From Lilliput to Brobdingnag

When the Microscope was Invented at the beginning of the 17th Century, it revealed an entire new order of creation to mankind. Below the range of the visible was an unsuspected universe of living creatures, dwindling down, down, down to unimaginable minuteness. This discovery, coming at the same time as the telescope's revelations at the opposite end of the scale, set men thinking about the question of size.

One of the earliest -- and certainly the most famous -- results of that thinking was Gulliver's Travels. The genius of Swift seized upon the change of perspective caused by magnification as a means of satire, and both Lilliput and Brobdingnag have now passed into our language. As also, though invariably misquoted, has Swift's stanza on the same theme: "So, naturalists observe, a flea/Has smaller fleas that on him prey/And these have smaller still to bite 'em/And so proceed ad infinitum."

Although it was quickly discovered, to the general relief, that Swift's Brobdingnag existed nowhere on Earth, the rather more attractive idea of minute or even microscopic races of men continued to fascinate writers. (It is more attractive, of course, because we are all scared of giants, whereas we feel that we could cope with midgets. In reality, it would be just the reverse.) The classic story of the microworld is Fitz-James O'Brien's The Diamond Lens, published in 1858, when the author was still in his 20s, with only four years of life ahead of him before his brilliant career would be cut short by the Civil War. The Diamond Lens describes what is perhaps the most frustrating romance in literature; it is the tragedy of a microscopist who falls in love with a woman too small to be visible to the naked eye, and who lives in the world of a water drop.

Later writers did not let such an obstacle as mere size stand in the way of the plot; they invented drugs which contracted or expanded their characters as desired. The immortal Alice was perhaps the first to taste one of these potions, not yet listed in the pharmacopoeia; and nowhere else have the difficulties they could cause been so vividly described.

The idea of the microworld received a fresh lease on life in the 1920s, when the work of Rutherford and others laid bare the nuclear nature of the atom. The thought expressed in Swift's stanza was revived on a far more breathtaking scale. Every atom might be a miniature solar system, with electrons playing the role of inhabited planets -- and, conversely, our solar system might be merely an atom in a superuniverse.

This theme was taken up with enthusiasm by the prolific science-fiction writer Ray Cummings, who had training that many of his colleagues might have envied: he was Edison's secretary for five years. In The Girl in the Golden Atom (1919) and later stories, Cummings shrank a whole series of heroes down to subelectronic size, passing somewhat glibly over such problems as the navigation of internuclear space and the location of the right atom (and the right girl) among the several million million million million different atoms that exist in a few ounces of gold.

Not long ago, Hollywood surprised many of us by making a remarkably good movie on the theme of smallness; I refer to The Incredible Shrinking Man, which 90 percent of intelligent filmgoers probably judged by its unfortunate title and decided to miss. The most incredible thing about the Shrinking Man (and I imagine that we can thank the author and scriptwriter Richard Matheson for this) was the fact that he was so credible, and the avoidance of the conventional happy ending left his final fate both moving and strangely inspiring. But perhaps I am too easily satisfied; it is so rare to meet a glimmer of intelligence in what film producers are pleased to call science-fiction movies that one's gratitude (continued on page 116) From Lilliput (continued from page 102) tends to overflow.

These stories of miniature and micro-worlds raise two distinct questions: could such worlds exist (not necessarily on our planet), and if so, could we observe or enter them?

As far as the first question is concerned, I think we can give a definite answer, based upon laws familiar to all engineers and biologists, but not to those journalists who love to trot out such ancient fallacies as: "If an ant were as big as a man, it could carry a load of 10 tons." In fact, it couldn't carry itself.

At any level of size, certain things are possible and others are impossible. The whole world of living creatures, with all its wonderful richness and variety, is dominated and controlled by the elementary fact of geometry which states: if you double the size of an object you multiply its area four times, but its volume (and hence weight) eight times. From this mathematical platitude, the most momentous consequences flow. It implies, for instance, that a mouse cannot be as big as an elephant, nor an elephant as small as a mouse -- and that a man cannot be the size of either.

