Immanuel Kant
Immanuel Kant (; ; 22 April 1724 – 12 February 1804) was a German philosopher who is a central figure in modern philosophy. In his doctrine of transcendental idealism, he argued that space, time and causation are mere sensibilities; "things-in-themselves" exist, but their nature is unknowable. In his view, the mind shapes and structures experience, with all human experience sharing certain structural features. He drew a parallel to the Copernican revolution in his proposition that worldly objects can be intuited "a priori" ("beforehand"), and that intuition is therefore independent from objective reality. Kant believed that reason is the source of morality, and that aesthetics arise from a faculty of disinterested judgment. Kant's views continue to have a major influence on contemporary philosophy, especially the fields of epistemology, ethics, political theory, and post-modern aesthetics.
Intuition
Immanuel Kant finds intuition is thought of as basic sensory information provided by the cognitive faculty of sensibility (equivalent to what might loosely be called perception). Kant held that our mind casts all of our external intuitions in the form of space, and all of our internal intuitions (memory, thought) in the form of time. Intuitionism is a position advanced by Luitzen Egbertus Jan Brouwer in philosophy of mathematics derived from Kant's claim that all mathematical knowledge is knowledge of the pure forms of the intuition – that is, intuition that is not empirical. Intuitionistic logic was devised by Arend Heyting to accommodate this position (and has been adopted by other forms of constructivism in general). It is characterized by rejecting the law of excluded middle: as a consequence it does not in general accept rules such as double negation elimination and the use of reductio ad absurdum to prove the existence of something.