In the early chapters of Mere Christianity, C.S. Lewis builds up an argument for God’s existence based on our sense of morality: what Lewis calls the “Law of Human Nature”. I don’t propose to look at that argument in this post, but just at one particular point Lewis makes in response to a common objection:
Some people say that though decent conduct does not mean what pays each particular person at a particular moment, still, it means what pays the human race as a whole; and that consequently there is no mystery about it. Human beings, after all. have some sense; they see that you cannot have any real safety or happiness except in a society where every one plays fair, and it is because they can see this that they try to behave decently.
I think an equivalent view today would be that the human moral sense has evolved; that there is (we surmise) a selection advantage in our having mechanisms that lead us to act against our immediate selfish interests.
However, Lewis argues that, while it is true that human society can indeed only exist (let alone flourish) if individuals and nations are “honest and fair and kind to each other”, this “misses the point” as an explanation for our sense of right and wrong:
If we ask: ‘Why ought I to be unselfish?’ and you reply ‘Because it is good for society’ we may then ask, ‘Why should I care what’s good for society except when it happens to pay me personally?’ and then you will have to say, ‘Because you ought to be unselfish’ – which simply brings us back to where we started.
And Lewis continues:
[I]f a man asks what is the point of behaving decently, it is no good replying, ‘in order to benefit society,’ for trying to benefit society, in other words being unselfish (for ‘society’ after all only means ‘other people’), is one of the things decent behaviour consists in; all you are really saying is that decent behaviour is decent behaviour. You would have said just as much if you had stopped at the statement, ‘Men ought to be unselfish.’
And that is where I do stop. Men ought to be unselfish; ought to be fair. Not that men are unselfish, not that they like being unselfish, but that they ought to be.
It’s that word “ought” that leaps out at me; that notion of “oughtness”, that our sense of right and wrong corresponds to something external to us, something which has (in some sense) an existence independent of us and which has (in some sense) a claim upon us; that “oughtness” is in some way built into the fabric of reality. Because it’s not simply that we acknowledge that unselfishness (or honesty, or justice, or courage, or any other virtues) are beneficial, but that we experience them as having this sort of claim upon us, of being something we “ought” to do or to be.
Again, no polemics here; I am no doubt being very philosophically naive, and so I am open to enlightenment and correction; but I fail to see how an atheist (or secular humanist, or whatever term you wish to apply) can avoid admitting that “oughtness” in this sense is ultimately an illusion. That to say one “ought” to be unselfish (say) ultimately means nothing more than saying “there is a selection advantage (or some other benefit) for human beings, not only from behaving unselfishly, but from behaving as if to do so were an external moral imperative, something they ‘ought’ to do”. In which case, I don’t see how there is a way out of the circular reasoning identified by Lewis above.
Of course, if there is no external “oughtness” in this sense, then to say “nevertheless, it is beneficial for us to act as if there were” is preferable to nihilism. But in that case I think we’d need to admit that that’s the game we’re playing, and (to go back to my previous post) I think we’d need to be aware of the fact that an “oughtness” that is a useful social construct is likely to be an “oughtness” whose claims are easier to set aside when they become inconvenient to us.