Robin Smith

Scholars of classical philosophy have long disputed whether Aristotle was a dialectical thinker. Most agree that Aristotle contrasts dialectical reasoning with demonstrative reasoning, where the former reasons from generally accepted opinions and the latter reasons from the true and primary. Starting with a grasp on truth, demonstration never relinquishes it. Starting with opinion, how could dialectical reasoning ever reach truth, much less the truth about first principles? Is dialectic then an exercise that reiterates the prejudices of one's times and at best allows one to persuade others by appealing to these prejudices, or is it the royal road to first principles and philosophical wisdom? In From Puzzles to Principles? May Sim gathers experts to argue both these positions and offer a variety of interpretive possibilities. The contributors' thoughtful reflections on the nature and limits of dialectic should play a crucial role in Aristotelian scholarship.

At the beginning of the Posterior Analytics, Aristotle says that “all learning and all rational teaching arises from previously existing knowledge”. How, then, can we have any knowledge? If all our knowledge is acquired by learning that depends on previously existing knowledge, then we would have an infinite regress of still prior knowledge, with the result that we cannot learn anything without having learned something else first. If we reject this possibility, then the only one that remains is that we have some knowledge that we did not learn. This might happen in two ways: either we have some knowledge that we never acquired at all, or we have some knowledge that we acquired but without learning it. We would have knowledge that we never acquired if there was never a time at which we did not have it (which would entail, of course, that we were born with it). Plato held that we do have such knowledge, and indeed that all the genuine knowledge that we have is innate in this way. Aristotle, however, denies that we have innate knowledge (for instance at An. Post. II.19, 100a10). Since he nevertheless does think that we have knowledge, he must think that we have some knowledge which we did not acquire by learning. In fact, he does present such a view in Posterior Analytics II.19, where he claims that our knowledge of the principles ( ¢¡¤£¦¥¨§ ) of sciences comes to us through perception and induction and that the state of knowledge of them is “intelligence” or “thought” ( © ). Aristotle says explicitly that in this process the mind is passive; therefore, it is reasonable for us to regard it as not being a kind of learning (or at any rate as a kind of rational learning). Thus, Aristotle’s overall position is consistent.

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).

I argue that Prior analyticsII.5?7, 8?10, and 1.45 actually contain studies of processes for transforming arguments into other arguments which Aristotle carried out before having completed the theory of perfecting syllogisms by reduction to first-figure moods as presented in Prior analytics1.4?7. This position rejects Ross's opinion that these passages are ?mental gymnastics?, and Patzig's view that some of these texts contain studies of alternative axiomatizations or other logical studies posterior to the completion of the basic theory of syllogisms

I consider the proper interpretation of the process of ecthesis which Aristotle uses several times in the Prior analytics for completing a syllogistic mood, i.e., showing how to produce a deduction of a conclusion of a certain form from premisses of certain forms. I consider two interpretations of the process which have been advocated by recent scholars and show that one seems better suited to most passages while the other best fits a single remaining passage. I also argue that ecthesis for Aristotle really means ?setting out? the case to be proved using letters. Aristotle?s remarks about the use of letters in mathematical proofs suggest that he had some understanding of rules equivalent to universal generalization and existential instantiation; the ?proofs through ecthesis? are so called because they rest on the latter rule, with which use of letters is involved in a special way