Transcendental subject

Transcendental idealism is a doctrine founded by German philosopher Immanuel Kant in the 18th century. Kant's doctrine maintains that human experience of things is similar to the way they appear to us—implying a fundamentally subject-based component, rather than being an activity that directly (and therefore without any obvious causal link) comprehends the things as they are in themselves.

Although it influenced the course of subsequent German philosophy dramatically, exactly how to interpret this concept was a subject of some debate among 20th century philosophers. Kant first describes it in his Critique of Pure Reason, and distinguished his view from contemporary views of realism and idealism, but philosophers do not agree how sharply Kant differs from each of these positions.

Transcendental idealism is associated with formalistic idealism on the basis of passages from Kant's Prolegomena to any Future Metaphysics, although recent research has tended to dispute this identification. Transcendental idealism was also adopted as a label by the subsequent German philosophers Fichte and Schelling, Schopenhauer, and in the early 20th century by Husserl in the novel form of transcendental-phenomenological idealism.

Perhaps the best way to approach transcendental idealism is by looking at Kant's account of how we intuit (German: anschauen) objects, and that task demands looking at his accounts of space and of time. Before Kant, some thinkers, such as Leibniz, had come to the conclusion that space and time were not things, but only the relations among things. Other thinkers, including Newton, maintained that space and time were real things or substances. Leibniz had arrived at a radically different understanding of the universe and the things found in it. According to his Monadology, all things that humans ordinarily understand as interactions between and relations among individuals (such as their relative positions in space and time) have their being in the mind of God but not in the Universe where we perceive them to be. In the view of realists, individual things interact by physical connection and the relations among things are mediated by physical processes that connect them to human brains and give humans a determinate chain of action to them and correct knowledge of them. Kant was aware of problems with both of these positions. He had been influenced by the physics of Newton and understood that there is a physical chain of interactions between things perceived and the one who perceives them. However, an important function of mind is to structure incoming data and to process it in ways that make it other than a simple mapping of outside data.

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