linos 
Published: September 2018

In Byzantium from the ninth century through to the fifteenth century, philosophy as a discipline remained the science of fundamental truths concerning human beings and the world. Philosophy, the ‘wisdom from without’, was invariably contrasted with the ‘philosophy from within’, namely theology. The view that philosophy is ‘the handmaiden of theology’, which the Greek Church Fathers derived from Philo and the Alexandrian school of theology, was not the dominant position in Byzantium as it was in the West; philosophy, and logic in particular, was never treated as a mere background to, or tool of, theology. By the same token, theology in Byzantium never developed into a systematic method of dialectical inquiry into Christian truths, or a science. Thus the initial distinction between philosophy and theology remained intact.
In terms of institutional practice, theological schools and studies did not exist in Byzantium and the main purpose of higher studies was to train state functionaries. This instruction, based on philosophy and the quadrivium, was mainly private, but it received support from the emperor and the church and we do hear of occasional interference by the secular or ecclesiastical authorities, perhaps because of professional or personal rivalries among the philosophy teachers. Furthermore, Byzantium had no independent universities or centers of study instituted by monastic orders as there were in the West, where social and political conditions were different.
Philosophy in Byzantium also steered clear of involvement in the theological controversies that arose from time to time. The prevalent model of the thinker in Byzantium was a sort of encyclopedic teacher of philosophy, an erudite scholar who kept in touch with the sciences of the quadrivium (arithmetic, geometry, astronomy and music) and other disciplines and set the philosophical tone of the scientific curricula. The development of philosophy in Byzantium was thus very different from that of Western scholasticism.
Henry of Ghent (early 13th century–1293)
Authors: Marrone Steven P. 
Published: September 2018

Perhaps the most influential theologian between Thomas Aquinas and Bonaventure in the third quarter of the thirteenth century and John Duns Scotus at the beginning of the fourteenth century, Henry of Ghent stands at a turning point in scholastic philosophy. He was a defender of traditional Neoplatonic positions and has often been seen as the epitome of thirteenth-century Augustinianism. Yet his convoluted metaphysics and a theory of knowledge weaving together Neoplatonic and Aristotelian strands inspired novel philosophical trends in the fourteenth century, particularly among Franciscan thinkers. His work thus constituted the point of departure for scholastic giants like Duns Scotus and William of Ockham, who not only used him as a foil against which to articulate their own system of thought but also absorbed much of his fundamental philosophical outlook and terminology.
Characteristic of Henry’s metaphysics was an essentialism so pronounced that critics accused him of positing a realm of essences separate from worldly actuality. In his defence, Henry insisted that essences, though prior to actual existence, were separate only as grounded in the divine exemplars of things, but the Platonism of his approach struck his contemporaries as extraordinary nonetheless. Ironically, Henry’s understanding of essence as congruent with intellectual coherence provided an opening for a more logic-based analysis of modality, especially possibility, in succeeding thinkers such as Duns Scotus.
The emphasis on essence re-emerged in Henry’s theory of knowledge, and at least in his early writings he offered a vision of knowing truth through divine illumination often taken as paradigmatic of medieval Augustinianism. Even his later attempts to cast epistemology in a more Aristotelian light retained the insistence that true knowledge somehow entails access to the exemplary essences in God’s mind. The same essentialism led Henry to formulate what he called an a priori proof for God’s existence, best approximation in the thirteenth century to Anselm’s ontological argument. Again, however, Henry’s Augustinianism provided an unintended springboard for innovation, leading to Duns Scotus’ theory of the univocity of being and metaphysical proof of God’s existence.
Liber de causis
Authors: Jarka-sellers Hannes 
Published: September 2018

The Liber de causis (Book of Causes) is a short treatise on Neoplatonist metaphysics, composed in Arabic by an unknown author probably in the ninth century in Baghdad. Through its twelfth-century Latin translation, it greatly influenced mature medieval philosophy in the West.
Drawing heavily on the Greek Neoplatonist Proclus, the Liber de causis represents a development of late Neoplatonism along two lines. On the one hand, the author modifies and simplifies Proclus’ theory of causes to accord more closely with the three-part division of ultimate causes advanced by the founder of Neoplatonism, Plotinus. On the other hand, the author introduces some of the metaphysical principles of Qu’ranic or biblical monotheism. The result is a metaphysically provocative reinterpretation of Neoplatonist thought which, because it seemed to accommodate Platonist philosophy to the medieval worldview, made the Liber de causis a natural source text for medieval philosophers.