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Science as Metaphor
At the leading edge of experience in philosophy, science and feeling there is inevitably a groping for language to translate the insecure novelty of noticing and understanding into a precision of meaning and imagery.
— Frank Oppenheimer
Oppenheimer wrote these words in the introduction to a series of readings at The Exploratorium on "The Language of Poetry and Science." Poetry and science? Not so strange when you consider that Niels Bohr himself once wrote, "When it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images."
Science, after all, involves looking mostly at things we can never see. Not only quarks and quasars but also light "waves" and charged "particles"; magnetic "fields" and gravitational "forces"; quantum "jumps" and electron "orbits." In fact, none of these phenomena is literally what we say it is. Light waves do not undulate through empty space in the same way as water waves ripple over a still pond; a field is not like a hay meadow, but rather a mathematical description of the strength and direction of a force; an atom does not literally leap from one quantum state to another; and electrons do not really travel around the atomic nucleus in circles any more than love produces literal heartaches. The words we use are metaphors, models fashioned from familiar ingredients and nurtured with imagination. "When a physicist says 'an electron is like a particle,'" writes physics professor Douglas Giancoli "he is making a metaphorical comparison, like the poet who says, 'love is like a rose.' In both images a concrete object, a rose or a particle, is used to illuminate an abstract idea, love or electron."
Over the centuries the metaphors of science have taken a multitude of forms. Recently, physicists struggling to understand new evidence for a repulsive force in the universe could be heard tossing around terms like "quintessence," "X matter," "smooth stuff," and "funny energy." The more mysterious the emerging landscape, the further they must reach for appropriate imagery to describe it. But there's nothing necessarily odder about this language than the terms scientists have always used to pin down the ineffable.
Here's Francis Bacon's seventeenth-century description of heat: "Heat is a motion of expansion, not uniformly of the whole body together, but in the smaller parts of it, and at the same time checked, repelled, and beaten back, so that the body acquires a motion alternative, perpetually quivering, striving, and irritated by repercussion, whence spring the fury of fire and heat."
And Isaac Newton's account of what we now call chemical reactions: "And now we might add something concerning a most subtle spirit which pervades and lies hid in all gross bodies, by the force and action of which spirit the particles of bodies attract one another at near distances and cohere, if contiguous ... and there may be others which reach to so small distances as hitherto escape observations ... and electric bodies operate to greater distances, as well repelling as attracting the neighboring corpuscles; and light is emitted, reflected, refracted, inflected, and heats bodies; and all sensation is excited and ... propagated along the solid filaments of the nerves."
And Hans Christian Oersteds early-nineteenth-century image of electricity: "The electric conflict acts only on the magnetic particles of matter. All nonmagnetic bodies appear penetrable by the electric conflict, while magnetic bodies, or rather their magnetic particles, resist the passage of this conflict. Hence they can be moved by the impetus of the contending powers."
Compare those with excerpts from a paper proposing a new kind of "dark matter," by physicists Daniel Chung, Edward Kolb, and Antonio Riotto: "The goal of this paper is to show that the Universe might be made of superheavy WIMPs (we will refer to them as X particles), with mass larger than the weak scale by several (perhaps many) orders of magnitude. ... To see the effects of vacuum choice and the scale factor differentiability on the large X mass behavior of the X density produced, we start by canonically quantizing an action of the form (in the coordinate ds = dt - a(t)dx) ..."
The subjects of science are not only often unseeable; they are also untouchable, unmeasurable, and sometimes even unimaginable. The only way to examine these elusive entities is to scale them up, or shrink them down, or give them a familiar, solid form so that we might finally get at least a temporary handle on them. But even in 1882, physicist and lawyer Johann B. Stallo recognized that the current models of the universe were only "logical fictions," useful tools for understanding but in the end only "symbolic representations" of the real world.
When it comes to science — like so many other things — we find ourselves literally at a loss for words. Thus are metaphors born. When botanist Robert Brown first noticed the quick random motion of plant spores floating in water (now known as Brownian motion), he described it as a kind of "tarantella," according to physicist George Gamow, who went on to anthropomorphize it as "jittery behavior." (Brownian motion was the first convincing evidence for the existence of molecules, since it was bombardment by water molecules that made the plant spores dance.)
Later, Gamow described X rays as a mixture of many different wavelengths of invisible light. "Being suddenly stopped in their tracks [by a target], the electrons spit out their kinetic energy in the form of very short electromagnetic waves, similar to sound waves resulting from the impact of bullets against an armor plate." Thus in German they are called Bremsstrahlung, or "brake radiation."