Let us consider the case of man. He is already a giant -- one of the very largest of all the animals. This thought comes as something of a surprise to most people, who forget that the animals larger than man could have their names written on a single sheet of paper, while those that are smaller would fill volume after volume.

Homo sapiens shows a considerable range in size, though the extremes are very rare. The tallest man who has ever lived was perhaps five times the height of the smallest, but you would have to search through millions of cases to find a ratio of four to one -- unless you happened to hit on a circus exhibiting both an eight-foot giant and a two-foot midget. And if you did, you would probably find that both were sick and unhappy people, with little chance of reaching the normal span of life.

For the human body is a piece of architecture that has evolved to give its best performance when it is five or six feet tall. Double its height, and it would weigh eight times as much, but the bones which supported it would be increased in area of cross-section only four times. The stresses acting upon them would therefore be doubled in intensity; a 12-foot giant is possible, but he would always be breaking his bones, and would have to be very careful how he moved. To make a 12-foot version of Homo sapiens practical would involve a major redesign, not a straight scaling up. The legs would have to be proportionally much thicker, as the example of the elephant proves. The horse and the elephant both follow the same basic quadrupedal design -- but compare the relative thicknesses of their legs! The elephant must be near the sensible limit of size for a land animal; this was reached (if not exceeded) by the 40-ton brontosaurus and that largest of all land mammals, the incredible rhinoceros baluchitherium, which stood 18 feet high at the shoulder. (The head of a giraffe is only 16 feet from the ground.)

Beyond this size, no structure of flesh and bone could support itself against gravity; if real giants exist anywhere in the universe, their bones will have to be made of metal, which would involve some difficult problems in biochemistry. Or they will have to live on worlds of low gravity, possibly in space itself, where weight ceases to exist. One of the most interesting questions in extraterrestrial zoology is whether life can adapt itself to space by purely evolutionary processes. Almost all biologists would say, "Certainly not!" but I think it unwise to sell nature short at the present state of our ignorance, and shall have a few more words to say on this subject later.

In the direction of smallness, the problems that arise are not quite so obvious, but they are equally fundamental. At first sight there seems no very good reason why a man one foot high need not be a working proposition. There are plenty of mammals this size, based upon the same general design; some of the smaller monkeys, for example, are very much like little men.

Closer examination, however, reveals that their proportions are quite different, their limbs much more slender than man's. For just as a man enlarged to a height of 20 feet would be impractically fragile and underpowered for his weight, so, conversely, one diminished to a height of a foot would be hopelessly clumsy and overmuscled. Small animals need much smaller limbs, as is dramatically shown by the insects with their often unbelievably delicate legs and wings. By the time the Incredible Shrinking Man started to measure his height in inches, his grossly overpowered muscles would have torn him to pieces.

But long before then, so many other things would have gone wrong that he would be dead from a dozen causes. All the elaborate mechanisms of the body -- respiration, blood circulation, temperature control, to mention only the most obvious -- would have failed. When he was a tenth of his original size, the little fellow would have a thousandth of his starting weight. (We won't inquire where that missing 99.9 percent has gone; if he still has it, of course, he is 50 times as dense as platinum and has fallen through the floor.) Yet the area of his lung surfaces, stomach walls, and vein and artery cross-sections has diminished not by a thousand, but only by a hundred. His entire metabolism would proceed at 10 times the previous rate per unit of his mass; he would probably die of heat stroke through overproduction of energy.

This sort of argument can be followed to the same conclusion for every one of the body's functions, and makes it perfectly clear that even if the means existed for expanding or contracting a man, he would be incapacitated and then killed by quite a modest change of scale. There is no chance that any man will ever be able to stalk warrior ants through the jungles of the grass, still less marry a Princess in a Golden Atom.

Having made this point. I would like to add one slight reservation. A very good case can be made to the effect that man is now considerably larger than he need be. Physical strength and the size that necessarily goes with it will be needed less and less in the future. Indeed, size will be a handicap -- especially in the cramped quarters of space vehicles -- and it has been half-seriously suggested that one way of alleviating the coming shortages of food and raw materials is to breed smaller people. Even a 10-percent reduction in the average height of the human race would have a very considerable effect, for smaller people would need smaller homes, cars, furniture, clothes -- all the way along the line.

