The actual book is comprised of three smaller books. The first book, which we read for this class, proves the existence of some overarching Power that created what Lewis calls the "Moral Law." His reasoning seems sound. He first explains the basics of the Moral Law, how everyone has ingrained within them a sense of right and wrong. Even within different cultures and societies, the basics of the Law of Nature remain the same. Stealing is still wrong in the middle of sub-Saharan Africa as well as in Ancient Greece.
I was not sure at this point that I agreed with his idea of the Moral Law. How could one Law govern so many different cultures? If what is right and wrong for me is the same as for any other person, then why do we have so many arguments over things like abortion. If it is wrong in my mind, then shouldn't this concept of the Moral Law lead to the conclusion that it will be wrong in other people's minds as well? How do we excuse the fact that there are different opinions on issues such as this?
Lewis sort of deals with this issue in saying, "some of the things we learn are mere conventions which might have been different." I guess this does explain differences in some ways, but I feel that there are some large differences between my own moral compass and some other people's.
Other than this argument, I agree with Lewis's conclusions. After concluding that there is a Moral Law, one must conclude that someone outside of ourselves must have put it into place. This finally proves at least the existence of some outside Power, which is above this world.