WHEREAS HUNTER-GATHERERS DIDN'T MAKE IT TO MIDDLE-AGE:

What allowed humans to become history's most successful species, he argues, was our ability to construct and unify small groups behind certain "fictions" - everything from national legends and organised religion to modern value systems like human rights, and the modern limited liability company with thousands of employees and vast credit lines at its command.

Any band of Neanderthals, Harari suggests, can raise a few dozen people for a hunt but humans can tell the stories needed to ensure co-operation in groups of 150 or more - numbers large enough to organise mass hunting using prepared traps, raise modern armies, or subdue the natural world.

Also woven into this theory of humankind are his own convictions about eating meat. Sapiens devotes large sections to unsparing accounts of the domestication and factory farming of cows, pigs and chickens. This, he contends, has made them some of the most genetically "successful" creatures in history but the most miserable too. [...]

I tell Harari I like the idea of fiction as the supreme human construct. When reading a novel, I am happy to suspend disbelief and believe the characters are real people; does the same principle apply in other areas? "Yes, it really is the main thing," he says. "We can suspend disbelief about Harry Potter, and we do the same thing with God, and we do the same thing with human rights, and we do the same thing with money."

Limited liability companies, he writes, are among humanity's most ingenious inventions but "exist as a figment of our collective imagination", even if we have grown so used to them that we have forgotten this. Whereas an early human business lived or died on the fortunes of its owner-founder, the modern corporation (from "corpus" for body, Harari reminds us) has a life of its own thanks to our collective faith in the "fiction" of the legal code.

"Everybody since the '60s has been saying the nation is a fiction, the nation is an imaginary unity, but people didn't connect the dots and say all human endeavours sprang from the same principle," he says.

Harari's achievement in Sapiens is applying the same postmodern theories to history, anthropology, capitalism, and other areas and arguing that the whole power of humankind arises from that. "If you take 10,000 chimpanzees and cram them together into Wembley Stadium or the Houses of Parliament, you will get chaos," he says. "But if you take 10,000 people who have never met before, they can co-operate and create amazing things."

His thesis is vivid, provocative and enlightening. But in places I did feel Harari was stretching his universal theory to reflect personal hunches or biases. He regards the hunter-gatherer period, for example, as a golden age when people had balanced diets and a meaningful, healthy and active life, and suggests that history took a wrong turn somewhere around the agricultural revolution, which tied man to settlements and their oppressive institutions.

"Nothing in the comfortable lives of the urban middle class can approach the wild excitement and sheer joy experienced by a forager band on a successful mammoth hunt," he writes. I point out that we are two middle-aged men about to eat a vegan meal, and that I for one would not make a very good hunter-gatherer.

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