Avicenna's Philosophy Handout 07 (Logic)

Outline 

1.    Logic

a.     Its position

                                                             i.      In the greater picture of peripatetic school

                                                           ii.       as an instrumental science

                                                         iii.      Regulative, not constitutive
                                                                Sources of Avicenna's Logic

b.    General structure of Avicennian Logic:

                                                             i.      Definition

1.    Categories

a.     Essence

                                                                                                                                     i.      Genus

                                                                                                                                   ii.      Differentia

b.    Accidents

                                                           ii.      Demonstration

1.    Form

a.     Modus Ponens & Modus tollens (Hypothetical syllogism)

b.    Deductive syllogism

c.     Induction

d.    Induction

2.    Content

                                                         iii.      The five modes of argument

1.    syllogism

2.    rhetoric

3.    polemic

4.    poetic

5.    fallacies

c.     Avicenna’s original contributions to Aristotelian Logic:

                                                             i.      Propositional Logic: introduction and formulation of Deductive/hypothetical syllogism

                                                           ii.      Modalities:

1.    Introduction of Time and temporality as the fifth modality (Aristotelian four being necessity, possibility, probability and impossibility)

2.    Introduction of necessity by existence (as long as fire exists, it is hot; but even a mental triangle has three angles – it’s not necessary by existence, but by essence)

1.    Introduction of conditional or temporal necessity (any writer holds pen by necessity as long as he actually is writing)

2.    Completion of the division between first and secondary intelligible (Farabi had roughly introduced it)

                                                           

Book Excerpts and Papers

Avicenna's Conception of the Modalities by Allen Back

Links

Avicenna's Logic Stanford

Aristotle on Genus and Differentia Edgar Herbert Granger