In the philosophy of mathematics, intuitionism, or neointuitionism (opposed to preintuitionism), is an approach to mathematics as the constructive mental activity of humans. That is, mathematics does not consist of analytic activities wherein deep properties of existence are revealed and applied. Instead, logic and mathematics are the application of internally consistent methods to realize more complex mental constructs.
Read more about Intuitionism: Truth and Proof, Intuitionism and Infinity, History of Intuitionism, Contributors To Intuitionism, Branches of Intuitionistic Mathematics