A speculative human history

Riddle

There are a great many mysteries about humans. Why aren't humans covered in fur like almost all other mammals? Why do they walk upright on their hind legs? Why don't they have tails and claws and sharp teeth? Why do they have such large brains? Why do they speak languages? Why do they make tools, and wear clothes, and build houses, and cook food? Why do they create art and music and literature? Why does recorded human history only go back about 5,000 years, when anatomically modern humans have been extant for 150,000 years?

Is it really very surprising, given all these differences, that humans regard themselves as set apart from other forms of life?

The current view is that all these differences evolved very slowly. It seems to be part of the evolutionary mindset to think of changes taking place slowly and almost imperceptibly. And so we imagine humans gradually losing their fur, gradually standing upright, gradually developing larger brains, gradually learning how to make tools, and weave garments, and build shelters, and paint the walls of caves with images of deer and bison.

From the point of view of Idle Theory, this corresponds to a slow growth in idleness of human life from some original circumstance of unrelenting toil. In Idle Theory, tools serve to increase human idleness, by making work easier. And clothes and houses and farms are tools like any other. And while useful tools serve to increase idleness, luxuries like art and music and literature are what humans use their idle time to create. And so the rich tapestry of human culture which we know today is the result of having much more idle time than our busy ancestors. And since every science and technology always starts life as a kind of luxury - a fascinating toy of one sort or other -, it is only in idle time that innovation and invention can flourish. And so once humans had some idle time, they were able to innovate more rapidly, and produce more tools, and increase their idleness yet more, in an accelerating process. And so most human innovations have been recent ones. And we still live in age of ever-accelerating innovation, with rockets and airplanes, cars and computers and antibiotics, many of them only produced in the last 100 years.

But if the ancestors of modern humans lived such busy, hard-working lives, why did they not become extinct? For a busy life is a life lived at the brink of extinction. And here perhaps is a clue. For humans appear to be the sole survivors of a variety of hominid types. All the rest are extinct. The neanderthals only died out about 30,000 years ago. And homo erectus too. Some sort of disaster seems to have overtaken the hominid type. It is as if there was once a whole boatload of them, and they were all lost in some shipwreck, and drowned one by one. All except homo sapiens, as we like to call ourselves.

But humans don't look like they are a hard-working sort of animal. They are not particularly muscular. They can't run very fast. They have small teeth and residual claws. They have no insulating fur, or protective horns or spines. Humans look like soft creatures that belong to a lost era far warmer than the present day, and in which fruits and foods of every variety were abundantly available to hand. Humans look like they should be living idle lives in a tropical environment, wandering around naked, picking and eating apples and mangoes and strawberries. That doesn't fit very well with a notion of a busy, hard-working, ancestral humanity. It is quite the opposite.

One of our oldest books - the book of Genesis - tells a story which may provide a clue. In this story, an ancestral human couple - Adam and Eve - lived in a garden of Eden. And, one day, after some misdemeanour involving eating the forbidden fruit of a particular tree, they were expelled from the garden into an arid world in which Adam had to work 'by the sweat of his brow' to survive. And it has remained thus ever since. And it is called the Fall of Man.

And perhaps this is what happened to ancestral humans. At one time they lived in a tropical paradise, flowing with milk and honey, and then one day the world fell in, and life became very hard. Of course, it may be that the ancestral Adam and Eve were indeed to blame for their own misfortune. But equally as likely they blamed themselves for events which simply overtook them, and which they had neither the power to initiate, nor the power to stop.

What might have happened to drive ancestral Adam and Eve out of their garden of Eden? There is one very good candidate. And it had nothing to do with eating any forbidden fruit. And it is that Adam and Eve found themselves being overtaken by an ice age in which global temperatures fell dramatically, and sheets of ice several kilometres thick spread out from the poles, and plants grew less abundantly and profusely, and produced fewer fruits and seeds. And so, after having been adapted to an easy life in a tropical paradise, Adam and Eve found themselves having to work harder and harder in a world that was becoming colder and colder.

