section_path: Philosophy/Doctrine of transcendental idealism
section_name: Doctrine of transcendental idealism
paragraph_text: Doctrine of transcendental idealism
  
  The section of the Critique entitled "The transcendental aesthetic" introduces Kant's famous metaphysics of transcendental idealism. Something is "transcendental" if it is a necessary condition for the possibility of experience, and "idealism" denotes some form of mind-dependence that must be further specified. The correct interpretation of Kant's own specification remains controversial. The metaphysical thesis then states that human beings only experience and know phenomenal appearances, not independent things-in-themselves, because space and time are nothing but the subjective forms of intuition that we ourselves contribute to experience. Nevertheless, although Kant says that space and time are "transcendentally ideal"—the pure forms of human sensibility, rather than part of nature or reality as it exists in-itself—he also claims that they are "empirically real", by which he means "that 'everything that can come before us externally as an object' is in both space and time, and that our internal intuitions of ourselves are in time". However Kant's doctrine is interpreted, he wished to distinguish his position from the subjective idealism of Berkeley.
  
  Paul Guyer, although critical of many of Kant's arguments in this section, writes of the "Transcendental Aesthetic" that it "not only lays the first stone in Kant's constructive theory of knowledge; it also lays the foundation for both his critique and his reconstruction of traditional metaphysics. It argues that all genuine knowledge requires a sensory component, and thus that metaphysical claims that transcend the possibility of sensory confirmation can never amount to knowledge."