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6

Only Entropy Comes Easy

I waited for a few more seconds, but Imogen didn’t appear again on Dorm Cam Two.

Her words stayed with me though.

Go out. Good advice.

Wandering through to the kitchen, I balanced my mug on top of all the other dirty crockery in the sink, then poked about inside the washing machine for something vaguely clean to wear.

I looked around, taking in the pile of plates in the sink, the remains of cooking, curry pots, jammy bread crusts, fish and chip papers, baked beans tins, empty Pot Noodles. The phone cables might have their rough spots, I thought, but this, my friend, is a total systemic collapse.

The only thing necessary for the triumph of chaos is for repairmen to do nothing.

Imogen had always been the organised, tidy, well-prepared one. Without her around, things tended to go south pretty quickly. Written on the fridge door in multicoloured, magnetic plastic letters is an old message from her:

St y Alert: Entropy Wants th s Kitch n.

Just before we went to bed one night, I’d plucked the ‘a’, the ‘i’ and the ‘e’ out of their respective words and arranged them at the bottom of the door, making it look like they’d fallen down in a heap. I remember lying in bed the next morning and hearing her call out oh, how we laughed as she opened the door to get milk for her tea.

Question: do you know why time works the way it does?

It’s all down to entropy.

To see why, I’ll need you to imagine that my kitchen is the universe. Or, if you’d rather, you can imagine your own kitchen is the universe – it doesn’t really matter. But pick a kitchen.

So. There are only a relatively small number of ways for this kitchen to be tidy. Only a relatively small number of ways for the boxes to fit in the cupboards, the bowls to fit on top of the plates, the bottles to stand up in the fridge door, all those things. Relatively small, I mean, against the countless billions of different ways the same kitchen can be messy. If the Rice Krispies are anywhere else but in the Rice Krispies box, the kitchen is messy. If the milk bottle is anywhere else but standing upright in the fridge (with the milk still in it), the kitchen is messy. If one or more of the bowls are on the worktop, on the floor, on the table, smashed in the sink, anywhere else but stacked neatly away in a cupboard – then the kitchen is messy.

You get the idea. Messy is more likely than tidy. But in order to see the full picture, we need to understand just how much more likely messy really is.

To get a good look at the massive improbability of tidiness compared to messiness, let’s empty all the plates, cups, bowls, food, drinks, cutlery, cloths, sponges, towels, powders and cleaning products out of our kitchen, then put just a single item back in – the butter. Now. Let’s say the butter can be in maybe five hundred different places around the empty kitchen that we would call messy and maybe five places we would call neat. So there’s a one in a hundred chance that the butter is somewhere we would describe as neat. Let’s move up to two items – the butter and a butter knife. Assuming the butter knife has the same number of messy and neat positions as the butter, the chances of them both being in a place we could call neat goes from one in one hundred to one in ten thousand. At three items – the butter, the butter knife and a slice of bread – the chances of all three being in a place we would describe as neat are now one in a million.

Already, messy is a million times more likely than neat – and this is a kitchen with only three objects in it. Three. Now go ahead and put back all the many hundreds of other objects into your ordinary, everyday kitchen and you start to get some sense of just how very unlikely neat is versus messy.

Of course, the universe is a lot bigger than a kitchen, and made of a lot more things. And those things are made up of things, which are also made up of things, all the way down to a basic, atomic level. There’s also an added complication – the universe does not have the benefit of someone coming along once in a while to tidy the place up. Taken together, what all this means is that when a thing – the butter, the butter knife, a brick, a stone, a screw, an atom – happens to move into a new position somewhere in the universe, it is a countless billion times more likely to move into a messy position than into a neat position.

Without someone around to tidy and fix it up from time to time, the kitchen and the house around it would progressively get messier until the whole thing fell apart. Everyone knows this happens to old houses because they’ve seen it – uncared-for structures fall into disrepair and eventually collapse. This is common sense. Why it happens is simple: because there are countless billions of messy situations for all the things that make up the house – bricks, beams, nails, lintels, joists and all their atoms – to be in, any of which would cause it to fall down, and only a handful of neat situations where the house stays standing.

This ever-increasing movement towards messiness is called entropy.

But here’s the thing. We wouldn’t say ‘the house fell down due to the gradual movement of its component elements from a low-entropy state to a high-entropy state’ (at least, most people wouldn’t). We’d say – the house fell down over time.

Entropy is what drives time forwards, and only forwards. It’s the reason you can’t un-stir the milk from your coffee, the reason you can smash but can’t un-smash a glass vase, and the reason that if you did smash a glass vase then fixed it really well, somebody might say, ‘it looks as good as new’. People get old and die over time, things get lost over time, stuff gets broken over time. Entropy is the inevitable sliding of all things from an ordered state towards disorder and meaninglessness; ice cubes melting, tea cooling, roofs caving in, glass vases smashing, people ageing, all manner of things we might casually associate with time passing.

And as everything gets messier, more and more things end up in the wrong places, until – eventually – there are no wrong places any more, because the bigger things that the smaller things were once a neat part of have also completely fallen apart. The more our universe moves towards a maximum entropy state of affairs – from a confusing jumble of broken and out-of-place things, to a heap of barely recognisable bits, to a heap of interchangeable particles – the less can actually happen, and the more slowly the arrow of time can move forward. To begin to get an idea of this, think about stirring a pile of sand with a stick. No matter how much you stir, it doesn’t make the pile of sand any more disordered, because there’s no order to the sand grains anyway – it doesn’t matter where the individual grains go, it’s still just a pile of sand. Because things can’t get any messier within the pile of sand, entropy cannot increase and so there cannot be a discernible before or after, nothing can happen, nothing can change or, to put it another way, time does not pass.

‘Avoid the world,’ Kerouac said, ‘it’s just a lot of dust and drag and means nothing in the end.’ Well, the diagnosis might’ve been premature, but you can’t fault the science. When entropy reaches a universal maximum, nothing can be anything, or do anything, or mean anything. Our universe will not see out its days by barrelling towards some big, climactic, Revelations-style ending, but by slouching through an increasingly meaningless jumble of dispersing elements, then limping on towards the most bland, uniform, entirely generic middle you can possibly imaginable, and dying there.

This is all a little bleak, I realise, but it’s important to get the facts down on paper. It’s also important, and maybe even a little heartening, to say that there’s a speck of scientific fairy dust to be found amongst all this gloom and collapse. You see, entropy and the arrow of time are not driven by a hard constant – like, say, the speed of light – but by probability, and probability alone. What I mean is, there is no rule specifically saying that everything in the kitchen can’t fall, bounce or somehow shift from a messy state to a neat state by sheer chance. It’s just that the odds against such things are so astonishingly, incredibly, mind-bogglingly, unimaginably huge, compared to the usual ‘neat to messy’ movement, that for practical purposes we say it doesn’t ever happen.

But it could.

You’d have to watch countless billions of kitchens for countless billions of years to glimpse even the beginnings of something like that, but – it could happen, in theory.

How would it feel to experience something like that?

The overwhelming sensation would probably be that something magical and impossible had happened – a visit from the fairies. But also, wouldn’t there be a sense that you had somehow travelled back in time?

____________

Our pile of sand is sitting inside a wider closed system (our universe) where entropy can still increase and time can still flow, however. You can walk over and clean up the pile of sand, write your name in it, make a sandcastle out of it, if you want to. But if the whole universe and everything in it (including you) had reached the same maximum entropy state as the pile of sand, then this would be completely impossible. There would be no outside looking in. Entropy could not increase, so there would be no possibility of real, meaningful change, and nothing could or would ever happen. The arrow of time would simply stop.