And it was not just that there was one ice age, but a whole succession of them, one after the other, interrupted with periodic brief warm respites during which the world briefly returned to its previous warm and lush environment.

And it was this succession of deepening ice ages that most likely shaped humanity. If the world had remained a lush, tropical paradise, there would have been no need for humans to start to wear clothes or build houses. If life had not entailed harder and harder work to survive, there would have been no need for tools like flint axes and spears and arrows. It was because life had become difficult that it became vital to innovate in these ways. Because if humans did not innovate, they would not survive.

But if, in a deepening ice age, humans had to innovate to survive, why didn't other animals innovate as well? The answer perhaps is that other animals reproduced much faster than humans, and so could produce innovative variants of themselves, with slightly more fur, and slightly sharper teeth, and all sorts of other slight variations, much faster than humans could. A newborn mouse is ready to reproduce after just a few weeks, and so he or she can produce a whole set of slight variant versions of themselves, some with a bit more fur, some with a bit less. And in a deepening ice age, the furrier ones would tend to survive better than the less furry ones. And so these slightly furrier mice would have even furrier offspring. And so, in the space of a few decades, almost hairless mice would become very hairy mice with thick coats of fur.

But larger, slow-reproducing humans couldn't adapt so quickly. They only reach puberty at the age of 15 years or so. Cattle and horses reach sexual maturity aged 1 or 2 years, dogs and sheep after 7 months. while most animals could rely on natural selection to rapidly adapt them to their environment, humans could not adapt so quickly. They couldn't grow themselves coats of fur, or sharper teeth and claws. They were stuck.

So if humans were to survive, they had to innovate. They had to find some alternative way of keeping warm in the chilling world they found themselves in. They had to find sharp tools to provide them with the teeth and claws their animal cousins were rapidly evolving to produce.

All the large, slow-reproducing animals of that time were probably facing extinction. And humans were facing extinction too. And so were other hominids like them. If humans survived by making tools, clothes, shelters, it was probably because they were uniquely able to make such things. They had highly adaptable hands which could clutch hold of all sorts of things. If humans had hooves or trotters or paws, they would have undergone extinction. But because humans were uniquely able to take hold of things in their hands, and pile up wood and leaves to make shelters, or weave together strands of hair to make clothes, and sharpen sticks to make spears, they were able to artificially adapt to their new environment.

And because they had not adapted to this environment by growing thick coats of fur and sharp teeth like they mouse cousins, and had instead fashioned clothes and shelters and pointed sticks, they never did get to grow coats of fur, or sharp teeth and claws. They remained as they had been before the ice age descended.

But having hands wasn't all they needed. Before they could fashion clothes, or build shelters, or sharpen sticks, they first had to have had the bright idea to do these things. And it may not have occurred to many of them to do any such thing. And so it was the more imaginative and inventive humans who undertook these innovations. And if being imaginative is something that comes with a larger brain, then it would have been the humans with imaginative larger brains, who'd figured out how to weave garments and build huts and sharpen staves, who tended to survive, and to live slightly more imaginative and bigger-brained offspring.

And in addition to this, humans may have come together to form co-operative communities in the deepening ice age, because sharing work is a way of lightening work: it's easier, for example, for one person to cook for everybody than it is for everyone to cook for themselves. And as they came together in communities, they had to learn to get along with each other, and to communicate with each other. And so those humans who could speak a bit, and who could create words for things like "trees" and "apples" and "water", could co-operate more easily and effectively with each other. And humans learned to trade with each other, because trade also saves work, and increases idleness: it is easier if one person collects lots of shellfish and brings them back to a human community than it is for everyone to go and get them themselves. And so human societies, and human trade, and human ethics, and human language all grew out of the same deepening catastrophe. And dexterity and innovation and language and morality all required their own extra intelligence, and so their extra few cubic centimetres of grey matter. The human brain is a sort of muscle, and, much like muscles, it grows bigger when it has to work harder, as humans are selected for intelligence.

