Выбрать главу

According to these books, the result of having lived with a brain which we think we direct using a kind of tiller, but which actually is continually affected by cross-winds, occasional storms, rain and warm sun that provokes us into lazy days, is that we have evolved a series of memories with different flavours. Or, the result of having lived with a brain that we think we direct using a kind of automobile steering wheel and foot controls, but whose route is actually continually affected by long-term goals that change (`Let's go to a hotel, not to Auntie Janie's again'), short-term road signs and other traffic, is that we have evolved a series of memories with different flavours. Or, each of us has a personal history which we explain internally by feelings attached to emotional memories, so we have evolved a series of memories with different flavours.

Damasio has imported emotional biasing into how we think about our own intentions, choices, other people, memories, and prospective plans. He claims that this is what emotion is `for', and most psychologists now agree that emotionally labelled memories are the effect of having a brain whose interaction with its body paints emotions on to memories and intentions.

We habitually assume that real physical history, and particularly social history, works the same way as our own personal histories, with events labelled `good' or `bad' ... but it doesn't. It's misleading to think of the Big Bang, for example, as an explosion like a bomb or a firework, seen from outside. The whole point of the Big Bang metaphor is that at the moment the universe was bom, there was no outside. More subtly, perhaps, we tend to think of the birth of the universe in the same way that we think of our own birth, or even our conception.

Real history, post whatever the Big Bang `really' was, relies on the accumulation of countless tiny sequences of cause-and-effect. As soon as we begin to think about what any of these sequences looks like, taking it out of the context that drives it, we lose its causality. This seething sea of processes and appearances and disappearances, where no causality can be isolated, is sometimes called `Ant Country'. The name reflects three features: the seething, apparently purposeless activity of ants, which, in aggregate, makes ant colonies work; the metaphorical Aunt Hillary in Douglas Hofstadter's Godel, Fscber, Bach, who was a sentient anthill and recognised the approach of her friend the anteater because some of her constituent ants panicked; and Langton's Ant, a simple cellular automaton, which shows that even if we know all the rules that govern a system, its behaviour cannot be predicted except by running the rules and seeing what happens. Which in most people's book is not `prediction' at all.

For similar reasons, it is impossible to forecast the weather accurately, even a few weeks ahead. Yet, despite this apparent absence of causality at the micro-levels of weather, the impossibility of isolating causality in the swirling butterflies ... despite the chaotic nature of meteorology in both the large and the small, weather makes sense. So does a stone tumbling downhill. So does a lot of physics, engineering, and aeronautics: we can build a Boeing 747 that flies reliably. Nevertheless, all of our physical models are rooted in brains that get most of their perceptions wrong.

Shouting at the monkeys in the next tree. That's what brains evolved to do. Not mathematics and physics.

We get ecology and evolution mostly right, but often wrong, for the same reasons. The scenarios we build don't work, they're as false to fact as `weather'. But we can't help building them, and they're useful sufficiently often to be `good enough for government work'.

To underline this point, here's an important evolutionary example. Think of the first land vertebrate, that fish that came out of the water. We have the strongest feeling that if we took a time machine back to the Devonian, when that first important fish was emerging from the sea, there ought to be a moment that we could isolate: `Look, by wriggling out on to the mud that female has escaped that predator, so she's lived to lay her eggs, and some of them will become our ancestors ... If she hadn't got those leggy fins, she wouldn't quite have made it, and we wouldn't be here.'

Grandfather paradox again? Not quite, but we can illuminate the grandfather paradox neatly with this example. Ask yourself what would happen if you killed that fish. Would humanity never have happened? Not at all. By isolating a single event, we have tried mentally to make history follow a thin thread of causality. But we made the Adam-and-Eve mistake: ancestors don't get fewer as you go back, they multiply. You have two parents, four grandparents, maybe only seven great-grand parents, because cousin marriages were commoner then. By the time you've gone back a couple of dozen generations, a significant proportion of all the breeders of that period were your ancestors. That's why everyone finds some famous ancestors when they look - and the fact that famous people were rich and powerful and sexually successful helps too, so that they are reproductively better represented in that generation's descendants.

Note that we said `breeders' and `many'. Nearly all sexually produced creatures don't breed, including humans of most previous generations. Not only are most of the people alive at that previous generation young children who won't survive to breed; many of the apparently successful breeders contribute to lineages that die out before they get to the present day, because they are excluded from the limited ecosystem by more successful lineages as the generations pass.

So when we look at those Devonian fishes, there simply isn't just one that was our ancestor. All of the breeders, a very unsystematic small proportion of the fish population, contributed to the recombining and mutating mix of genes that passed down from those fishes that left the water, through generations of amphibians and mammallike reptiles, into the early mammals, were newly selected to characterise the early primates, and eventually ended up in us. There wasn't a single grandfather fish, or one grandfather primate, no thin line of descent, just as there isn't a thin line of causality leading from a butterfly's wing flap to a hurricane. Nearly any fish you went back and killed would make virtually no difference to history. We'd still be here, but history would have taken a slightly different route to get to us.

But that doesn't mean that history has no important accomplishments.

Some physicists, especially, have argued from this indeterminacy and chaotic influences at all the micro-levels that there is no pattern to history, that Heisenberg uncertainty rules. Wrong. Just because we cannot predict the weather more than about a week ahead, with the best and biggest computers, doesn't mean that there isn't such a thing as weather. Our thin-causal-thread evolutionary scenarios for the emergence of those fishes on to the land don't work, but that doesn't mean we must throw away all ideas of causality in evolution. Any event, when looked at in detail, seems not to have a clear cause, but that just means that our Damasio-minds are not suited to that way of analysing history.

We are much better at totally disregarding all the micro stuff, and making big guesses: I guess it'll be sunny again tomorrow; or I guess that among all those fishes eating each other on the Devonian mudflats, some will escape on to the land. We're confirmed in that guess by finding climbing perch, mudskippers and lots of other separate fish lineages doing exactly that on mudflats today.

The great evolutionary biologist Stephen Jay Gould got this point wrong in Wonderful Life: if evolution ran again, he stated, we would not get people, because of all the tiny chaotic butterflies that determined evolutionary outcomes, so there were no thin causal threads. We disagree: we might not, almost surely would not, get the same primate coming down from the trees, but equivalent major innovations would occur in the new and different lineages. People are good at finding high-level groupings, making analogies and metaphors, arguing from what Aunt Janie does today to what she'll do tomorrow, or did twenty years ago. But we oversimplify when we try to disentangle the maze of tiny causalities that lies behind any historical event, because we can't handle that kind of complexity.