It is usually assumed that what Kant called the Copernican Revolution in philosophy marks his most important achievement and constitites the essence of his transcendental turn. The author shows, however, that not only had Kant several predecessors in his highlighting the role of the cognising subject but also that the new epistemic perspective that endows the subject with the power to gain objectively valid knowledge was already present in Kant's precritical writings, which means that the idea did not belong specifically to his transcendental philosophy. These observations lead the author to believe that the more important achievement than the Copernican Revolution was the proposal of the synthetic unity of apperception. It was more important, as the subject in Kant's philosophy is an entity that produces a uniform picture of the world while remaing itself completely invisible and unaccountable for its contribution. The elusive manner of its operation and the consistent, uniform and interpersonally compatible effect of its work are more characteristic of Kant's transcendental philosophy than the claim that the active role of the subject guarantees epistemic validity of its findings.