Darwinism
CHARLES DARWIN published On the Origin of Species in 1859 and The Descent of Man in 1871. He changed the world. Although there were those who continued to stand firm against evolution—indeed, as is well known, there are still those who continue to stand firm against evolution—generally, even the religious accepted that organisms, including humans, are the end point of a long, slow process of natural development. As in the Hans Christian Andersen tale about the lad who said openly that the king has no clothes, so when Darwin said “evolution,” nigh everyone said that they had known it all along! Natural selection had more mixed success. Everyone accepted it to some extent. Huxley, for instance, always had some doubts about its universal power and applicability, but when it came to humans physically, he was fully convinced of its overwhelming importance. This said, the scientific community was slower in coming to full acceptance, and it was more in the popular domain that natural selection—and even more sexual selection—was a huge success. Poets, novelists, politicians, and many others harped on and on about its importance. Thus, the poet Constance Naden (1858–89), joking about these things—poking fun at young people of both sexes—in a delightful burst of mock despair wrote:
I HAD found out a gift for my fair,
I had found where the cave men were laid:
Skulls, femur and pelvis were there,
And spears that of silex they made.
But he ne’er could be true, she averred,
Who would dig up an ancestor’s grave—
And I loved her the more when I heard
Such foolish regard for the cave.
My shelves they are furnished with stones,
All sorted and labelled with care;
And a splendid collection of bones,
Each one of them ancient and rare;
One would think she might like to retire
To my study—she calls it a “hole”!
Not a fossil I heard her admire
But I begged it, or borrowed, or stole.
But there comes an idealess lad,
With a strut and a stare and a smirk;
And I watch, scientific, though sad,
The Law of Selection at work.
Of Science he had not a trace,
He seeks not the How and the Why,
But he sings with an amateur’s grace,
And he dances much better than I.
And we know the more dandified males
By dance and by song win their wives—
’Tis a law that with avis prevails,
And ever in Homo survives.
Shall I rage as they whirl in the valse?
Shall I sneer as they carol and coo?
Ah no! for since Chloe is false
I’m certain that Darwin is true.1
From pseudoscience to popular science. When was evolutionary theory to become professional science, in the sense of something studied in university departments and with senior researchers and graduate students, grants, journals, and so forth? This happened starting around 1930 and picked up—particularly in England (where it became known as neo-Darwinism) and in America (where it became known as the synthetic theory of evolution)—over the next decades.2 By 1959, somewhat arbitrarily choosing the hundredth anniversary of the Origin, one had (to use a somewhat hackneyed term) a fully functioning paradigm.
This was a Darwinian theory, in the sense that natural selection played (and continues to play) the central causal role, a status brought about by the melding of selection with the newly found and developed theory of heredity, Mendelian (and then later molecular) genetics. At the beginning of the twentieth century, the work of the somewhat obscure Moravian monk Gregor Mendel was rediscovered, and with this, the big hole in Darwin’s theorizing could be filled.3 Thanks particularly to the work in the second decade of the century by Thomas Hunt Morgan and his associates at Columbia University, it was seen that the crucial unit of heredity—the gene—is a physical thing (now known to be long threads of nucleic acid) on the chromosomes in the nuclei of cells. These genes maintain their integrity from generation to generation, thus giving selection something stable and heritable on which to act. However, every now and then the genes spontaneously change (“mutate”)—much is now known about the causes but the important thing is that Darwin’s insight was correct, the changes are random both in not appearing to order and in not necessarily bringing on new features of any use to the possessor.
