'...badness cannot succeed even in being bad in the same way in which goodness is good. Goodness is, so to speak, itself: badness is only spoiled goodness. And there must be something good first before it can be spoiled. We call sadism a sexual perversion; but you must have first had the idea of a normal sexuality before you talk of its being perverted...'
CS Lewis, Mere Christianity, p.44.
