Full House

by Stephen Jay Gould

  We may easily designate belief in progress as a potential bias, but some biases are true: my utterly subjective rooting preferences led me to love the Yankees during the 1950s, but they were also, objectively, the best team in baseball. Why should we suspect that progress, as the defining thrust of life’s history, is not true? After all, and quite apart from our wishes, doesn’t life manifestly become more complex? How can such a trend be denied in the light of paleontology’s most salient fact: In the beginning, 3.5 billion years ago, all living organisms were single cells of the simplest sort, bacteria and their cousins; now we have dung beetles, sea-horses, petunias, and people. You would have to be a particularly refractory curmudgeon, one of those annoying characters who loves verbal trickery and empty argument for its own sake, to deny the obvious statement that progress stands out as the major pattern of life’s history.

  This book tries to show that progress is, nonetheless, a delusion based on social prejudice and psychological hope engendered by our unwillingness to accept the plain (and true) meaning of the fourth Freudian revolution. I shall not make my case by denying the basic fact just presented: Long ago, only bacteria populated the earth; now, a much broader diversity includes Homo sapiens. I shall argue instead that we have been thinking about this basic fact in a prejudiced and unfruitful way—and that a radically different approach to trends, one that requires a revision of even more basic mental habits dating at least to Plato, offers a more profitable framework. This new vantage point will also help us to understand a wide range of puzzling issues from the disappearance of 0.400 hitting in baseball to the absence of modern Mozarts and Beethovens.

  Can We Finally Complete Darwin’s Revolution?

  The bias of progress expresses itself in various ways, from naive versions of pop culture to sophisticated accounts in the most technical publications. I do not, of course, claim that all, or even many, people accept the maximally simplistic account of a single ladder, with humans on top—although this imagery remains widespread, even in professional journals. Most writers who have studied some evolutionary biology understand that evolution is a copiously branching bush with innumerable present outcomes, not a highway or a ladder with one summit. They therefore recognize that progress must be construed as a broad, overall, average tendency (with many stable lineages "failing" to get the "message" and retaining fairly simple form through the ages).

  Nonetheless, however presented, and however much the sillier versions may be satirized and ridiculed, claims and metaphors about evolution as progress continue to dominate all our literatures—a testimony to the strength of this primary bias. I present a few items, almost randomly selected from my burgeoning files:

  From Sports Illustrated, August 6, 1990, Denver Broncos veteran Karl Mecklenburg, on being shifted from defensive end to inside linebacker to a new position as outside linebacker: "I’m moving right up the evolutionary ladder."

  From a correspondent, writing from Maine on January 18, 1987, and puzzled because he cannot spot the fallacy in a creationist tract: The pamphlet "shows that well dated finds of many species of man show no advancement within a species over the thousands of years the species existed. Also many species appear to have existed concurrently. Both these finds contradict the precepts of evolution which insists each species advances towards the next higher."

  From another correspondent, in New Jersey (December 22, 1992), a professional scientist this time, expressing his understanding that life as a totality, not just selected lineages at pinnacles of their groups, should progress through time: "I assume that as evolution proceeds, a greater and greater degree of specialization occurs with regard to structure and physiological activity. After a billion years or more of biological evolution I would think that the extant species are relatively highly specialized."

  From a correspondent in England on June 16, 1992, really putting it on the line: "Life has a sort of ’built-in’ drive towards complexity, matched by no drive to de-complexity.... Human consciousness was inevitable once things got started on Complexity Road in the first place."

  From a leading high school biology textbook, published in 1966, and providing a classic example of a false inference (the first sentence) drawn from a genuine fact (the second sentence): "Most descriptions of the pattern of evolution depend upon the assumption that organisms tend to become more and more complicated as they evolve. If this assumption is correct, there would have been a time in the past when the earth was inhabited only by simple organisms."

  From America’s leading professional journal, Science, in July 1993: An article titled "Tracing the Immune System’s Evolutionary History" rests upon the peculiar premise, intelligible only if "everybody knows" about life’s progress through time, that we should be surprised to discover sophisticated immune devices in "the lower organisms" (their phrase, not mine). The article claims to be reporting a remarkable insight: "the immune system in simpler organisms isn’t just a less sophisticated version of our own." (Why should anyone have ever held such a view of "others" as basically "less than us," especially when the "simpler organisms" under discussion are arthropods with 500 million years of evolutionary separation from vertebrates, and when all scientists recognize the remarkable diversity and complexity of chemical defense systems maintained by many insects?) The article also expresses surprise that "creatures as far down the evolutionary ladder as sponges can recognize tissue from other species." If our leading professional journal still uses such imagery about evolutionary ladders, why should we laugh at Mr. Mecklenburg for his identical metaphor?

