The Possible and the Impossible, by Elizabeth Kay
This is part of a paper I gave at the Harry Potter Conference in 2005. It’s a bit more technical than the things I usually post, but what the hell.
I think children’s writers have a duty not to disseminate false or misleading information, and an obligation to present the world as something to be cherished, explored, and enjoyed. A fantasy world is always a metaphor for the real world, as we have nothing else to plunder for subject matter.
A big change in authorial responsibility occurred during the second half of the last century in a close relative of fantasy, science fiction. We stopped wondering what effect the aliens would have on us, and started to worry about what effect we would have on them. We began to observe ourselves a little more objectively, and we didn’t like what we saw. Neither do children, on the whole – they worry about what we’re doing to the planet; they have ideals and integrity, and they want to do what’s right. They believe what they read when they’re told it’s fact, and they suspend disbelief when they’re told it’s fiction. But fiction is, of necessity, based on fact.
The principle of similitude tells us that if an animal doubles its linear dimensions but retains the same proportions, its surface area is quadrupled. Its volume, however, and therefore its weight, goes up by a factor of eight.
This has profound effects. The strength of an animal’s bones are proportional to their cross-sectional areas – so mice have very thin slender bones. If you made a mouse the same size as an elephant, it would have to have bones as thick as an elephant’s, and it would look a lot more like an elephant than a mouse. A fourfold increase in strength must support an eightfold increase in weight.
An external skeleton is fine for a small creature, but every hollow structure grows weaker as it grows larger. Gravity will have its pound of flesh. The extra strength needed for the supporting structure of the internal skeleton exacts a ponderous price. Increase an animal’s size too much, and it will no longer be viable. Once supported by water, though, everything changes – so perhaps there is still a slim chance of a breeding colony of monsters in Lock Ness.
Four times the lung capability must service eight times the bodymass. Among arthropods, gases pass in and out by a diffusion process. Over short distances a tracheal respiratory system is incredibly efficient, but an increase in the length of the tracheoles leads to an increase in friction and diffusion is retarded. Therefore, a giant spider would not have a workable respiratory system.
Size impacts on many things – respiration, strength, speed, heat loss, food consumption, jumping ability, flight... The heavier a bird is, the faster it must fly to remain aloft. Nevertheless, there is an instance of a bird that was big enough to be capable of preying on man – the Haast eagle of New Zealand, which lived there during the Pleistocene, and flourished right up until the arrival of Polynesian man in the 14th century. It had a wingspan of 2.6 metres and was the top predator, feeding on moas. The cry it gave was passed down by word of mouth – hokioi-hokioi. It was recorded in rock paintings – but, unsurprisingly, it rapidly became extinct. Man is the neighbour you least want if you’re top predator.
Size even has an effect on hearing and vision. The diameter of the eardrum is significant – elephants use infrasound, below our range of hearing. Bats squeak well above it. The smaller the creature, the shorter its vocal cords will be and, consequently, the higher-pitched its voice. Even our perception of time depends on our size. Tiny creatures live life at a different rate. D’Arcy Thompson, on page 34 in On Growth and Form, says:
…A minute insect may utter and receive vibrations of prodigious rapidity; even its little wings may beat hundreds of times a second. Far more things happen to it in a second than to us; a thousandth part of a second is no longer negligible, and time itself seems to run a different course to ours.
Being small is even more weird than being big – to a tiny insect, we all move in slow motion. Therefore, decreasing the size of something can also be a problem. D’Arcy Thompson, again, on page 25 in On Growth and Form:
…a mouse will eat half its own weight in a day; its rate of living is faster, it breeds faster, and old age comes to it much sooner than to man. A warm-blooded animal much smaller than a mouse becomes an impossibility; it could neither obtain nor yet digest the food required to maintain its constant temperature, and hence no mammals and no birds are as small as the smallest frogs or fishes.
So – The Borrowers would have squeaky little voices, scuttle about at considerable speed, listen to batsong in the evenings, spend most of the time eating and live for just a couple of years. On the other hand, King Kong would move at a snail’s pace, and his voice would be so deep that his roar would be inaudible; nevertheless, the fallout from sound that is below our range of hearing could be considerable. Infrasound has disturbing effects, not all of which are yet known to us. It’s not just the giants – elephants and whales – that use it, either. Elizabeth von Muggenthaler, a bioacoustician from the Fauna Communications Research Institute in North Carolina, notes that a tiger's roar contains an 18 hertz component that induces feelings of terror in humans and can paralyse prey for up to 10 seconds.
The difference in the optical equipment of King Kong and Arietty would be far less pronounced, however. The rods and cones that detect light and colour in the retinal eye are optically limited by the interference patterns of light waves. The eye of a whale is tiny, in proportion to the animal itself, whilst the eye of a bush-baby seems enormous by comparison. An insect is just too small to obtain a clear image with a retinal eye, so it has united simple eyes into the compound multi-faceted version we have seen magnified to totally unrealistic proportions in the bug-eyed monsters of science fiction films.
As our knowledge of the physiology and anatomy of life increases, so does our knowledge of what is possible and what is impossible. Sir Arthur Conan Doyle’s Lost World would be a different place today.
Myths exist in science, as well as in fiction. The statement that according to the laws of aerodynamics a bumblebee can’t fly is, itself, a myth. Rumour has it that this was based on a mathematical model scribbled on a piece of paper over dinner – but there are differences between a real bumblebee and a mathematical model of one. What was demonstrated was not the superiority of biology over aerodynamics, but the fact that a simple mathematical model wasn’t adequate for describing the complex flight of a bumblebee. On page 17 in On Growth and form, D’Arcy Thompson says:
…Everywhere Nature works true to scale, and everything has its proper size accordingly.
We do not know what is possible, in the great diversity of life that’s past, life that’s present, and life that is to come, but we are pretty sure that some things are impossible.
Should we only invent things that don’t violate the laws of physics? Storytelling is one of the ways in which we enrich our lives,explore our fears, and celebrate our diversity. Storytelling celebrates the imagination, without ,
The Divide and Shelob. Although it is important be able to discriminate between fact and fantasy, each has its proper place, and each can be appreciated for what it is. Maybe the role of fantasy creatures in children’s literature is to demonstrate that life doesn’t come in black and white, it comes in shades of grey – and every colour of the rainbow, as well. That’s what we ought to be teaching our children – to learn the facts, weigh the evidence, and think for themselves.