The Flamingo’s Smile

by Stephen Jay Gould

  In order to produce a world that should be precisely adapted in every detail for the orderly development of organic life culminating in man, such a vast and complex universe as that which we know exists around us, may have been absolutely required.

  How could a man doubt that his favorite medium might contact the spirit of dear departed Uncle George when evidence of disembodied mind lay in the structure of the universe itself?

  Wallace’s argument had its peculiarities, but one aspect of his story strikes me as even more odd. During the last decade, like the cats and bad pennies of our proverbs, Wallace’s argument has returned in new dress. Some physicists have touted it as something fresh and new—an escape from the somber mechanism of conventional science and a reassertion of ancient truths and suspicions about spiritual force and its rightful place in our universe. To me it is the same bad argument, only this time shorn of Wallace’s subtlety and recognition of alternative interpretations.

  Others have called it the “anthropic principle,” the idea that intelligent life lies foreshadowed in the laws of nature and the structure of the universe. Borrowing the term from an opponent who used it for scorn, physicist Freeman Dyson proudly labels it “animism,” not because the idea is lively or organic but from the Latin anima, or “soul.” (Dyson’s essay, “The Argument from Design,” in his fine autobiography, Disturbing the Universe, provides a good statement of the argument.)

  Dyson begins with the usual profession of hope:

  I do not feel like an alien in this universe. The more I examine the universe and study the details of its architecture, the more evidence I find that the universe in some sense must have known that we were coming.

  His defense is little more than a list of physical laws that would preclude intelligent life, were their constants just a bit different, and physical conditions that would destroy or debar us if they changed even slightly. These are, he writes, the “numerical accidents that seem to conspire to make the universe habitable.”

  Consider, he states, the force that holds atomic nuclei together. It is just strong enough to overcome the electrical repulsion among positive charges (protons), thus keeping the nucleus intact. But this force, were it just a bit stronger, would bring pairs of hydrogen nuclei (protons) together into bound systems that would be called “diprotons” if they existed. “The evolution of life,” Dyson reminds us, probably “requires a star like the sun, supplying energy at a constant rate for billions of years.” If nuclear forces were weaker, hydrogen would not burn at all, and no heavy elements would exist. If they were strong enough to form diprotons, then nearly all potential hydrogen would exist in this form, leaving too little to form stars that could endure for billions of years by slowly burning hydrogen in their cores. Since planetary life as we know it requires a central sun that can burn steadily for billions of years, “then the strength of nuclear forces had to lie within a rather narrow range to make life possible.”

  Dyson then moves to another example, this time from the state of the material universe, rather than the nature of its physical laws. Our universe is built on a scale that provides, in typical galaxies like our Milky Way, an average distance between stars of some 20 million million miles. Suppose, Dyson argues, the average distance were ten times less. At this reduced density, it becomes overwhelmingly probable that at least once during life’s 3.5-billion-year tenure on earth, another star would have passed sufficiently close to our sun to pull the earth from its orbit, thus destroying all life.

  Dyson then draws the invalid conclusion that forms the basis for animism, or the anthropic principle:

  The peculiar harmony between the structure of the universe and the needs of life and intelligence is a manifestation of the importance of mind in the scheme of things.

  The central fallacy of this newly touted but historically moth-eaten argument lies in the nature of history itself. Any complex historical outcome—intelligent life on earth, for example—represents a summation of improbabilities and becomes thereby absurdly unlikely. But something has to happen, even if any particular “something” must stun us by its improbability. We could look at any outcome and say, “Ain’t it amazing. If the laws of nature had been set up just a tad differently, we wouldn’t have this kind of universe at all.”

  Does this kind of improbability permit us to conclude anything at all about that mystery of mysteries, the ultimate origin of things? Suppose the universe were made of little more than diprotons? Would that be bad, irrational, or unworthy of spirit that moves in many ways its wonders to perform? Could we conclude that some kind of God looked like or merely loved bounded hydrogen nuclei or that no God or mentality existed at all? Likewise, does the existence of intelligent life in our universe demand some preexisting mind just because another cosmos would have yielded a different outcome? If disembodied mind does exist (and I’ll be damned if I know any source of scientific evidence for or against such an idea), must it prefer a universe that will generate our earth’s style of life, rather than a cosmos filled with diprotons? What can we say against diprotons as markers of preexisting intelligence except that such a universe would lack any chroniclers among its physical objects? Must all conceivable intelligence possess an uncontrollable desire to incarnate itself eventually in the universe of its choice?