And so, in this new account of human history, it is supposed that almost everything we think of as uniquely human was the consequence of human adaptation to an ice age. Human idleness began to plunge as the ice age was entered, and temperatures fell, and plants grew less abundantly. It was only when humans began to come together in co-operative communities, fashioning clothes, building shelters, lighting fires, making tools, that their idleness began to rise. Or at least stopped falling so precipitately.

And so, in this formation of human society, born out of necessity rather than free choice, modern human life began. It was a busier life than that of the solo, naked, untooled nomadic humans before them. It was busier because there was so much more that had to be done simply to survive, in making clothes and houses, gathering firewood, digging for scarce roots, trapping fleeing animals. But if it was busier, it was at least a way of survival.

We might look at the logic of what happened rather more closely.

Ice Age

Over the past several million years, the Earth has been gripped by recurrent ice ages, during which large sheets of ice, several kilometres deeped, formed over Europe and North America. There were also glaciers in the Atlas mountains of north Africa, and in east Africa. During these ice ages, temperatures plunged by up to 10 degC. The ice ages typically lasted 100,000 years or so, but were regularly interrupted by warm interglacial periods of the kind we are now enjoying.

These ice ages, or at least the last four of them, followed a similar pattern. A brief interglacial periodcame to an end, and temperatures plunged sharply by 5 degc over a short period of time. And then, through the subsequent 100,000 year ice age, the temperatures continued to gradually fall, until at the nadir the temperatures equally suddenly rose to give way to another brief interglacial period.

How would naked, untooled human nomads have experienced this succession of ice ages? How would they have responded?

Falling temperatures would have resulted in reduced plant growth, and fewer or smaller plant fruits and roots. And this would have meant that humans would have had to work harder to find food, and that their idleness would have fallen.

Body Heat Loss

Falling ambient air temperatures would have brought increased heat losses from the human body. Humans could have responded in several ways to counter this loss.

• They could have generated more body heat by becoming more active. This would have required gathering and eating more food to provide this energy, which would have meant more work, and reduced idleness.

• They could have used fires to raise air temperatures. This would have required cutting wood, which would mean more work and lower idleness.

• They could have made insulating clothes for themselves to reduce heat losses. This would have required acquiring animal fur or wool.

• They could have constructed shelters. This would have required cutting wood as building material, and reduced idleness.

• They could have grown fur like other mammals. This would have required gradual adaptation over many generations, but would not have entailed any extra work.

Of these, the last - growing fur - would have only been a realistic option if temperatures had fallen gradually. For fast-reproducing animals, facing exactly the same heat balance problem, adaptation of this kind would have been much easier, and may well have been achieved in a few decades. But rapid falls in temperatures over a matter of a few decades would have been too much for humans and other slow-reproducing animals to respond to by adaptation of this kind. And as can be seen in the temperature record above, temperatures fell very sharply 120,000 years ago after the end of the Eemian interglacial period. They may well have fallen too rapidly for humans to adapt.

Instead humans would have had to adopt one or several of the other alternative courses of action. They had to either become more active, and eat more, or build fires to warm themselves, or they had to make clothing and shelter. All these courses of action would have entailed extra work of one sort or other, and so human idleness would have fallen as ambient temperatures fell.

If humans had opted to become busier and eat more food as temperatures fell, they would have found that they would be looking for more food just when foods were becoming scarcer, because all living things would have been working harder to survive, and would have had less capacity to reproduce to produce their former abundance of fruits, nuts, seeds, eggs and other produce.

And furthermore, just when humans would have been looking for more food, other animals would have been too. Predators of every kind would have become more active as temperatures fell, and humans may well have found themselves subjected to increased predation. And this may well have resulted in a need for defensive measures against predators, which would have required yet more work.

The result would most likely have been that humans began to construct shelters that served not only to keep them warm, but also served as defences against predatory attacks. Humans would have spent nights in these shelters, only going out in daylight to gather or hunt for food.

