Another argument for God’s existence comes from our almost universal agreement on something we call moral or natural law. It appears that every human society believes that there are certain rules that should govern our conduct; and there is a remarkable degree of consistency in these rules from society to society, even in pagan societies. Where do these unwritten rules come from?
Some suggest that these moral concepts evolved naturally as humans themselves evolved over the years. There is no real evidence that it happened in that way, and there are solid arguments against it. I doubt that the moral law could have evolved in this way. I believe it came to us from an outside source, and I believe that source to be God.
We all believe in this law, even though we often violate it or may even deny its existence. In the American Declaration of Independence, for instance, the author wrote that we hold certain truths to be self-evident. What are these self-evident truths? If we assert some things are true, we must also believe that some things are not true.
If we don’t believe there are rights and wrongs, how can we honestly attack someone else for his or her actions? Some may say that the entire world is cruel and unjust, from whence comes that person’s definition of just and unjust? How do you call a line crooked unless you have a straight line to compare it to? Without moral law, our society would be complete chaos.
One way we might expect God to manifest Himself would be inside ourselves as an influence or command trying to get us to behave in a certain way — and that’s exactly what we find! Each of us has a conscience. If confronted with a choice between the two, somehow, each of us knows right from wrong, and this is a knowledge that transcends time and place. There is a universal standard. Marcus Aurelius was acknowledged to be a good man in the second century A.D. He would be recognized as a good man today. Caligula and Nero and Hitler would be considered evil men in any century — and in almost any culture. Men like Caligula suppressed their consciences to the point that they lost their humanity and became like beasts.
It is true that much of what we consider to be the moral law is learned, but that makes it no less true. All of us learned the multiplication table at school, but it does not follow that the multiplication table is simply a human convention that we could have made different if we wished to. The laws of mathematics exist outside of human reason. Our reason comes into play only in helping us understand these laws. The moral law belongs in much the same class as mathematics. It is universal. It is timeless. It is from outside ourselves. Some people, and even entire groups of people, may have a clearer perception of the moral law than others; but most individuals, if they will only be still, look, and listen, are able to recognize which interpretation of the law comes closest to the universal standard — to God’s standard.
As a Christian I believe that God’s law reached its purest expression in the life of Jesus Christ, His Son.
Note: Some of these arguments were lifted almost verbatim from C.S. Lewis’ book Mere Christianity. I find his reasoning persuasive.