The demon-haunted microworld

Here's a bigger and illustrated version of an article published in Aeon magazine. It is part of a larger project to be revealed soon.

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If small means invisible, we fear what it holds

When the Dutch cloth merchant Antony van Leeuwenhoek looked at a drop of pond water through his home-made microscope in the 1670s, he didn’t just see tiny ‘animals’ swimming in there. He saw a new world: too small for the eye to register even the faintest hint, teeming with invisible life. The implications were as much theological as they were scientific.

Invisibility comes in many forms, but smallness is the most concrete. Light ignores very tiny things as ocean waves ignore sand grains. During the seventeenth century, when the microscope was invented, the discovery of such objects posed a profound problem: if we humans were God’s ultimate purpose, why would he create anything that we couldn’t discern?

The microworld was puzzling, but also wondrous and frightening. There was nothing especially new about the idea of invisible worlds and creatures – belief in immaterial spirits, angels and demons was still widespread. But their purpose was well understood: they were engaged in the Manichean struggle for men’s souls. If that left one uneasy in a universe where there was more than meets the eye, at least the moral agenda was clear.

But Leeuwenhoek’s ‘animulcules’ and their ilk indulged their opaque, wriggly ways everywhere one looked: in moisture, air, body fluids. In human semen – Leeuwenhoek studied his own, transferred with jarring haste from the marital bed – there were tadpole-like ‘animulcules’ writhing like eels. In 1687 the German mathematician Johann Sturm suggested that disease is caused by breathing in such invisible animals in air. The Jesuit priest Athanasius Kircher proposed that the plague might be caused by the microscopic ‘seeds’ of virulent worms that enter the body through nose and mouth – just a step away, it seemed, from a germ theory of contagion, although the impossibility of seeing bacteria and viruses with the microscopes of the time obstructed that leap until Louis Pasteur and Robert Koch made it in the late nineteenth century.

Pestilence was everywhere, unseen and impossible to fend off – just like medieval demons. The narrator in Daniel Defoe’s Journal of the Plague Year (1722) attests he has heard that if a person with the plague breathes on glass, “there might living Creatures be seen by a Microscope of strange, monstrous and frightful Shapes, such as Dragons, Snakes, Serpents and Devils, horrible to behold.” He admits some doubts about whether this is true, but the message is clear: the invisible microworld is labelled “Here be dragons”.

Little has changed. Electron microscopes now reveal miniature viral monsters like science-fiction aliens, with arachnoid legs and crystal heads from which they inject genetic venom into cells. MRSA bacteria lurk unseen on hospital door handles and bed sheets. We sprinkle anti-bacterial fluids like holy water to fend off these invisible fiends.



The invisible world

The idea that matter might be composed of particles and processes too small to see – the atoms of Democritus, the whirling vortices of Descartes and the corpuscles of Newton – has a long history. But this fine-grained nature of matter only came to seem like an ‘invisible world’ when the advent of the microscope enabled us, first, to appreciate the intricacy with which it was wrought, and second, to identify life amidst the grains. When Galileo used one of the first microscopes to study insects, he was astonished and repelled, writing to his friend Federico Cesi in 1624 that
“I have observed many tiny animals with great admiration, among which the flea is quite horrible, the mosquito and the moth very beautiful… In short, the greatness of nature, and the subtle and unspeakable care with which she works is a source of unending contemplation.”

This wonder at nature’s invisible intricacy was echoed by Robert Hooke, whose 1665 book Micrographia put microscopy on the map. Crucially, Hooke’s volume was not merely descriptive: he included large, gorgeous engravings of what he saw through the lens, skilfully prepared by his own hand. The rhetorical power of the illustrations was impossible to resist. Here were fantastical gardens discovered in mould, snowflakes like fronds of living ice, and most shockingly, insects such as fleas got up in articulated armour like lobsters, and a fly that gazes into the lens with 14,000 little eyes, arranged in perfect order on two hemispheres.



This was surely a demonstration of the infinite scope of God’s creative power. “There may be as much curiosity of contrivance in every one of these Pearls”, Hooke wrote, “as in the eye of a Whale or Elephant, and the almighty’s Fiat could as easily cause the existence of the one as the other; and as one day and a thousand years are the same with him, so may one eye and ten thousand.”
In comparison, the finest contrivances of man – a needle’s tip, a razor’s edge, a printed full stop – looked crude and clumsy under the microscope.

What excited Hooke and his contemporaries most was that the microscope seemed to offer the possibility of uncovering not just the invisible structures of nature but, in consequence, its hidden mechanisms. Where in previous ages natural philosophers had attributed the cause of processes to invisible, occult forces and emanations – vague and insensible agencies – the mechanistic philosophers of the seventeenth century argued that nature worked like a machine, filled with levers, hooks, mills, pins and other familiar devices too small to be seen. Now at last these structures might be revealed. Henry Power, whose Experimental Philosophy advertised the virtues of the microscope a year before Hooke’s, wrote that we could expect to see at last “the magnetical effluviums of the loadstone [magnet], the solary atoms of light, the springy particles of air.” Hooke too insisted that “‘Those effects of Bodies, which have been commonly attributed to Qualities, and those confesse’d to be occult, are performed by the small Machines of Nature.” He never quite found them; but there was no shortage of other marvels.

