6

The Imaginative Animal

Uncovering the dynamism of culture

In the background of one of Salvador Dalí’s most famous paintings, an indistinct ocean fades into a vague sky. The work is ‘The Persistence of Memory’—but the name is an instance of the artist’s ironic sense of humour, because every image in the composition illustrates the evanescence, weakness, wobbles, and waywardness of our powers of recall. The vanishing ocean erodes a neighbouring cliff. A tree withers. Sands shift. Gigantic clocks and watches buckle, melt, and sag with the passage of time. They corrode or house corrupting, devouring bugs and parasites. In the middle of the canvas, a watch mutates into one of Bosch’s monstrous fantasies. This seems apt: memories do become monsters.

It is astonishing to me how little interest historians take in the cognitive science of memory, because so many of the sources on which we rely pass through the medium of remembrance before they get to us. Some of us are aware that memories are socially or culturally constructed. Some of us ask our students to read the work of Maurice Halbwachs on social or so-called collective memory and reflect on his maxim that ‘the past is not preserved but is reconstructed on the basis of the present.’ ¹ Yet the problems of memory go much further than that: to the roots of individual recollections, on which social memory depends and of which most historical sources are composed. We know very little about individual memory except that it is usually bad. There has been an enormous amount of work in recent years by psychologists, anthropologists, but above all by neuro-physiologists, which combines to undermine our faith in memory even further.

In the work of a psychologist such as Alan Baddeley, it resembles a trick-mechanism for evading awkward facts, as much as a trap for capturing them. ² We practise convenient oblivion. We retrieve memories through rosy filters. The memory is the massage. Among anthropologists, in work well represented by a paper by Jack Goody and Ian Watt, ³ it is now a maxim that in non-literate cultures orally transmitted memories are not fossilized, word for word, in bardic retrieval-systems. Perpetual retelling substantially recreates, re-invents them. Memory is wired to be warped. It is not a highway for time travel: the past to which it takes you never really happened quite in the way you think. Recall is a siren call.

Surprisingly, perhaps, this is just what one would expect from the results of experimental work in recent years by cognitive scientists working with literate subjects. Memories are ‘recorded’ or registered in an environment of hectic neural activity, in which synapses fire and proteins are generated: in the judgement of the leading authority, Daniel Schacter, it is practically impossible to suppose that memories are recorded unchanged:

Memories are never exact replicas of external reality. Psychophysical studies and electrical recordings from the brain have shown that incoming sensory information is not received passively…In this sense all memories are ‘created’ rather than simply ‘received’. No memory or mental image exactly replicates the constellation of nerve impulses associated with the initial sensation. Past experience, encoded in the strength of synaptic connections throughout the activated neural networks, modifies the incoming information. ⁴

This is, for historians, equivalent to the uncertainty principle for physicists. The environment in which memories are retrieved introduces more levels of uncertainty, while often at the same time deluding the memorist into ‘a conviction of accuracy which the empirical data does not support’. ⁵ So memory is always removed from reality, though, for reasons we still do not know, it works better in some cases than others. Unless and until we understand how differences between good and bad memory arise, caution and scepticism are our best recourse.

Despite the glaring deficiencies of human memory, we seem glibly to assume that we must be better at remembering than other animals are. According to a long-standing shibboleth, humans are our planet’s only time travellers: only we can remember and therefore situate ourselves in the dynamic of time—revisiting the past, envisioning the future. Obviously animals have to be able to remember objective facts; otherwise they could never return to their caches or nests or retrieve their routes, but most academic experts have endorsed the belief that human memories are of a different order, because self-consciousness enhances them. ⁶ Most people still share Robert Burns’s opinion of his ‘wee, sleekit, tim’rous, cowering’ mouse, whom, he thought, ‘the present only toucheth’, as if the little creature were arrested in time, aware only of the immediate. ⁷

The distinction between brute memories, isolated in the present, and human memories, comprehending time, now seems false. Western scrub-jays can remember not just what food they hide but also where and when it was hidden. Experimenters with rats have emulated the success of those who work with jays. Rats, who can find their way around mazes the complexity of which would leave me lost, return unerringly to the places where they formerly encountered food. They also pass tests designed to tell whether they can remember the order in which they encounter smells. ⁸ Clive Wynne, an elegant advocate for believing in non-human minds, who is well known for imagining what it would be like to be a bat, summarizes some of the relevant experiments:

In the laboratory, pigeons can remember which out of hundreds of arbitrary visual patterns will be followed by food, and their memories show little sign of degradation months after the initial experiment. Pigeons also remember what their neighborhood looks like, so that they can find their own loft as they return from homing flights. Honeybees remember which parts of a maze contain food. Chimpanzees in the wild can remember where they left the good heavy stones that make excellent anvils for bashing nuts open. Chimpanzees in the laboratory can remember the correct order to press a series of numerals on a computer screen in order to obtain a food treat. Vampire bats can remember who has given them a blood donation in the past and use that information in deciding whether to respond to a petitioner who is begging for a little blood. ⁹

It would be reasonable to object that although we class all these instances as memory, they may represent phenomena best understood as of different types. People who want to belittle non-human memory might insist that many of the non-human animals’ responses more resemble conditioned reflexes or reactions to stimuli than recollections retrieved from a permanent store. But, apart from prejudice, we have no good grounds for making such a distinction. St Augustine thought that a horse could remember a path when he was following it, but could not recall it back in his stall. But even St Augustine cannot really have known that: he was making an assumption on the basis of dogma: God could not, in his view, have deigned to give horses minds resembling those of His chosen species. Deniers of non-human animal memory today make pretty much the same mistake.

