WHEN TO STOP

Dick Pountain/Idealog 274/05 May 2017 11:06

You're probably familiar with the expression "Beauty is in the eye of the beholder", but what exactly do you think it means? The  obvious interpretation is relativist: what I find beautiful need not be what you find beautiful. But we could also take it literally, namely that beauty is property of, or a process within, the human eye (or visual cortex, or brain in general) rather than a property of external objects.

My two main "hobbies", regularly chronicled in this column, are fiddling with photographs in PhotoShop Elements 5, and composing algorithmic music using my own software recently rewritten in Python. What these activities have in common is firstly that they are both pursued on a computer, and secondly that they are both iterative in nature: I make a change, look at it or listen to it, decide whether or not it's for the better or the worse, accept or reject it, then make another, and so on until I'm sufficiently satisfied to stop and call it a finished "work".

You may have already spotted that this is the very same process practiced by artists of all eras, on all materials and in all styles - with one  exception made possible by the computer and the digital nature of its material. That exception is that in most real-world materials, the step changes are irreversible. That's most clearly true for a sculptor who chisels off chips of marble that can't be replaced, but partially so for an oil painter who applies daubs that can't be removed, only overpainted, or a water colourist who lacks even that option. Writers, before the advent of word-processing, had recourse to crossing-out, the india rubber, Tippex or the waste-paper basket. None of that matters so much as does the end point of the process, knowing when to stop, and in this the computer hinders rather than helps.

That tempting Undo icon means I could go on fiddling with the same piece until death, or the heat-death of the universe (whichever comes first). There is a defence against such runaway fiddling though, and that's the number of parameters involved. When processing a photo I have available 120+ filters, 23 blend modes and 20 other adjustments that, when applied even to just two layers, makes for 3 billion possible combinations per iteration, and I make dozens of iterations. Documenting all the parameters for each step, to make the whole process reproducable, would be impossibly tedious, but in any case I don't want to. I'm happy to play on the same level field as Michelangelo and Beethoven, even if my game is far less impressive.

Playing on the same field is another way of saying that it's our eyes, ears, arms, legs, brains that decide when to stop, the decision that creates what we call beauty. (Actually it's noses and tongues too, if you're prepared, as I am, to include cooking and perfumery as arts). This ability to know when to stop may have been hard-wired into our brains by evolution. Animal brains contain many pattern analysing circuits, some imparted by evolution, some further trained by early experience. On the evolutionary side it's been suggested that colour vision offered a dietary advantage in distinguishing ripe from unripe fruit (many carnivores lack it), and it's also deeply involved in sexual display, and hence selection, particularly among birds and insects.

When Pablo Picasso drew a freehand squiggle it always looked better than my own squiggles, and I propose that's a matter of radii of curvature: some curves are right and some are wrong (too acute, jerky). In other words some curves are just sexier than others, and I'll leave the evolutionary "explanation" to you. We could analyse this mathematically using line integrals, div, grad and curl, but that would be pointless. Our pattern circuits are connected to our limbic system, source of emotions, that is, of dopamine reward. No amount of maths can substitute for looking, then feeling good at what you see.

Another possible evolutionary advantage of curve sensing is for landscape recognition. I used to spend time in a small croft near the sea in northern Scotland, where the seaward skyscape was dominated by seven distinctive humps of hills that we, of course, called the Seven Sisters. I can still imagine that shape if I close my eyes, leading me to hypothesise that this ability to recognise your home landscape may have had great survival advantage in the epochs before roads, church steeples or GPS. To zealots of strong AI, I'll just say this: we might analyse all such sensual recognitions and turn them into algorithms, but so far there's no way that a computer can *feel* good, and without that it can't have any real understanding of what beauty is.