We want to focus on Husserl’s critique of Kantian ethics and to develop the following questions. As opposed to the empiricist orientation of Hume’s ethics, the Kantian foundation of ethics has an a priori character; does this character have to be identified with the origin of ethical principles in pure subjectivity? If not, what is its phenomenological signification? The meaning of the Copernican revolution is that structures of objects accord with the universal structures of the finite subject; Husserl refuses this principle and assumes that every sort of object determines a regulative structure in the subject; is it possible to apply this anti-Copernican principle to the ethical sphere? As opposed to the Kantian principle of the supremacy of practical reason, we find in Husserl’s thought a supremacy of theoretical reason; what is the meaning of this inversion? The concept of foundation has great importance in Husserlian phenomenology: every sort of truth of a higher degree is founded on the lower level of sensible truth; is it possible to apply this principle to the ethical sphere? Finally, the Kantian concept of liberty is not an empirical one, but a cosmological and practical idea; what is the phenomenological meaning of liberty?