The other day I went to see Downsizing from writer/director Alexander Payne. It's set in a world where humanity is on the brink of mass-exinction (like real life). Carbon emissions are edging us toward climate catastrophe, there isn’t enough energy for a growing population and we don’t have the resoures to sustain our economy (like real life). The root cause of all our problems is determined to be overpopulation (I’d have put my money on Barbara Streisand, but oh well). There’s simply too many people for a planet this size and a solution must be found. Either we cut the population down or we minimise its impact.
As the movie starts, a group of Norwegian scientists make a game-changing discovery which could solve our problems and turn the tide on impending armageddon: shrink humans down to a fraction of their original size. Smaller people don’t eat as much, they don’t need as much electricity, they take up less space, require less raw materials and so on. If everyone shrinks, so does their impact on the environment.
Furthermore, anyone who underwent this procedure would immediately become wealthier. The price of fuel, medicine and food would remain the same, but you’d only need a small amount so your money would count for more. You could run a miniature car for a thimble of petrol and you could live in a mansion because it’s no more than a dollhouse. It seems like miniaturisation would be the solution not only to environmental problems but to those of social inequality as well.
Once these preliminaries are established, the film tells the story of Paul Safraneck (Matt Damon), a failed medic who decides to abandon his regular-sized world and regular-sized friends in order to minimise and relocate to a tiny city. From there, the film shows the ups and downs of what life would be like for the very small...at least, it tries to.
The film's message is noble but, if I’m honest, the actual story becomes very boring very quickly. There are a few funny and poignant moments but it’s a meandering affair, structured like a collection of short movies rather than a feature film. There's not much of a narrative and every time you think something's going to happen, it doesn't. I want to make some witty joke about how they needed to downsize the script but it's not a passionate enough movie to be worthy of such a pun. The whole thing is a wasted opportunity that feels like sitting on a laborious train journey while your uncle Derek talks you through his wristwatch collection. You smile out of politness but you want the whole thing to be over as soon as possible.
Bring On The Science
The idea of human-miniaturisation is fascinating and lots of writers have toyed with it. Probably the first example was the isle of Liliput in Jonathan Swift’s novel Gulliver’s Travels, although it’s made clear that the tiny Liliputians are a different species altogether, rather than shrunken humans.
The same is true in The Borrowers novels by Mary Norton, in which a family of miniature people live inside a London family house, stealing things and not contributing to the rent. In The Borrowers Afloat they go down a river on a toy boat, in The Borrowers Aloft, they get in a minature hot air balloon and in The Borrowers Discover Vacuum Cleaners things don’t go so well.
My personal favourite book in the "tiny human" subgenre is The Shrinking Man by Richard Matheson in which a radioactive fog alters the molecular sturcture of the protagonist Scott Carey. He descends into the realm of the microscopic, losing all ties with his wife before fighting a spider in his basement and eventually reconciling with a new personal philosophy. My question is: could it really happen?
There are obvious problems to consider from a Biological perspective. Smaller animals lose heat faster, need to be hydrated more regularly and their eyes aren't as good, but let's say we decided not to worry about such things and just go for it. Would it be possible?
Well, if we take a look at how living things on Earth are made, we find that everything is built from the same basic stuff. At the smallest level we get the fundamental particles; things like electrons and quarks. These are arranged into stable configurations called atoms and molecules, which meet each other in chemical reactions. The reactions take place inside cells (also made of atoms and molecules) and cells are stacked up to make a living thing.
Tiny creatures obviously exist in nature, and since they are made from the same ingredients list, it certainly makes the whole endeavour tantalising. So let’s consider what our options might be.
1) Shrink the Cells
This is the approach used in Downsizing. A cell is a membrane-bag of chemicals needed to perform certain functions, if we just made the bag smaller the resulting person would be smaller as well, right? Unfortunately it turns out this wouldn't work and the reason is simple: cells are always the same size.
Cells are chemical reaction factories and for reactions to take place in the correct way, you need the right concentrations. If the cell is smaller, you’re essentially cramming all your finely-balanced reactants together and reactions start happening which shouldn't. Not to mention the fact that the membranes are no longer absorbing and releasing the correct amounts of carbon dioxide and oxygen for their relative size.
If we corrected for this by lowering the concentrations of chemicals inside, there just wouldn’t be enough of each chemical to actually perform the necessary jobs. Cells are jam-packed already and they have to be. Lower concentration means removing the necessary ingredients for the cell to live.
Animals come in all different sizes, but smaller animals don’t have smaller cells, they just have less of them. Nature has found the optimum size for cells and uses it for everything. This option isn't going to work.
