The Hazards of Prophecy

Before one attempts to set up in business as a prophet, it is instructive to see what success others have made of this dangerous occupation -- and it is even more instructive to see where they have failed.

With monotonous regularity, apparently competent men have laid down the law about what is technically possible or impossible -- and have been proved utterly wrong, sometimes while the ink was scarcely dry from their pens. On careful analysis, it appears that these debacles fall into two classes, which I will call Failures of Nerve and Failures of Imagination.

The Failure of Nerve seems to be the more common; it occurs when even given all the relevant facts the would-be prophet cannot see that they point to an inescapable conclusion. Some of these failures are so ludicrous as to be almost unbelievable.

It is now impossible for us to recall the mental climate which existed when the first locomotives were being built, and critics gravely asserted that suffocation lay in wait for anyone who reached the awful speed of 30 miles an hour. It is equally difficult to believe that, only 80 years ago, the idea of the domestic electric light was pooh-poohed by all the experts -- with the exception of a 31-year-old American inventor named Thomas Alva Edison. When gas securities nose-dived in 1878 because Edison (already a formidable figure, with the phonograph and the carbon microphone to his credit) announced that he was working on the incandescent lamp, the British Parliament set up a committee to look into the matter. The distinguished witnesses reported, to the relief of the gas companies, that Edison's ideas were "good enough for our transatlantic friends ... but unworthy of the attention of practical or scientific men." And Sir William Preece, Engineer-in-Chief of the British Post Office, roundly declared that "Subdivision of the electric light is an absolute ignis fatuus." One feels that the fatuousness was not in the ignis.

The most famous, and perhaps the most instructive, Failures of Nerve have occurred in the fields of aero- and astronautics. At the beginning of the 20th Century scientists were almost unanimous in declaring that heavier-than-air flight was impossible, and that anyone who attempted to build airplanes was a fool. The great American astronomer, Simon Newcomb, wrote a celebrated essay which concluded:

"The demonstration that no possible combination of known substances, known forms of machinery and known forms of force, can be united in a practical machine by which men shall fly long distances through the air, seems to the writer as complete as it is possible for the demonstration of any physical fact to be."

Oddly enough, Newcomb was sufficiently broad-minded to admit that some wholly new discovery--he mentioned the neutralization of gravity -- might make flight practical. One cannot, therefore, accuse him of lacking imagination; his Failure of Nerve lay in not realizing that the means of flight were already at hand. For Newcomb's article received wide publicity at just about the time that the Wright Brothers, not having a suitable antigravity device in their bicycle shop, were mounting a gasoline engine on wings. When news of their success reached the astronomer, he was only momentarily taken aback. Flying machines might be a marginal possibility, he conceded -- but they were certainly of no practical importance, for it was quite out of the question that they could carry the extra weight of a passenger as well as that of a pilot.

Such refusal to face facts that now seem obvious has continued throughout (continued on page 56)Prophecy(continued from page 51) the history of aviation. Let me quote another astronomer, William H. Pickering, straightening out the uninformed public a few years after the first airplanes had started to fly.

"The popular mind often pictures gigantic flying machines speeding across the Atlantic and carrying innumerable passengers in a way analogous to our modern steamships. ... It seems safe to say that such ideas must be wholly visionary, and even if a machine could get across with one or two passengers the expense would be prohibitive to any but the capitalist who could own his own yacht."

It so happens that most of his fellow astronomers considered Pickering far too imaginative: he was prone to see vegetation -- and even evidence for insect life -- on the Moon. His, again, was a Failure of Nerve. By the time he died in 1938 at the ripe age of 80, Professor Pickering had seen airplanes carrying considerably more than "one or two" passengers.

Closer to the present, the opening of the Space Age has produced a mass vindication (and refutation) of prophecies on a scale and at a speed never before witnessed. The idea of space flight as a serious possibility first appeared before the general public in the 1920s, largely as a result of newspaper reports of the work of the American Robert Goddard and the Rumanian Hermann Oberth. When their ideas, usually distorted by the press, filtered through to the scientific world, they were received with hoots of derision. For a sample of the kind of criticism the pioneers of astronautics had to face, I present this masterpiece from a paper published by one Professor A. W. Bickerton in 1926. It should be read carefully; as an example of arrogant ignorance it would be very hard to beat.

"This foolish idea of shooting at the Moon is an example of the absurd length to which vicious specialization will carry scientists working in thought-tight compartments. Let us critically examine the proposal. For a projectile entirely to escape the gravitation of the Earth, it needs a velocity of seven miles a second. The thermal energy of a gram at this speed is 15,180 calories. ... The energy of our most violent explosive -- nitroglycerin -- is less than 1500 calories per gram. Consequently, even had die explosive nothing to carry, it has only one-tenth of the energy necessary to escape the Earth. ... Hence the proposition appears to be basically impossible."

