In this post, we’ll begin looking at chapter 3 in book 1 of Mere Christianity.
Having dealt with some potential objections in chapter 2, Lewis now gets back to advancing his argument for the existence of the Moral Law. To do that, he picks back up where he left off at the end of chapter 1: Humanity has a sense of a Moral Law, and humanity fails to follow it.
Here’s an interesting difference between the Moral Law, which we might call the Law of Human Nature, and the Laws of Nature that we find in the physical universe. The Law/s of Nature are not laws for nature to obey, but rather a description of how nature actually behaves: “what Nature, in fact, does.”
But contrast that with the Moral Law, or the Law of Human Nature. It does not refer to “what human beings, in fact, do” because many do not obey it and no one obeys it completely.
“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. In other words, when you are dealing with humans, something else comes in above and beyond the actual facts. You have the facts (how men do behave) and you also have something else (how they ought to behave). In the rest of the universe there need not be anything but the facts.”