Life writ small

Micrographia recorded life in this microscopic realm too, but none that could not be discerned, with effort, by the eye alone: “eels” in vinegar and mites in cheese. Leeuwenhoek’s discoveries, reported in 1676 and verified by Hooke a year later, brought home the full force of a teeming, invisible microworld. The anxieties about scales of perception that run through Swift’s Gulliver’s Travels make it clear how unsettling this was. In the land of the gigantic Brobdingnagians, Gulliver is disgusted by their bodies when seen so close up: “Their skins appeared so coarse and uneven, so variously coloured when I saw them near, with a mole here and there as broad as a trencher, and hairs hanging from it thicker than pack-threads.” Among the common folk he is repelled by the immense lice crawling on their clothes, possessing “snouts with which they rooted like swine.”

Even with refinements of the microscope in the nineteenth century that enabled scientists to peer into the invisible world with unprecedented resolution, there remained questions about what might be happening down there. In 1896 the pioneering British psychiatrist Henry Maudsley proclaimed that
“The universe, as it is within [man’s] experience, may be unlike the universe as it is within other living experience, and no more like the universe outside his experience, which he cannot think, than the universe of a mite is like his universe.”

Maudsley’s avowal of ignorance was an attack on the ready assumptions of some scientists, such as the chemist William Crookes, that invisible realms were peopled with beings like us. But this lack of knowledge could equally supply licence for the most exotic of speculations. The beginnings of molecular science engendered an appreciation that life as it was known could have a minimal possible size. But when the ‘indivisible’ atom began to display a finer-grained structure of subatomic particles, and light waves proved to have much finer oscillations in the form of X-rays, no one could rule out the possibility of an entire hierarchy of material existences on smaller scales. The physicist George Johnstone Stoney, who gave the name to subatomic electrons discovered in 1897, declared that the physical universe is really an infinite series of worlds within worlds. Another physicist, the Irishman Edmund Fournier d’Albe, developed these ideas in Two New Worlds (1907), where he envisaged an “infra-world” at a scale below that which microscopes could register, peopled like Leeuwenhoek’s drop of water with creatures (“infra-men”) that “eat, fight, and love, and die, and whose span of life, to judge from their intense activity, is probably filled with as many events as our own.” The human body, he estimated, could play host to around 10**40 of these infra-men, experiencing joys and woes “without the slightest net effect on our own consciousness”.

As ever is the case with scientific advance, the new and unfamiliar are popularly interpreted by reference to the old and prosaic. Littleness has been a consistent theme in the folklore and traditions of demons and faeries. Mischievous imps and fairies that interfere in domestic matters were a stock of folk tradition, and if these beings were not necessarily invisibly small, their diminutive stature enabled them to pass unseen. One might be tempted to imagine that by the late nineteenth century such beliefs reached no further than rural backwaters – but that would be to underestimate the grip of the invisible world on the imagination. Nowhere is this better illustrated than in the ‘demon’ of James Clerk Maxwell, perhaps the most profound physicist of the nineteenth century.

Maxwell’s idea was a response to the gloomy prediction of a ‘cosmic heat death’ of the universe. In 1851 William Thomson (later Lord Kelvin) pointed out that the second law of thermodynamics, which can be expressed as the condition that heat energy must always flow from hot to cold, must eventually create a universe of uniform temperature, from which no useful work can be extracted and in which nothing really happens.

As a devout Christian, Maxwell could not accept that God would let this happen. He believed that the second law is statistical rather than fundamental: temperature gradients get dissipated because it is far more likely that faster, ‘hotter’ molecules will mingle with slower ones, rather than by chance congregating into a ‘hot’ patch. But what if there were, as Maxwell put it in 1867, a “finite being”, small enough to ‘see’ each molecule and able to keep track of it, who could open and shut a trapdoor in a wall dividing a gas-filled vessel? This being could let through fast-moving molecules in one direction so as to congregate the heat in one compartment, separating hot from cold and creating a temperature gradient that could be tapped to do work.

Maxwell didn’t intend his creature to be called a demon. That label was applied by Thomson, where he defined it as “an intelligent being endowed with free will, and fine enough tactile and perceptive organization to give him the faculty of observing and influencing individual molecules of matter.” Maxwell was not pleased. “Call him no more a demon but a valve”, he grumbled – albeit a ‘valve’ with intelligence and autonomy, or as Maxwell once put it “a doorkeeper, very intelligent and exceedingly quick.”

