Noteworthy Figures

Question 1

Aristotle

Answer 1

(384-322 b.c.e)

• Crowning achievement is the theory of the categorical syllogism
• Considered the father of logic

Question 2

Chrysippus

Answer 2

(280-206 b.c.e.)

• Often considered to be the originator of propositional logic
• Introduced inferential rules (modus ponens, modus tollens, disjunctive syllogism)

Question 3

Peter Abelard

Answer 3

(1079-1142)

• Generally considered the greatest logician of the Middle Ages
• Developed a truth-functional propositional logic and a theory of entailment

Question 4

William of Ockham

Answer 4

(1285-1347)

• Known for his theory of truth conditions for categorical propositions, preliminary work on three-valued logic, and for work in the foundations of inductive reasoning
• Ockham’s razor: the simplest one is the best