Exploring Aristotle's philosophical method and the merits of his conclusions, Irwin here shows how Aristotle defends dialectic against the objection that it cannot justify a metaphysical realist's claims. He focuses particularly on Aristotle's metaphysics, epistemology, philosophy of mind, and ethics, stressing the connections between doctrines that are often discussed separately.

This essay argues that aristotle's doctrine of nominal definition is his semantic theory for natural-Kind terms. It offers a new interpretation of that doctrine. On this interpretation nominal definitions are initial working theoretical accounts of natural kinds which serve as starting points for scientific inquiry. As such, Nominal definitions have existential import. They make an implicit reference to the most familiar actual instances of the kinds they define and they define the essences of those kinds by reference to those instances. (...) Nominal definitions are, Thus, Accounts of real essences as much as real definitions. They are initial incomplete accounts of such essences and it is as such that they explicate the meanings of (natural-Kind) terms. (shrink)

In 1928, Friedrich Solmsen argued that Aristotle'sPosterior Analyticswas largely composed before thePrior Analytics. Ross rejected Solmsen's position in 1939, and a rather lengthy series of rebuttals and counter-attacks between the two scholars followed. Quite recently, Jonathan Barnes has revived this issue with arguments in favour of something very close to Solmsen's thesis: that Aristotle first developed a theory of demonstration (‘apodeictic’) before he had worked out the syllogistic, and that thePosterior Analyticswas originally conceived against this background. Subsequently, when Aristotle formulated (...) a syllogistic, he is supposed by Barnes to have revised or added to the contents of thePosterior Analyticsso as to make syllogistic the logic of Aristotelian science. Thus, Barnes says: ‘the syllogism is in fact an incidental adjunct to the theory of demonstration: the theory can be formulated without reference, explicit or implicit, to Syllogistic, and itcould havebeen discovered by someone who knew nothing whatever about the Syllogism’ (pp. 33–4). (shrink)