If humans were still living nomadic lives, these shelters would have had to be portable tents, to be carried from one hunting ground to the next. Or they would have been temporary shelters thrown up in a day or two using locally available materials, earth and leaves and branches.

Only when humans began to form settled trading societies would their shelters have become more robust and enduring structures, made from wood and clay and thatch, or later from brick or stone.

It was probably easier for humans to build shelters than to make garments for themselves by sewing together the pelts of animals or weaving fabrics from plants or hair. Clothing of any sort has to be flexible enough to permit easy movement, light enough to not be a burden, and strong enough to endure many kinds of stresses. Shelters for the most part would not need to be carried, nor would move very much, nor have to endure a great variety of stresses. And so building shelters was probably easier than making garments, and so probably preceded making such garments.

Humans would have made insulating garments out of animal furs. But they may also have learned to weave a variety of materials into fabrics. They may even have used their own superabundant head hair to weave cloth.

Whichever of these strategies humans adopted, it would have meant that they would not have adapted like the animals around them by growing additional body hair. For once they were reliant on clothing and shelter and fire, there would have ceased to be any need to grow a thick coat of fur. And this was probably one reason why the naked ape was to remain naked.

As the ice age deepened, and temperatures continued to fall, humans may have had to use all the various strategies open to them to maintain a heat flow balance. They may have worn clothes inside well-insulated dwellings permanently warmed by fires, and consumed hot food and drink, and also kept physically active.

And this may offer an explanation for another human custom: the dance. After spending a busy day outdoors, in the evenings when no work could be done, in this idle time chilly humans may have kept themselves physically active - and warm - by dancing until they fell asleep exhausted. Much the same may have applied to athletic sports, which may have been a way of keeping warm as well as passing idle time.

Food

In the interglacial prior to the ice age, when plants flourished, and produced abundant fruits and seeds, humans may well have lived almost entirely off plant foodstuffs.

But in the ice age, during which plant fruits and seeds and roots were much less abundant, humans were probably forced to adopt a carnivorous lifestyle, feeding off those grazing animals which fed from still-abundant plant leaves.

Humans would probably also have wanted the furs of such animals, to make into garments of one sort or other. And they probably found uses for animal bones, horns, guts, and sinews.

Humans probably also began to cook food around this time. Cooking food served to make it more readily digestible. And by killing off bacteria and insects, it served also to preserve foods. And eating hot food was also a way to directly warm the interior of the human body. And the fires on which foods were cooked served also to heat human dwellings.

Work

In their nomadic past, wandering naked in a hot environment, they may well have had little need for shelter or warmth or hot food, and so had little demand for wood. One of the consequences of building shelters from wood, and burning wood in fires for heating and cooking, and also perhaps using wood to make furniture and tools, would have been that humans in the depths of the ice age had need of large amounts of wood. The few loose twigs and fallen branches to be found would not have sufficed. Humans would have needed to cut down substantial trees.

And most likely for this purpose they used stones to split and pulverise the wood. And the best stones for this purpose were flints which could be knapped to produce a sharp edge. The trade in flints from many miles away may well have been primarily driven by the need to cut large amounts of timber, either to burn or to use in building construction.

And at the same time that they were cutting down trees and chopping them up, prior to the domestication of horses and oxen, humans would also have been themselves carrying this wood several miles back to their dwellings.

The result would have been that, in addition to carrying food back to their dwellings, humans would also have been carrying wood, flints, and any number of other things quite considerable distances, particularly when these were items traded with other humans. In fact it may well have been that most of the physical work that humans performed was in carrying one thing or other - fruits, animals, wood, stones - distances of several miles.

And this may well have required humans who were carrying objects in bags or baskets, held in their hands or carried upon their shoulders or heads, to adopt a near perfect upright stance. For to the extent that they could keep a straight back and straight, the load would be passed directly down through their spine and leg bones. And to the extent that their spines or legs were curved or bent, to that extent they would have needed to hold themselves erect using muscles in their legs and back, which would have soon led to excruciating pain, and to premature arthritis as joints between bones ground repeatedly together. Human males who were every day carrying considerable burdens became selected for broad shoulders and straight backs.

