Gutting asked, "Is one of religion’s merits that it provides a foundation (intellectual and practical) for morality through the idea of God as divine lawgiver?" To which Ruse replied,
I am on record as an “evolutionary skeptic.” I don’t deny substantive morality — you ought to return your library books on time — but I do deny objective foundations. I think morality is a collective illusion, genetic in origin, that makes us good cooperators. And I would add that being good cooperators makes each one of us individually better off in the struggle for existence. If we are nice to other people, they are much more likely to be nice to us in return.Ruse's response raises several questions. If morality is merely a set of "substantive" rules that we ought to follow if we want other people to treat us well, what if I can get along perfectly well in the "struggle for existence" without following these rules? Would it be wrong for me to ignore them? What if it actually promotes my chances for evolutionary success to flout the rules, would it be wrong to flout them? What if I don't give a fig for my evolutionary success, why should I follow those rules?
However, as the philosopher J.L. Mackie used to argue, I think we “objectify” substantive ethics — we think it objectively the case that we ought return library books on time. But we do this (or rather our genes make us do this) because if we didn’t we would all start to cheat and substantive ethics would collapse to the ground. So I don’t buy the moral argument for the existence of God. I think you can have all of the morality you need without God.
Consider a concrete example. I choose to ignore, let us say, the suffering of children in some other part of the world. I'm in a position to help them, I even present myself to others as one who is helping them, but in fact am not. Am I doing anything wrong by ignoring them? What obligates me to help them? Why is it wrong to pose as their benefactor when in fact I am not? On Ruse's view why is it wrong to refuse to help others who will never be in a position to ever return the favor?
Or consider a very powerful ruler who has life and death authority over his subjects. If no harm can come to him for anything he does, what's wrong, on Ruse's view, with such a man treating his political opponents cruelly? Imagine further that this man is able to deceive his people into thinking that he is in fact a kind and benevolent ruler when in fact behind the scenes he's a terribly cruel tyrant. Would Ruse think that would be wrong? It's hard to see how.
Ruse's position leads inevitably to egoism, the view that my good is the only good I need be concerned about. When he says that morality is an illusion that our genes create to get us to cooperate with each other he undercuts any ground for taking morality seriously. Why should we take an illusion seriously? Why should we think that a random, impersonal process like genetic evolution could ever impose a duty on us to behave one way rather than another?
Unless there is an objective moral law established by a transcendent moral authority able to enforce the law and hold us accountable to it there simply is no right or wrong behavior. There are only actions that some of us like and others dislike.
In other words, one can hold that it's wrong to be cruel or one can hold that there is no God (setting aside the matter of how we should properly conceptualize God), but what one cannot do is hold both of these propositions simultaneously. If one is true the other is false.
Atheist philosopher Richard Rorty saw this clearly. He famously observed that "For the secular man there's no answer to the question 'Why not be cruel?' "
On atheism, morality is nothing more than a set of subjective preferences and tastes, of no more significance than a person's preference of one flavor of ice cream over another. That being the case, when an atheist says anything more about another person's behavior than that they like it or don't like it, they're acting as if God exists while simultaneously denying that he does, and that's irrational.