Sometimes the metaphors get confused. A mixture of many colors is called white, but we also call a mixture of sounds "white" noise; we speak of "loud" colors. Something that is "going to seed" is deteriorating, yet "seedy" really means "fertile," since seeds are the origin of new growth. The universe is described alternately as a bubble, a void, or a firecracker. Time is "fluid," or "grainy," or both. Electrons are waves, and light waves are particles. If it all sounds as if the scientists don't know what they're talking about, it is at least in part because a lot gets lost in translation.
Imagining the unseeable is hard, because imagining means having an image in your mind. And how can you have a mental image of something you have never seen? Like perception itself, the models of science are embedded inextricably in the current worldview we call culture. Imagine (if you can) what the planetary model of the atom would have looked like, its satellite electrons orbiting its sunlike nucleus, if people had still thought the earth was flat. It would have been literally unthinkable. "A model or picture will only be intelligible to us if it is made of ideas which are already in our minds," wrote physicist Sir James Jeans. It was geneticist J. B. S. Haldane who noted that the inner workings of nature are "not only queerer than we suppose, but queerer than we can suppose."
Unable to suppose what the universe is really like, we rely on our rather limited but comfortably familiar models. The look of those models changes periodically, with the result that our view of the universe changes drastically. It's a long way from Newton's mechanical universe, controlled by invisible pulleys and springs, to today's image of forces as wrinkles in space, of matter as mere vibrating wisps of energy, of the physical world we know as but a shadow of a higher eleven-dimensional reality. "Scientific theories," writes Isaac Asimov, "tend to fit the intellectual fashions of our times."
Asimov goes on to detail the specific case of the atom, as good an example as any, since atoms are still essentially unseeable — or at least require a completely different kind of seeing than the one we are used to. The Greeks, who specialized in geometry, saw atoms as differing primarily in shape. Fire atoms were jagged, so fire hurt. Water atoms were smooth, so water flowed. Earth atoms were cubical, so earth was solid. Along came 1800, and the world had gone metric — in the sense of being mainly interested in measuring. Shape was no longer interesting; only amounts mattered. Thus atoms became featureless little billiard balls, differing mainly in the quantity of mass they contained. Later still, in the 1890s, the fashion in science was the notion of the force field — and so atoms were seen to differ mainly according to the configuration of their outer electron clouds. All these images persist today in one form or another, with physicists still focusing on quantities, organic chemists on the shapes of molecules, and so on.
Another familiar example of this phenomenon is plainly visible in the night sky. The stars in the Northern Hemisphere are clustered into constellations that mirror the images that danced in the heads of the Greeks who named them: All romance and adventure, the stars tell stories of queens and warriors, gods and beasts. The stars of the Southern Hemisphere, on the other hand, were named by a more modern culture, whose main interest was navigation. They did not see bears and lovers in the sky but rather triangles, clocks, and telescopes. "The division of the stars into constellations tells us very little about the stars," wrote Jeans, "but a great deal about the minds of the earliest civilizations and of the mediaeval astronomers."
Of course, it's not surprising that the way we see atoms and stars should change, since images of more everyday things also change drastically from time to time. Any cultures perception of childhood, the role of women, work, religion, government, all look very different in different eras. The ever adorable Judy Garland in The Wizard of Oz looks positively fat compared to todays child models.
Metaphors are drawn from common experiences. There is no way to imagine the unknown except in terms of the known, and so the landscape of the unfamiliar gets filled in mostly with familiar images. The images we use to describe both the unseeable subjects of science and the unseen future necessarily are fashioned from the "seeable" world we experience every day. And there's the rub. We do not experience the very large or the very small, the invisible forces and mathematical fields, the curvature of space or the dilation of time. We cannot crawl inside an atom or zoom along at the speed of light. "The whole of science is nothing more than a refinement of everyday thinking," wrote Einstein. But everyday "common sense," he also pointed out, is merely that layer of prejudices that our early training has left in our minds.
Common sense is both necessary and useful. It becomes dangerous only "if it insists that what is familiar must reappear in what is unfamiliar," writes J. Robert Oppenheimer. "It is wrong only if it leads us to expect that every country that we visit is like the last country we saw." Yet this is precisely what people do. The truth is that a model, like a foreign language, isn't really useful until you can take it somewhat for granted. It's hard to speak a language fluently when you have to keep rummaging around in the back of your mind for the right word or phrase. And it's hard to understand complicated ideas when the simple ideas and assumptions that lead up to them are still tenuous and elusive. You can't learn much about atoms if you keep having to remind yourself, "Let's see. Now, the nucleus is the thing in the middle. The electron is the much smaller thing on the outside. Is the electron the negatively charged one? Right, I remember." And so on. Being fluent means having words and ideas on the tip of your tongue. But once you become fluent in a language or in a set of ideas, you have internalized them to the extent that other languages and ideas sound automatically strange and foreign.
