 Nowadays, few Western ethicists would argue that you should treat your body in such-and-such a way purely because of divine authority (“God abhors tattoos!”) or natural teleology (“Your blood belongs in your own body!”). But the history of philosophy teems with prim pronouncements on the proper way to treat one’s body, and philosophers continue to debate whether certain kinds of bodily modification are immoral as a matter of duty to oneself, as well as whether certain kinds of self-enhancement are permissible or even obligatory.