Scientific knowledge has advanced more over the course of the twentieth century than it had in two thousand years. It is a curious paradox, however, that the more progress science has made, the more modest the philosophical reflections on science have proved to be. In the seventeenth century, philosophers such as Locke and Descartes had become convinced that the knowledge that comes to us through the senses is deceptive. Behind what we perceive as colors, sounds, and odors, nothing exists but extension and motion. Or at least, the substance of reality was believed to lie therein. A century later, Kant would denounce that illusion, claiming that space and time are also forms that our sensibility takes. The human mind imposes constraints on the world, and if the mind aspires to reason beyond its own limits, it runs up against insoluble contradictions. But that stricture also constitutes our strength: by definition, the world as we perceive it obeys the rules of our logic, since that perception is merely the refraction of an unknowable reality through the mind’s architecture.
Since the birth of astrophysics and quantum physics, we must renounce even that claim because science in its new guise confronts us with an incompatibility between what we believe it is possible to know and the rules regulating how our thought process functions. The idea that the universe has a history and that it began with what is conventionally called the Big Bang restores the reality of time and space, but at the same time it obliges us to admit—if this expression were not monstrously contradictory—that there was a time when time did not yet exist, an embryonic universe that was not already in space, since space is said to have appeared along with it. And when astrophysicists explain to the layman (that is, to all of us) that the universe has a known diameter of about ten billion light years, that our galaxy and its neighbors are moving within it at a speed of six hundred kilometers a second, and so on, we must confess that for ordinary people these are empty words and that we are unable to visualize what they represent.
We are told that, on the scale of the infinitely small, a particle and even an atom can be both here and somewhere else, everywhere and nowhere, that it can behave sometimes like a wave and sometimes like a corpuscle. All these propositions have a meaning for the scientist because they stem from mathematical calculations and experiments so complicated that he alone can interpret them. They remain untranslatable into ordinary language, however, because they violate the laws of logical argument, and in the first place the principle of identity.
There is no denying it: like the most extravagant mythic constructions, phenomena that belong to orders of magnitude—large or small—whose existence was long unimagined run counter to common sense. For the nonspecialist, and even more so for the man in the street, the world that physicists attempt to describe for their own purposes reconstitutes an equivalent of sorts to what our remote ancestors conceived as a supernatural world, where everything happens differently than in the ordinary world, usually backward. The ancients and (closer to our own time) peoples without writing invented myths in an attempt to imagine that supernatural world. Ironically, in so doing they sometimes prefigured fables that physicists now invent when they try to make the results of their research and the hypotheses they derive from it accessible to the rest of us.
Here is a lovely example, which involves an amusing transposition to the macroscopic level of phenomena that quantum physics describes at the microscopic level. A myth of the Seneca Indians (one of the five nations composing the Iroquois confederacy) includes a curious episode. A girl agrees to marry a man who, she knows, is the son of a powerful witch, and she follows him to his mother’s village: “The husband walked in the lead, and they arrived at a point where the path divided into two trails forming a sort of oblong ring that closed farther along. To her great surprise, the woman saw her husband split in two, and each of the two bodies followed one of the trails. She was astounded by that, not knowing which path she herself ought to take. Fortunately [the myth does not say what would have happened otherwise], she chose the one on the right and soon observed that the two trails joined and that her husband’s two bodies once again merged at that point. Hence the origin of that strange individual’s name, so they say: it means ‘they are two paths running parallel.’” A grammatical plural therefore designates a single being.
The Iroquois, then, conceived a world—different, to be sure, from that of ordinary experience—where a body behaves sometimes like a refracting wave, sometimes like a particle that retains its individuality. This episode is part of a myth too long and complicated to describe in detail here. Suffice it to say that the protagonists, some of them twins, spend their time losing, finding again, borrowing, or exchanging one or both of their eyes, as if vision, which can be monocular or binocular, were a model provided by nature for an operation that remains identical to itself whether it passes through a single channel or through two at once.
This story of a man who splits in two when two paths are offered him bears an astonishing resemblance to the fables that physicists concoct when, in books for the general public, they want to help us understand how a cluster of particles passing through either one or two slits in a screen behaves sometimes like a wave train and sometimes like corpuscles.
In making that comparison, I refrain from engaging in mysticism. Nothing allows us to create or perpetuate confusion between archaic forms of thought and scientific thought. In the realm of experience, one is valid, the others are not, even though they draw from the same lexicon to express themselves in ordinary language. The idea that matter is made up of atoms dates back to remote antiquity, but in that case it was a gratuitous hypothesis that remained unverifiable by the only means of observation available, the sense organs. It would acquire validity only when applied to phenomena and events so small that for a long time they remained inaccessible. That is even more true for the duality between the wave and the corpuscle.