And if women were carrying children on their hips, this might well have served to shape women to give them a lower centre of gravity.

In this manner, humans may have been shaped by the work they performed, just as much as the tools they used were shaped by the purposes for which they were employed.

Measuring Idleness

As the idleness of ice age societies fell with falling temperatures and scarcening food supplies, and rose as they adopted new tools and techniques, it would have been a matter of primary concern to know exactly how idle (or busy) their lives were, and to keep track of the rising and falling trends. Because they probably knew very well that if work became continuous, they had reached the point at which they faced collective death. There would have been many societies which simply ceased to be able to survive. Traders returning to far off communities would have often found them deserted, and all their members dead. Or one or two suvivors may have struggled out from them bearing harrowing stories of unbearable hardship.

And there would have been at least one simple way for these societies to accurately measure their own idleness. And this would have been to separate busy time from idle time. Rather than interspersing their busy lives with short intervals of idle recuperation, they would have kept them entirely apart. Over some period of time - perhaps 10 days - they would have set out to gather in a few days all the food and timber and water that was needed for 10 days of life, and when this task had been completed, all would spend the last few days of the 10 day period in complete idleness. And so if their idleness was 30%, they would have found that it took 7 days to do all the necessary work for 10 days of life, and they would have 3 days of idle time. If idle time was distributed throughout the same 10 days, it would have been far harder to discern what their true idleness might be.

And at the same time as this division of time into a busy working week and an idle weekend or sabbath was instituted, they would have begun to discover who was more idle or less idle than others. And they could have acted to redistribute work so as to ensure that no one person was too heavily burdened. It may have been that the idle weekends would not begin until everybody had completed their work, and those who finished work early would assist those whose work was not yet completed.

And this division of work from leisure would also allow them to see which tasks were taking longer and which shorter, and direct their innovative skills to divising ways to make work easier.

The idle weekends would not have been periods of doing nothing. It would have been during these weekends that that they would have gathered to discuss their lives, to air their concerns, to settle grievances. And it would have been during these idle weekends that they would have toyed with innovations. The woodcutter might try out a new axe, the potter a new kind of pot, the ropemaker a new kind of knot.

And while it would have been impermissible to idle during the working week, it would have been equally impermissible to work during the idle weekend, because if either of these happened, the accuracy of the measure would be compromised.

In this manner, in idle times they would have enjoyed long weekends, and in the busiest of times short weekends. And woe betide them if they grew careless and ceased to measure their idleness, or take idle time for granted.

Ice Age Human Society

The human ice age society which is emerging from this analysis is one in which humans lived very busy lives. Not only were they gathering plant foods and hunting animals, but they were also chopping down numerous trees, and carrying food and timber and water over considerable distances. Life in an ice age village would have been lived in a haze of smoke from many fires, and in the constant din of wood being chopped.

And it was above all a social life in which all concerned were entirely dependent for their continued survival on everyone else. They would have been spending most of their time working on behalf of other people, gathering food, cutting wood, hauling water, cooking food. There would have been little individual freedom.

It might be supposed that these societies were highly coercive in nature, and many of their members were driven slaves working under hard taskmasters. But there are several powerful arguments that they were not. And the first of these is that coercive societies - slave societies - must always be performing extra work in coercing unwilling slaves. Slave societies need slavemasters wielding whips, and chains and manacles, and punishments, and this is all extra work. And this means that coercive societies must always be less idle than co-operative societies whose willing members voluntarily obey orders without any need to beat them or whip them into action. And so when a deepening ice age drove human idleness down towards zero, and extinction, it would have been the voluntary societies with willing members who would have outlived coercive slave societies. Slavery was a luxury that could not have been afforded. Ice age human societies must have been made up of human members who willingly and regularly acted for a common good which coincided with their own good.