Experiments with chimpanzees and gorillas provide material directly comparable with human experience. Panzee, an exceptionally adept, symbol-toting, female chimpanzee at Georgia State University, presented the head of her lab, Charles Menzel, with a unique opportunity for research into the memory of a non-human animal with whom it is possible to converse: Panzee communicates using cards or keyboard. While she watched, the research team hid dozens of kiwi fruits, pineapples, and toys—including rubber snakes, balloons, and paper. Unprompted, after long intervals of up to sixteen hours, Panzee let her keepers know where the goodies were. She recalled the locations of more than 90 per cent of them. She had never before had to obtain food by pointing to places outside her enclosure. She got no unconscious help from her keepers, who received no advance information on the whereabouts of the treats. She showed not just that chimps benefit from an instinct for finding food in the wild, but also that they—or at least she—can remember unique events and plan the application of her knowledge. ¹⁰ Menzel says ‘animal memory systems have always been underestimated—the upper limits are not really known’. ¹¹

Our memories are bad by comparison with those of other species, at least in some ways. Everyone can summon anecdotal evidence of this fact. My dog is infinitely better than I at remembering how people look (or, I suppose, smell). After seeing Beau, my dachshund, at work, I can believe the Homeric tale of how Odysseus returned home after a twenty years’ absence, unrecognized by everyone except his dog. ¹² On one occasion, Beau showed he recognized a visitor he had not seen for six years by bringing her a toy he had received from her on her previous visit—having gone to rummage for it in some hidden locality, as he never, to my knowledge, played with it himself. He is also prodigious in remembering routes—a skill I cannot emulate. One need only set out for some destination: even if it is only Beau’s second journey along the route concerned, after a long interval since the first, he will bound ahead in utter confidence. We do not have to rely on anecdote. Controlled studies support our conviction that in some respects our memories are feeble by other animals’ standards.

Ayuma, a quick-witted chimpanzee in a research unit in Kyoto, became famous in 2008 when she starred in a TV show, beating human competitors in a computerized memory game. The contestants had to recall images of numerals flashed on a screen for 210 milliseconds. Ayuma recalled 80 per cent accurately. Her nine human rivals all scored zero. ¹³ Some humans have cried ‘unfair!’ because, with practice, they can ape Ayuma. ¹⁴

‘Ape Memory’ has become a popular video-game worldwide, as members of our species try to get up to chimpanzee levels of excellence. ‘Gorilla Memory’ is a comparable game, inspired by King, a gorilla resident of Monkey Jungle, Miami, Florida, who is good at counting. King waves and points to icons printed on cards to communicate with humans. At thirty years of age, he was well stricken with maturity when primatologists picked on him for memory tests, and was well attuned to human peculiarities. He showed that he could master past events in time and array them in order by remembering, with a level of performance significantly well above chance, each of three foods, reversing, when asked to do so, the order in which he ate them. ¹⁵ In his memory, he can connect particular individuals with foods they gave him, even when his keepers have forgotten. He would make a far better witness than most humans at a criminal identity parade. Primatologist Bennett Schwartz has led a team performing acts King had never previously seen. They would do physical jerks, or pretend to steal a ’phone, or play a guitar. When they asked King who had done which performance, he got the answer right 60 per cent of the time: the score may seem unimpressive, but few humans could attain it. ¹⁶

It is not necessary for my case to demonstrate the superiority of non-human memories over human ones. I make the comparisons simply to draw attention to human memory’s poverty, unreliability, deficiency, and distortions. It is always hard to forfeit self-regard. We prize our memories and take pride in them because they seem so precious for our sense of self—something we are only just beginning to concede to other animals. Memory is one of the mental faculties we deploy in devising and preserving so much human culture—our histories, our myths—and which we call on for our inventiveness, starting, whenever we think or make something new, with what we remember of whatever we thought or made before. Most people recoil when you tell them that human memories are not the best on our planet, but the evidence is suggestive and subversive. It is worth pausing to think about this counter-intuitive notion. Humans have almost always assumed that any faculty that might justify us in classifying ourselves apart from other beasts must be a superior faculty. But maybe we should have been looking at something inferior—at least, inferior in some respects—in us.

How can this forfeiture of human superiority have happened?

Daniel Schacter’s explanation is convincing: evolution has given us bad memories, because good ones would make life intolerable. We have to shift clutter out of the lumber room. We have to be able to discard relatively unimportant data to focus on what we really need.

This fact allies memory closely with imagination. Memory is a faculty of seeing something that is not present to our senses—a description that matches imagination with equally perfect accuracy. To put it succinctly, both faculties make us see what is not there. The fact that our memories distort recollections of events that once really happened shows that memory has creative power: it can recast reality as fantasy, experience as speculation. Work on how the brain works confirms the contiguity of memory and imagination, which, as far as we can tell, ‘happen’ in overlapping areas. The electrical and chemical activity that goes on in the brain when imagination is at work is almost identical with that which accompanies the registration and retrieval of memory. This should not surprise us: memory works by forming representations of facts and events—which is also what imagination does. Mnemotechnics, the ancient ‘art of memory’ that Cicero used to deliver speeches in the Roman courts and senate, assigns a vivid image—which may not be a naturally suggestive symbol—to each point the speaker wants to make. A bloody hand might stand for a humdrum point of procedure, a lovely rose or a luscious fruit for the deplorable vices of the speaker’s opponent. ¹⁷

