For example, Professor Lewis Dartnell describes how, by about 5,000 BC, humanity had learned to domesticate a wide diversity of edible plant species in a variety of climatic zones and landscapes, with cereal crops being by far the most significant.  Grains have supported millennia of human civilisation, with wheat, rice and maize providing around half of all the human energy intake around the world.  Cereal crops are all species of grass, so the astonishing truth is that we are no different from the cattle, sheep or goats that we leave out to pasture – humanity survives by eating grass! 

Talking of animals, the distribution of wild ones around the world was uneven from the start, with societies across Eurasia receiving an advantage.  The attributes of a wild animal that make it amenable to domestication by humans include offering nutritious food, a docile nature and lack of inherent fear of humans, a natural herding behaviour and the ability to be bred in captivity.  Yet only a relatively small number of wild animals qualify on all these factors, with the zebra, as regular readers will know, failing on pretty much all counts. 

According to Professor Dartnell, of the 148 species of large mammals around the world, 72 are found in Eurasia, of which 13 were domesticated.  Of the 24 found within the Americas, only the llama and the alpaca were domesticated in South America.  North America, sub-Saharan Africa and Australia completely lacked domesticable large animals.  The five most important animals through human history – the sheep, goat, pig, cow and horse – as well as the donkey and the camel that provided transport in particular regions, were present only in Eurasia, and within a few thousand years of their domestication had spread across the continent.  It is the large mammalian species that have proved most influential throughout history, not only for their meat, but also for their secondary products – milk, hide and wool – and their muscle power. 

He goes on to explain that the development of agriculture offered huge advantages to the societies that adopted it, despite the continuous labour involved in working the land and nurturing the crops.  Settled peoples are capable of much faster population growth than hunter-gatherers.  Children do not have to be carried long distances and babies can be weaned off breast milk much earlier, to be fed with milled grain, meaning that women can give birth more often.  And in agricultural societies, more children are an advantage because they can help care for crops and livestock, mind their younger siblings and process food at home.  Farmers beget farmers very effectively. 

Even with primitive techniques, an area of fertile land can apparently produce ten times more food for humans when under cultivation than when used for foraging or hunting.  But agriculture is also a trap.  Once a society has adopted cultivation and its numbers have grown, it is impossible to revert to a simpler lifestyle: the larger population becomes entirely dependent on farming to produce enough food for everyone.  There is no turning back.  And there are other consequences too.  High-density, settled populations supported by farming soon develop highly stratified social structures, resulting in reduced equality and a greater disparity in wealth and freedom compared to hunter-gatherers. 

But once you create a hierarchical society, those with the most vested interests go out of their way to perpetuate the status quo.  As ‘You Know Who’  highlights in ‘Sapiens’, most socio-political hierarchies lack a logical or biological basis – they are nothing but the perpetuation of chance events supported by myths, which is a good reason to study history.  If the division, he says, into whites and blacks or Brahmins and Shudras, for example, was grounded in biological realities then biology would be sufficient for understanding human society.   

Since the biological distinctions between different groups of Homo sapiens are, in fact, negligible, biology cannot explain the intricacies of American racial dynamics or Indian society.  We can only understand these phenomena by studying the events, circumstances and power relationships that transformed figments of imagination into cruel – and very real – social structures. 

He goes on to explain that the insight of polytheism is conducive to far-reaching religious tolerance.  Since polytheists believe, on the one hand, in one supreme and completely disinterested power, and on the other hand in many partial and biased powers, there is no difficulty for the devotees of one god to accept the existence and efficacy of other gods.  Polytheism is inherently open-minded, and rarely persecutes ‘heretics’ and ‘infidels’.  For example, more Christians were killed by fellow Christians in the St Bartholomew’s Day Massacre in France in 1572 than by the polytheistic Roman Empire throughout its entire existence.   

Monotheists have tended to be far more fanatical and missionary than polytheists.  A religion that recognises the legitimacy of other faiths implies either that its god is not the supreme power of the universe, or that it received from God just part of the universal truth.  Since monotheists have usually believed that they are in possession of the entire message of the one and only God, they have been compelled to discredit all other religions.  Over the last two millennia, monotheists repeatedly tried to strengthen their hand by violently exterminating all competition. 

Professor Harari rounds off this part of his argument by saying that the last 300 years are often depicted as an age of growing secularism, in which religions have increasingly lost their importance, which is largely correct when talking about theist religions.  But if we take into consideration natural-law religions, then modernity turns out to be an age of intense religious fervour, unparalleled missionary efforts and the bloodiest wars of religion in history. 

The modern age has witnessed the rise of a number of natural-law religions, such as liberalism, Communism, capitalism, nationalism and Nazism.  These creeds do not like to be called religions, preferring to call themselves ideologies.  But he believes this is just a semantic exercise.  If a religion is a system of human norms and values that is founded on belief in a superhuman order, then Soviet Communism, he argues, was no less a religion than Christianity. 

No wonder it is often easier for many of us just to think about chocolate at Easter!