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. (shrink)

In the atomism of Leucippus and Democritus, as transmitted by Aristotle, elements are the atoms and everything else are atomic compounds. Still according to Aristotle, all of the physical features of sensible compounds must be traceable down to their elementary chemical constituents. He puts this same kind of demand to the atomic theory and considers that it falls short, because their impassive and immutable atoms cannot suffer the fundamental chemical processes that we witness in nature: generation and alteration. According to (...) Aristotle, there is the atomism of Leucippus and Democritus something we could name as a theory of differences. Chemical processes would not be real, but only the expression of the aggregation and segregation of atoms moving through the void. The differences observed in compounds and attested by the senses would be caused by differences between atoms and by their relative positions. In this paper, I explore this theory of differences, showing that it makes sense, but also that it is more complex than Aristotle’s initial suggestion. In atomism, not only the different geometric shapes of the atoms matter, but also the relationships that atoms establish among themselves, as well as the structure of the compound, which presupposes the void, and the atomic motion, summing up a total of seven fundamental differences that respond for most of the functions that Aristotle would like to find in the elements of a chemical theory. (shrink)

Translation of Aristotle's Metaphysics Lambda into Portuguese.

Translation of Aristotle's Metaphysics I-III into Portuguese, with a few notes and introduction. The translation, which was made at 2007, is preliminary and its publication was intended to provide a didactic tool for courses as well as a provisional resource in research seminars. It needs some revision. I am currently working (slowly...) on the revision of the translation and a new revised one will surely appear at some point.

In this paper, I discuss the use made by Aristotle of the term “element” when dealing with the atomist theory of Leucippus and Democritus. My goal is to verify which aspects of the atomist theory play the role of elements according to the definitions of Aristotle, who seems to have certain expectations regarding what can be designated as elements in the strict sense. One of them is the possibility of reciprocal transformation, the so-called “generation of elements”, which is the chemical (...) aspect at the level of the simple bodies that makes change possible at the level of sense-perceived bodies. Furthermore, I evaluate whether it is possible to find and whether it is adequate to speak of the presence of the four elements – fire, air, water and earth – in the atomist doctrine. (shrink)

Hicks' edition of the De Anima contains valuable commentary from Hicks as well as useful summaries of the views of earlier commentators.

This is the fullest existing collection of the texts, for the moment only in Italian translation, with an introduction, notes, general presentation of the texts, various indexes (part of this material is to be found in an attached CD).