Resistance to the fact that memory and imagination overlap has come from two academic communities: philosophers and jurisprudents. ¹⁸ Aristotle prejudiced philosophers by insisting, with his usual common sense, that memories must refer to the past—and the past really happened. But life sometimes traduces common sense. In practice memories fuse with imaginings. Instead of recalling that uncorrupted past we mingle it with features it never had. Women who remember faithfully the real pain of childbirth would not be as anxious to repeat it as they commonly are; nor would soldiers return to the trenches, unless they suppressed or romanticized the horrors of war. Old men remember their feats—good authority tells us—with advantages. As well as self-interested modifications, we make outright errors, mistaking imaginatively transformed memories for literal copies of the events we recall. Memories ‘recovered’ in hypnosis or psychotherapy or psycho-analysis have life-changing power, but sometimes they are really inventions or transformations. The vices that raddle individual memory—the self-interest, the rose-colouring, the sins of transmission, have their part in shaping social memory, too. Propaganda engraves falsehood in monuments, writes it into textbooks, plasters it onto billboards, insinuates it into ritual. It helps make social memory intractable, unresponsive to facts or historical revision. False memory syndrome, which psychology detects in individuals, is detected by history in whole societies. When individual memories are shared and recorded in enduring forms, the outcome is social memory: a received version of the past, which can reach back to times no individual can claim to remember. We can live with the mercurial nature of our individual memories. But they get turned into social memory by dialogue, context, the input and feedback of those around us.

Some people who work in jurisprudence are reluctant to acknowledge that memory and imagination are similar. For the work of law courts, it would be convenient to separate fanciful repicturings of events in question from real accounts of what happened. We know, however, that any two such accounts rarely tally in practice. The text everyone cites whenever the subject crops up is decisive: ‘In a Grove’, the short story of 1922 by Royonosuke Akutagawa, inspired one of the great works of cinema, Kurosawa’s Rashomon, which forms part of every bourgeois education in movies. Each witness to a murder gives contradictory evidence from his or her own observations. A shaman releases the testimony of the victim’s ghost. But the reader—or the audience of the movie version—remains unconvinced. Every trial, every comparison of testimony, confirms the unreliability of memory. ‘You were all in gold,’ sings a character in the stage-musical version of Gigi. When the lady corrects him (‘I was dressed in blue’), ‘oh yes,’ he says, ‘I remember it well’. We all remember equally badly.

Poorly functioning memory is a vital part of what makes humans imaginative creatures. Every false memory is a glimpse of a possible new future—a reconfigured world that we can aim for if we like.

* * *

The distortions of memory help us by enlarging imagination. Memory is not, however, the whole of imagination. Interesting work by a biomedical researcher, Robert Arp, posits what he calls ‘scenario visualization’, which is really just a fancy name for practical imagination. He links it with a hypothetical psychological adaptation that arose in our hominid history in response to the demands of tool making, such as constructing spear-throwing devices for hunting. He thinks this is a faculty unique to humans—the power of the mind’s eye to transform a stick into a javelin, and then, by a further imaginative leap, to add a throwing spear. No other animal, as far as we know, re-envisions a stick quite so radically, but many find practical uses for sticks in solving other problems—building a nest, fishing for termites, enhancing an aggressive charge in a bid for alpha status, smiting nuts. All problem solving surely involves some ‘scenario visualization’ or capacity for imaginatively foreseeing a solution. When a rat finds its way through a maze, I take it the creature knows where he or she is going. My dog devised an excellent (though ultimately unavailing) strategy for catching squirrels: he took to positioning himself at a point perpendicular to the line between trees, at the mid-point, to maximize his chances of a kill. I am sure he did not do so instinctively, as I watched him learn by trial and error over a period of weeks. I do not class his behaviour as cultural, because he did not acquire it from another dog nor teach it to any of his kind; but I do think he displayed, in small degree, the same kind of foresight that we exhibit in imagination.

He also dreams: the evidence that dogs and cats dream is incontrovertible; they twitch and scrabble with their paws when asleep and make noises consistent with wakeful moods of thrill or agitation. They may be rehearsing or relishing games they have played or look forward to playing, or perhaps they are reliving adventures they have had or hope to have with prey or other food. In any case they are engaged in visions of the unreal. This does not mean they are imaginative in the same sense as humans: sleep is a special, untypical form of consciousness. But it does show some overlap with a visionary property of human minds. ¹⁹

Like Arp’s tool makers, my dog hunts. I do not advocate a return to the concept of ‘Man the Hunter’ as a source of insights in evolutionary psychology, because feminist critics have made the term seem charged with gender (though, to me, ‘man’ is a term of common gender, with which I am happy). The Human Forager is a better term anyway because hunting is a specialized and extremely demanding form of foraging, and even if hunting has a long history as a preserve mainly of men, we need to examine the behaviour of both sexes. Still, Arp surely did well to look to hunting as an activity that peculiarly stimulates and intensively deploys imaginative powers. It does so, I suggest, because all foraging creatures need to evolve a faculty I call anticipation.

Anticipation, like memory, is the power of seeing what is not there—at least not yet: seeing what danger or opportunity might lurk behind the next clump or tree or hummock, envisaging (if not recalling) where food will be found. I take it to be an evolved faculty. Culture might be able to enhance it, but not to create it. Predators and prey both need it: each needs to anticipate the movements of the other. Some need it more than others. Humans, I suggest, need it most, for two reasons.

First, we are deficient in other evolved faculties that might have made our ancestors competitive as scavengers, gatherers, and hunters. We are relatively slow when it comes to eluding our predators or outstripping the competition in a race to a food source. We are poor climbers, unendowed with tails—which condemns us to a limited range of accessible foodstuffs and denies us a timely refuge from the chase. Our senses of smell and sight are poor compared with those of most of our competitor species. Our fangs and claws are small and weak. To compensate for these deficiencies, I can think of no other physical equipment evolution has given us, except for bipedalism, which frees our hands and hoists our standing bodies to a modest but useful degree of elevation, and a good throwing arm, which gives us the means to kill prey we cannot catch and deter predators who can catch us. But the missile faculty only works in combination with keenly developed anticipation, since the thrower has to be able to track the moving target in advance. Anticipation, therefore, is the key skill that made our foraging ancestors fit to survive.

