In the first four chapters of Mere Christianity, Lewis talks about how the existence of universal moral law of the human race shows strong evidence of God’s existence. He talks about how even those who claim to have no universal code of conduct and behavior, will protest about something being unfair; everyone, whether they like it or not, has some type of “code of justice.” Lewis says that any discrepancies in morals between different cultures do not indicate a lack of universality, but of a progression in morality as the human race changes and grows. He says that the fact that we can look at different cultures throughout the history of humankind and see which ones are better than others, shows that there is still some universal standard of goodness which we have not obtained.
Lewis then draws the distinction between the law of morality and a scientific law. He says that we cannot call moral law a law of nature because laws of nature merely describe the behavior of matter in the natural world. For example, the scientific law of gravity describes that all objects are attracted to one another and the larger an object, the larger the force of attraction will be towards it. Notice that this law is not a rule – your pencil does not fall to the ground when you drop it because we wrote a scientific law stating it should. Natural laws are only descriptions of how we expect processes in the natural world to occur. Moral law is not like this. Moral law is actually quite often disobeyed. People do not always act as we should. It is not the description of our actions, but the sense of what makes something right or wrong which is considered moral law.
Further, Lewis points out that “…there is something above and beyond the ordinary facts of men’s behavior, and yet quite definitely real – a real law, which none of us has made, but which we find pressing on us.” This moral law comes from something greater, better, and beyond us. Unlike the laws of the physical universe, our universal moral standards come from a higher authority – this higher authority, Lewis concludes is “a Power behind the facts, a Director, a Guide.” This authority is God himself.
I really liked Lewis’ perspective that the sense of universal morality each of us has is in itself evidence that there is some Good which guides us. We would not and could not have this sense of right and wrong if we were just some chance result of biochemical reactions, simply organized and functional masses of matter. There is something more to us – we have been designed by Someone. Not only have we been designed, but we have had a sense of how to do the will of God instilled in us. Relating back to “The Weight of Glory”, we have been created to yearn, to long for the God who created us.