# nLab Peirce's law

Peirce’s law is a proposition that involves only conditionals and is valid in classical logic but not intuitionistic logic:

$((p \Rightarrow q) \Rightarrow p) \Rightarrow p$

It is named after Charles Sanders Peirce.

Revised on November 16, 2009 09:47:43 by Toby Bartels (173.60.119.197)