  The allure of this conventional imagery is so great that I have fallen into the trap myself—by presenting my examples as an ascending ladder from the central pop icon of a sports hero, through letters of increasing sophistication, to textbooks, to an article in Science. Yet the last shall be first, and my linear sequence bends into a circle of error, as both my initial and final examples misuse the identical phrase about an "evolutionary ladder." At least the linebacker was trying to be funny!

  These lists of error could go on forever, but let me close this section with two striking examples representing the pinnacle (there we go with progress metaphors again) of fame and achievement in the domains of popular and professional life.

  Popular culture’s leading version: Psychologist M. Scott Peck’s The Road Less Traveled, first published in 1978, must be the greatest success in the history of our distinctive and immensely popular genre of "how-to" treatises on personal growth. This book has been on the New York Times best-seller list for more than six hundred weeks, placing itself so far in first place for total sales that we need not contemplate any challenge in our lifetime. Peck’s book includes a section titled "The Miracle of Evolution" (pages 263-68).

  Peck begins his discussion with a classic misunderstanding of the second law of thermodynamics:

  The most striking feature of the process of physical evolution is that it is a miracle. Given what we understand of the universe, evolution should not occur; the phenomenon should not exist at all. One of the basic natural laws is the second law of thermodynamics, which states that energy naturally flows from a state of greater organization to a state of lesser organization.... In other words, the universe is in a process of winding down.

  But this statement of the second law, usually portrayed as increase of entropy (or disorder) through time, applies only to closed systems that receive no inputs of new energy from exterior sources. The earth is not a closed system; our planet is continually bathed by massive influxes of solar energy, and earthly order may therefore increase without violating any natural law. (The solar system as a whole may be construed as closed and therefore subject to the second law. Disorder does increase in the entire system as the sun uses up fuel, and will ultimately explode. But this final fate does not preclude a long and local buildup of order in that little corner of totality called the earth.)

  Peck designates evolution as miraculous for violating the second law in displaying a primary th
rust toward progress through time:

  The process of evolution has been a development of organisms from lower to higher and higher states of complexity, differentiation, and organization.... [Peck then writes, in turn, about a virus, a bacterium, a paramecium, a sponge, an insect, and a fish—as if this motley order represented an evolutionary sequence. He continues:] And so it goes, up the scale of evolution, a scale of increasing complexity and organization and differentiation, with man who possesses an enormous cerebral cortex and extraordinarily complex behavior patterns, being, as far as we can tell, at the top. I state that the process of evolution is a miracle, because insofar as it is a process of increasing organization and differentiation it runs counter to natural law.

  Peck then summarizes his view as a diagram (redrawn here as Figure 2), a stunning epitome of the grand error that the bias of progress imposes upon us. He recognizes the primary fact of nature that stands so strongly against any simplistic view of progress (and, as I shall show later in this book, debars the subtler versions as well)—rarity of the highest form (humans) versus ubiquity of the lowest (bacteria). If progress is so damned good, why don’t we see more of it?

  Peck tries to pry victory from the jaws of defeat by portraying life as thrusting upward against an entropic downward tug:

  The process of evolution can be diagrammed by a pyramid, with man, the most complex but least numerous organism, at the apex, and viruses, the most numerous but least complex organisms, at the base. The apex is thrusting out, up, forward against the force of entropy. Inside the pyramid I have placed an arrow to symbolize this thrusting evolutionary force, the "something" that has so successfully and consistently defied "natural law" over millions upon millions of generations and that must itself represent natural law as yet undefined.

  Note how this simple diagram encompasses all the major errors of progressivist bias. First, although Peck supposedly rejects the most naive version of life’s ladder, he places an explicit linear array right under his apex of progress as the motor of upward thrusting. Two features of this reintroduced ladder reveal Peck’s lack of attention and sympathy for natural history and life’s diversity. I am, I confess, galled by the insouciant sweep that places only "colonial organisms" into the enormous domain between bacteria and vertebrates—where they must stand for all eukaryotic unicellular organisms and all multicellular invertebrates as well, though neither category includes many colonial creatures! But I am equally cha- grined by Peck’s names for the prehuman vertebrate sequence: fish, birds, and animals. I know that fish gotta swim and birds gotta fly, but I certainly thought that they, and not only mammals, were called animals.

  Second, the model of life’s upward thrust versus inorganic nature’s downward tug allows Peck to view progress as evolution’s most powerful and universal trend, even against the observation that most organisms don’t get very far along the preferred path: against so powerful an adversary as entropy, all life must stand and shove together from the base, so that the accumulating force will push a favored few right up to the top and out. Squeeze your toothpaste tube from the bottom, just as Mom and the dentist always admonished (and so few of us do), and the pressure of the whole mass will allow a little stream to reach an utmost goal of human service at the top.

  FIGURE 2 Two biased views of evolution as progress from M. Scott Peck’s best-selling The Road Less Traveled. Above, the supposed pyramid of life’s upwardly driving complexity. Below, the same scheme applied to the supposed development of human spiritual competence.

