On World Book Day, earlier this year, celebrities recommended books for Tony Blair to read. Will Self, that literary grump, said that the prime minister should read John Gray's Straw Dogs, as it would provide a "strong corrective to his messianic belief that he, personally, is in a position to effect global change".

Having just read the book, I struggle to see why Blair should take any more notice of Gray's opinions than the drunk bloke on the tube platform I saw last night ranting about how we were all bloody bastards who did not smile enough.

But Straw Dogs could have been an interesting book, if only it was written by someone without such a large chip on his shoulder. But Gray has written the philosophy book for grumpy old men, full of doom-laden predictions for the human race, attacks on a long list of philosophers for having ever had any faith in humanity and a perspective on individuals that entirely rules out free will.

I suspect an evening out with Mr Gray would not be a particularly jolly affair. Gray agrees with James Lovelock, author of Gaia, that the Earth suffers from a "plague of people". Humanity today should be classified not as homo sapiens but homo rapiens, he says. At one point, presumably written in the early hours of the morning after a long chat with a fellow grump, he writes: "the Earth will forget mankind. The play of life will go on."

The joy continues with Gray's claim that war is an inevitable part of human existence. He then predicts that wars in this new century may be so severe that "we may look back on the twentieth century as a time of peace." With such a bleak outlook, it should come as little surprise that Gray would actually welcome the decimation of the human race; such a scenario would be his "utopia".

The core claim of the book is that humanity should not try to improve or remake the world. Humanism, with its faith in progress, the central idea behind Enlightenment thinking, Gray claims, is merely a secularised version of the Christian faith. "Humanism is the transformation of [the] Christian doctrine of salvation into a project of universal human emancipation."

But this project is "irrational" and, though technological progress "is a fact", progress in knowledge is a double-edged sword, for "Progress and mass murder run in tandem … As the hope for a better world has grown, so has mass murder."

Our society's faith in progress also prevents us from being happy, says Gray. He quotes Joseph Conrad, "Action is consolatory. It is the enemy of thought and the friend of flattering illusions." Those that struggle to change the world for the better are not heroes; instead, they are selfish and only fooling themselves, for they "seek consolation for a truth they are too weak to bear … their faith … is a denial of their own mortality".

Gray's doom-laden predictions for the fate of the planet would suggest that he would support the causes of environmentalists, but no. For him, environmentalists are just another foolish group trying, in vain, to remake the world.

On the other hand, with all his criticisms of modernity, you might think that he would agree with other postmodern thinkers, but no again. He manages to discuss, and then dismiss, the entire canon of postmodernism in a single page.

However, Gray is postmodernist. In its literal sense, postmodernism merely refers to those authors that come after modernism, and that criticise modernism, just like Gray. His glib dismissal of all of postmodernism, that it is "just the latest fad in anthropocentrism", is lightweight and only serves to reveal Gray's own 'anthropophobic' tendencies.

The title of the book comes from a Taoist saying and helps to illustrate Gray's perspective on humanity. In ancient Chinese rituals, straw dogs were used as offerings to the gods. During the ritual, they were treated with reverence, but afterwards they were trampled on and tossed aside. The saying goes, "Heaven and earth are ruthless, and treat the myriad creatures as straw dogs".

Gray's frequent references to Taoist thought are interesting, but ultimately unsatisfying in terms of the book's thesis. The good life, according to such thinking, is "only the natural life lived skilfully". According to this line of thought, I would have thought that the best response to the challenges of contemporary life is not to write an angry little book railing against how everyone thinks in the wrong way, that most of life is pointless and implying that we are probably better off dead.

Kurt Vonnegut, author of Slaughterhouse 5, does a much better job at putting forward many of Gray's views, but always does it with so much more panache, more meaning and is far, far funnier. In Timequake, Vonnegut has his science fiction writer alter ego, Kilgore Trout, say all the depressing lines.

In one of Trout's odd short stories, he writes, "What grownups have done to grownups left no doubt that the human race should be exterminated. Rehashing ad nauseam what grownups had done to children would be gilding the lily, so to speak."

Elsewhere in the book, Trout says that "being alive is a crock of shit"; this seems a much more straightforward way of putting it than Gray's claim that "the good life is not found in dreams of progress, but in coping with tragic contingencies".

Another problem with Straw Dogs is, almost inevitably, the straw men. Gray spends all his time angrily denouncing a set of ideas that few people believe. Who today says that it is within human beings' power to "emancipate" the whole of humanity?

There was a time when politicians and scientists did believe that human beings could remake the world: an era of five computers running the Earth, of free energy from atomic power and limitless space travel. But then people started pulling down the massive concrete housing estates built in the 1960s for the poor, the Soviet Union collapsed and we rebelled against 'Frankenstein foods'. Politically and socially, modernism is over. Intellectually, Gray is at least two decades behind the times.

And what would happen if everyone adopted Gray's morality-free morality? If we all sat back and contemplated, as he says we should, with "the aim of life … being simply to see", what would happen? Hard to say, but surely any universal claim such as this is contrary to his arguments that there is no single universally applicable good life. It is also curious, but hardly surprising, that Gray's definition of the good life reads very much a description of his own job – he is Professor of European Thought at the LSE.

Also, and as might be typical for a grumpy old man, Gray's definition of the good life has one notable absence: other people. As some science demonstrates, and as most people know anyway, happiness comes from being with other people. Contrary to Gray's claim that people trying to change the world for the better are simply cowards running away from the truth of their own mortality, many people help others simply for the social engagement such projects bring. Most people, I think, would find Gray's ascetic vision of the good life cold and selfish.

As ever, Vonnegut's perspective on life is better: "We are here to help each other get through this thing, whatever it is."