Adaptations—characteristics with ends, with purposes—are as vital to modern evolutionary biology as they were to Darwin. Final-cause talk, thinking of organisms in terms of design, is all-important. One thing realized by today’s evolutionists is that Darwin was unduly pessimistic in thinking (as he did) that we will never see natural selection in action. In the right circumstances, it is readily observable. A justly celebrated demonstration of selection in action producing features that are directed toward ends is that of the couple Peter and Rosemary Grant and their long-term study of Geospiza—better known as “Darwin’s Finches”—on an islet in the Galapagos Archipelago.4 The Grants demonstrated unambiguously that in times of plenty, the beaks of the species they were studying were relatively fine and all-purpose—for cracking seeds, eating insects, and whatever—but that during times of drought, when the only available foodstuffs seemed to be hard-shelled nuts, the beaks evolved in a direction of stubbiness and strength. To put the matter teleologically: Why did the successful finches have stubby beaks? For the purpose of breaking up nuts with hard shells. And that was a very good thing from the viewpoint of the finches.
Paleontologists are into this game too. They think in terms of design, as if someone had sat down and built an organism to achieve a certain end. They are looking for purposes, for functions, for ends. A nice case in point is that of the strange noses of the duck-billed dinosaurs (hadrosaurs).5 Flourishing some seventy-five million years ago, these were very peculiar-looking animals, with duck-like bills (very efficient for eating vegetation) and often very fancy crests on the skulls. In one group in particular (lambeosaurines), these crests were long, hollow growths, starting with the nose and going back across the head and sticking out at the back. After toying with a number of hypotheses—Could they be snorkels for foraging in water? Not likely, because they were essentially land animals—researchers narrowed their gaze to sexual selection and hypothesized that they were for producing noise to attract females. It seems that the structure would be ideal for this, and, in fact, the brutes reminded people of a trombone-like music maker, a medieval German wind instrument called the krummhorn. One can work out the physics of the airflow through the nasal tubes, and it turns out that the dinosaurs could produce a huge amount of noise, particularly at low frequencies. Honking hadrosaurs, to use a phrase. One should add that there are other bits and pieces of evidence supporting this hypothesis; for instance, we know a lot about their hearing apparatus (thanks to discovered ear bones), and all fits together very nicely.6
Refinements
It is worth noting two more points about modern thinking—extensions on Darwin’s day. First, many worry (understandably) about how selection can possibly be effective if new variations are random in not arriving in time to order, as it were. A major advance in our thinking in this respect is due to the Russian-born American geneticist Theodosius Dobzhansky (1900–1975). He made much of what is known as “balanced superior heterozygote fitness.”7 Genes are paired with mates on corresponding chromosomes. Sometimes these genes are identical (homozygotes) and sometimes different (heterozygotes). An interesting situation ensues when heterozygotes do better in the struggle (are fitter) than either homozygote. A famous case in point concerns the awful genetic disease sickle-cell anemia. A person born a homozygote for a certain gene is going to die (without drastic medical intervention) from anemia, at the age of four. However, a person who is a heterozygote with one sickle-cell gene and one normal gene is going to be fitter than a homozygote for the normal gene. The reason is simple: namely, that being a heterozygote gives you a natural immunity to malaria, one not possessed by those with two normal genes. It is for this reason that the sickle-cell gene is found only in parts of Africa where malaria is endemic, or in populations from such areas, particularly North Americans of African descent. The important point to note is that no matter how bad the sickle-cell gene, it will persist in the population—in the “gene pool”—because of its virtues for heterozygotes.
Dobzhansky seized on this fact and generalized, assuming that such a phenomenon is widespread and that consequently any population is going to carry a large variety of genes—those from the same chromosome position are known as “alleles”—on which selection can act immediately without waiting for favorable mutations.8 Superior heterozygote fitness is not the only putative way of getting in-group variation. Selection for rareness would also do the trick. Suppose a predator has to learn something about its prey before it can strike—color markings, for instance. A rare form would be at a selective advantage and thus start to spread, until it was so common that the predator would more quickly learn to seek it out, so positive selection would ease off and you might expect a balance between different forms. What is exciting is that at this point molecular biology (barely ten years after the discovery of the DNA model) came to the aid of organismic (evolutionary) biology by showing through new techniques (gel electrophoresis) that natural populations do harbor huge amounts of genetic variation.9 Selection can indeed be effective. To use an analogy, imagine you were asked to write an essay on dictators for a course and the only source material available was the Book of the Month Club. You could wait for ten years for something, say on Hitler, to come up, by which time the deadline would have passed and you would have failed the course—or, analogously, gone extinct. But suppose you had a library at your disposal. If there was nothing suitable on Hitler, then perhaps there was something on Napoleon. Or on Stalin. Or on others. You might not be able to write on a topic you like, but you could write on something and pass the course. Similarly, if a new predator turns up, perhaps there is an adaptive-camouflage gene waiting in the gene pool. Or one that enables you to change ecological niches where you are now safe. Or something that makes you extremely unpalatable to the predator. There is no guarantee that you will not go extinct, but there is probably some useful tool in your tool box. All in all, selection is highly plausible as an important creative force.
