Here is a quotation from CS Lewis that I think relates well to my previous post.
If no set of moral ideas were truer or better than any other, there would be no sense in preferring civilized morality to savage morality. (Source: Twitter)
I think this exemplifies what is wrong with a strictly pragmatic view of law. Who decides what is pragmatic? What is to stop the Deciders from pragmatically formulating barbaric laws? The answer, of course, is nothing whatsoever. Understand please the context in which Lewis says this: if various moral ideas are all equal in value — if none is objectively truer or better than any other — then there is no objective standard by which to reject the barbarous and favor the civilized.
But we all know this to be nonsense. Clearly it is better for all if there are laws against murder, against rape, against theft. Why? Because men and women by their very nature are worthy of life and safety. If this foundation is taken away, then all laws in defense of either society or individuals are reduced to the arbitrary and become subject to the whims of those who make the laws. If there is no intrinsic reason why my life should be protected, I guarantee you that one day a government will come along which sees no reason at all why it should be protected.
Lewis knew this. He understood the necessity of natural law. What is natural law? Aquinas says this (quoted in CCC 1955):
The natural law is nothing other than the light of understanding placed in us by God; through it we know what we must do and what we must avoid. God has given this light or law at the creation.
There is no question of laws being arbitrary; they must conform to natural law, which is to say that they must conform to right reason:
The natural law, the Creator’s very good work, provides the solid foundation on which man can build the structure of moral rules to guide his choices. It also provides the indispensable moral foundation for building the human community. Finally, it provides the necessary basis for the civil law with which it is connected, whether by a reflection that draws conclusions from its principles, or by additions of a positive and juridical nature. (CCC 1959)
We are not trapped with no way to know what laws are just or unjust, thought it isn’t necessarily easy, either.
The precepts of natural law are not perceived by everyone clearly and immediately. In the present situation sinful man needs grace and revelation so moral and religious truths may be known “by everyone with facility, with firm certainty and with no admixture of error.” (CCC 1960)
So, with all due respect to my thoughtful interlocutor, we are not trapped between a choice between law as rhetoric and law as pragmatic.
[Written with StackEdit].
Aquinas, Etc. 
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