What Johnston does is to take the authentic moral message of religion to what he sees as its logical extreme. To truly abandon our selfish nature, he argues, would be to give up the specious promise of an afterlife in which our faithfulness is rewarded. For a truly redeemed human being would no longer need an "illusory" arena, in which "we can imagine our acquisitive desires being comprehensively slaked, even after death". Such supernatural rewards, in Johnston's eyes, make a mockery of the true sacrifice of Christ. For the salvation Christ proclaimed (and something similar might be said about the message of the best of the Old Testament prophets) was not about placating a supernatural God or about "making it all better", but rather was about "the grace of finding a way to live that keeps faith with the importance of goodness and love even in the face of everything that can happen to you".

Johnston is surely right that much of the resonance of the Judaeo-Christian worldview lies in its luminous moral insights and its power to change our lives here and now. But it is surely wishful thinking to suppose that this power can be retained while bracketing off, or deleting, the traditional faith in a loving creator God. Johnston constantly helps himself to terms like "holy", "grace" and "gift", to which, as a naturalist, he is not properly entitled. In the end, his naturalism must mean that, despite his sympathy for true religion, and despite his frequent use of the word "God", and phrases like "The Highest One", he cannot really believe in anything like the personal God of the traditional Abrahamic faiths. Instead, drawing on Alfred North Whitehead's "process theology", he identifies God with "a universal process understood as outpouring and self-disclosure". Here, God is "no longer in the category of substance, as in traditional theology, but in the category of activity". 

Traditional theology (for example in Thomas Aquinas) described the Creator in terms of "pure activity". But Johnston means something very different; for when his own religious-sounding language is deciphered, all he can really mean by "God" is the natural process itself — the whole flux of activity that is the universe. He asks, perhaps a little wistfully, whether the holiness of the world, instead of deriving from its being the work of a transcendent divine Creator, might not consist instead "just in the sheer givenness of the world — that is, in its existence and disclosure". 

Unfortunately, the short answer, so it seems to me, must be no. For the natural process, understood as nothing more than a natural process, is manifestly not holy. As understood in modern physicalist cosmology, it is the debris of a vast explosion, full of violence and chaos, out of whose dust we and our planet happen to be formed. And, what is more, it is a process that (so the inexorable second law of thermodynamic tells us) is decaying, gradually cooling, inevitably running down. Johnston's spiritual and moral aspirations are admirable. But he cannot, in my view, have them realised while remaining wedded to the dogma of naturalism — the insistence that the natural, purely physically-based process is all there is.

A similar adherence to naturalism pervades André Comte-Sponville's L'esprit de l'athéisme (translated as The Book of Atheist Spirituality, Bantam Books, 2008). Like Johnston, Comte-Sponville firmly subscribes to the view, as he puts it, that nature is the "totality of reality" and that the supernatural "does not exist". Again like Johnston, in rejecting the divine creator, he is drawn instead to an immanentist view: "Everything is immanent to the All." (The capital letter, he swiftly adds, is due to "convention rather than deference".) So there is no God here, only the whole of Nature. Nevertheless, throughout the book a strong wish emerges to preserve "the sacred" — the existence of "a value that seems absolute, that imposes itself unconditionally and can be violated only on pain of sacrilege or dishonour".