 However, because these ends are putatively set for us not by a contingent act of will but rather by our nature as morally engaged, knowledge-seeking beings, some philosophers regard them as categorical rather than instrumental imperatives. In other words, they take these norms to say not merely that if we want to achieve various hypothetical ends, then we have the prima facie obligation to believe in such-and-such ways. Rather, the norms say that we do have these ends as a matter of natural or moral necessity, and thus that we prima facie ought to believe in such-and-such ways.