Look, you just don't eat people, ok! Ugh! No! Yes, it's bad to do it - but it is itself a paradigm of such badness, not something that drops out of some independently understood general moral rule. If regarding this you ask 'why?' in a sincere manner, the problem is probably not that, lacking a decent justification for not eating others, you risk casually scoffing the odd person pasty without the requisite baulk .... but rather that you are already a psychopath. The philosopher wants to help us feel more justified, grounded, reasonable, in our moral judgement - but to the extent that they invert the order of praxis and precept they risk, despite their best intentions, alienating us from our moral sensibilities. They risk - one might say, if one accidentally took or pretended to take them seriously - courting a moral catastrophe - in which we are no longer standing by and in our judgment, no longer simply embodying the form of moral sensibility in our assured moral stand-taking, but - rather like the obsessive who wants to derive and support what for them has somehow ceased being a certainty-in-action from and with certainty-of-memory or decency-of-evidence, but who in this cart-before-horse manner just makes things worse - instead imagining and feeling a need to be plugged by reason to justify why we should judge as we do. (That was a ridiculously long sentence. But it works. It expresses a clear thought. I promise.)
Here then is once again my master thought, the one I endlessly keep writing about, recalling, coming back to. It is: that the judgement of sanity vs insanity is itself similarly groundless. That psychiatry, especially the philosophy of psychiatry, but also academic clinical psychiatry and psychology, so often aims to find some principle to separate the sheep of sanity from the goats of insanity. But the principle is always hopeless, since it is either normatively inert (being a merely statistical norm, for example) or facile (since it really only applies to, and this since it tacitly presupposes that here we actually have to do with, the types of thoughts enjoyed by the sane). Sometimes these get cobbled together (as in definitions of delusion which mark it as culturally unusual (in, presumably, a statistical sense) and merely false or inadequately reasoned). And, my thought goes, the reason why the theorist or clinician so inexorably indulges this desire to provide or deploy criteria for true madness is both because of the unenviable responsibility in making the clinical judgement and because of what we might think of as a form of contamination anxiety (how can I be sure I'm not mad too?). If it seems dangerous to let loose mental health professionals on populations with nothing more than clinical judgement to guide them then - well, then perhaps we ought to give more thought to the non-operational finessing of practical judgement itself. After all, the thought could go, we are not in any magically better shape when it comes to our moral judgement itself of the possible ill that such necessarily unprincipled practice could inflict. Praxis precedes precepts applies, I'm suggesting, as much to the moral as to the clinical domain. Courage, good-heartedness, and casuistry are the names of the game.