  If we return now to Wallace’s earlier formulation of the anthropic principle, we can understand even better why its roots lie in hope, not impelling reason. First, we must mention the one outstanding difference between Dyson’s and Wallace’s visions. Dyson has no objection to the prospect of intelligence on numerous worlds of a vast universe. Wallace upheld human uniqueness and therefore advocated a limited universe contained within the Milky Way galaxy and an earth impeccably designed, through a series of events sufficiently numerous and complex to preclude repetition elsewhere, for supporting the evolution of intelligent life. I do not know the deeper roots of Wallace’s belief, and I have little sympathy for psychobiography, but the following passage from his conclusion to Man’s Place in the Universe surely records a personal necessity surpassing simple inference from scientific fact. The preexisting, transcendent mind of the universe, Wallace writes, would allow only one incarnation of intelligence, for a plurality

  …would introduce monotony into a universe whose grand character and teaching is endless diversity. It would imply that to produce the living soul in the marvellous and glorious body of man—man with his faculties, his aspirations, his powers for good and evil—that this was an easy matter which could be brought about anywhere, in any world. It would imply that man is an animal and nothing more, is of no importance in the universe, needed no great preparations for his advent, only, perhaps, a second-rate demon, and a third or fourth-rate earth.

  This major difference in opinion about the frequency of intelligent life should not mask the underlying identity of the primary argument advanced by Wallace and by modern supporters of the anthropic principle: intelligent life, be it rare or common, could not have evolved in a physical universe constructed even a tiny bit differently; therefore, preexisting intelligence must have designed the cosmos. Wallace’s description of his supporters could well include Dyson: “They hold that the marvellous complexity of forces which appear to control matter, if not actually to constitute it, are and must be mind-products.”

  Yet the universe used by Wallace to uphold the anthropic principle could not be more radically different from Dyson’s. If the same argument can be applied to such different arrangements of matter, may we not legitimately suspect that emotional appeal, rather than a supposed basis in fact or logic, explains its curious persistence? Dyson’s universe is the one now familiar to us all—awesome in extent and populated by galaxies as numerous as sand grains on a sweeping beach. Wallace’s cosmos was a transient product of what his contemporaries proudly labeled the “New Astronomy,” the first, and ultimately faulty, inferences made from a spectrographic examination of stars.

  In Wallace’s limited universe, the Milky
Way galaxy spans some 3,600 light-years in a cosmos that, by Lord Kelvin’s calculation, could not be more than twice as large in total diameter (space beyond the Milky Way would be populated by few, if any, stars). A small “solar cluster” of stars sits in the center of the universe; our own sun lies at or near its outer limit. A nearly empty region extends beyond the solar cluster, followed, at a radius of some 300 light-years from the center, by an inner ring of stars and other cosmic objects. Another and much larger region of thinly populated space lies beyond the inner ring, followed by a much larger, densely filled outer ring, the Milky Way proper, with a span of 600 light-years, and lying 1,200 to 1,800 light-years from the center.

  Wallace’s version of the anthropic principle holds that life requires each part of this intricate physical universe, and that life could only arise around a sun situated where ours resides by good fortune, at the outer edge of the central solar cluster. All these rings, clusters, and empty spaces must therefore reflect the plan of preexisting intelligence.

  A.R. Wallace’s universe, constructed with precision to make human life possible. See text for explanation. FROM WALLACE, 1903. REPRINTED FROM NATURAL HISTORY.

  Wallace’s argument requires that distant stars have a direct and sustaining influence upon our earth’s capacity to support life. He flirts with the idea that stellar rays may be good for plants as he desperately tries to argue around a contemporary calculation that the bright star Vega affords the earth about one 200-millionth the heat of an ordinary candle one meter distant. He even advances the dubious argument that since stars can impress their light upon a photographic plate, plants may also require the same light to carry out their nighttime activities—quite a nimble leap of illogic from the fact that film can record to the inference that living matter needs.

  But Wallace didn’t press this feeble, speculative argument. Instead, he emphasized that life depends upon the detailed physical structure of the universe for the same reason that Dyson cites in his two major examples: the evolution of complex, intelligent life requires a central sun that can burn steadily for untold ages, and such stable suns develop only within a delicate and narrow range of physical laws and conditions. Dyson emphasizes stellar density and diprotons; Wallace argued that appropriate suns could only exist in a universe structured like ours and only at the edge of a central cluster in such a universe.

  In Wallace’s universe, stars are concentrated in three regions: the outer ring (or Milky Way proper), the inner ring surrounding the central cluster, and the central cluster itself. The outer ring of the Milky Way is too dense and active a region for stable suns. Stars move so rapidly and lie so close to each other that collisions and near approaches will inevitably disrupt any planetary system before intelligent life evolves.

  Wallace then claims that solar stability cannot (as we believe today) arise as a product of a star’s own fuel supply (he knew little of radioactivity and nuclear fusion). Stars can burn steadily only if they are constantly supplied with new matter flowing from elsewhere. This matter moves, by gravitation, from outer regions of the universe (particularly from the ring of the Milky Way) toward the center, where our sun resides. The inner ring cannot harbor stable suns, since too much extraneous matter bombards it. The center of the solar cluster won’t do, because it receives too little nurturing material. Only at the outer edge of the solar cluster, where (and surely by design) our sun resides, can a star obtain the proper balance of material to burn steadily for enough time to foster the evolution of intelligence.