In both cases, however, what is interesting is that pure intellectual speculation could offer a representation—preliminary, crude, and confused, to be sure—of an order of reality that human beings were in no position to know.
Greek philosophy from the earliest days, as it was outlined twenty-five hundred years ago by the pre-Socratics, prompts the same order of reflections. One thinker claimed that water constitutes the primordial reality from which everything emerged; another says it was fire, and a third, air. Some claimed that reality originally formed a homogeneous whole, others that it was and continues to be composed of atoms. These same philosophers inquired into the nature of existence and alteration, immobility and change, and so on. In so doing, they explored concepts without any reference to reality and were concerned only with seeing how far they could pursue their intellectual gymnastics. They engaged in a systematic inventory of the
possibilities delimited by the mind’s constraints. Their philosophical reflections did not deal with the world but rather set about mapping mental frameworks. They drew up a table, some of whose boxes would be filled in through the future progress of knowledge, while others would remain vacant, temporarily or permanently. The control experiment, testing of the facts, was absent. The mind, not yet disciplined by research, became intoxicated by its own power and by the discovery of its virtualities.
An exemplary anecdote on this subject is recounted by Plutarch in his Table Talks. Its hero is one of the most famous pre-Socratic philosophers. One day when Democritus was eating a fig, he found it had the flavor of honey, and he asked his servant where the fruit had come from. She indicated an orchard, and Democritus wanted her to take him there immediately so that he could consider and examine the place and there discover the cause of that sweetness. “Don’t bother,” said the servant, “because, without paying attention, I put those figs in a vase that had contained honey.” “Your telling me that makes me angry,” Democritus replied. “I intend to pursue my idea, and I will seek the cause as if the sweetness came from the fig itself.”
According to tradition, Democritus widely practiced empirical observation. In the present case, his first impulse led him in that direction, but he could not resist the pleasure he had promised himself to exercise his mind, even in a vacuum or on the basis of false premises. That, Plutarch observes, is a secondary detail, once one is presented with “a subject and a subject matter worth discoursing on.”
Ever since humanity has existed, always and everywhere “pursuing one’s idea” has been a constant occupation. That exercise brings human beings satisfaction; they find an intrinsic interest in it, not even asking where that exploration will lead. It is true—as demonstrated by the history of scientific thought and, especially, of mathematics—that the exploration of the powers of the mind always leads somewhere, even if several centuries or millennia go by before the fantastic-sounding ideas are revealed to be simply a reflection of a long-hidden level of the real world.
The myths that human beings fed on for so long may amount to the same thing: a systematic and never useless exploration of the resources of the imagination. Myths depict all sorts of creatures and events, absurd or contradictory when compared to ordinary experience, which will cease to be totally meaningless only at a level incommensurate with the level where the myths were first elaborated. It is because these myths are already inscribed—as a dotted line so to speak—in the mind’s architecture, which is “of the world,” that one day or another the images of the world set forth by myths will prove to be adequate to that world and well-suited to illustrate aspects of it.
It is therefore easier to understand why Niels Bohr, one of the fathers of quantum physics, invited his contemporaries to turn to ethnologists and poets as a means of overcoming the contradictions of their discipline. As he acknowledged forty years ago at a conference where ethnologists were gathered, “the traditional differences between human cultures resemble in many respects the different but equivalent ways that physical experience can be described.” Only the images of a wave and a corpuscle, employed simultaneously, allow us to grasp the properties of a single object; in the same way, ethnologists form an idea of culture, a universal human idea, only through beliefs, customs, and institutions that contradict one another and are often self-contradictory.
As for the poets, they make an original and synthetic use of language to reach truths located at a deeper level than that of ordinary experience: they multiply perspectives to define the outlines of an object that remains elusive, and they juxtapose words with incompatible meanings (the old grammarians called them oxymorons). Myths could be included as well since every myth allows for a plurality of variants. Through different and often contradictory images, these variants seek to make perceptible a structure that escapes direct efforts at description.
Scientific thought in its most modern form therefore invites us to recognize that in language, and probably from the very first, metaphor and analogy have enjoyed a legitimate existence, as Vico affirmed. He denied they were “ingenious inventions of writers.”
1 The parallel evolution of the human and natural sciences leads in the same direction. It too encourages us to see figurative language as a fundamental mode of thought, which moves us closer to reality rather than cutting us off from it, as was once believed. Back in the eighteenth century, Vico denounced “two common errors of the grammarians: that prose speech is proper speech, and poetic speech improper; and that prose speech came first, and afterwards speech in verse.” According to him, what was true at the beginning of humankind may now be becoming true once again.