Let us very clearly understand that, in a certain sense, it is no more possible to invent a new ethics than to place a new sun in the sky. Some precept from traditional morality always has to be assumed. We never start from a tabula rasa*; if we did, we should end, ethically speaking, with a tabula rasa.
~ C.S. Lewis, Christian Reflections, "On Ethics" (1943)
*"blank slate" or "blank page"
Aristotle said that only those who have been well brought up can usefully study ethics: to the corrupted man, the man who stands outside the Tao, the very starting point of this science is invisible.
~C.S. Lewis, The Abolition of Man, (1943)