A second argument is that, at very low levels of idleness, human societies cannot tolerate large disparities of idleness between individuals. It is simply not possible, at low levels of idleness, for a toiling majority to support an idle minority. In busy societies there will always be an approximate equality of idleness between the richest or idlest members of society and the poorest and busiest. In ice age human society, living not far from the brink of zero idleness extinction, their kings would have lived lives that were just as busy as any of their wood-hewing subjects. And the king gained nothing from his office, except the power to command. The king was just one toiling worker among many. It was simply that it was his task to make decisions which affected everybody's lives, rather than to chop up wood, or carry water from the nearby stream.

And finally, in the busiest of societies, in which there is next to no time for individual personal choice, most humans would not have cared much to preserve their choiceless lives. Why should anyone wish to prolong a life of endless toil? How much nobler to sacrifice it, to heroically give up one's life for one's friends. What was there, in that toiling life, that anyone would want to cling on to? It is in relatively idle societies that people tend to value their lives, and to become unwilling to sacrifice that life for the sake of others.

There would have been few luxuries in this life. There would have been little time to make toys and trinkets, or to enjoy the pleasure of them. Or rather, it would only have been during their idle weekends that they would have whittled dolls from pieces of wood, or decorated their clothes.

They would have been immensely practical people. They would have been interested in any and every innovative technique or tool. They would have had little time in which to reflect upon their lives, and so would not have been of an intellectual or philosophical nature. They would, much like soldiers in wars, have had a strong sense of camaraderie. Of 'one for all, and all for one'. And perhaps also the same fatalism and superstitiousness as soldiers.

Interglacial

The ice ages seem to have regularly ended with temperatures rapidly rising some 10 degC, the ice sheets melting, sea levels rising with the added melted ice.

And these rising temperatures would have entirely reversed the trend of the previous 100,000 years. Instead of life always getting harder, life would have begun to rapidly become a lot easier.

And with this reversal, everything went into reverse. It became less and less necessary to chop down trees to light fires to keep warm, or to build substantial dwellings against the bitter cold. Miserly nature burgeoned into florid abundance. Human idleness rose sharply.

But while this would have undoubtedly been very welcome, it would have spelled the end for the ice age civilisation. For, almost overnight, most of its technology would have become redundant. There would have been no need for for timber to burn or use to constuct robust dwellings, and no need for a regular supply of flint axes. Established patterns of trade would have broken down.

And disciplined, co-operative human societies began to disintegrate. Whereas once ice age human communities had gained willing members from starving solo nomads, they now began to lose them. If nothing else, human societies which had been constrained to small geographical areas could now survive in ever-widening geographical areas. Formerly highly cohesive human societies began to break up as their members began to strike out towards new frontiers. There was no longer any need for the tightly disciplined ice age civilisation. It had become obsolete. Humans began to disperse across the warming globe. Given a more idle existence, humans began to live longer, and human numbers began to rise.

And with this the modern interglacial age was born. If it was one in which a new human civilisation arose, it was also one in which an older human civilisation collapsed. The new civilisation was primarily a much more idle civilisation, whose idle time was increasingly devoted to cultural activities - to art , music, architecture, dance, theatre, literature, poetry, philosophy, history, science, games, holidays, tourism. It was a far more playful civilisation. It was far more free and individualistic. It was far less co-operative. As the shackles of unrelenting work fell away, so also did human community, human morality and law, even human language. The dispersing humans began to speak different languages.

And it was forgetful of its past. And there were regular attempts made to 'restore order', and rediscover the discipline and selflessness and social cohesion of a lost ice age civilisation. As well as art and music and high culture, it was in this disintegrating ice age civilisation that slavery and persecution and intolerance first appeared.

Modern Anthropology

In the foregoing account, it is assumed that global temperatures fell sharply during the ice ages, and that plants grew less abundantly, and produced fewer edible seeds and fruits, and that consequent;y humans had to work harder to survive, and their idleness fell.

