Single Idea 8078

[catalogued under 5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens]

Full Idea

Modus ponens is just one of the five different inference rules identified by the Stoics.

Clarification

'Modus ponens' says if p implies q, and p is true, then q must be true

Gist of Idea

Modus ponens is one of five inference rules identified by the Stoics

Source

report of Chrysippus (fragments/reports [c.240 BCE]) by Keith Devlin - Goodbye Descartes Ch.2

Book Reference

Devlin,Keith: 'Goodbye Descartes: the end of logic' [Wiley 1997], p.36


A Reaction

Modus ponens strikes me as being more like a definition of implication than a 'rule'. Implication is what gets you from one truth to another. All the implications of a truth must also be true.