On Universal Darwinism, the nature of foresight, and the virtues of flailing aimlessly…

by adamsopticks

I first saw this extract – culled from the BBC’s ‘Life’ series – during my final year at university, and to this day I honestly cannot help but gasp for breath on every re-watch. Mesmerising, isn’t it?

Placing sheer wonder-value to one side, however, I want to focus in particular on the image of the passionflower tentacle ‘flailing aimlessly’ in search of a hold, and to use that coiling limb to pull together my thoughts on a variety of topics I’ve encountered in my science-based reading over the past couple of years. These include things like evolution, consciousness, cosmology, creativity, culture and the history of ideas. But first: back to wonder.

The illusion of foresight in the natural world

What is it about seeing plant-life through the medium of time-lapse that fascinates us so? I rather think the key to answering that lies in the type of language employed by David Attenborough in the above clip: for the young plants too little light means death, this poses them a problem, though they need not be passive. Even before the comparison with ‘fingertips searching for a hold’ is made, it’s clear that the narration has slipped – quite understandably – into anthropomorphism. Following the American philosopher Daniel Dennett, we might say that Attenborough is adopting ‘the intentional stance’: a cognitive filter (normally reserved for other human beings) through which the plants are rendered as wanters, believers, strategists.

‘They’re alive!’ yells a voice in our heads, ‘And they know what they’re doing!’

Is this an error? I’ll come back to that question, but for now it is enough to say that of course plants are alive – but that they certainly don’t foresee their own deaths, nor strategise to avoid them, as Attenborough (perhaps carelessly) implies. They’re blind, mechanistic, protein-processes, responding only to their genetic recipes and basic cues from their environment. They may look like they know what they’re doing, but that’s only because they’ve inherited their lifecycles from a billion-year chain of ancestors, each of which enjoyed at least a base-level of reproductive fitness bequeathed them by their parents, and every now and then a particularly potent genetic reshuffle (or perhaps a novel mutation) that gave them an incremental edge over their counterparts.

But there is another, perhaps more important, kind of fortune enjoyed by every organism that belongs to a successful lineage of plant or indeed animal life, and that’s this: Not being one of the missteps. It’s a cheering thought that not a single one of our direct ancestors ever failed to pass on their genes; to recognise that each of us is the latest in an unbroken chain of successful procreators that stretches right back to some great granddaddy bacterium. But (and here’s the nub) this vision of a perfect line, or lines, of descent through the generations is only one half of the great evolutionary narrative: in every generation of every species, there are always creepers with pads not quite sticky enough (or too sticky), or giraffes with necks not quite long enough (or too long), or those organisms of any kind that suffer deleterious rather than adaptationary mutations. Each of our successful ancestors will likely have had brothers and sisters who did not quite make the grade. Richard Dawkins has referred to natural selection as ‘The Blind Watchmaker’ – and it is true to say that its workshop floor is littered with the corpses of the Not-Quite-Rights.

As distressing as that might sound, however, we ought not to bemoan it – because without a little trial and error there would be no natural selection at all. Or, to grasp my theme more fully, I should say that evolution – just like the passionflower – has no foresight, and must flail aimlessly before striking upon success.

The temptations of teleology and the evolution of scientific knowledge

In many ways Darwin’s elimination of foresight from biology strikes me as analogous to a similar reversal in physics. Right up until the scientific revolution of the late sixteenth and seventeenth centuries, the prevailing view of the physical world in Western learning was that of Aristotle’s, in which all matter – divided neatly into the four elements – was said to tend toward its God-given place: ‘earth’ (the very stuff of our planet) sat in the middle of creation, about which rested layers of water, air and fire in that order. It’s still a readily attractive worldview in many ways: the ground, the sea, the sky, and the sun are all put in their proper places – and simple physical processes like a stone sinking in water, or the upward flickering of an open fire, can be explained in terms of the elements attempting to reach their ‘natural’ positions.

‘They’re alive!’ yells a voice in our heads, ‘And they know what they’re doing!’