There would be no midgets, of course, if everyone were three feet high, and the world could then quite comfortably support twice its present population. Few futures, however, seem less likely than this, for thanks to better food and medical care men are growing rather than shrinking. (Harvard graduates, admittedly a privileged class, have been gaining an inch a generation -- an astonishing rate which suggests that they will be in real trouble around the year 3000.) Only a ruthless and all-powerful world dictatorship could reverse this trend; dictators are nearly always small people and one can imagine some future Hitler or Mussolini determined to assuage his inferiority complex by making his subjects even smaller than he -- though he could hardly expect to see any noticeable results in his own lifetime.

Although small living creatures cannot be manlike, and no man could continue to function if drastically reduced in size, this does not rule out the possibility that extremely small yet intelligent beings might exist if they were constructed upon nonhuman lines. By altering her designs nature can circumvent, to a quite remarkable degree, the limitations imposed by size. Consider, for example, the difference between the albatross and the tiniest midge, barely visible to the eye. Both are aerial creatures that fly by flapping their wings -- and there the resemblance ceases. Anyone knowing only the midge could make a very convincing case for the impossibility of the albatross -- and vice versa. Yet both exist, and both fly, though one weighs a billion times as much as the other. They represent the extreme ends of the evolutionary spectrum, when the resources of biological materials and mechanisms have been stretched to the limit. No bird much larger than an albatross could fly, as is demonstrated by the ostrich, the moa, and their giant ancestors, as terrifying as dinosaurs. No insect much smaller than a midge could have any control of its movements through the air; though it might float as helplessly as the planktonic creatures drift through the sea, it could not fly.

Even a complete redesign, therefore, permits only a limited, and not an indefinite reduction in size. Sooner or later we come up against the fact that the basic structural elements of living creatures -- the building blocks of life -- cannot be made much smaller than they already are. All animals are constructed of cells, and all cells are of much the same size. Those from an elephant are only twice the size of those from a mouse. It is as if all living creatures are like houses, built from bricks which vary only slightly in size. It follows, therefore, that very small animals must also be very simple animals, because they can contain only a limited number of components.

Intelligence, whatever else it may be, is at least partly a by-product of cellular complexity. Small brains cannot be as complex as large brains, because they must contain fewer cells. One can imagine the human brain still functioning well at half its present size -- but not at one tenth. If, on planets with powerful gravitational fields, living creatures are reduced to a height of a few inches, they cannot be intelligent -- unless they make up for their lost height by increasing their area, to give an adequate volume of brain. There might be doll-like animals on 50-g worlds, but anything capable of rational thought would look not like a mannequin, but a pancake.

Not only intelligence, but life itself, becomes impossible as we continue down the scale of size. Only just beyond the limit of today's microscopes the essential granularity of nature makes its appearance. As the cell is the basic building block of all living creatures, so atoms and molecules are the building blocks of the cell. Some minute bacteria are only a few score molecules on a side; the viruses, which mark the frontier between life and nonlife, are even smaller. But no house can be smaller than a single brick, and nothing that lives can be smaller than a single protein molecule, which is the chemical basis of life. The largest proteins are about a millionth of a centimeter long: that is a nice round figure to remember, as the last milestone on the road down from the world of life.

Although it is conceivable that more efficient types of organisms may have evolved on other planets (indeed, it is somewhat immodest to assume otherwise), it seems very unlikely that they could be so much more efficient that they could alter those conclusions. We can dismiss, therefore, those ingenious stories of midget (and even microscopic) spaceships as pure fantasy. If you are ever persistently buzzed by a strange metallic object that looks like a beetle, it will be a beetle.

There is not much that can or need be said about theories of the subuniverse and the suggestion that atoms may be miniature solar systems. Stories based on this theme are now virtually extinct; they were killed when it was discovered that electrons behaved in a most unplanetary fashion, being waves at one moment and particles the next. The cozy and easily pictured Rutherford-Bohr atom lasted only a few years -- and even in that model, electrons were assumed to jump instantaneously from orbit to orbit, which would have been very unsettling to their inhabitants. Wave mechanics, the uncertainty principle, and the detection of such puzzling particles as mesons and neutrinos made it very clear that atoms were nothing like solar systems, or indeed anything that the minds of men had ever envisaged before.

