Phronesis 60 (�0�5) �67-309 brill.com/phro The Beginnings of Formal Logic: Deduction in Aristotle’s Topics vs. Prior Analytics Marko Malink Department of Philosophy, New York University, 5 Washington Place, New York, NY 10003. USA
[email protected] Abstract It is widely agreed that Aristotle’s Prior Analytics, but not the Topics, marks the begin- ning of formal logic. There is less agreement as to why this is so. What are the distinctive features in virtue of which Aristotle’s discussion of deductions (syllogismoi) qualifies as formal logic in the one treatise but not in the other? To answer this question, I argue that in the Prior Analytics—unlike in the Topics—Aristotle is concerned to make fully explicit all the premisses that are necessary to derive the conclusion in a given deduction. Keywords formal logic – deduction – syllogismos – premiss – Prior Analytics – Topics 1 Introduction It is widely agreed that Aristotle’s Prior Analytics marks the beginning of formal logic.1 Aristotle’s main concern in this treatise is with deductions (syllogismoi). Deductions also play an important role in the Topics, which was written before the Prior Analytics.2 The two treatises start from the same definition of what 1 See e.g. Cornford 1935, 264; Russell 1946, 219; Ross 1949, 29; Bocheński 1956, 74; Allen 2001, 13; Ebert and Nortmann 2007, 106-7; Striker 2009, p. xi. 2 While the chronological order of Aristotle’s works cannot be determined with any certainty, scholars agree that the Topics was written before the Prior Analytics; see Brandis 1835, 252-9; Ross 1939, 251-2; Bocheński 1956, 49-51; Kneale and Kneale 1962, 23-4; Brunschwig 1967, © koninklijke brill nv, leiden, ���5 | doi �0.��63/�5685�84-��34��86 268 Malink a deduction is (stated in the first chapter of each).