Second, although all primates seem well endowed with anticipation, we are probably the only surviving primate species with a long history of hunting behind us. Chimpanzees also hunt. But no one observed them doing so until about half a century ago. So maybe it is a relatively new activity for them, induced by the environmental stresses human encroachments inflicted on them. In any case, chimpanzee hunting plays a tiny part in chimpanzees’ lives, compared with the role it has had in most human societies for most of the past of our species. Typically, hunting chimps get up to 3 per cent of the calorific content of their diet from the hunt, whereas a study of ten typical hunting peoples in tropical environments similar to those that chimps favour yielded an average figure of nearly 60 per cent. ²⁰ Overwhelmingly, chimpanzee hunters focus on one species, the colobus monkey, whereas every human community has a rich range of prey. It takes up to twenty years for a chimpanzee to learn hunting—chiefly, perhaps, because it is still a relatively infrequent practice and the young have only occasional opportunities to learn—while human children can become proficient after a few expeditions. ²¹ If hunting hones anticipation, it is not surprising that homo sapiens has a more developed faculty of anticipation than other, comparable creatures—even more than our most closely related surviving species. This insight, if it is correct, helps to explain why non-human apes exhibit so much imagination—why, as we have seen, some of them paint pictures, some coin new words, some invent new technologies, some introduce new cultural practices, some adorn themselves—but never take it anything like as far as humans.

Highly developed powers of anticipation are likely to precede fertile imaginations. When we anticipate, we imagine prey or predator behind the next obstacle. We guess in advance the way a threat or chance will spring. But imagination is more than anticipation. It may be, in part, the consequence of a superabundant faculty of anticipation because, once one can envisage enemies or victims or problems or outcomes ahead of their appearance, one can, presumably, envisage other, ever less probable, objects, ending with what is unexperienced or invisible or metaphysical or impossible—such as a new species, a previously unsampled food, unheard music, fantastic stories, a new colour, or a monster, or a sprite, or eternity, or infinity, or a number greater than infinity, or God. We can even think of nothing—perhaps the most defiant leap any imagination has ever made, since the idea of Nothing is, by definition, unexampled in experience.

Imagination is not a faculty that the theory of evolution can predict because, once it reaches beyond the range accessible to anticipation it exceeds the demands of survival and confers no competitive edge. It is, however, a product of the coincidence of two evolved faculties: our bad memories that distort experience so wildly that they become creative; and our overdeveloped powers of anticipation that crowd our minds with images beyond those we need. Culture stimulates imagination further still, partly by rewarding it and partly by enhancing it with psychotropic behaviour. We praise the bard, pay the piper, fear the shaman, obey the priest, revere the artist. We unlock visions with dance and drums and music and alcohol and excitants and narcotics.

‘Don’t we have imagination because we have language?’ a friend asked, who was kind enough to enquire about this book while I was writing it (cf. above, pp. 122–34). The question needs careful parsing, because some people think or claim to think that it is impossible to conceive of anything unless you have a term for it. Jacob Bronowski, the incomparable polymath who, until his death in 1974, was an eloquent spokesmen for the role of imagination in distinguishing humankind from the rest of creation, put it like this: ‘the ability to conceive of things which are not present to the senses is crucial to the development of man. And this ability requires the existence of a symbol somewhere inside the mind for something that is not there.’ ²² Some kinds of thinking are clearly language-dependent, and the languages we speak have measurable effects on how we perceive the world ²³ (though not as much as scholars used to think), ²⁴ but experiments with human infants show that they make systematic choices before they make symbolic utterances. ²⁵ Without broaching the barrelful of studies of the problem of how thought can happen without language, I hope readers will agree that it is at least possible to conceive of a thing first and invent a term or other symbol for it afterwards. So it makes just as good sense to say that language is the result of imagination as that it is a necessary precondition. Of course, once we have a repertoire of symbols the effect on imagination is freeing and fertilizing; and the more abundant the symbols, the more prolific the results. Language (or any symbolic system) and imagination nourish each other, but they may originate independently.

If they are cause and effect, it is at least as likely that language is an effect of imagination than the other way round. Symbols—and language is a system of symbols, in which utterances or other signs stand for their referents—resemble tools. Both are possible because of the ability of the creatures that devise them to see what is not there: to replace absence, to re-envisage one thing as if it were something else. A stick or stone becomes a proxy for an absent limb, or the absent extension of a limb, or a lens for an eye. A sound stands in the place of an emotion or object. A term evokes the entity it denotes, even if no such entity is there. My home, as I write, is hundreds of miles away; so are my wife and my dog; but I can summon their presence symbolically by mentioning it. I possess no wristwatch, but because I have an image of one in my mind, I can conjure the phantasm of it in speech or in writing.

* * *

Imagination is the motor of culture. We look around us. We see our world. In our mind’s eye we see it differently—improved or made more conformable to some imagined model or pattern, ideal or order; or, if our taste so inclines us, we envision its destruction or reduction to chaos. Either way, we recraft our world imaginatively. We act to realize the world we have re-imagined. That is how and why cultures change.

