"...Men have differed as regards what people you ought to be unselfish to-whether it was only your own family, or your fellow country men, or everyone. But they have always agreed that you ought not to put yourself first. Selfishness has never been admired. Men have differed as to whether you should have one wife or four. But they always have agreed that you must not simply have any woman you liked." (p. 6)
"...surely the reason we do not execute witches is that we do not believe there are such things. If we did-if we really thought that there were people going about who had sold themselves to the devil and received supernatural powers from him in return and were using these powers to kill their neighbors or drive them mad or bring bad weather-surely we would all agree that if anyone deserved the death penalty, then these filthy quislings did? There is a difference of moral principle here: the difference is simply about a matter of fact. It may be a great advance in knowledge not to believe in witches: there is no moral advance in not executing them when you do not think they are there. You would not call a man humane for ceasing to set mousetraps if he did so because he believed there were no mice in the house" (p. 14-15)
This factor certainly is a powerful support of the moral argument for the existence of God, as it shows us that He has inscribed His moral laws into the hearts of us all.
If, however, moral relativism is true, then it would be difficult to imagine how the golden rule (love your neighbor as yourself) can be found in ancient human civilizations outside the Judeo-Christian framework. This all seems to point to a moral law giver, with the problem being our sin nature that we inherited due to the fall of Adam and Eve.
Let us suppose for the sake of argument that nobody knew of a universal law code that governed human conduct. That would still not refute the existence of objective moral truths, any more than if an entire chemistry class got a wrong answer to a test question proves that there is no correct answer.