S. Marc Cohen
Aristotle's Physics is a study of nature (phusis) and of natural objects (ta phusei). According to him, these objects—either all of them or at least some of them—are in motion. That is, they are kinoumena, things that are subject to change. The first book of the Physics is largely devoted to this task. The account of substantial change in the Physics is devoid of any commitment to prime matter. Aristotle also takes up the topics of alteration and coming-to-be in De Generatione et Corruptione. He adopts a kind of conservation principle: “the corruption of one thing is the generation of another, and vice versa.” In addition, Aristotle points out that all changes involve both a subject (hupokeimenon) and an attribute (pathos) of a sort which can be predicated of the subject, and says that either one of these is capable of “change” (metabolê).
Presocratic atomism was one of the most influential of the early theories: both Plato and Aristotle thought of it as a major competing theory, and it was an important source for post-Aristotelian Hellenistic theories. It has been commonplace that the atomism developed first by Leucippus of Abdera and then by Democritus of Abdera was a reaction to the Eleatic arguments of Zeno and Melissus, but the details of that influence have sometimes seemed rather hazy. This article brings them into sharper focus. This article considers the Eleatic foundations of atomism, especially the question of the importance of Zeno and Melissus for Democritus. By concentrating on some of the less-studied aspects of atomism and especially of the development of the concept of the unlimited into the notion of the infinite, it furthers the understanding of not only the development of early atomism but also the Eleatics Zeno and Melissus.
Daniel W. Graham
The founder of atomic theory, according to Aristotle and Theophrastus, is Leucippus. His very existence has been called into question. Three of the best minds of nineteenth-century scholarship were embroiled in a vehement debate on this question, which thereupon became a cause célèbre, with scholars weighing in on both sides for the next half century. Ultimately this debate seems to have ended in stalemate and exhaustion rather than in any clear-cut decision. After briefly reviewing the debate, this article argues that there are indications of an atomic theory different from Democritus's that can plausibly be attributed to Leucippus. It considers indications that the atomic theory was known in the mid-fifth century, and then tentatively explores Leucippus's contributions to atomism in a way that will illuminate Democritus's contributions.
M. R. Wright
This article explores early Greeks' cosmological speculation, showing how they explored the possibility of a “theory of everything” and human understanding of the cosmos. In the exposition of competitive cosmologies, there are three questions still unresolved: the form of most of the matter in the universe is not known; the process of beginning of the universe is not known; and whether the universe is finite or infinite is also not known. Presocratic solutions to these problems, still perplexing to the contemporaries, are tackled in this article, with the addition of a note on what is called the anthropic principle, which addresses the place of human life and human observation in the whole.