Nevertheless, this kind of ‘teleological’ explanation, in which final destinations are given prominence over prior causes, is a dying breed in most sciences. One still finds it in the ‘equilibrium’ models of economists (according to which financial systems tend toward a perfectly balanced state), or in James Lovelock’s new-agey Gia-theory (in which the planetary ecosystem does much the same thing) – but in general scientists these days would rather uncover the lower level mechanisms that do the pushing than posit the existence of a never-actually-observed ideal that somehow pulls the phenomena toward it. (What balanced economy? What balanced ecosystem? Doesn’t anybody watch the news?).

As such theories die off, and new ones take their place, it has tempted philosophers of science to account for scientific progress itself as a kind of evolutionary process. Karl Popper is the touchstone here, but I’m going to attempt my own account. The evolutionary view of science is one in which:

  1. every intellectual innovation of every working scientist (good or bad) is to be considered a comparatively minor mutation in the larger body of ideas inherited from the previous generation, and
  2. the practice of science (with its attendant insistence on logical argument and empirical support) is understood to act as the selection pressure by which the useful mutations are singled out and perpetuated (at the expense of the ineffectual ones that simply wither away).

What I find especially appealing about this argument is the challenge it poses to that popular history of science in which a few intellectual juggernauts (the Darwins, Newtons, Einsteins et al) are portrayed as having cast aside the prevailing intellectual myopia of their day and paved the way into the future with their great genius. The challenge is two-fold. Firstly, the evolutionary view of science points to the fact that even the most revolutionary ideas build upon an existing inherited framework. Einstein himself once wrote of his forebear Ernst Mach,

[His writing] clearly recognised the weak spots in Classical Mechanics and was not far from requiring a General Theory of Relativity … it is not improbable that Mach would have come across Relativity if, at the time when he was in his prime, physicists had concerned themselves with the significance of the constancy of the speed of light’.

It is worth remembering, likewise, poor old Alfred Russel Wallace – the second man to have struck upon the theory of natural selection, independently of Darwin, and nigh-on simultaneously. The temporal proximity of their discoveries can only be explained, to my mind, by the two men’s existence in a shared intellectual culture – one that made the great leap of evolutionary theory a small step capable of being taken by anybody with sufficient immersion in the debates of the time (and at least a modest sense of iconoclasm).

The second challenge posed by evolutionary science to the traditional history of scientific genius has to do with the notion of luck: if all theoretical advances are mere chance mutations, then progress may be less a matter of great individuals being able to ‘see’ the solution to a problem, and more to do with an entire crowd of scientists each throwing suggestions at it, and each hoping that theirs in the one that sticks. As Popper surmises in Conjectures and Refutations,

So my answer to the questions ‘How do you know? What is the source or the basis of your assertion? What observations have led you to it?’ would be: ‘I do not know: my assertion was merely a guess. Never mind the source … if you are interested in the problem which I tried to solve by my tentative assertion, you may help me by criticizing it as severely as you can…

Perhaps it is the case that science and great scientists – just like the passionflower – have no foresight, and must flail aimlessly before striking upon success.

Universal Darwinism and the ‘survival of the stable’

The application of Darwinian logic to subjects other than biology is known as Universal Darwinism, and it’s a difficult game to stop playing once you’ve grasped the rules. Perhaps the most famous example is Richard Dawkins’ ‘meme theory’, first propounded in The Selfish Gene, in which the entirety of human culture is recast as the history of the differential survival of self-replicating ideas, or ‘memes’. The overall picture is akin to the account of science I’ve just given – only with a rather less formal set of selection pressures. Scientific ideas are whittled down and developed over the course of generations under the weight of questions like ‘does-it-work-as-an-explanation?’ and ‘what-testable-predictions-does-it-make?’. Culture, meanwhile, asks only ‘is-it-catchy?’. Catchy songs, paintings, practices, religions – these spread, while boring ones die out.

I’m simplifying – but meme theory is an effective meme in itself, and so there’s little reason to go into the detail here. Instead, I’d like to take the opportunity to quote another passage The Selfish Gene (one of my favourites):

Darwin’s ‘survival of the fittest’ is really a special case of a more general law of ‘survival of the stable’. The universe is populated by stable things. A stable thing is [that which] is permanent enough or common enough to deserve a name.

