If the main argument of this book is correct, in what sense does it provide an answer to moral scepticism? I believe that no form of scepticism, whether epistemological or moral, can be shown to be impossible. The best one can do is to raise its cost, by showing how deep and pervasive are the disturbances of thought which it involves. —T. Nagel, The Possibility of Altruism (Oxford: Clarendon Press, 1970), p. 143

”Moral scepticism” refers, I think, to ‘why should I be moral?’ from the likes of Thrasymachus.