Aristotle’s Syllogistic from the Standpoint of Modern Formal Logic

Introduction

Łukasiewicz wrote the book in Dublin and published it with Oxford University Press in 1951; the second edition of 1957 added chapters on Aristotle’s modal syllogistic. It argues that Aristotle’s syllogisms are not inference rules but conditional sentences (“if A belongs to all B and B belongs to all C, then A belongs to all C”), and that the syllogistic is an axiomatic theory resting on a propositional logic that Aristotle used without stating it. Łukasiewicz formalised the system in his notation, used results of his student Jerzy Słupecki to show that it is decidable. The book renewed the study of ancient logic. From the 1970s John Corcoran and Timothy Smiley proposed a reading of the syllogistic as a system of natural deduction, which many scholars now prefer.

Connections

Builds on

• Organonc. 350 BCE · Aristotle

More works by Jan Łukasiewicz

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