Bickerton's main error, without mincing words, is due to sheer stupidity. What of it, if nitroglycerin has only a tenth of the energy necessary to escape from the Earth? That merely means that you have to use at least 10 pounds of nitroglycerin to launch a single pound of payload.

For the fuel itself has not got to escape from Earth; it can all be burned quite close to our planet, and as long as it imparts its energy to the payload, this is all that matters. When Lunik II lifted, 33 years after Professor Bickerton said it was impossible, most of its several hundred tons of kerosene and liquid oxygen never got very far from Russia -- but the half-ton payload reached the Imbrium Mare.

Right through the 1930s and 1940s, eminent scientists continued to deride the rocket pioneers -- when they bothered to notice them at all. An example that makes a worthy mate to the one I have just quoted is to be found in a paper by the distinguished Canadian astronomer, Professor J. W. Campbell, of the University of Alberta, entitled Rocket Flight to the Moon. After several pages of analysis, he arrives at the conclusion that it would require a million tons of take-off weight to carry one pound of payload on die round trip.

The correct figure, for today's primitive fuels and technologies, is very roughly one ton per pound -- a depressing ratio, but hardly as bad as that calculated by the professor. It is really quite amazing by what margins competent but conservative scientists and engineers can miss the mark, when they start with the preconceived idea that what they are investigating is impossible.

When the existence of the 200-mile-range V-2 was disclosed to an astonished world, there was considerable speculation about intercontinental missiles. This was firmly squashed by Dr. Vannevar Bush, the civilian general of the U.S. scientific war effort, in evidence before a Senate Committee on December 3, 1945. Listen:

"There has been a great deal said about a 3000-mile high-angle rocket. In my opinion such a thing is impossible for many years. The people who have been writing these things that annoy me have been talking about a 3000-mile high-angle rocket shot from one continent to another, carrying an atomic bomb and so directed as to be a precise weapon which would land exactly on a certain target, such as a city.

"I say, technically, I don't think anyone in the world knows how to do such a thing, and I feel confident that it will not be done for a very long period of time to come. ... I think we can leave that out of our thinking. I wish the American public would leave that out of their thinking."

The outcome was the greatest Failure of Nerve in all history, which changed the future of the world. Faced with the same facts and the same calculations, American and Russian technology took two separate roads. The Pentagon -- accountable to the taxpayer -- virtually abandoned long-range rockets for almost half a decade, until the development of thermonuclear bombs made it possible to build warheads five times lighter yet 50 times more powerful than the amusing firecracker that was dropped on Hiroshima.

The Russians had no such inhibitions. Faced with the need for a 200-ton rocket, they went right ahead and built it. By the time it was perfected, it was no longer required for intercontinental rocketry; but with it they won the race into space.

Of the many lessons to be drawn from this slice of recent history, the one that I wish to emphasize is this: Anything that is theoretically possible will be achieved in practice, no matter what the technical difficulties, if it is desired greatly enough. It is no argument against any project to say: "The idea's fantastic!" Most of the things that have happened in the last 50 years have been fantastic, and it is only by assuming that they will continue to be so that we have any hope of anticipating the future.

To do this -- to avoid that Failure of Nerve for which history exacts so merciless a penalty -- we must have the courage to follow all technical extrapolations to their logical conclusions. Yet even this is not enough. We must try to avoid also the Failure of Imagination.

This second kind of prophetic failure is less blameworthy, and more interesting. It arises when all the available facts are appreciated and marshaled correctly -- but when the really vital facts are still undiscovered, and the possibility of their existence is not admitted.

A famous example of this is provided by the philosopher Auguste Comte, who in his Cours de philosophie positive (1835) attempted to define the limits within which scientific knowledge must lie. In his chapter on astronomy he wrote these words concerning the heavenly bodies:

"We see how we may determine their forms, their distances, their bulk, their motions, but we can never know anything of their chemical or mineralogical structure; and much less, that of organized beings living on their surface. ... We must keep carefully apart the idea of the solar system and that of the universe, and be always assured that our only true interest is in the former. Within this boundary alone is astronomy the supreme and positive science that we have determined it to be. ... The stars serve us scientifically only as providing positions with which we may (continued on page 102)Prophecy(continued from page 56) compare the interior movements of our system."

In other words, Comte decided that the stars could never be more than celestial reference points, of no intrinsic concern to the astronomer. Only in the case of the planets could we hope for any definite knowledge, and even that knowledge would be limited to geometry and mechanics. Comte would probably have decided that such a science as astrophysics was a priori impossible.

