If you had to choose just three theories to explain as much of the world as possible, which would you select?
The ship is sinking. The hot rush of air from below startles you into action and you pause to consider a monumental decision. Splayed across your cabin are all of your favourite theories. But you can only carry three. Which do you take?
Later, reclining in the shade of a palm to escape the heat of the tropical sun, the only soul on an uncharted island deep in the Pacific, you ponder your decision. So many phenomena, so few theories with which to explain them…
Pity the meteorologist. Even equipped with the most formidable supercomputers humanity has yet devised, she still cannot predict the temperature two weeks from today with precision. However, she can tell you with some confidence that it will be hotter at midday than at midnight. And it will certainly be hotter at midsummer than at midwinter.
The world is a frighteningly complex place. Subtle forces beneath our notice exert disproportionate effects on the phenomena that surround us. A gust of wind on Tuesday might result in a rainstorm on Sunday. But from the very depths of this apparent chaos emerge patterns and regularities that hint at a deeper underlying order at work.
Our intuition – the product of millions of years of evolution – is impressively effective at helping us navigate the everyday world. At least, the everyday world of the Pleistocene savannah. However, it stalls when it comes to offering explanations of complex phenomena like the weather, the stock market or even human behaviour.
Our intuitions want us to think that the world is basically linear, that a small change here results in a small effect there. But one need only miss a single traffic light by seconds on the way to a job interview to realise that life can turn out a whole lot differently than it would have otherwise. Chaos theory is a way of explaining this phenomenon, and in doing so, finding order in a wild world.
Any good explanation starts by looking at the world at the right level. Where at one level phenomena might appear to be entirely random, they might galvanise into a clear pattern at another. The gyrations of billions upon billions of particles might seem meaningless until one zooms out and sees them coalesce into a single bird winging it from perch to perch. And the zip and wheel of a thousand individual birds might seem incomprehensible until one zooms out and sees it as part of a single grand flock. Phenomena galvanise, and it’s at those points where they collapse into manageable chunks that academic disciplines emerge. It’s just a matter of picking the right one for the job.
Chaos theory is the art of gleaning the order from the cacophony of phenomena that confront us on a daily basis, carving it up into manageable chunks, and exerting it to further scrutiny. It is from the order out of chaos that any useful enquiry can begin.
The ocean wants to be flat. It, like everything else in the universe, desperately seeks equilibrium. Forces continuously push and pull against each other, always striving for that point of perfect balance. And most of the time they find it.
But a small fraction of the world is in disequilibrium. That’s where stuff happens. The churning of the waves persists while wind and heat – themselves straining for equilibrium – conspire to disrupt the delicate balance of forces that seek a glassy surface. It’s in understanding where these equilibrium points are and how they’re disrupted that we can begin to understand why things are the way they are. And why people behave the way they do.
People want to be in equilibrium too. Forces push and pull against us, influencing our actions just as gravity and pressure influence the ocean. Not least of these forces is our interests and desires, as well as the interests and desires of others. This makes our equilibrium points more slippery than with many other things. If you stand still, I can easily pass you. But if you step left, I should step right, otherwise we’re going to collide. Things become strategic.
One might think that finding our optimal equilibrium point would be a simple matter of factoring in each of our interests and coordinating our actions to yield the best outcome for us both. If everyone was nice to everybody else, we’d all be better off. That’s obviously true, but game theory tells us there’s a crucial catch: that the world is not in equilibrium.
I must factor in what you’re going to do, and you must do the same. If you’re going to help me harvest my grain, after we’re finished I can refuse to help you with yours, saving myself the effort and reaping the reward of our collaborative endeavour. But if you think I’m going to refuse to return the favour – and that would be the rational thing for me to do – then why would you help me in the first place? So neither of us ends up helping the other. That’s a tragic equilibrium – a Nash equilibrium. Yet neither of us desires that outcome, and around it goes.
The complexity of strategic interaction is full of surprises. Even if people aren’t perfectly rational – and it’s pretty clear they aren’t – it seems people still gravitate towards equilibria. What game theory tells us is that equilibria can often be elusive, and unstable. In many of the most interesting interactions, dynamism and disequilibrium are the norm.
Change is everywhere. Much of it is random, undirected, and passes as soon as it arrives. But some of it sticks. And when you hone in on that sticky kind of change, something eerie emerges: it looks for all the world as though things aren’t just changing willy-nilly, but gravitating towards their equilibrium point with their environment. In a sense, they’re improving.
From the predator’s pointy fangs, to the crumpet button on your new toaster, it almost seems as if things are striving towards ever more effective forms. It’s as if they’re driven to reach some goal of perfect sympathy with their environment. You can almost smell the funk of teleology about them.
This would all be terribly easy to explain were there a designer. However, for all the forces that influence lasting change, few of them involve design. Life, in all its unimaginable complexity and splendour, lacks a designer. And even human artefacts that have been built for a purpose often succeed or fail despite the best efforts of their inventor. Progress is more down to serendipity and sweat than insight.
If chaos theory reveals hidden patterns and regularities in the world, and game theory helps us understand how things interact, then evolution tells us how things change. And, moreover, why this change isn’t just one damned thing after another, but why this thing transforms into that thing rather than something else. How things make their way towards their elusive equilibria.
It’s as simple as this: wherever there is heritable variation and selection, there will be evolution. This applies to amoebas, to toasters, to internet memes and, in fact, to any kind of system you can imagine. And while we intuitively place a lot of emphasis on the variation side of the equation (that’s the appeal of Intelligent Design), it’s really selection that is doing the heavy lifting.
The key is that selection is a gloriously destructive force. It doesn’t pick the winners for tomorrow, it culls the losers of today. It kills off those things furthest from the equilibrium point, allowing the rest to remain. However, this is no linear path. It is filled with bumps and perturbations, and it’s strategic. The survivors today represent the environment of tomorrow.
The end result is a vast web of interactions between myriad things, a web where chaos and game theory play out, where subtle variations here and strategic interactions there shape how things change from one thing into another. It doesn’t explain everything, but it explains a lot.
Tim Dean is currently researching the implications of evolution on moral philosophy and exploring the insights that evolution can yield on this strangest of human capacities.