One of the most common things said by people who leave religious belief is that they did not lose their morality when they left — that they remained caring, honest, committed to justice, and in many cases more genuinely ethical than some of the religious people around them. This is often true. It is also beside the point.
The question is not whether irreligious people can be good. They clearly can. The question is whether irreligion can adequately explain why goodness is real — whether, on a purely secular account of reality, moral facts exist, and if so what sustains them.
The lived experience and the philosophical problem
Here is the gap. When an irreligious person says “torturing children for entertainment is wrong,” they are typically not saying “I dislike this” or “my culture disapproves of this.” They are saying something stronger: this is genuinely, objectively, morally wrong — wrong regardless of what any individual or culture believes about it, wrong in a way that holds even if everyone on earth decided it was acceptable.
That stronger claim is moral realism. And moral realism is very difficult to ground on a purely secular account of reality.
The physical universe, as science describes it, is a system of descriptive facts — facts about what is the case. Moral facts are normative — facts about what ought to be the case. The gap between descriptive and normative facts is one of the oldest problems in philosophy. You cannot derive an “ought” from an “is” by any logical operation on purely physical descriptions. Where, then, do moral facts live in a universe that contains nothing but physical processes?
The secular alternatives
Several secular alternatives to moral realism are on offer. The most honest is moral error theory — the view that moral claims are systematically false because there are no objective moral facts. This is a coherent position, but almost no one actually lives by it. The moment you treat someone unjustly and they protest, you are both appealing to a standard that you implicitly believe is real.
Another option is to ground morality in human flourishing: actions are right if they promote flourishing, wrong if they diminish it. This has genuine force. But it faces the question: why ought we to promote flourishing? That question is itself a moral question — it cannot be answered by appealing to the facts about flourishing without already assuming that what is good for humans morally matters, which is precisely what needs grounding.
A third option is evolutionary ethics: moral beliefs are the output of natural selection, shaped because they promoted survival and reproduction in ancestral environments. This explains why we have the moral beliefs we do. It does not give us any reason to think those beliefs are true. Evolution selects for adaptive behaviour, not moral accuracy. An evolutionary account of morality, followed honestly, leads not to moral realism but to the conclusion that our moral beliefs are useful fictions — which is not what the person making confident moral claims actually believes.
What theism offers
Theism offers a grounding for moral realism that secular accounts lack. On the theistic account, moral facts are not invented by human beings or selected by evolution. They are grounded in the nature of God — not in arbitrary divine commands, but in the objective standard of goodness that a being of unlimited goodness constitutes. Moral facts are necessary truths about value, analogous to mathematical truths, grounded in a reality that does not change with human cultural fashion.
This does not mean that only theists can be good. It means that the moral experience irreligious people rely on — the felt reality of genuine right and wrong — is better explained by theism than by any secular alternative. The person who left religion but kept their morality has kept more of the theistic framework than they realise.