When ancient astronomical conjectures had failed in predicting the movements of celestial bodies, a science based on the assumption that the bodies move around the spectator, Copernicus hypothesized that the spectator is revolving itself.
Kant claims his strategy in the Critique of Pure Reason is a Copernican strategy. His hypothesis is that hitherto to the Critique, all metaphysics assumes that the spectator’s knowledge conformed to what is real apart from the spectator. Kant calls these "objects". He says this is demonstrably false, since human reason has always defended itself cogently with contradictory knowledge about the objects.
Human reason is "brought to a stand", and what philosophers have done before is say we must merely "retrace our steps". But this does not "lead us in the direction in which we desire to go" according to the desires of natural reason. Natural reason wants to simply accumulate more and more knowledge about the objects themselves without examining knowledge of the perceiver.
What Kant suggests is the possibility that the spectator’s knowledge forces the objects to conform to the spectator. Or more succinctly, that objects conform to the human mind. Objects of human experience are not only “appearances” but also “mere representations”. The spectacles of human experience have, to use a phrase from Debord, “succeeded in totally colonizing” human reason.
It is not that objects are not themselves existent in themselves, but that they are not existent the way in which they appear to us. However, that distinction might easily give way to Berkeleyian idealism (to be is to perceive) if further pressure is applied. Kant denies this since his idealism only extends to properties of objects and not the existence of the objects. This position relies on a kind of Cartesian supposition that illusion presupposes reality that only a god can truly know.
At any rate, the change in the way of thinking ("Umänderung der Denkart") Kant calls for is likened to the change in the way of thinking that took place within Copernicus. The realism hitherto to Copernicus was that objects were exactly the way they appeared to him. Only under further examination the appearances change their appearance in the way they are understood by Copernicus.
This is not a shift from realism to idealism, but rather a shift from a primitive realism to a more sophisticated realism, from one appearance to another. (Maybe this is secretly Kant’s position.) The original Copernican strategy is ultimately still a transcendental realist position that is fundamentally anthropocentric. Kant’s change in the way of thinking is from transcendental realism to transcendental idealism, and therefore an attempt to attack all forms of anthropocentrism. But Kant's change in the way of thinking becomes anthropocentric too, since now the locus of human understanding is placed entirely inside the human mind itself, as if that were the center of the universe.
The Copernican analogy does not contain the basic elements of Kant’s own Umänderung der Denkart. It is understandable, however, that analogies are simply approximations of the subject at hand, and by virtue of not being identical, the Copernican Revolution cannot contain the exact same elements of the Kantian Revolution.
Copernicus did not ask whether knowledge about the stars were possible; he did not move the locus of understanding within himself, but only made alterations to his previous position. He moved the locus of earlier anthropocentrisms more closely to his relative position in the universe, thus amplifying the scope of his anthropocentrism. Copernicus is too naive to understand where his understanding is actually coming from, according to Kant. It is commonly thought that Copernicus' change in the way of thinking is a step away from anthropocentrism to heliocentrism, but I argue that it is only a better-fortified articulation of anthropocentrism a fortiori. If it is a step away from anything, it is a step away from his fellow dogmatists and colleagues (such as the priests, townsfolk and—all except the sailors—including philosophers) "mock-combated" over at the time of his discovery.
Copernicus doesn’t ask, "What kind of thing am I that I should understand what kind of thing is the star?" But rather, "What kind of thing is the earth such that I should understand what kind of thing is the star?"
It is based on predictions of objects rather than predictions of concepts. I use predict in the sense that it implies Copernicus’ empiricism while at the same time it proclaims to make use of dictums prior to any examining experience of the subject-constituted object.
The failures of discovering a "secure path" on which metaphysics can tread is what transitioned Kant into discussing similarities between Copernicus’ primary hypothesis and Kant’s own hypothesis. In