However, many anthropologists seem to believe that human idleness during the palaeolithic period (which includes the last ice age) was actually quite high. Marshall Sahlins in Stone Age Economics suggests that palaeolithic humans had plenty of leisure time. He cites two hunter-gather societies living in Australia in the 1960s, who could gather sufficient food with only 5 hours of work each day. Sahlins seems to have assumed that the life of Australian hunter-gatherer societies in the 1960s would have been much like hunter-gatherer life in the palaeolithic.

Also, contrary to earlier notions, anthropologists are now generally agreed that people in small-scale hunting societies traditionally have had ample time for leisurely pursuits. As Sahlins has suggested, "hunters keep bankers' hours." For palaeolithic man leisure was likely the expected norm, and free time at a surplus.
(Kendall Blanchard. The anthropology of sport. p 97)

But was this a reasonable assumption? Were the anthropologists right to agree? The answer must be No. There isn't really a single 'hunter-gatherer lifestyle' which is always as leisurely as that of Australian aborigines. A hunter-gatherer lifestyle will only be as leisurely as there are plants and animals sufficiently abundant to support it. The Australian hunter-gatherers were enjoying the modern global interglacial climate. Palaeolithic hunter-gatherers would have mostly been enduring an ice age climate which may well have be 10 degC cooler, and with fewer plants and animals. And because of this they would have necessarily been busier. Not just humans, but almost all living creatures would have found life harder during ice ages, and would have flourished with higher temperatures.

But once it was accepted that palaeolithic life was a largely leisurely existence, it poses a puzzle as to why the successors of palaeolithic humans should have adopted a much less leisurely agrricultural existence.

These [late Palaeolithic] paintings alone reveal a society that was confident, settled, and with enough spare capacity to support specialists and intellectuals. Life, for human beings, has surely never been better. Such a vision feels good: it is what our psyches are geared to.
So why give it up? Why turn to full-time agriculture?
(Colin Tudge. The idle shall inherit the earth.)

Tudge's explanation is that the agriculturalists had adopted a work ethic in place of a leisure ethic. They had become materialistic and acquisitive and bourgeois. It was, in short, a moral choice they made.

But this is to suppose that palaeolithic humans living idle hunter-gatherer lives opted to surrender those lives in favour of a hard-working agricultural existence, after weighing up the pros and cons of the two ways of life.

It was almost certainly not like that at all. What would have happened would have been that, while the hunter-gatherer lifestyle may initially have offered a leisurely existence, as environmental conditions changed, and plant and animal foods became increasingly scarce, it offered a less and less idle existence. In order to survive, hunter-gatherers had to not only gather plant foods but also to plant their seeds to ensure a future harvest. And they may have also had to clear away encroaching plants. And they may have had to dig irrigation canals. And they may have build hedges or fences to keep other animals from consuming the harvest. And in this process the hunter-gatheres would have gradually metamorphosed into agriculturalists. This agricultural life would have entailed a lot more work - planting, weeding, watering, fencing - than the original hunter-gatherer lifestyle of gathering a natural windfall and moving on. But once the hunter-gatherer lifestyle ceased to be a viable way of life, and hunter-gatherers died out, the agricultural lifestyle would have been the only way left to survive. No change in values was required. No acquisitive, bourgeois materialism needs to be invoked to explain the transition form hunter-gatherer to agriculturalist.

It is exactly the same as with humans during an ice age, who have taken to making clothes and building shelters, and feeding fires. This was all extra work relative to their relatively idle naked precursors in the preceding interglacial period. But that is the wrong comparison to make. The simple fact of the matter was that in the ice age it had ceased to be possible to survive by continuing to live a naked, unsheltered, and untooled existence as before. Anyone who had tried to do that would have found themselves working harder and harder to live, until it became impossible. It wasn't that ice age humans swapped an idle, naked, untooled interglacial lifestyle for a busy, clothed, tooled glacial lifestyle because their values had changed, and they had become bourgeois home owners. It was that there was no other way to survive.