The first migrants from the cradle-land of homo sapiens were pursuing a vision of a life they had never experienced. The first builders saw in advance how they could transform leaves and bones into shelter. The adapters of utterance for communication imagined others’ response. The first cannibals anticipated the effects of appropriating their victims’ prowess and virtues. The first artists in ochre could envision their bodies adorned. The first cave-painters saw a world inside the rocks. The first shamans imagined themselves as animals, with animals’ power over prey. The first magicians imagined themselves manipulating nature. The first mathematicians looked at a plural world and inferred the possibility that numbers might exist independently of their instantiations. The first framers of fields and cities imagined a re-ordered environment, laid out according to an aesthetic that arose in their minds.

I cannot prove any of these speculative reconstructions of the thinking of the long-dead, but I find them convincing—more convincing than locating all these innovations along a putative path signposted by scientific laws. In the formulation of the ingenious French cognitive scientist Dan Sperber, the peculiarities of human culture are the product of humans’ ‘outstanding meta-representational abilities’ ²⁶ —in other words, of imaginations capable of making one thing stand for another.

Another way of putting much the same point is to say that ideas drive cultural change. By ideas I mean thoughts that do not merely represent, or map, or record, or reproduce experience, but exceed it or distort it. Ideas are products of imaginative efforts, because you cannot have them simply by describing the existing world. Ideas have a peculiar property: they ‘breed’. ²⁷ Or, to be more exact, they stimulate each other and become more prolific when they interact. Sometimes they reproduce like amoebas, generating their own progeny. More commonly, they issue from the interactions of minds. An interlocutor’s distinctive take on a subject inspires a new response. A book or broadcast or image or object ignites a new train of thought. A model from an alien culture alerts recipients to new possibilities for changing direction. Misunderstanding intervenes creatively. We misunderstand someone else’s idea: the result is a new idea of our own. Many new ideas are just old ideas misunderstood. The kinds of change thinking ignites—technical innovations, new ways of organizing life—can create conditions propitious for the further multiplication of ideas: this is not to say that technology and social or cultural change cause ideas, but that they help make new ideas possible by facilitating communication or stimulating imaginations.

In consequence, the most culturally productive societies—the most intensely creative, the most innovative, the most dynamic, and the most mutable—tend to be in touch with each other and to experience change most when their contacts are closest. In the early twentieth century anthropologists, mainly working with Franz Boas or in other schools dedicated to fieldwork, accumulated evidence of how cultures develop through borrowing from each other. ²⁸ The proposition is easy to test historically by looking at the circumstances of some of the most spectacular and intensive episodes in the history of ideas in the West: the ‘age of sages’ of the first millennium bce in the eastern Mediterranean; the ‘renaissance’ and intellectual revolution of the high middle ages; and the periods of ‘scientific revolution’ and European ‘Enlightenment’ in the seventeenth and eighteenth centuries.

* * *

In about 33 bce a penniless poet received a gift from the chief minister of the Roman empire: a small farm on the River Tiber, in appreciation of the brilliantly understated verse-satires he had written for Roman salons. It was just what Horace wanted. For the rest of his days he devoted much of his best poetry—some of the cleverest, loveliest work any wordsmith has ever forged—to extolling the simple life of the farm, and praising his patrons. In one poem, he imagined Maecenas, the minister, worrying over what the Chinese might be plotting. In others, Horace pictured Augustus, the ruler, intimidating them with his power, or engendering a future conqueror of China. This was outrageous flattery: there was no likelihood of the Roman and Chinese empires engaging in conflict, or even having much contact of any kind. In 79 ce, China did send an envoy to Rome, but Kan Ying turned back at the Black Sea, deterred by warnings from local enemies of Rome, who did not want the mission to succeed: ‘if the ambassador is willing to forget his family and home, he can embark’. He sent home a favourable report on the Romans: ‘the people have an air comparable to those of China.…They trade with India and Persia by sea.’ ²⁹ That was probably as close as the Roman and Chinese empires ever got to direct mutual dealings. But the fact that Horace was aware of China, and realized that events at the far end of Eurasia could affect Roman interests, shows how communications had transformed the world of the first millennium bce, making it ‘smaller’, as we say now.

Indian world-maps of the period look like the product of stay-at-home minds. Four—then, from the second century bce onwards—seven continents radiated from a mountainous core. Around concentric rings of rock flowed seven seas, respectively of salt, sugar-cane juice, wine, ghee, curds, milk, and water. One should not suppose, on the basis of this formal, sacred cosmography, that Indians of the time were ignorant of the world: that would be like inferring from the subway map that New Yorkers could not build railways. Real observations are detectable under the metaphors of the maps: a world grouped around the great Himalaya; the triangular, petal-like form of India, with Sri Lanka falling from it like a dewdrop; an ocean divisible into discrete seas, some of which may have been fantastic, imaginary, or little-known, but others of which represented routes to frequented destinations and commercial opportunities: the Sea of Milk, for instance, corresponded roughly to what we now call the Arabian Sea, and led to Arabia and Persia. The Sea of Butter led to Ethiopia. Stories of Indian seafaring from late in the first millennium bce, or soon after, appear among Jatakas or tales of Buddhahood, where pilotage ‘by knowledge of the stars’ is a godlike gift. The Buddha saves sailors from cannibalistic goblin-seductresses in Sri Lanka. He extemporizes an unsinkable vessel for a pious explorer. A merchant from Benares, following the advice of an enlightened sage, buys a ship on credit and sells the cargo at a profit of 200,000 gold pieces. Manimekhala, a guardian deity, saves shipwreck victims who have combined commerce with pilgrimage ‘or are endowed with virtue or worship their parents’. ³⁰

These are legends (though they only make sense against a background of real navigation). In Persian sources, similar legends are backed by accounts of real voyages. Towards the end of the sixth century bce, Darius I—an emperor enthusiastic for exploration—ruled Persia. He ordered a reconnaissance of the ocean between Suez and the Indus: this probably extended the range of navigation in the region, since the Red Sea, with its concealed rocks and variable currents, was notoriously hard to navigate. Among the consequences were penal settlements on islands of the Persian Gulf, and a canal from Suez to the Nile: there must have been existing traffic for it to serve, and the result was to increase this further.