Yet within half a century of his death, almost the whole of astronomy was astrophysics, and very few professional astronomers had much interest in the planets. Comte's assertion had been utterly refuted by the invention of the spectroscope, which not only revealed the chemical structure of the heavenly bodies but has now told us far more about the distant stars than we know of our planetary neighbors.

Comte cannot be blamed for not imagining the spectroscope; no one could have imagined it, or the still more sophisticated instruments that have now joined it in the astronomer's armory. But he provides a warning that should always be borne in mind: even things that are undoubtedly impossible with existing or foreseeable techniques may prove to be easy as a result of new scientific breakthroughs. From their very nature, these breakthroughs can never be anticipated, but they have enabled us to bypass so many insuperable obstacles in the past that no picture of the future can hope to be valid if it ignores them.

Another celebrated Failure of Imagination was that persisted in by Lord Rutherford, who more than any other man laid bare the internal structure of the atom. Rutherford frequently made fun of those sensation-mongers who predicted that we should one day be able to harness the energy locked up in matter. Yet only five years after his death in 1937, the first chain reaction was started in Chicago. The wholly unexpected discovery of uranium fission made possible such absurdly simple (in principle, if not in practice) devices as the atomic bomb and the nuclear chain reactor. Rutherford, for all his wonderful insight, suffered in this question a Failure of Imagination: he failed to imagine the discovery of a nuclear reaction that would release more energy than that required to start it.

It is highly instructive, and stimulating to the imagination, to make a list of the inventions and discoveries that have been anticipated -- and those that have not. Here is my attempt to do so.

All the items listed under The Unexpected have already been achieved or discovered, and all have an element of the unexpected or the downright astonishing about them. To the best of my knowledge, not one was foreseen very much in advance of the moment of revelation.

Listed under The Expected, however, are concepts that have been around for hundreds or thousands of years. Some have been achieved; others will be achieved; others may be impossible. But which?

The Unexpected

X rays

Nuclear energy

Radio, TV

Electronics

Photography

Sound recording

Quantum mechanics

Relativity

Transistors

Masers; Lasers

Superconductors; superfluids

Atomic clocks; Mössbauer Effect

Determining composition of celestial bodies

Dating the past (Carbon 14, etc.)

Detecting invisible planets

The Ionosphere; Van Allen Belt

The Expected

Automobiles

Flying machines

Steam engines

Submarines

Spaceships

Telephones

Robots

Death rays

Transmutation

Artificial life

Immortality

Invisibility

Levitation

Teleportation

Communication with the dead

Observing the past, the future

Telepathy

The Expected list is deliberately provocative; it includes sheer fantasy as well as serious scientific speculation. But the only way of discovering the limits of the possible is to venture a little way past them into the impossible. As a first and as it were exploratory penetration of this area, I suggest that we scrutinize the question of invisibility.

Though this confession leaves me thoroughly dated, back there with Rin-Tin-Tin and Mary Pickford, for me one of the big moments in movies was when Claude Rains unwrapped the bandages around his head -- and there was nothing inside them. The idea of invisibility, with all the power it would bestow upon anyone who could command it, is eternally fascinating; I suspect that it is one of the commonest of private daydreams. But it is a long time since it has appeared in adult science-fiction, because it is a little too naive for this sophisticated age. It smacks of magic, which is now very much out of fashion.

Yet invisibility is not one of those concepts that involve an obvious violation of the laws of nature; on the contrary, there are plenty of objects that we know exist, yet cannot be seen. Most gases are invisible; so are some liquids and a few solids, in the right circumstances. I have never had the privilege of looking for a large diamond in a tumbler of water, but I have searched for a contact lens in a bath, and that's as near to invisibility as I wish to get. Most of us have seen those arresting photos of workmen carrying large plate-glass windows; when glass is clean, and coated with an antireflection layer, it is almost as impossible to see as air.

This gives the fantasy writer (and in The Invisible Man, Wells was writing fantasy, not science-fiction) an easy way out. His hero has "merely" to invent a drug that gives his body the same optical properties as air, and he will promptly become invisible. Unfortunately -- or luckily -- this cannot be done, and it is easy to show why.

Transparency is a most unusual property of a few exceptional substances, arising from the internal disposition of their atoms. If their atoms were arranged differently, they would no longer be transparent -- and they would no longer be the same substances. You cannot take any compound at random and chemically torture it into transparency. And even if you could do so in the case of one particular compound, this would hardly help you to become an Invisible Man, for there are literally billions of separate and unbelievably complex chemical compounds in the human body. I doubt if the human species would last long enough to run the necessary research program on each one of these compounds.

