260 years since the birth of Fichte give a good reason to turn to his Wissenschaftslehre, which, together with Kant’s critical philosophy, is a bridge from the past to the future state of philosophical and scientific culture. The first and second parts of the article explore the little-known to Russian historians of philosophy controversy about the spirit and letter of Kant’s teaching, which flared up at the end of the 18th century in Germany and had a discrepancy between Kant’s intention to turn metaphysics into a science and the negative result of all three of his “Critics” in this point. In a dispute with Reinhold, Kreuzer, Schulze (Enesidem), Schmid and Krug, who interpreted Kant’s critical philosophy as based on sensory-rational experience, Friedrich Schlegel, Schelling and Hegel acted as a united front on the side of Fichte. Their consolidation was needed in order, in the struggle against the quasi-philosophy of their time, to support the movement started by Kant and continued by Fichte to reveal the basis of experience, neutralizing dogmatic and skeptical conclusions from the naive-realistic theory of knowledge. In the third part of the article, the reason for this instructive controversy is clarified and it is shown that the innovations of the late period of Fichte’s work do not concern the monistic principle of Wissenschaftslehre, but affect that has become negative the thinker’s attitude to the history of philosophy. It is concluded that the need to overcome Fichte’s ahistorism does not detract, but, on the contrary, only increases the relevance of Fichte’s Wissenschaftslehre as one of the most important moments of the historical development of the logical method.