I might mention, with a slight shudder, that in Amazing Stories during 1932-1935 one J. W. Skidmore produced an entire series of tales about a subatomic romance between an electron, Nega, and a proton, Posi. How any author could have spun this horrid whimsy out over five stories (or even one) I cannot now imagine; his success may be judged from the fact that though I read the entire Posi-and-Nega series at the time of publication, I cannot for the life of me remember whether boy eventually met girl, and, if so, what happened.

Almost invariably, stories of microcosmic universes have ignored the fact that a change of size always involves a corresponding change of time rate. Small creatures live short, active lives; to birds and flies, we must be very slow moving, sluggish creatures. If we go to the limiting case of the atom and suppose that the orbiting electrons are in fact worlds in their own right, they must have fantastically short "years." In the Rutherford-Bohr model of the hydrogen atom, the single orbital electron makes about a million billion revolutions around the nucleus every second. If this corresponds to the 88-day year of Mercury, the innermost planet in our solar system, it would mean that time in the hydrogen atom must pass about 10,000 million million million times more swiftly than it does in our macroscopic universe.

No science-fiction hero, therefore, could ever make two visits to the same subatomic world. If he stepped back into his own universe for a single hour. and then returned to the atom, he would find that hundreds of billions of years had passed. And, conversely, any round trip to the microworld would have to be practically instantaneous in our time, otherwise the traveler would die of old age among the atoms. I do recall one story in which a scientist sent his daughter and his assistant on a brief visit to the subatomic universe and was disconcerted to welcome back several hundred of their great-great-great-great-grandchildren a couple of minutes later; even so, I fear that the author, though he was on the right track, grossly underestimated the magnitude of the problem. It would not be a question of a few human generations -- but the lifetimes of many suns.

For time can be a barrier more unyielding than space; this will be particularly true if we ever discover, and attempt to communicate with, extremely large intelligent entities. A number of writers have explored this idea, which does not conflict with my earlier remarks about the impossibility of giants. I was speaking then of planetary environments -- and there may be creatures larger than planets.

One writer to handle this theme was Fred Hoyle -- and whatever views one may take of Professor Hoyle's cosmology, nobody doubts that he knows his physics. In The Black Cloud he described, with great plausibility and convection, a gaseous invader from interstellar space, some hundred million miles in diameter -- in fact, a kind of intelligent comet.

Even if the "thoughts" of such a creature were propagated by radio waves, as Hoyle suggested, it would take 10 minutes for a single impulse to travel from one end of it to the other. A nerve impulse can make the trip across the human brain in a few thousandths of a second, so mental operations involving the whole of the Black Cloud would take perhaps a million times longer than those of a human mind. We would get very tired waiting for its answers; a short sentence would take a couple of months to deliver.

However, the Black Cloud might be able to talk to us at our own rate, or even at the rate of our fastest teleprinters, by detailing a minute and localized fraction of itself to deal with so trivial a problem. In that case, we could hardly claim to be in communication with it as a whole, any more than an ant could claim to have made contact with a man, because his toe twitched when it walked across his foot.

These are rather humbling thoughts, but I do not think that they are necessarily fantastic. Looking down toward the atom we can see, a few orders of magnitude beneath us, first the end of intelligence, then the end of life. There is no such finality in the other direction, and as yet we have no inkling of our position in the hierarchy of the Universe. There may be intellects among the stars as vast as worlds, or suns -- or solar systems. Indeed, the whole galaxy, as Olaf Stapledon suggested long ago, may be evolving toward consciousness, if it has not already done so. It contains, after all, 10 times as many suns as there are cells in a human brain.

The road to Lilliput is short, and it leads nowhere. But the road to Brobdingnag is another matter; we can see along it only a little way, as it winds outward through the stars, and we cannot guess what strange travelers it carries. It may be well for our peace of mind if we never know.