a rule of antilogism. The other, the third thema, was a cut rule by which chain syllogisms could be reduced to simple syllogisms. The purpose of Stoic syllogistic was not merely to create a formal system. It was also understood as the study of the operations of reason, the divine reason (logos) which governs the universe, of which human beings are a part. The goal was to find valid rules of inference and forms of proof to help people find their way in life. According to Sextus Empiricus, Chrysippus held that dogs use disjunctive syllogism, such as when using scent to pick which path to run down. This was in contrast to a tradition since Aristotle, who saw reasoning (and reasoning deductively) as man's defining aspect. Other logical work Chrysippus analyzed speech and the handling of names and terms. He also devoted much effort in refuting fallacies and paradoxes. According to Diogenes Laërtius, Chrysippus wrote twelve works in 23 books on the Liar paradox; seven works in 17 books on amphiboly; and another nine works in 26 books on other conundrums. In all, 28 works or 66 books were given over to puzzles or paradoxes. Chrysippus is the first Stoic for whom the third of the four Stoic categories, i.e. the category somehow disposed is attested. In the surviving evidence, Chrysippus frequently makes use of the categories of substance and quality, but makes little use of the other two Stoic categories (somehow disposed and somehow disposed in relation to something). It is not clear whether the categories had any special significance for Chrysippus, and a clear doctrine of categories may be the work of later Stoics. Later reception Chrysippus came to be renowned as one of the foremost logicians of ancient Greece. When Clement of Alexandria wanted to mention one who was master among logicians, as Homer was master among poets, it was Chrysippus, not Aristotle, he chose. Diogenes Laërtius wrote: "If the gods use dialectic, they would use none other than that of Chrysippus." The logical work by Chrysippus came to be neglected and forgotten. Aristotle's logic prevailed, partly because it was seen as more practical, and partly because it was taken up by the Neoplatonists. As recently as the 19th century, Stoic logic was treated with contempt, a barren formulaic system, which was merely clothing the logic of Aristotle with new terminology. It was not until the 20th