  Every detail of cosmic design conspires to permit life on a planet circling such a fortunately situated sun. We need the Milky Way to supply external fuel. We need the inner ring as a filter, allowing just the right amount of fuel to pass through. We need a central cluster where stars move slowly and do not interfere with each other. Could all this have happened without some directing intelligence? Eighty years after Wallace’s book, our universe could not be more radically different, yet human hope continues to impose the same invalid argument upon it.

  A final, important difference separates Wallace from Dyson and most modern supporters of the anthropic principle. Our contemporary advocates develop their arguments and then present their conclusion—that mind designed the universe, in part so that intelligent life might evolve within it—as a necessary and logical inference. Wallace was far too good a historical scientist to indulge in such fatuous certainty; he understood only too well that ordered and complex outcomes can arise from accumulated improbabilities. He therefore recognized and presented forthrightly the alternative interpretation:

  One considerable body, including probably the majority of men of science, will admit that the evidence does apparently lead to this conclusion, but will explain it as due to a fortunate coincidence. There might have been a hundred or a thousand life-bearing planets, had the course of evolution of the universe been a little different, or there might have been none at all.

  This fine scientist, wearied by age and by so many lonely battles for idiosyncratic causes, but still incisively self-critical, then presented his favored interpretation, honestly recognizing its basis in a comforting view of life that could not be proved:

  The other body, and probably much the larger, would be represented by those who, holding that mind is essentially superior to matter and distinct from it, cannot believe that life, consciousness, mind, are products of matter. They hold that the marvellous complexity of forces which appear to control matter, if not actually to constitute it, are and must be mind-products.

  I cannot deny that this second view, the anthropic principle, is a possible interpretation of the evidence, although I favor the first explanation myself. (Always be suspicious of conclusions that reinforce uncritical hope and follow comforting traditions of Western thought.) I do not object to its presentation and discussion, so long as its status as a possible interpretation, not a logical inference, receives proper identification—as Wallace did eighty years ago, and Dyson did not in our own time. I, for one, will seek my hope elsewhere. I would also be surprised, but not in the slightest displeased, if, mirabile dictu, Wallace and Dyson were right after all.

  Postscript

  Several readers informed me (as I should have remembered) that Mark Twain’s famous essay, “The damned human race,” was written as an explicit response to Wallace’s version of the anthropic principle. Part 1 of this series, entitled “Was the world made for man?,” carries as its epigraphic quote: “Alfred Russell [sic for Russel] Wallace’s revival of the theory that this earth is at the centre of the stellar universe, and is the only habitable globe, has aroused great interest in the world.” Twain, in his inimitable manner, then retells the history of life in five pages, assuring us that all the rich and unpatterned diversity could only represent a long pageant of preparation for that geological final second of human habitation!—so much for Wallace’s assertion that the universe must have been designed with us in mind.

  I was fascinated to read how many other themes of these essays lie embedded in Twain’s succinct satire. For example, he explicitly cites Kelvin as his authority for the earth’s great age—an affirmation of my argument (see essay 8) that Kelvin’s work, in his own day and contrary to the common myth portraying him as an arrogant villain against empirical science, was interpreted as proof of the earth’s comfortable antiquity, not as a constraint upon the immensity of time: “According to these [Kelvin’s] figures, it took 99,968,000 years to prepare the world for man, impatient as the Creator doubtless was to see him and admire him. But a large enterprise like this has to be conducted warily, painstakingly, logically.”

  Mark Twain’s ending presents a wonderful metaphor (literature and popular science contain so many) for the earth’s great age relative to the length of human habitation. (I view it as a kind of literary ancestor to John McPhee’s image in Basin and Range—that if we envision geological time as the old English yard, the distance from the King’s nose to the tip of his outstretched arm, one stroke of a
file applied to the nail of his middle finger would erase all of human history):

  Such is the history of it. Man has been here 32,000 years. That it took a hundred million years to prepare the world for him is proof that that is what it was done for. I suppose it is. I dunno. If the Eiffel Tower were now representing the world’s age, the skin of paint on the pinnacle-knob at its summit would represent man’s share of that age; and anybody would perceive that that skin was what the tower was built for. I reckon they would, I dunno.

  27 | SETI and the Wisdom of Casey Stengel

  SINCE THE STUDY of extraterrestrial life lacks any proven subject, opinions about the form and frequency of nonearthly beings record the hopes and fears of speculating scientists more than the constraints of evidence. Alfred Russel Wallace, for example, Darwin’s partner in the discovery of natural selection and the first great evolutionist to consider exobiology in any detail, held firmly that man must be alone in the entire cosmos—for he could not bear the thought that human intelligence had not been the uniquely special gift of God, conferred upon an ideally suited planet. He wrote in 1903 that the existence of abundant and brainy extraterrestrials “would imply that man is an animal and nothing more, is of no importance in the universe, needed no great preparations for his advent, only, perhaps, a second-rate demon, and a third or fourth-rate earth” (see previous essay for a full version of this quotation and discussion of Wallace’s views).