Aristotle and Copernican Revolutions

Abstract

Aristotle, Professor Irwin tells us, was a realist.' There are, of course, many different sorts of realist: realists as opposed to nominalists, realists about possible worlds, realists about moral values, realists as opposed to idealists. Like the word on Austin's view of the matter,2 the word gets its meaning in any given context from its contradictory in that context, from what it is opposed to. We do not understand William when he tells us that the ducks over there are real ducks until we see that he is telling us that they are not decoy ducks. Similarly, a philosopher can be intelligibly said to be advancing a realist doctrine, only if we have some idea what the -ism is which she is supposed to be rejecting. The realism Irwin is attributing to Aristotle is the realism that is opposed to idealism. The trouble here is that it is difficult to see that there were in Aristotle's day any idealist doctrines around for him to take the trouble to oppose.3 Protagorean teachings might reasonably be described as subjectivist, but they hardly amounted to idealism in the sense in which the term applies to eighteenth and nineteenth century philosophies. Kant had not yet made his monstrous proposal: Hitherto it has been assumed that all our knowledge