The American Heritage® Dictionary of the English Language, 4th Edition
n. Philosophy The theory that truth or certain truths are known by intuition rather than reason.
n. Philosophy The theory that external objects of perception are immediately known to be real by intuition.
n. Philosophy The theory that ethical principles are known to be valid through intuition.
n. Philosophy The view that the subject matter of mathematics consists of the mental or symbolic constructions of mathematicians rather than independent and timeless abstractions, as is held in Platonism.
n. An approach to mathematics/logic which avoids proof by contradiction, and which requires that, in order to prove that something exists, one must construct it.
the GNU version of the Collaborative International Dictionary of English
n. Same as intuitionalism.
The Century Dictionary and Cyclopedia
n. The doctrine of Reid and other Scotch philosophers that external objects are immediately known in perception, without the intervention of a vicarious phenomenon.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. (philosophy) the doctrine that knowledge is acquired primarily by intuition
Word Usage
"In Brouwer's philosophy, known as intuitionism, mathematics is a free creation of the human mind, and an object exists if and only if it can be (mentally) constructed."