The main idea presented by C.S. Lewis is the notion that all humans are born with an innate general sense of "Right and Wrong" that guides their outlook on acceptable behavior. As people grow and interact in the world around them, these rules become more clear as you are expected to behave within the parameters. Many of these standards include common virtues such as honesty, fulfilling promises, along with other socially courteous actions that are generally accepted values across the planet. Lewis refers to these rules as "the Law of Human Nature", similar to other scientific truths such as the laws of gravitation and chemistry with the exception that humans have the choice of adhering to the law or not.
The point is that they are one more proof of how deeply, whether we like it or not, we believe in the Law of Nature. If we do not believe in decent behaviour, why should we be so anxious to make excuses for not having behaved decently? The truth is, we believe in decency so much-we feel the Rule of Law pressing on us so-that we cannot bear to face the fact that we are breaking it, and consequently we try to shift the responsibility. For you notice that it is only for our bad behaviour that we find all these explanations. (pp. 802)
Lewis explains that as everyone occasionally strays away from these basic norms, we automatically deem our actions justifiable to escape potential judgement and repercussions. This furthers confirms just how significant the role of the Law of Human Nature plays in our everyday lives. These unwritten rules are embedded in our society and are understood at a very young age.
I personally feel that Lewis has a strong argument that is revelatory in a sense. He expresses an opinion that every human can relate to and often isn't conscious about. He made very valid points when using the examples of other civilizations that may have different social systems but still have similar expectations for basic morals and what constitutes an honorable man. His use of hypothetical scenarios made it easy to understand what he meant by the Law of Human Nature. He also made it personable by using his own experiences with making excuses for behavior he didn't feel was appropriate. As good as his argument was, I'm not completely sold. Although there was the slight acknowledgment of possible sociopaths where Lewis makes his colour-blind analogy, he never really mentions the possibility of people simply challenging what they view as socially constructed values. He also lacks solid evidence when suggesting everyone's shifting of responsibility. I understand where Lewis is coming from for the most part, but I don't view the Law of Human Nature as a universal truth.