Moreover, the essential properties of many (if not most) depend upon the fact that they are not transparent. This is obvious in the case of the light-sensitive chemicals at the back of the eye, upon which we rely for our vision. If they no longer trapped light, we should be unable to see; and if our flesh were transparent, the eye would be unable to function, since it would be flooded with radiation. You can't build a camera out of clear glass.

Less obvious is the fact that myriads of the biochemical reactions upon which life depends would be thrown utterly out of balance, or would cease altogether, if the molecules taking part in them were transparent. A man who achieved invisibility by drugs would not only be blind; he would be dead.

Many insects and land animals have developed remarkable powers of camouflage, but their disguise, being fixed, is effective only in the right surroundings; it may be worse than useless in others. The greatest masters of deception, who can change their appearance to fit their background, are to be found not on the land but in the sea. Flatfish and cuttle-fish have an almost unbelievable control over the hues and patterns of their bodies, and are able to change color within a few seconds when the need arises. A plaice lying on a checkerboard will reproduce the same pattern of black and white squares on its upper surface, and is even reputed to make a creditable attempt at a Scots tartan.

The ability to match the scene behind you would be a kind of pseudotransparency, but it is obvious that it could only fool observers looking at you from a single direction. It works with the flat-fish simply because it is flat and is trying to hide itself from predators swimming above it. The same trick would not work anything like so well in the open water, though it is still worth trying; this is why many fish are dark-colored on the upper parts of their bodies and light-colored beneath. It minimizes their visibility from above and from below.

Another conceivable method of achieving invisibility is by means of vibrations. Today we know much more about vibrations than we did a generation ago when, with a capital V, they were part of the stock-in-trade of every spiritualist and medium. Radio, sonar, infrared cookers, ultrasonic washers and the rest have brought them firmly down to earth, and we no longer expect them to produce miracles.

Vibrational invisibility is, however, a little more plausible than the naive chemical variety peddled by Wells. It is based on a familiar analogy: everyone knows how the blades of an electric fan vanish when the motor gets up speed. Well, suppose all the atoms of our bodies could be set vibrating or oscillating at a sufficiently high frequency.

The analogy is, of course, fallacious. We don't see through the fan blades, but past them; at every moment some of the background is uncovered, and at high enough speeds persistence of vision gives us the impression that we have a continuous view. If the fan blades overlapped, they would remain opaque -- no matter how fast they were spinning.

And there is another unfortunate complication. Vibration means heat -- in fact it is heat -- and our molecules and atoms are already moving as fast as we can take. Long before a man could be vibrated into invisibility he would be cooked.

The situation does not look promising; the Cloak of Invisibility appears to be a dream beyond scientific realization. Yet now comes a surprise; perhaps we have been approaching the problem from the wrong angle. Objective invisibility may well be impossible -- but subjective invisibility is possible, and has often been publicly demonstrated.

An expert hypnotist can induce by post-hypnotic suggestion what is known as negative optical hallucination. This means that the subject will be unable to see a certain person, even if that person is standing in full view. The subject will go to extraordinary lengths to "explain away" the invisible man even when the latter tries to prove that he is present: the individual under hypnosis may eventually get hysterical if, for example, he sees what he believes are unattached articles such as a glass of champagne moving around the room -- carried, of course, by the invisible person.

This fact is almost as amazing as genuine invisibility would be, and it suggests that, in the right circumstances and under appropriate influences (air-borne drugs, subliminal suggestion, diversion of attention -- to mention a few ideas) a person or object might be made effectively invisible to a fairly large group of people who were quite sure that they were in full possession of their senses. I advance this idea with some diffidence; but I have a hunch that if invisibility is ever achieved, it will be along these lines. It won't be done by optical devices or vibrations.

And I advance, with somewhat less diffidence, the suggestion that we have here a case in which there was a splendid opportunity for a Failure of Imagination. The leap that we took at the end of our examination of objective invisibility, after we had apparently exhausted the subject -- that was where the imagination might have failed; that was where the temptation was great to declare categorically, "It can't be done." To be sure, the probability is overwhelming that it never will be done, but at least I have shown one way in which it might be done on a large enough scale to have practical applications. I can be contacted by the Nobel Prize Committee through Playboy magazine.

What, then, about teleportation, levitation, and other items on the list of expected but heretofore unrealized accomplishments? I shall deal with a number of them in future Playboy articles. Throughout this inquiry into the limits of the possible I have been aware of one primary hazard: the dangers of incredulity. For, as I glance down the Unexpected column, on page 102, I am aware of a few items which, only 10 years ago, I should have thought were impossible. Even as I write these words, this room and my body are sleeted by billions of particles that I can neither see nor sense. Some of them -- unsuspected just few years ago -- are sweeping upward in a silent gale through the solid core of the Earth itself. Before such marvels incredulity is chastened; and it would be wise to be skeptical even of skepticism.