The Science of Discworld II

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    One of the commonest generic evolutionary tricks is to cheat. As soon as a bunch of organisms has evolved some specific ability or behaviour, a new possibility arises: subverting that behaviour. Predictable behaviour patterns provide a natural springboard from which organisms can leap out into the space of the adjacent possible. Bees evolved the abilities to collect nectar and pollen, to feed themselves. Later, we subverted that activity by providing them with better homes than they would find in nature. We get to steal their honey, by providing them with hives as the up-market adjacent-possible homes.
    Many evolutionary trends have arisen from subversion. So, as the ability to put specific thoughts into the minds of others became established, it was natural for evolution to experiment with methods for subverting that process. You didn’t have to put your own genuine thoughts into the minds of others: you could try to put different thoughts there. Perhaps you could gain an advantage by misleading the creatures you were ‘communicating’ with. The result was the evolution of lying.
    Many animals tell lies. Monkeys have been observed making the troupe’s ‘danger’ call-sign. Then, as the rest of the troupe heads off for cover, the liar grabs the food that they have temporarily abandoned. On a more primitive but just as effective level, mimicry in the animal kingdom is a form of lying. A harmless hover-fly displays the black-and-yellow warning bands of a wasp, telling the lie ‘I am dangerous, I can sting’.
    As humanity evolved, those monkey lies turned into more sophisticated ape lies, then hominid lies, then human lies. As we became more intelligent, our capacity for telling lies co-evolved alongside another important ability: the ability to tell when someone was lying to you. A monkey troupe can evolve several defences against a member who abuses the danger-signal for his own ends. One is to recognise that this individual can’t be trusted, and ignore their calls. The nursery tale of the little boy who cried ‘wolf’ exposes the dangers inherent in this area, both for the troupe and for the individual. Another is to punish the individual for telling the lie. A third is to evolve the ability to tell the difference between a lying danger-signal and a true one. Is the monkey crying ‘danger’ staring at someone else’s food with a greedy glint in their eye?
    Just as there are sound evolutionary reasons for telling lies, so there are sound evolutionary reasons for being able to detect them. If others are trying to manipulate you to their advantage, then it is very probably to your disadvantage. So it is in your best interests to realise that, and avoid being manipulated. The result is an inevitable arms race, in which the ability to tell lies is played off against the ability to detect them. It is no doubt still going on, but already the result is some very sophisticated lying, and some very sophisticated detection. Sometimes the look on a person’s face tells us they’re telling an untruth; sometimes the tone of voice.
    One effective way to recognise a lie is to put yourself inside the other person’s mind, and ask yourself whether what they are saying is consistent with what you have convinced yourself they are thinking. For instance, they are saying what a sweet little child you have, but you remember from previous encounters that usually they can’t stand kids. Maybe your child is different, of course, but then you notice that worried look in their eyes, as if they’d rather be somewhere else …
    Empathy is not just a nice way to understand someone else’s point of view. It’s a weapon that you can use to your own advantage. Having understood their point of view, you can compare it with what they’re saying, and work out whether to believe them. In this manner, the existence of lies in language’s phase space of the adjacent possible encouraged the development of human empathy, and with it,individual intelligence and collective social cohesion. Learning to tell lies was a major step forward for humanity.
    We can put ourselves inside the minds of other people with some degree of credibility, because we are people ourselves. We do at least know what it’s like to be a person. But even then, we are probably deluding ourselves if we think that we really know exactly what’s going on inside someone else’s