This text is an attempt to present some of the questions dealing with Hegel's critique of the intellectual intuition and of the form of the mathematical deduction, which had lead us to approach a few aspects of the philosophies of Kant and Fichte. We have tried, departing from Hegel's Science of Logic, to observe the possible mathematical inspiration for what Hegel names Reflexionsphilosophie (Kant, Jacobi, Fichte), and, with it, to observe how, in Hegel's opinion, only a severe criticism of the mathematical procedure would be able to change reflection up into effective negation.