Single Idea 8080

[catalogued under 4. Formal Logic / A. Syllogistic Logic / 1. Aristotelian Logic]

Full Idea

Aristotle identified four 'figures' of argument, based on combinations of Subject (S) and Predicate (P) and Middle term (M). The addition of 'all' and 'some', and 'has' and 'has not' got the property, resulted in 256 possible syllogisms, 19 of them valid.

Gist of Idea

Aristotelian identified 256 possible syllogisms, saying that 19 are valid

Source

report of Aristotle (Prior Analytics [c.328 BCE]) by Keith Devlin - Goodbye Descartes Ch.2

Book Reference

Devlin,Keith: 'Goodbye Descartes: the end of logic' [Wiley 1997], p.42


A Reaction

[Compressed version of Devlin] What Aristotle did was astonishing, and must be one of the key ideas of western civilization, even though a lot of his assumptions have been revised or rejected.