To Greek traders, the Seas of Milk and Butter were ‘the Erythraean Sea’—source of aromatics and resins, especially frankincense, myrrh, and an Arabian cinammon-substitute called cassia. Many important ports for long-range trade lined Arabia’s shores. At Gerrha, for instance, probably near modern Al Jubayl, merchants unloaded Indian manufactures. Nearby, Thaj also served as a good place to warehouse imports, with its walls of dressed stone, more than a mile and a half in circumference and fifteen feet thick. From Ma’in—one of the south Arabian states conquered by Saba—a merchant supplied Egyptian temples with incense in the third century bce: we know this because he died in Egypt and his sarcophagus is engraved with the outline of his life. This background explains the death-bed wish of Alexander the Great, the would-be world-conqueror who died in 323 bce, to launch a conquest of Arabia. Before he died, he sent naval expeditions to explore the Red Sea route to the Indian Ocean, and reconnoitre the way to the Persian Gulf from the mouth of the Indus. Thereafter, Greek writers began to compile sailing directions, and geographical and ethnographical data for the shores of the Erythraean Sea.

Arabia, in effect, was a fulcrum of long-range commerce, linking the maritime worlds of the Mediterranean Sea and the Indian Ocean. Omani emporia had a glowing reputation among Roman and Greek writers in the two centuries around the birth of Christ. Yemen was a land so rich in spices that men were said to ‘burn cassia and cinnamon for their everyday needs’. The author of the a text of the second century ce, the Periplus of the Eythraean Sea, believed that ‘no nation seems to be wealthier than the Sabaeans and Gerrhaeans, who are the agents for everything that falls under the name of transport from Asia and Europe. It is they who have made Syria rich in gold and have provided profitable trade and thousands of other things to the enterprise of people in the Mediterranean Levant.’ ³¹

The reason for the long seafaring, sea-daring tradition of the Indian Ocean lies in the regularity of the wind system. Above the equator, north-easterlies prevail in winter. But when winter ends the direction of the winds is reversed. For most of the rest of the year, the winds blow steadily from the south and west, sucked towards the Asian landmass as air warms and rises over the continent. By timing voyages to take advantage of the predictable changes in the direction of the wind, navigators could set sail, confident of a fair wind out and a fair wind home. It is a fact not often appreciated that, overwhelmingly, the history of maritime exploration has been made into the wind: presumably because it was at least as important to get home as to get to anywhere new. This was how the Phoenicians and Greeks opened the Mediterranean to long-range commerce and colonization. The same strategy enabled South-sea Island navigators of this period to begin the long project of exploring and colonizing most of the islands of the Pacific.

Conditions in the Indian Ocean liberated navigators from such constraints. One must try to imagine what it would be like, feeling the wind, year after year, alternately in one’s face and at one’s back. Gradually, would-be seafarers realized how the changes of wind made outward ventures viable: they knew the wind would change. So they could risk an outward voyage without fearing that they might be cut off from the chance of returning home.

The Indian Ocean has many hazards: it is Sinbad’s sea, the setting of countless tales of the mutability of fortune; it is wracked by storms, especially in the Arabian Sea, the Bay of Bengal, and the deadly belt of habitually bad weather that stretches across the Ocean below about 10° south of the equator. But the predictability of a homeward wind made this the world’s most benign environment for long-range voyaging. Fixed-wind systems as vast as those of the Atlantic and Pacific were almost uncrossable with ancient technology: we know of no round trips across them. Even compared with other navigable seas, the reliability of monsoon conferred insuperable advantages. No reliable sources record the length of voyages during this period, but, to judge from later statistics, a trans-Mediterranean journey from east to west, against the wind, would take fifty to seventy days: with the monsoon, you could cross the entire Erythraean Sea, between India and a port on the Persian Gulf or near the Red Sea, in three or four weeks in either direction.

In the long run, sea routes were more important for global history than land routes: they carried more goods, faster, more economically, in greater quantities. Nevertheless, in the early stages of the development of trans-Eurasian communications, most long-range trade was small-scale, in goods of high value and limited bulk. It relied on ‘emporium-trading’—onward transmission through a series of markets and middlemen—rather than expeditions across entire oceans and continents. In the first millennium bce, the routes that linked Eurasia by land were at least as important, in the history of cultural contacts, as those by sea.

From around the middle of the period, scattered examples of Chinese silks appeared across Europe, in Athens, in Budapest, and in a series of south German and Rhineland burials. By the end of the millennium, a route for diffusion of Chinese manufactures became traceable, from the southern Caspian to the northern Black Sea, and into what were then gold-rich kingdoms in the south-west stretches of the Eurasian steppe. Meanwhile, starting from Greece, Alexander’s armies had used the Persian royal roads to cross what are now Turkey and Persia, conquer Egypt and Mesopotamia, reach the Persian Gulf, and, at the extremities of their eastward march, touch the Pamir mountains and cross the Indus. Merchants could also have used these routes.