The second point about modern evolutionary thinking is that no one (starting with Darwin, as we have seen) thinks that every last thing about organisms, living or dead, has to be (or had to be) adaptive. The late Stephen Jay Gould, paleontologist and popular science writer, made much of this. Greatly influenced by German biology, he focused on the homologies between organisms, stressing their importance for establishing the fact of evolution but their irrelevance for proving the force of natural selection.10 More broadly, in a well-known article, coauthored by Richard Lewontin, “The Spandrels of San Marco,” Gould argued strongly that Darwinian evolutionists assume far too readily that living nature is adaptive, that it is full of purpose.11 He felt that evolutionists slide into some kind of panadaptationism, thinking that every last organic feature has to be functional, the product of natural selection. Referring to the Leibnizian philosopher in Voltaire’s Candide, he accused evolutionists of Panglossianism, thinking that these must be the best of all possible features in the best of all possible worlds. And to make the case complete, supposedly, evolutionists invent “just so” stories—thus named from Rudyard Kipling’s fantasy stories—with natural selection scenarios leading to adaptation.
As a counter, Gould (and Lewontin) drew attention to the triangular decorative aspects of the tops of pillars in medieval churches, arguing that although such “spandrels” seem adaptive, they are in fact by-products of the builders’ methods of keeping the roof in place. “The design is so elaborate, harmonious, and purposeful that we are tempted to view it as the starting point of any analysis, as the cause in some sense of the surrounding architecture.” This, however, is to get things precisely backward. “The system begins with an architectural constraint: the necessary four spandrels and their tapering triangular form. They provide a space in which the mosaicist worked; they set the quadripartite symmetry of the dome above.”12 Who knows but that we have a similar situation in the living world? Much that we think adaptive is merely a spandrel, and such things as constraints on development prevent anything like an optimally designed world. Perhaps things are much more random and haphazard—non-functional—than the Darwinian thinks possible.
A deal of ink—a very great deal of ink—was spilled over these claims. General reaction by Darwinian evolutionists—who make up perhaps 95 percent of this population—was that much that Gould said was true but well-known already.13 One phenomenon bringing on the nonadaptive is so-called genetic drift. This is where the vagaries of breeding—the chance encounters between organisms—can be sufficiently powerful to counter the effects of selection. This was the basis of a theory put forward in the early 1930s by the American population geneticist Sewall Wright—the “shifting balance theory of evolution.”14 Drift is most likely to occur in small populations and, based on an extensive study of shorthorn cattle, he argued that evolution proceeds by drift, creating innovative new features when large populations are fragmented, with these features then spreading through the whole group when the fragmentation comes to an end. As it happens, there has been much criticism of Wright’s overall theory.15 Yet no one denies that drift probably does have some role—and it is agreed that it probably has a major role at the molecular level below the winnowing effects of the struggle for existence. (I will discuss this in more detail later.) More generally, no one denies that many features are going to be nonadaptive, or perhaps were once adaptive and no more. Why do vertebrates have four limbs rather than six like the insects? John Maynard Smith argued that this may be a relic of when vertebrates were aquatic and two limbs fore and two limbs aft were very effective for raising or lowering the body immersed in water.16 There is nothing sacrosanct about numbers. There are some fossil vertebrates with eight or nine digits rather than five.
