Does The Term 'Moral Law' Have Any Practical Relevance?

Throughout his writings Thomas Aquinas believed that moral awareness is a kind of natural law that inheres in the nature of things, due to our being made in the image of God. C.S. Lewis, in his The Abolition of Man, posited a variant on the natural law idea (what he called the "Tao”) - appending the idea of a moral law as having a real, objective platonic existence independent of human evolution

Now as regards the idea of a moral law, it might be easier to posit a set of maxims that convey universal wisdom if everyone agreed on every moral issue – but as you probably have noticed, they do not. In some cases it is difficult to find a universally applicable set of truths on which humanity can have coalescence of ideals, whereas in other cases there are consistent consensus-views pretty much right across the board. 

 

If we wish to state some moral truths as being near-universal, and by that we mean that they apply to humanity in general by virtue of the evidential ways we can strive to live as peacefully as we can in co-existence, or even simply as evolved mental compositions out of which human minds are made, then I have no objection. Even if a universal consensus is too difficult to obtain, this would at least make the concept of the 'moral law' a semantic utility with which we can create targets and goals to which individuals would find it beneficial to aspire. 

So regarding morality, instead of it being a 'law' in the sense that Newton's law of gravitation is a law, what we have is more of a set of universal maxims for humanity; they are, in a sense, universal ideas we have constituted that benefit the survival, propagation and quality of life of the human race.

A fairly obvious corollary ought to follow – morality is describable in terms of ‘laws’ in the same way that, say, human physiology is describable in terms of ‘laws’ – a moral law like ‘it is good if we do no intentional harm to innocent people’ is comparable to something like ‘it is good for our bodies if we take on optimum liquid, eat healthily, and have optimum exercise’. The reason they can be called ‘laws’ is not because they convey universal truths about nature – nature is fallen like us and has no absolute strategy when it comes to humans – it is because they show a highly consistent probability of returning positive outcomes much more frequently that negative ones. 

Such laws do not have to be absolutely true in every given scenario, they only need relate to a series of tangibly accurate hypotheses and associated rules that are accepted as being the best ideological or methodological systems for a particular set of phenomena related to humanity.