Immanuel Kant (22 April 1724 – 12 February 1804), was a German philosopher from Königsberg in East Prussia (now Kaliningrad, Russia). He is regarded as one of the most influential thinkers of modern Europe and the last major philosopher of the Enlightenment.
Kant was a proponent of
Transcendental Idealism is the philosophy that makes us aware of the fact that the first and essential laws of this world that are presented to us are rooted in our brain and are therefore known a priori. It is called transcendental because it goes beyond the whole given phantasmagoria to the origin thereof. Therefore, as I have said, only the Critique of Pure Reason and generally the critical (that is to say, Kantian) philosophy are transcendental.
Schopenhauer
— Parerga and Paralipomena, Volume I, "Fragments for the History of Philosophy," § 13
