# 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.

Last revised on November 16, 2009 at 09:47:43. See the history of this page for a list of all contributions to it.