"Familiarity is soporific," writes physicist B. K. Ridley. It breeds consent to whatever models we're used to. It's a tender, powerful trap. "Consider the danger of familiarity," he goes on. "It seems clear that an object cannot be in two places at once; but an electron suffering diffraction can. It also seems clear that though size and position are infinitely variable, everything shares the same time; but, as Einstein showed, this is not so. We must check our intuitive ideas all the time."
It's not so easy to check these intuitive ideas, because, well, they're intuitive! Embarking on new territory requires a fresh supply of words and images. But where are they to spring from? Often unknowingly, we keep returning to the same old well. Or as Einstein put it: "We have forgotten what features in the world of experience caused us to frame [prescientific] concepts, and we have great difficulty in representing the world of experience to ourselves without the spectacles of the old, established conceptual interpretation. There is the further difficulty that our language is compelled to work with words which are inseparably connected with those primitive concepts."
In a word, language can easily turn "into a dangerous source of error and deception," Einstein said. Science has a special language problem, however, in that it borrows words from everyday life and uses them in contexts that exist only in realms far removed from everyday life. When I first tried to explain the newly discovered force particles in terms of "the force you feel when you stub your toe," I found that I had stumbled upon a semantic thicket, because "force" on a macroscopic scale and "force" on a submicroscopic scale can masquerade as very different things. Physicists borrowed the idea of force from Newtons mechanics and applied it to quantum mechanics, where it was modified — at least, to a layperson — almost beyond recognition. How can force have meaning in a system that barely allows for the notion of cause and effect? But still physicists talk about "force particles," and we who were left back with our billiard-ball images of particles and "pushing and pulling" notions of forces stay hopelessly, irretrievably confused.
"Often the very fact that the words of science are the same as those of our common life and tongue can be more misleading than enlightening," says J. Robert Oppenheimer, "more frustrating to understanding than recognizably technical jargon. For the words of science — relativity, if you will, or atom, or mutation, or action — have a wholly altered meaning."
Many physicists are particularly uneasy about terms applied to subatomic particles: "Quark" for example, was borrowed from a phrase in Finnegans Wake; in German it means something like "cream cheese." But "quark," to most people, doesn't mean much of anything. Far worse, say the physicists, are those words that do. The subatomic world is teeming with strange species of particles bearing oddly familiar names. "Strange" is one of them. Yet particles called "strange" or "charmed" or variously "colored" or "flavored" are not in any way particularly unusual or pleasant or green or good-tasting. The words are worse than nonsense (say some physicists), because they are downright deceiving.
Physicist Richard Feynman, for example, objected that this was "lousy" terminology: "One quark is no more strange than another quark. Maybe charm is OK, because it's so far out you know it isn't really charmed. But people think that up quarks are really turned up somehow, so it's very misleading." Victor Weisskopf concurs: "I always get the creeps when people talk about virtual particles," he says. "There is no such thing. It's a mathematical concept to describe the strength of a field." The term "virtual" refers to the very short-lived nature of such particles, but even the term "particle," Weisskopf points out, "is only there to remind you that the field has quantum effects."
It's hardly fair to pick exclusively on modern words like "charm" and "color." Where does a term like electric "charge" come from? Is it like a charge account? A charge in battle? (Obviously the usage "to get a charge out of" something comes from the science and not vice versa.) We speak of positive and negative electricity, when in fact there is no such thing — and if there were, the positive would be negative and vice versa. (Something with a negative charge actually has an excess of electrons, the particles of electric charge. Something with a positive charge has fewer electrons than it needs to make it neutral.) When an atom gets "excited," it does not sit on the edge of its seat (although it may dance around a bit). On the subatomic level, "force" means something closer to "interaction," and the strength of a force becomes the probability of its occurring.(Continues…)
Excerpted from "First You Build a Cloud"
Copyright © 1999 K. C. Cole.
Excerpted by permission of Houghton Mifflin Harcourt Publishing Company.
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Table of Contents
PART I: The Art of Knowing,
PART II: Movers and Shakers,
PART III: Threads and Knots,
Forces and Influences,
Selected Bibliography and Recommended Reading,
Connect with HMH,