  Peck ends this section with a crescendo based on one of those forced and fatuous images that sets my generally negative attitude toward this genre of books. Human life and striving become a microcosm of life’s overall trend to progress. The force of entropy (also identified as our own lethargy) still pushes down, but love, standing in for the drive of progress (or are they the same?), drives us from the low state of "undeveloped spirituality" toward the acme, or pyramidal point, of "spiritual competence." Peck concludes by writing, "Love, the extension of the self, is the very act of evolution. It is evolution in progress. The evolutionary force, present in all of life, manifests itself in mankind as human love. Among humanity love is the miraculous force that defies the natural law of entropy." Sounds mighty nice and cozy, but I’ll be damned if it means anything.

  A similar vision from the professional heights. My colleague E. O. Wilson is one of the world’s greatest natural historians. If anyone understands the meaning and status of species and their interrelationships, this unparalleled expert on ants, and tireless crusader for preservation of biodiversity, should be the paragon. I enjoyed his book The Diversity of Life (1992), and reviewed it favorably in the leading British journal Nature (Gould, 1993). Ed and I have our disagreements about a variety of issues, from sociobiology to arcana of Darwinian theory, but we ought to be allied on the myth of progress, if only because success in our profession’s common battle for preserving biodiversity requires a reorientation of human attitudes toward other species—from little care and maximal exploitation to interest, love, and respect. How can this change occur if we continue to view ourselves as better than all others by cosmic design?

  Nonetheless, Wilson uses the oldest imagery of the progressivist view in epitomizing the direction of life’s history as a series of formal Ages (with uppercase letters, no less)—a system used by virtually all popular works and textbooks in my youth, but largely abandoned (I thought), for reform so often affects language first (as in our eternal debates about political correctness and the proper names for groups and genders), and concepts only later:

  They [arthropods as the first land animals] were followed by the amphibians, evolved from lobe-finned fishes, and a burst of land vertebrates, relative giants among land animals, to inaugurate the Age of Reptiles. Next came the Age of Mammals and finally the Age of Man.

  These words do not represent a rhetorical slip into comfortable, if antiquated, phraseology, for Wilson also provides his explicit defense of progress, ending with a line that I found almost chilling:

  Many reversals have occurred along the way, but the overall average across the history of life has moved from the simple and few to the more complex and numerous. During the past billion years, animals as a whole evolved upward in body size, feeding and defensive techniques, brain and behavioral complexity, social organization, and precision of environmental control.... Progress, then, is a property of the evolution of life as a whole by almost any conceivable intuitive standard, including the acquisition of goals and intentions in the behavior of animals. It makes little sense to judge it irrelevant. Attentive to the adjuration of C. S. Peirce, let us not pretend to deny in our philosophy what we know in our hearts to be true.

  Peirce may have been our greatest thinker, but his line in this context almost sounds scary. Nothing could be more antithetical to intellectual reform than an appeal against thoughtful scrutiny of our most hidebound mental habits—notions so "obviously" true that we stopped thinking about them generations ago, and moved them into our hearts and bosoms. Please do not forget that the sun really does rise in the east, move through the sky each day, and set in the west. What knowledge could be more visceral than the earth’s central stability and the sun’s subordinate motion?

  Darwin was born on the same day as Lincoln, and "officially" inaugurated the revolution that bears his name when he published the Origin of Species in 1859. During the centennial celebrations in 1959, the great American geneticist H. J. Muller dampened festivities with an address titled "One Hundred Years Without Darwin Are Enough." Muller treated the revolution’s failure to penetrate at two opposite ends of a spectrum— creationism’s continuing hold over much of American pop culture, and limited understanding of natural selection among well-educated people content with the factuality of evolution.

  But I think that something even larger, and standing in the middle of this spectrum, has always ranked as the greatest impediment to completing the Darwinian revolution. Freud was
right in identifying suppression of human arrogance as the common achievement of great scientific revolutions. Darwin’s revolution—the acceptance of evolution with all major implications, the second blow in Freud’s own series—has never been completed. In Freud’s terms, the revolution will not be fulfilled when Mr. Gallup can find no more than a handful of deniers, or when most Americans can give an accurate epitome of natural selection. Darwin’s revolution will be completed when we smash the pedestal of arrogance and own the plain implications of evolution for life’s nonpredictable nondirectionality—and when we take Darwinian topology seriously, recognizing that Homo sapiens, to recite the revised litany one more time, is a tiny twig, born just yesterday on an enormously arborescent tree of life that would never produce the same set of branches if regrown from seed. We grasp at the straw of progress (a desiccated ideological twig) because we are still not ready for the Darwinian revolution. We crave progress as our best hope for retaining human arrogance in an evolutionary world. Only in these terms can I understand why such a poorly formulated and improbable argument maintains such a powerful hold over us today.