In his practical philosophy (ethics), so insists Fichte, Kant left many questions unsolved. For example, according to Fichte, the so-called “categorical imperative” is not the ultimate. Therefore, the categorical imperative also to be philosophically justified. The categorical imperative is in itself the principle, but is to be deducible from the other, more fundamental principle. The authentic principle is the imperative of the absolute independence of reason (absolute Selbstständigkeit der Vernunft).
Furthermore, in order to obtain a substantial moral theory and not just a formal ethics, the relationship between moral consciousness and natural impulses must be well elaborated and elucidated.