The first written evidence of this presumed commerce occurs in the report of Chang Ch’ien, a Chinese ambassador who set out for Bactria—one of the Greek-ruled kingdoms established in central Asia in Alexander’s wake—in 139 bce. His main missions were, first, to recruit allies against the aggression of steppeland imperialists who raided China’s northern borders and, second, to obtain horses for the Chinese army from the best breeders, deep in central Asia. His mission was one of the great adventures of history. Captured en route, he remained a hostage with the steppelanders for ten years, before escaping to continue his task, crossing the Pamir mountains and the River Oxus, and returning, without encountering any potential allies, via Tibet. He was captured again, escaped again, and got home, with a steppeland wife in tow, after an absence of twelve years. From a commercial point of view, his reports were highly favourable. The kingdoms beyond the Pamir had ‘cities, houses and mansions as in China’. In Ferghana, the horses ‘sweat blood and come from the stock of the heavenly horses’. He saw Chinese cloth in Bactria. ‘When he asked how they obtained these things, the people told him their merchants bought them in India, which is a country several hundred li south-east.’ From the time of his mission, ‘specimens of strange things began to arrive’ in China ‘from every direction’. ³²

In 111 bce a Chinese garrison founded the outpost of Tun-huang—the name means ‘blazing beacon’—beyond the western limits of the empire, on the edge of a region of desert and mountains. Here, according to a poem inscribed in one of the caves where travellers sheltered, was ‘the throat of Asia’, where ‘the roads to the western ocean’ converged like veins in the neck. We now call them Silk Roads. They skirted the Taklamakan Desert, under the mountains that line it to north and south. It was a terrible journey, haunted, in Chinese accounts, by screaming demon-drummers—personifications of ferocious winds. But the desert was so demanding that it deterred even bandits, and the mountains offered some protection from the predatory nomads who lived beyond them. The Taklamakan took thirty days to cross—clinging to the edges, where water drains from the surrounding mountains. Further west, to get to the markets of central Asia, or to reach India, some of the world’s most formidable mountains had to be crossed.

A few years after the founding of Tun-huang, a Chinese army, reputedly of 60,000 men, travelled this road to secure the mountain passes at the western end and to force the horse-breeders of Ferghana to trade. A painted cave shows the general, Wu-ti, kneeling before the ‘golden men’ that Chinese forces seized. (The painter made them Buddhas, perhaps fancifully.) In 102 bce, the Chinese invaded Ferghana, diverted a river and obtained 30,000 horses in tribute. Meanwhile, caravans from China reached Persia and Chinese trade goods became common in the Mediterranean Levant. ³³

The routes that bound Eurasia carried vectors of culture back and forth. We only know about a few individual cases. Alexander’s armies left colonists strewn across Asia in centres where hybrid art took shape, blending Indian and Greek aesthetics and producing, for instance, a surviving relief of the Trojan horse from Gandhara, with Cassandra flinging out her arms in despair in an image that owes more to the sinuous gestures of Indian houris or temple prostitutes than to the ecstasies of a Sybil. Pyrrho went to India with Alexander and conversed with Brahmins. There is no record of direct contacts of this kind in the first half of the millennium, but across Eurasia, from China and India to southwest Asia and Greece, from the fifth century bce onwards the sages’ subjects of debate and their techniques of rational and empirical enquiry had so much in common that it is inconceivable that unaided accident produced the coincidences. ³⁴ Scholarship on the origins of classical Athenian thought has captured the light that the ‘east face of Helicon’ cast on Greece; ³⁵ the worlds of the Levant and what are now Turkey and Persia, with which Greeks were in constant touch, could mediate thinking and transmit objects from central Asia, India, and China. So could the commerce of the Erythraean Sea.

Partly as a result of the contacts that linked the ends of Eurasia, and put schools and sages in touch with each other, new initiatives in thinking in the first millennium bce were remarkably similar in Greece, southwest Asia, India, and China. New religions—Zoroastrianism, Buddhism, Taoism, monotheistic Judaism, Christianity, and the beginnings of what became Hinduism—owed something, perhaps, to traditional magic, but they were genuinely new. They upheld the effectiveness of moral practice, alongside formal rituals, as ways to adjust humans’ relationship with nature or with whatever was divine: not just sacrificing prescribed offerings fittingly to God or gods, but modifying the way people behaved towards each other. They attracted followers with programmes of individual moral progress, rather than with rites to appease nature. They were religions of salvation, not just of survival. They promised the perfection of human goodness, or ‘deliverance from evil’—attainable in this world or, if not, by transfer to another world after death, or by a total transformation of this world at the end of time. The religious teachings of the sages were highlights in a world teeming with other new religions, most of which have not survived. In a period when no one recognized a hard-and-fast distinction between religion and secular life, spiritual ferment stimulated all kinds of intellectual innovation. It is still hard to say, for instance, whether Confucius founded a religion. After all, he ordered rites of veneration of gods and ancestors, but disclaimed interest in worlds other than our own. The other schools of the age in China—so numerous that they were called the Hundred Schools—shared similar priorities, but mixed what we would now think of as secular and religious thinking. Confucius’s opponent, Mo-tsu, is a case in point. He called for universal love, on secular grounds, 400 years before Jesus’s religious version.

