 Fundamental issues in moral philosophy must also be settled a priori because of the nature of moral requirements themselves, or so Kant thought. This is a third reason he gives for an a priori method, and it appears to have been of great importance to Kant: Moral requirements present themselves as being unconditionally necessary. But an a posteriori method seems ill-suited to discovering and establishing what we must do whether we feel like doing it or not; surely such a method could only tell us what we actually do. So an a posteriori method of seeking out and establishing the principle that generates such requirements will not support the presentation of moral “oughts” as unconditional necessities. Kant argued that empirical observations could only deliver conclusions about, for instance, the relative advantages of moral behavior in various circumstances or how pleasing it might be in our own eyes or the eyes of others. Such findings clearly would not support the unconditional necessity of moral requirements. To appeal to a posteriori considerations would thus result in a tainted conception of moral requirements. It would view them as demands for which compliance is not unconditionally necessary, but rather necessary only if additional considerations show it to be advantageous, optimific or in some other way felicitous. Thus, Kant argued that if moral philosophy is to guard against undermining the unconditional necessity of obligation in its analysis and defense of moral thought, it must be carried out entirely a priori.