2) Use less Cells
If we can’t make the cells smaller, can we just remove 90% of them instead? A fully grown human has an estimated 37 trillion cells in its body while a mouse has closer to 12 billion. The mouse seems to function just fine, so what if we kept all our body parts in the right proportion - just used less material to make them? This could actually work from a chemical and biological perspective. There's nothing stopping us from carving tiny bones or building miniature hearts The only problem however, is that if we’re removing cells from every part of the body that would include the brain.
The average human brain has a volume of just over a litre and it needs to be that big in order to house 86 billion neurons, each long enough to connect to 10,000 others around it. Shrinking the brain means either making each neuron shorter (less neural links possible) or using less neurons full stop. Shrinking down to mouse size by deleting a lot of the cells would be feasible, but we would lose our minds in the process. Literally.
A mouse’s brain can fit around 75 million neurons which is a remarkably complex structure, more advanced than our best supercomputers, but it's still a thousand times less circuitry than we are used to using.
To be clear, the size of your brain doesn’t automatically correlate with intelligence but there is clear a link. Bigger animals need bigger brains because they’ve got more body to control (that’s why whales and elephants have the biggest brains on Earth), so really it's brain-to body ratio we need to consider, but it’s also true that having more parts in a machine means it can do more things.
The smartest animals on the planet are humans, chimpanzees, dolphins, whales, elephants, pigs etc. and they all have big brains. Some small-brained creatures are smart for their size e.g. magpies and rats, but they don't have enough room in their skulls for higher-order thinking. A five-inch human would be one of the smartest animals on the planet for sure, but it would be utterly stupid compared to regular-sized humans.
3) Shrink the atoms
We need to preserve the number of cells but we also need to keep the number of molecules inside those cells the same. So what if we just shrunk the atoms? Smaller atoms would mean smaller molecules which would mean smaller cells and so forth.
You've probably come across pictures of atoms showing electrons orbiting a nucleus with empty space in between. For the purposes of Chemistry this is a reasonable approximation to make (I make it myself in my upcoming book) so you might think we can shrink atoms by pushing the electrons toward the nuclei, but in reality it’s not so simple. There’s a lot of complicated reasons why it doesn't work, but I'll stick to one which is easy to conceptualise.
The space between the nucleus and the electrons is not really empty at all. Actually it’s a heaving soup of energetic particles frothing into and out of existence like a bubbling cauldron. The energy of this “particle soup” does all sorts of wierd things to the electrons around an atom, including telling them where they can and can’t go. You can think of it like an outward-pressure, mainting the atom's size. Electrons can be squeezed toward the nucleus (where the density of the particle soup increases) but its reluctant to do so.
That’s not even taking into account the fact that electrons repel each other unless they are at extreme temperatures. An atom, just like a cell, is already at the optimum size. But while squishing a cell would be possible, squishing an atom is going against nature's preferences. Nature will fight back. Technically, with enough pressure pointed inwards you could just about do it, but it would probably turn the matter into a black hole. Atoms don't shrink.
4) Shrink the Particles
We can't squash the atoms because particles don't like being close to each other, but could we maybe shrink the particles themselves? If the particles in the centre of the atom weren’t so big, the surrounding particle soup wouldn’t take up as much space (roughly speaking) and the electrons (which would would also have to shrink in order to repel each other less) could get closer to one another. Would this help us make everything smaller?
No. Not at all. This is even less feasible than squishing the atoms. To change the size of fundamental particles is to change the fabric of the Universe itself. You can’t change a fundamental particle because it’s fundamentally the way it is. Hence the name! Fundamental particles have specifically defined behaviours and energies which don't seem to be programmable. Once you get down to the quantum level, there's nothing you can do to to keep control.
There is always a possibility, of course, that we’re wrong about these particles being truly the smallest things, but we’re pretty confident. We’ve got good reason to believe things like quarks and electrons are genuinely the bottom rung of the ladder. Squashing them would be like trying to make gravity run backwards. It's just not the way things go.
Not only that, but when you get right down to the quantum level, it’s not exactly obvious what size even means. Particles aren’t little nuggets floating around in a vacuum, they are fluctuating packets of energy and they don’t have clear dimensions. We sometimes talk casually about the amount of space a particle occupies but that isn’t really its size. It's an old-fashioned view for something which defies human intuition. Particles are the way they are and to change them is to change reality. Norwegian scientists are great, but they’re not gods.
It would seem, sadly, that there isn’t an obvious way to get around the problem of human size. We're stuck like this and we're stuck with all the problems it causes. So if we really want to change how our species affects the planet we can’t just change what we are. We need to change the way we act. We need to stop seeing the planet as our personal playground and more as our responsibility. Ultimately it's not are shape we need to shrink, it's our ego.
I love science, let me tell you why.