Peirce's law

English Etymology Named after the logician and philosopher Charles Sanders Peirce. Proper noun en logic The classically valid but intuitionistically non-valid formula of propositional calculus, which can be used as a substitute for the law of excluded middle in implicational propositional calculus. Consider Peirce's law, . If Q is true, then is also true so the law reads "If truth implies P then deduce P" which certainly makes sense. If Q is false, then so the law reads , which is intuitionistically false but equivalent to the classical axiom . Anagrams en aceeilprsw parcelwise en eponyms