I find this simple observation incredibly profound, and a powerful inoculation again the counter-intuitive unease that evolutionary arguments often provoke. It just seems crazy – does it not? – to suggest that those creepers don’t know what they’re doing. Or that life on earth, the General Theory of Relativity, or Catholicism, weren’t designed by conscious agents. Even if you accept the logic of the evolutionary argument, it’s still hard to really believe it sometimes. Nevertheless, if one imagines (contra Dawkins) a universe populated exclusively by unstable things – organisms that didn’t reliably survive and reproduce, sciences that answered no questions, melodies that no one could hum – then one can quickly appreciate that whenever this ceaseless chaos of nonsense, discordance and twisted limbs just so happened to produce something capable of lasting or perpetuating itself, then that ‘thing’ would soon become ubiquitous. Or at least catch our attention like nothing else. This is why the universe – perfectly capable of chaos – is populated for the most part by stable things.

I’ve even heard it suggested that the laws of physics themselves may have ‘evolved’ by such a process. It is quite easy to imagine that at one time nothing in the universe exhibited any regularity whatsoever; that no one particle colliding with any other could be relied upon to bounce off in predictable directions, or even last long enough to come into collision in the first place. Perhaps they just popped in and out of existence with genuine randomness. Perhaps they weren’t even particles, and so forth. Yet, from amongst this chaos, whenever phenomena did emerge – by accident – that happened to have the properties of lasting, and behaving in regular ways, then this would slowly become the norm. The central idea is that chaos must, by its nature, chance upon order sooner or later.

(I should point out that when I say I’ve ‘heard this suggested’, that’s quite literally true. I owe it to my friend Steve McKellar, who done told me it down the pub. You can find some of Steve’s fantastic evolutionary programming and artwork at http://www.bringuscloser.org/)

Conclusion: Dancing children and the everyday evolution of ourselves

Time for one last video:

When I first saw this documentary, I was putting together a DVD of home movie footage taken by my parents in the early nineties. What astonished me was the similarity between these digitally-evolved walkers and the sight of my one-year-old sister – emerging through the static – as she learnt to walk. Time and time again she would struggle to her feet, take a gamble on a few paces, and suffer the inevitable tumble. And yet, by the end of the year encompassed by the grimy old VHS tape, she’d learnt enough to be dancing with my dad and cousins on Christmas day.

It’s a very beautiful and moving sight – but one that got me thinking: ‘hey, is learning an evolutionary process too?’. That is, do we learn to walk (or talk, or master cryptic crosswords) by ‘allowing’ our bodies and brains to make a thousands mistakes amongst which the accidentally successful ones get reinforced by the rewards they bring us? The following passage from Dennett (on neuron growth) seems to chime with this idea:

It has been recognised for years that the human genome, large as it is, is much too small to specify (in its gene recipes) all the connections that are formed between neurons. What happens is that the genes specify processes that set in motion huge population growths of neurons – many more neurons than our brains will eventually use – and these neurons send out exploratory branches at random (at pseudo-random, of course), and many of these happen to connect to  other neurons in ways that are detectably useful (detectable by the mindless process of brain-pruning). These winning connections tend to survive, while the losing connections die, to be dismantled so that their parts can be recycled in the next generation of hopeful neuron growths a few days later.

And so it seems that even our brains are passionflower tentacles, sending out lightning fork ‘exploratory branches’ until we grasp a thought or habit toward which we may haul ourselves. Is this the recipe for all thought, all creativity? I like the idea that it might be. Perhaps, then, it is rather unfair to suggest that – unlike us – plants ‘don’t know what they’re doing’. Of course the speed and plasticity of our neuron growth far outstrips the once-in-a-lifetime ascent toward the sun exhibited by the creepers, but the essential mechanism remains the same. We should not speak of plants’ – or science’s – ‘lack of foresight’ when what we perceive as foresight in ourselves is precisely their ability to cast around in search of a hold.