Full Idea
That logic is a priori consists in the fact that we cannot think illogically.
Gist of Idea
Logic is a priori because we cannot think illogically
Source
Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.4731), quoted by Robin Jeshion - Frege's Notion of Self-Evidence 4
Book Reference
-: 'Mind' [-], p.973
A Reaction
A rather startling claim. Presumably we have to say that when we draw a stupid inference, then we weren't really 'thinking'?