Kant's Copernican Revolution in Metaphysics

Kant draws an analogy between his proposed revolution in metaphysics and the Copernican revolution in astronomy because both of these "revolutions" involve rethinking the relationship between the observer and what is observed. Before Copernicus, astronomers assumed that the motion of the stars was explainable by treating the observer as stationary (earth as the center of the universe), however, Copernicus suggested the opposite view, treating the observer as the one in motion. This reversal/revolution was important because it recognized that some of what we observe depends on the standpoint of the observer, a point Kant thinks is equally true of metaphysics.

Kant explains that metaphysics is in need of a similar revolution as it currently is in a crisis in which dogmatism has led to skepticism, resulting in "complete indifferentism." Kant explains that because traditional metaphysics had assumed that all cognition must conform to objects, philosophers repeatedly failed to gain a priori knowledge about objects as they are in themselves, causing disagreement and skepticism. Kant instead suggests that objects, at least as they appear to us, must conform to the conditions of our cognition. What we experience is not simply given by the object alone but depends in part on the forms of our sensibility and the concepts that structure our understanding. For Kant, this means we have knowledge only of objects as appearances, not of things as they are in themselves.

Kant believes this Copernican shift is necessary because metaphysics can become a science only if it explains how synthetic a priori knowledge is possible, knowledge that must hold universally and with necessity. If objects of experience must conform to the structures supplied by our cognitive faculties, then we can explain how such necessary knowledge is possible. Instead of deriving principles from experience, we identify the conditions that make experience itself possible. This strategy enables metaphysics to avoid both dogmatism and Humean skepticism and gives it a chance to establish itself on a genuinely scientific footing. In this way, the Copernican Revolution is Kant's attempt to put metaphysics on the path of a science.