Other innovators of the age formulated techniques that we still use for telling good from evil and truth from falsehood. Similar conflicts ensued over the nature of the state between moral optimists, who wanted to liberate human goodness, and pessimists, who felt the need for the state’s restraining force. Thinkers, observers, and experimenters who belonged to the Hundred Schools in China paralleled the achievements of Plato and Aristotle. In India, logicians known as the Nyaya school shared confidence in reason and the urge to analyse it, resolving arguments step by step. Similarities in thinking across Eurasia in the second half of the first millennium bce suggest that long-range cultural exchanges must have been going on. This was perhaps the critical difference that made Eurasian societies relatively prolific in a period when we know of no comparable achievements in intellectual life anywhere else in the world. ³⁶

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After a long period of disruption in late antiquity and the early middle ages, the routes of communication that linked Eurasia became active again in the twelfth century, when the Song reached westwards from China and crusaders colonized parts of the Levant, and with much greater intensity in the thirteenth and early fourteenth centuries, when the ‘Mongol Peace’ encouraged trans-Eurasian trade and opened new steppeland routes to long-range travellers. As a result a series of Chinese techniques and ideas reached and reinvigorated Christendom, planting most of the technologies that, in later periods, Westerners misidentified as world-changing inventions of their own. Paper money (the basis of Western capitalism), the blast furnace (the precondition for Western industrialization), the rudder and separable bulkhead (the technologies that made possible the world-ranging shipping of the modern West), and gunpowder (the starting-point for Western supremacy in firepower) were among the arrivals from China during the period. I suspect that the revival of empiricism—the fact-finding technique on which Western scientists congratulate themselves—was also the result of transmission from China, where it had never faded from sages’ minds. We know a lot about the individuals who travelled back and forth, carrying ideas and artefacts West from China, and about the travails they underwent: the Polo family, for instance, who crossed Asia in three years’ hard pounding, contending with the demons of the Taklamakan; John of Monte Corvino who declared proudly how he faced the daunting mountains of central Asia—‘but’, he said, ‘the Mongols crossed them, and so, with God’s help, did I’; or the merchants who travelled with the help of Francesco Balducci Pegolotti’s early fourteenth-century guidebook, which told them where along the road to change money, hire transport, get a shave, or employ a prostitute. ³⁷

The period of interchange between West and East did not last. In 1368, the Ming overthrew the Mongols and China reverted to autarchy. Merchants and monarchs on the Atlantic fringe of western Christendom dreamed of opening a sea route to the East, but the obstacles were formidable and ignorance led Columbus, among others, in the wrong direction. But the first Portuguese mission reached China via the Indian Ocean in 1512 and, little by little, European shippers got a foothold in the lucrative business of supplying the world’s richest economy with luxuries from India, south-east Asia, Japan, and the Americas. The great mediators of ideas, the Jesuit missionaries, did not succeed in establishing themselves as part of the acceptance world of the court in China until 1610—and their ascent was laborious, since the Chinese dismissed them at first as barbarians who had nothing to offer ‘except a picture of a woman and baby’ and dubious, purported relics of ‘the Immortals’. ³⁸ They inaugurated, however, a new era of exchange among the great civilizations of Eurasia by interesting the imperial court in their skills, first as cartographers, then as astronomers and experts in arts and engineering. At the same time, artefacts, ideas, and natural and human specimens from other parts of the world reached Europe as a result of the outreach of explorers, conquistadores, colonists, and long-range trade, accumulating in the West the raw materials of the world-ranging awareness of opportunities and vision of knowledge that we call the scientific revolution, and incubating—thanks in part to the reports of Jesuits and other European savants in China, India, and Japan—the new, radical, political and philosophical thinking of the Enlightenment. Some of the most spectacular intensifications of cultural change in the history of the world illustrate the productivity of the avenues of intellectual exchange that bind Eurasia. ³⁹

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This helps explain the effects of a phenomenon Jared Diamond has made familiar: the fact that Eurasia has been an arena of faster change than other parts of the world because its geography favours exchanges of culture between its indigenous civilizations. ⁴⁰ Geography, like genes, does not determine what we do, but it creates some opportunities and limits or impedes others. Isolation retards change, exchange stimulates it. As Diamond pointed out, New Guinea has a history of farming and sedentary life at least as long-standing as those of most other Asian civilizations, and probably longer than those of Africa, Europe, and the Americas, but isolation slowed or checked subsequent development. We can represent the world-wide difference in the mutual accessibility of civilizations diagrammatically. Civilizations privileged by mutual contacts generate more change than those that isolation obliges to devise their own new ideas. Often, and for protracted periods, Eurasian civilizations have been in close touch with one another, while those of the Americas and sub-Saharan Africa have been sundered by untraversible climatic zones or physical obstacles.

Fig. 6.1 Eurasia

Fig. 6.2 Other civilizations

It is legitimate to show Eurasian civilizations as overlapping because mutual accessibility has encouraged cultural exchange between them. Communications shrank the landmass to traversable proportions in the first millennium bce.

The reach and limits of cultural exchange affect non-human cultures too. On either side of the N’Zo-Sassandra River in Côte d’Ivoire, chimpanzees feed differently. On the west bank they crack open palm-nut kernels with stones to extract the oil. Their east-bank brethren leave the nuts unexploited. There is no environmental difference to explain the cultural divergence. The habitats are, for all practical purposes, identical. One group has discovered the relevant properties of stones and nuts and has enshrined the knowledge in culture. The other has not. ⁴¹ The process of passing on the data stopped at the river, just as for millennia the Atlantic prevented European ideas from reaching the Americas, and the geography of Eurasia helped interrupt the sporadic but powerful flow of culture between China and the West.

However that may be, the link between ideas and cultural change is unproblematic. We observe our world. We imagine it differently. We work to realize our imagined world. The best attested reason for the multiplication of ideas is the fertilizing effect of exchange. Ideas multiply as the result of dialogue. That is why we talk to one another. Cultures change, in part, at least, because unfamiliar ideas about how to do things impinge from outside. Cultures change most when they are in touch with other cultures.

Here, I want to suggest, we may have the key to the problem of why cultural change seems to accelerate—or to have accelerated for much of the past and to be accelerating at an unprecedented rate today. No scientific law mandates this. But we observe its pace all the time. Our next task is to try to see why.