Lewis is not yet done with explaining this Law of Right and Wrong as he writes Chapter 3 of "Mere Christianity." This should give all of as readers of "Mere Christianity" the distinct impression of just how important this Law is to his understanding of why he left atheism behind and became a committed Christian. But the religious conversion part of his story is a long way from yet being discussed. Chapter 3 continues building on the real existence of this Moral Law.
He begins by restating: "First, that humans are haunted by the idea of a sort of behavior they ought to practice what you might call fair play or decency or morality, or the Law of Nature. Second, that humans do not in fact adhere to the Law. The law of gravity tells you what stones do if you drop them; but the Law of Human Nature tells you what human beings ought to do and do not."
This is all about what we ought to do.
Again Lewis writes (paraphrased a bit by me): "Why ought I be unselfish?" and you reply "because it is good for society" we may then ask "why should I care what's good for society except when it happens to pay me personally." At this point you have to say "because you ought to be unselfish." And this simply brings us back again to where we started. But we cannot get rid of this idea that we ought to do the right thing and not the wrong thing. Consequently, this Rule of Right and Wrong, or Law of Human Nature,or whatever you call it, must somehow be a real thing -- a thing that is really there, not made up by ourselves. None of us made this law but we find it pressing on us."
Can you describe how this law is pressing upon you?
It is important to interrogate ourselves and our fundamental beliefs or we will end up living a superficial meaningless life. Lewis invited such challenges because they enabled him to rethink his position and determine if his conviction remained or had been shaken.
When I look into myself, I find his two statements about the Law of Morality to be real. I know that I should do right and avoid wrong. I need no Supreme Court to tell me this. Regrettably, I find myself often not living up to this standard. I usually try to rationalize my bad behavior, but inside my head, I know I was wrong. Do you find this Law of Morality equally strong in your life?
If you do, then Lewis has another very big question for you.
What Lies Behind this Law?
We move on to Chapter 4 of Mere Christianity -- a small book with a very big picture of life.