Why morality is a sickness just for us humans

In this short book, John Gray, professor of European thought at the London School of Economics, argues that philosophers should start to take evolutionary theory seriously. Darwin's insights require a complete revision of the western philosophical canon, which is still dominated by the rationalist assumptions of the Enlightenment. Echoing Anthony O'Hear's Beyond Progress , Gray argues that "progress" is nothing more than a desiccated and secularised version of the Christian notion of providence, and proceeds to debunk it with insights derived from cognitive science and sociobiology.

Unfortunately, he gets off to a shaky start on the first page with the anachronistic howler: "Darwin teaches that species are only assemblies of genes." But the book features an excellent presentation of the state of the art in consciousness studies, where Gray is attracted to the fashion for enactive and embodied approaches. His view on the phylogonetic origin of consciousness is close to that of Nicholas Humphrey, but he fails to acknowledge that this viewpoint is not shared by mainstream cognitive science, which still operates within a cognitivist-Cartesian framework.

The book includes a fascinating debate on the problem of free will, using the evidence from cognitive neuroscience (Benjamin Libet's "readiness potential") and literature - the inability of the hero in Joseph Conrad's Lord Jim to decide whether he jumped or "it seems I had jumped". Here, Gray is in line with the sceptical consensus - defenders of libertarian free will are increasingly hard to find.

In the chapter on morality, Gray recounts the case of a concentration camp prisoner who was raped by a guard. As any prisoner without a cap was executed, the guard stole the prisoner's cap, in order that the rape should perish with its victim. The prisoner then stole the cap of another inmate, who was duly executed. Gray takes this as an argument against Kant - morality is not universal and categorical, but a convenience to be relied on in normal times. But I am sure Kant would have argued that the very fact that we find this tale so disturbing is an indication of our innate moral nature. This is an interesting chapter - the argument that Christianity, in universalising ethics that were previously local and tribal, was a retrograde step, is a provocative claim.

Gray develops this point by drawing the distinction between ethics (the practice of virtues such as courage and wisdom), and morality - "a set of laws or rules that everyone must obey". According to Gray, ethics arises from our animal natures, whereas morality is "a sickness peculiar to humans", invented by Socrates, universalised by Christianity and still evident in its secularised form in the tradition of Kant and John Rawls.

Gray dismisses Moore's "naturalist fallacy" as an artificial conundrum, specific to the western tradition but incomprehensible to, say, the Taoists of ancient China.

The book's overall gloominess is partly on account of its author's ecological and Malthusian perspective. According to Gray, competition between expanding populations and limited resources will be the prime source of future conflicts. He also claims that population growth will be checked only by "a global authority with draconian powers". But is this right? Britain's fertility rate of 1.63 is the average for the developed world, and fertility declines with increasing prosperity (even in traditional Catholic countries such as Italy).

By a quirk of fate, I found myself writing this review in the same week that Sam Peckinpah's Straw Dogs , banned in the UK on account of a brutal rape scene, was re-released. The film was censored because the female lead appeared to enjoy being raped. While Gray does not expand on sociobiological theories of rape, he does have some Rochefoucauldian observations on other perverse human characteristics, such as: "It has long been known that those who perform great acts of kindness are rarely forgiven."

Such comments are designed to shock liberal sensibilities, but Gray is not interested in preaching to the converted - besides that, in my experience, the books that have profoundly influenced my life are ones that I started off hating. In the same way that Tamino discovers halfway through Mozart's opera The Magic Flute that Pamina's demonic kidnapper is in fact a kindly and wise sage, books such as this can induce a similar gestalt shift, if the reader can be persuaded not to storm out before the second act.

Unsurprisingly, given his contempt for Whiggery, there is no happy conclusion - the book ends with a plea that we may come to accept and rejoice in the purposelessness of life. This is more akin to Nietzsche than to Wagner, so there is no point waiting for the fat lady to sing.

Keith Sutherland is executive editor, Journal of Consciousness Studies .