ABSTRACT: Kant’s problem is transcendental knowledge, as absolutely pure knowledge, that is, completely possible a priori. The path of knowledge passes from feeling, through intellect, to reason. Knowledge through the senses corresponds to an aesthetic, which for the time being means a sensitive way of representation, related to the faculty of knowledge. The research of the intellect is provided by an analysis, revealing either the concepts or the principles/judgments. The investigation of reason, this time in a narrow sense, as a faculty of knowledge superior to the intellect, as complex as it is problematic, is guided by dialectics. Key words: rationality, morality, a priori, phenomenon, intellect