Introducing the revised version fo the Critique of Pure Reason, Kant, in a now proverbial analogy, likened the procedure of his philosophy to that of Copernican astronomy: both propose a change in the position of the observer in order to explain apparently errant or contradictory phenomena.
"We should then be proceeding precisely on the lines of Copernicus' primary hypothesis. ... A similar experiment can be tried in metaphysics as regards the intuition of objects. If intuition must conform to the constitution of objects, I do not see how we could know anything of the latter a priori; but if the object (as object of the senses) must conform to the faculty of intuition, I have no difficulty in conceiving such a possibility."
What is the basis for the comparison to Copernicus?
More generally, what is the relationship between philosophy and science in Kant?
Let us recall how precarious the “Copernican revolution” that Kant claimed to have introduced into philosophy has always been: how could he have made us believe that making the Object revolve around the human Subject could count as an abandonment of anthropocentrism? (Bruno Latour)
An example of the expression is to be found, for instance, in Charles W. Hendel's introduction to Cassirer's Philosophy of Symbolic Forms. Hendel characterizes Kant's transformation (of metaphysics)"as momentous as a Copernican revolution, a wholly new orientation toward the problem of knowledge. It is the hypothesis that, instead of human knowledge being shaped to reality, it is our human judgement which determines whatever is to have the character of being reality for us. The roles are reversed -- the judgement conditions reality." According to Kant, "we can have a priori knowledge only of those features of the things which we ourselves put into them." (Critique of Pure Reason, B xviii) Kant summarized his epistemology thus: The conditions of experience are at the same time the conditions of the objects of experience -- by which he meant that the process that we call experience and the representations that form its content and objects are subject to the same laws of the understanding. In fact the comparison with Copernicus seems inverted, for Copernican astronomy and transcendental philosophy move in opposite directions. In a sense, Kant is putting human understanding at the center of the subject's epistemic universe, when Copernicus is displacing the earth from the center of the Ptolemaic system. Yet while Copernicus seems to be abandoning the human terrestrial station for an imaginary solar standpoint, his system is as anthropocentric as the Ptolemaic system, but gives preference to man's delight in abstract theory, at the price of rejecting the evidence of our senses. The subsequent development that the work of Kepler and Newton would give to the Heliocentric theory could only underscore the ambitions of reason.
The stronger historical parallel may be to Newton, not Copernicus. Indeed the three general laws of the understanding laid out in the Critique of Pure Reason correspond to and underlie the three basic laws laid down by Newton: the law of inertia, the law of the proportionality of cause and effect, and the law of equality of action and reaction. But while the evidence for Newtonian science had become overwhelming over the course of the eighteenth century, the nature of the relationship between its elements remained famously occult. How was Kant to deductively relate the categories of metaphysics withough falling back on dogmatism?
Stephan Körner, in his introduction to Cassirer's book on Kant's life and thought, describes "Kant's Copernican revolution in philosophy...as consisting in asking and answering two kinds of questions..."questions of fact" and "questions of legality." (justifications of factual claims) The latter are raised in the transcendental arguments to the effect that the a priori features of objective experience are necessary to the conditions of its objective character.
Kant hoped to provide a philosophical model of estabishing disciplinarily independent, formative principles. In fact, he appealed to the life sciences in his Transcendental Deduction of the Categories, specifically in terms of preformation and epigenesis. Kant uses the concept of epigenesis in the generation of Metaphysical knowledge. (see G. Zoller in Kant Analysen. Probleme. Kritik.)