Abstract
The article concerns one of the principal and most important concepts of Kant’s philosophy, namely the concept of postulate. Kant’s understanding of this term differs from the previous tradition. For Kant, postulates are originally subjective propositions necessarily supposed as objective ones. Otherwise, systematic theoretical cognition and compliance with the moral law become impossible. However, this peculiarity of Kant’s terminology is often ignored, which causes misunderstanding of the role and functions of Kant’s doctrine of postulates as a whole.