Several of his contemporaries had little doubt that these ‘demons’ were to be taken literally. Thomson himself took pains to stress that the demon was plausible, calling it “a being with no preternatural qualities, [which] differs from real animals only in extreme smallness and agility.” Maxwell’s friend, the Scottish physicist Peter Guthrie Tait, evidently believed they might exist, and he enlisted them for an extraordinary cause. In 1875 Tait and fellow Scot Balfour Stewart, an expert on the theory of heat, published a book called The Unseen Universe in which they attempted to show that “the presumed incompatibility of Science and Religion does not exist.” There must be, they wrote, “an invisible order of things which will remain and possess energy when the present system has passed away.” Tait and Stewart were aware of the apparent conflict between the Christian doctrine of the immortality of the soul and the second law of thermodynamics, which seemed to enforce an eventual universe of insensate stasis. “The dissipation of energy must hold true”, they admitted, “and although the process of decay may be delayed by the storing up of energy in the invisible universe, it cannot be permanently arrested.” Maxwell’s demon gave them a way out. “Clerk-Maxwell’s demons”, they wrote, “could be made to restore energy in the present universe without spending work” – and as a result, “immortality is possible.”

Modern studies have shown that Maxwell’s demon cannot after all evade the second law, since even it has to dissipate heat as part of the process of gathering information about molecular speeds. The conceit is now generally regarded as an amusing thought experiment: it is forgotten that, in Maxwell’s day, invisibly small demons going about their micro-business seemed possible, even likely.

Nano nightmares

The demonization of invisible beings is as strong as ever, now adapted to the fantasies of our age: viruses are “alien invaders”, we go to “war” on “superbugs” with super-powers, repelling them like vampires with “magic bullets”. Children are taught that invisible “germs” are the omnipresent enemy, and they are enlisted, as imps and demons once were, to instil safe behaviour. It is a case, microbiologist Abraham Baron declared in 1959, of “man against germs”. When he explained that “we share the world with an incredible vast host of invisible things”, it was a warning and not an expression of wonder. In his 1912 study of the hazards of dust, physician Robert Hessler cautioned that “It is the invisible we have to guard against.”



This fear of the malevolent designs of imperceptibly small entities was evident in the early reception of nanotechnology, which seemed to be supplementing this gallery of invisible horrors. Among scientists, nanotechnology was a loosely defined collection of attempts to visualize and manipulate matter on scales ranging from ångstrøms (the size of atoms) to hundreds of nanometres (the size of small bacteria). But in public discourse it became dominated by a single entity, which nanotechnologists were allegedly aiming to construct: the nanoscale robot or nanobot. This, it was said, would be an autonomous device that would patrol the bloodstream for pathogenic invaders, or construct materials and molecules from the atoms up. It was, in other words, a human avatar on an invisible scale.

What if nanobots ran amok, as robots are (in fiction) almost predestined to do? A rogue robot might be a menace, but it is a comprehensible one, a kind of superhuman being. A rogue nanobot, capable of replicating like bacteria and of pulling matter apart atom by atom, would be an unthinkable threat. Hidden from sight, it could reduce anything in seconds to a formless mass of atoms, which would then be reconstituted into replica nanobots: an amorphous ‘grey goo’. The terror of this imagery was crudely but effectively exploited by Michael Crichton in his novel Prey (2002).

If the image is frightful, it is also familiar. Invisible powers have long been held capable of animating clay, creating the fearsome Golem, or of disintegrating and deliquescing matter and flesh (think now of the Ebola virus). What’s more, the nanobot connects with long-standing images of the exploration of new worlds, most notably the submarine Nautilus in which Captain Nemo explores the hidden deep sea in Jules Verne’s 20,000 Leagues Under the Sea. Once again, it seems we must remake the invisible microworld in our own image before we can explore its promise and peril. This was most explicit in the 1966 movie Fantastic Voyage (based on a short story by Isaac Asimov) and the parodic 1987 remake Inner Space, in which humans are shrunk to a scale that allows them to navigate through the human body.





The extreme miniaturization that has its ultimate expression in nanotechnology has not yet given birth to an invisible nemesis, and shows no sign of doing so. What it, in conjunction with the manipulation of invisible rays such as Marconi’s ‘wireless’ emanations, has done is create an age of technological invisibility, in which things happen with no mechanism in sight, indeed even without our volition, embedded in an omnipresent field of information. Items in stores speak to barriers and computers; miniaturized sensors control our cars and refine our household environment; libraries leap into our pockets. Dust, a metaphor for worthless matter while it was the smallest thing that could (just) be seen with the unaided eye, has become “smart dust”, a nanotechnological promise of particles laced with invisible circuitry, programmed with the intelligence to self-assemble as we will them: to make a Golem, perhaps, rebranded now as a ‘reconfigurable robot’.

It has become a commonplace that these advances would have seemed in earlier times to be magical. Less often acknowledged is how traditional reactions to invisibility can help us comprehend and negotiate the cultural changes that ensue. The boundaries between rationality and insanity can no longer be policed in behavioural terms. Is the person gesticulating and talking out loud in the street communing with demons of the mind, or with a friend? Is the person fretting over the invisible threats of nearby radio masts succumbing to some modern version of the mal aria theory of contagion, or do they have a point? We entrust our digital secrets to the intangible Cloud, assume that this nebulous entity can be summoned to regurgitate them at will. With invisibly small technology harnessed to the invisible ether, we have in a real sense animated the world.