The War of the World: History's Age of Hatred Read Online Free

group as somehow ‘subhuman’. While ‘demic diffusion’ has occurred peacefully and even imperceptibly in some settings, in others interracial relationships have been viewed as deeply dangerous. How, then, are we to explain this central puzzle: the willingness of groups of men to identify one another as aliens when they are all biologically so very similar? For it was this willingness that lay at the root of much of the twentieth century’s worst violence. How could Göring’s ‘great racial war’ happen if there were no races?
    Two evolutionary constraints help to explain the shallowness but also the persistence of racial differences. The first is that when men were few and far between – when life was ‘solitary, poor, nasty, brutish and short’, as it was for 99 per cent of the time our species has existed – the overriding imperatives were to hunt or gather sufficient food and to reproduce. Men formed small groups because cooperation improved the individual’s chances of doing both. However, tribes that came into contact with one another were inevitably in competition for scarce resources. Hence, conflict could take the form of plunder – the seizure by violence of another tribe’s means of subsistence – and downright murder of unrelated strangers to get rid of potential sexual rivals. Man, so some neo-Darwinians argue, is programmed by his genes to protect his kin and to fight ‘the Other’. To be sure, a warrior tribe that succeeded in defeating a rival tribe would not necessarily act rationally if it killed all its members. Given the importance of reproduction, it would make more sense to appropriate the rival tribe’s fertile females as well as its food. In that sense, even the evolutionary logic that produces tribal violence also promotes interbreeding, as captured womenfolk become the victors’ sexual partners.
    Nevertheless, there may be a biological check on this impulse torape alien females. For there is evidence from the behaviour of both humans and other species that nature does not necessarily favour breeding between genetically very different members of the same species. No doubt there are sound biological reasons for the more or less universal taboos on incest in human societies, since inbreeding with siblings increases the risk that a genetic abnormality may manifest itself in offspring. On the other hand, a preference for distant relatives or complete strangers as mates would have been a handicap in prehistoric times. A species of hunter-gatherers that could only reproduce successfully with genetically (and geographically) distant individuals would not have lasted long. Sure enough, there is strong empirical evidence to suggest that ‘optimal outbreeding’ is achieved with a surprisingly small degree of genealogical separation. A first cousin may actually be biologically preferable as a mate to a wholly unrelated stranger. The very high levels of cousin-marriage that used to be common among Jews and still prevail among the highly endoga-mous Samaritans have resulted in remarkably few genetic abnormalities. Conversely, when a Chinese woman marries a European man, the chances are relatively high that their blood groups may be incompatible, so that only the first child they conceive will be viable. Finally, it must be significant in its own right that separate human populations so quickly developed such distinctive facial characteristics. Some evolutionary biologists argue that this was a result not just of ‘genetic drift’ but of ‘sexual selection’ – in other words, a culturally triggered and somewhat arbitrary preference for eye-folds in Asia or long noses in Europe quite rapidly accentuated precisely those characteristics in populations that were isolated from one another. Like attracted and continues to attract like; those who are drawn to ‘the Other’ may in fact be atypical in their sexual predilections.
    A further possible barrier to interbreeding is that races may