Sahlins and Tudge can't seem to see the underlying physics of the changing human situation. For them the hunter-gatherer lifestyle offers a constant and unchanging 'leisurely' life, and agriculture offers a constant and unchanging 'hard-working' life, and so they hunt around for an explanation why anyone should exchange a leisurely life for a hard-working life, and they can only suppose that it is because the values of the agriculturalists are different from those of the hunter-gatherers, and that the agriculturalists have become greedy, acquisitive, and bourgeois. But what really changed was not the morality of agriculturalists, but the basic physical circumstances of life.

Summary

In the above account of human history, in the face of a deepening 100,000 year ice age, humans came together to form tool-trading communities. These human societies were more idle than untooled solitary nomads, who died out shortly after the beginning of the ice age. Human idleness remained low throughout the ice age, as temperatures continued to fall. At the nadir of the last ice age, when the temperatures were at their lowest, first Homo erectus and then Homo Neaderthalis became extinct. When the modern warm interglacial interlude began, the ice age human society disintegrated as humans began to spread across the warming globe.

More or less everything that goes to make up human civilisation was forged on the anvil of the ice ages. But for the ice ages, humans would have continued to live idle, lone, untooled, nomadic lives. It was during ice ages that humans had to wear clothes and build shelters and tend fires. It was during the ice ages that humans had to work hard to survive, and began to make a variety of useful tools - e.g. flint axes to cut down trees. It was during ice ages that humans were welded together into co-operative trading societies, because co-operative work-sharing and trade served to increase their idleness. These hard-working ice age communities proably had relatively little leisure time, and so were unable to produce much in the way of art or luxuries or amusements. These communities were probably highly disciplined, with strict moral codes. They were probably never very numerous.

At the end of the ice age, some 20,000 years ago, as temperatures rose and plants began to grow more abundantly this ice age civilisation disintegrated. Life got easier, and human numbers began to rise, and humans began to disperse across the entire globe. The discipline and morality of ice age civilisation was largely abandoned, along with most of its technology. Some humans may have reverted to a lone, untooled nomadic existence. In the new age, humans were more idle, independent, playful, and self-centred. In their relatively abundant idle time, they produced art, music, and literature. In time, despite the higher ambient air temperatures, humans began to face new difficulties. Perhaps, as their numbers rose, it became increasingly difficult to maintain a hunter-gatherer existence, and humans began to settle and build farms. What had been common land began to be fenced off and hedged around, and predatory animals and wandering nomads excluded from them. And this led to conflict, first between settled farming communities and wandering nomads, and then between rival farming communities seeking fertile lands.

The arguments that have been put forward here have been arguments from the simple physics of human energy expenditure and income. In the cold ice ages, when the land was relatively barren, humans would have had to work harder to survive. And this meant falling idleness. Joining together to form co-operative, trading, work-sharing societies was one way that humans managed to compensatorily increase idleness. Making clothes and building shelters and fashioning labour-saving tools was another way.

Humans never developed a thick coat of fur because they didn't reproduce quickly enough to do this if temperatures plunged too rapidly, and because they used clothing and shelter and fire instead. They didn't develop sharp teeth and claws because they produced tools in place of teeth and claws. They stood upright because they were frequently holding tools in their hands, or carryng loads in their hands or on their shoulders. They needed ever larger brains as they began to dream up new tools, fashion them dextrously, speak to other humans, and perform more and more complex tasks. They created art and music and other 'cultural' artefacts only to the extent that they had the idle time to do so. When conditions changed, and the ice age ended, an entire disciplined and hard-working way of life came to an end.

In this approach, human life is seen as being governed by a least action principle. Humans did what was easiest, even if what was easiest required a great deal of work. In fact, the more hard-working humans were, the more important it became for them to do what was easiest. It was only when life was easy, and humans had plenty of idle time, that humans began to choose to use this idle time in ways which were not governed by a least action principle - and began to take their leisure activities more seriously than their work, and became wilful individualistic moderns.