Rabbi Jonathan Sacks writes: [Darwin] was puzzled by a phenomenon that seemed to contradict his most basic thesis, that natural selection should favor the ruthless. Altruists, who risk their lives for others, should therefore usually die before passing on their genes to the next generation. Yet all societies value altruism, and something similar can be found among social animals, from chimpanzees to dolphins to leafcutter ants.

Neuroscientists have shown how this works. We have mirror neurons that lead us to feel pain when we see others suffering. We are hard-wired for empathy. We are moral animals.

The precise implications of Darwin’s answer are still being debated by his disciples — Harvard’s E. O. Wilson in one corner, Oxford’s Richard Dawkins in the other. To put it at its simplest, we hand on our genes as individuals but we survive as members of groups, and groups can exist only when individuals act not solely for their own advantage but for the sake of the group as a whole. Our unique advantage is that we form larger and more complex groups than any other life-form.

A result is that we have two patterns of reaction in the brain, one focusing on potential danger to us as individuals, the other, located in the prefrontal cortex, taking a more considered view of the consequences of our actions for us and others. The first is immediate, instinctive and emotive. The second is reflective and rational. We are caught, in the psychologist Daniel Kahneman’s phrase, between thinking fast and slow.

The fast track helps us survive, but it can also lead us to acts that are impulsive and destructive. The slow track leads us to more considered behavior, but it is often overridden in the heat of the moment. We are sinners and saints, egotists and altruists, exactly as the prophets and philosophers have long maintained.

If this is so, we are in a position to understand why religion helped us survive in the past — and why we will need it in the future. It strengthens and speeds up the slow track. It reconfigures our neural pathways, turning altruism into instinct, through the rituals we perform, the texts we read and the prayers we pray. It remains the most powerful community builder the world has known. Religion binds individuals into groups through habits of altruism, creating relationships of trust strong enough to defeat destructive emotions. Far from refuting religion, the Neo-Darwinists have helped us understand why it matters.

No one has shown this more elegantly than the political scientist Robert D. Putnam. In the 1990s he became famous for the phrase “bowling alone”: more people were going bowling, but fewer were joining bowling teams. Individualism was slowly destroying our capacity to form groups. A decade later, in his book “American Grace,” he showed that there was one place where social capital could still be found: religious communities.

While extolling the virtue of the altruistic tendencies of church- or synagogue-goers, Sacks misses an opportunity to make his message more ecumenically inclusive and include mosque-goers. That’s a strange omission given that charity is one of the pillars of Islam. Moreover, he seems to conflate religion and values — a distinction that is clear in most people’s minds since the drift away from organized religion much more often results from a rejection of religious beliefs than religious values.

The problem that we atheists face — and probably one of the many reasons religion survives — is that our disbelief gives us less to celebrate. Of course we can celebrate life, but we can’t so easily contrive occasions where, obedient to the passage of time, we come together and reaffirm our shared values. Religion provides such pretexts for social unity, without discussion, consensus building or the messy process of negotiation that secular, values-based, collective bonding would entail.

The virtue of ritual and celebration is that they invite a form of selfless participation. They are not burdened by association with individual inventors and thus remain untouched by the competing force of reinvention by innovators — those who might insist for instance that it really makes more sense to celebrate Christmas on December 21, the Winter Solstice.

Maybe at some point, secular traditions of celebration will emerge if, in accordance with Jeremy Rifkin’s hope, we succeed in constructing an empathic civilization — but I suspect that if this happens it will be the result of an incremental adaptation of religion and not because Richard Dawkins and others succeeded in persuading the religious to abandon their faith.