So where are we today in evolutionary thinking? Don’t go away with the message that, whatever they may hope for of the Design argument, biologists today are now questioning seriously what was labeled the first part of the argument, to the design-like nature of the world. In the world of organisms, adaptation is the norm—the hugely well-justified null hypothesis—and it is your task to make the contrary case if you so wish. Purpose thinking rules, and it is cherished.17 In a good Kantian sense, today’s biologists use end-directed thinking and language when they are dealing with organisms. The mountains on the moon have no purpose. The internal workings of the hadrosaur have a full and genuine purpose, to make a lot of noise of a particular kind. Going back in time, the young hadrosaur is here and now. The noise and the sexual combat are in the future. The bodily structure is to be explained in terms of growth and physiology (efficient causes) and of getting mates (final causes). And this is true even if the hadrosaur dies an unrequited virgin. Is it anything more than heuristic? Not really, but “anything more” is hardly the best way to think of it. Because the hadrosaur is design-like, it is appropriate to use the metaphor of design. There is no implication that there is a designer any more than there is an implication that you are really thin and slimy when I accuse you of having wormed your way into my affections and trust for your own nefarious ends. The metaphor remains, and Kant was right—you simply cannot do this kind of biology without it. In its own way, recognizing this is as much a challenge to or qualification of a simple, Cartesian, post–Scientific Revolution, mechanistic view of the world as is quantum mechanics. That is no small thing.
What then of value? We have seen that one of the defining marks of purpose talk is that it is enmeshed with value commitments. If something is directed to achieving some end, then in some sense the end is being valued and that which is helping to achieve it has value because of its role. We want, we desire food, and teeth are a means of chewing and subsequently digesting that food. The food has value for us and the teeth are valuable inasmuch as they enable us to use that food. However, this does raise a serious problem or at least question. Are we not in some sense finding values in the world—or perhaps in a Kantian sense imputing values to the world? And this is not to go against the metaphysics of modern science, which fully endorses Hume’s distinction between “is” and “ought.” Ontologically, the world as such is res extensa, molecules in motion. It has no intrinsic value.
My fellow philosophers have spent many happy hours analyzing this problem.18 Medieval theologians worrying about the number of angels who can dance on the head of a pin have nothing on analytic philosophers when they gear up—except, unlike today, the story of the scholastics is probably a calumny by later writers. Like me (as I mentioned in my acknowledgments), brought up in neo-Humean traditions, trying to avoid talk of values, philosophers have tied themselves in knots, meriting attention by Hilaire Belloc.
The chief defect of Henry King,
Was chewing little bits of string.
At last he swallowed some that tied,
Itself in ugly knots inside.
Alas, that was the end of poor Henry, not—one is relieved to say—the fate of the philosophers. From the viewpoint of finding adequate solutions, it might have been, for in trying to analyze purpose or function without reference to value, one is trying to square the circle. One popular neo-Kantian attempt lays itself open to all sorts of counterexamples—unable to distinguish between the heart pumping in order to circulate the blood, which does have value, from the heart pumping in order to make sounds, which does not have value.19 Another popular attempt simply ignores the end focus of purpose statements, which may perhaps cure the disease but at the expense of the patient’s life.20 If I sound cynically critical of others, the answer is (as so often) because I see the failings of my earlier self. I saw something was not right, but, too committed to my philosophical paradigm, the best I could suggest was one-up on ignoring the problem. I urged the dropping of all end talk.21 Which is one way of solving the problem, I suppose. Not exactly a solution appealing to your average paleontologist, let alone game strategist or moral educator. Although the spirit of my earlier self continues. One recent attempt to analyze function focuses on organisms maintaining themselves and ends up by saying explicitly that the reproductive organisms, with respect to their possessors, have no functions.22 Tell that to students in your freshman classes. Truly, the right move forward is not to deny or cover up the value component of teleological understanding but to embrace it fully. To be fair, I am not alone in now stressing the importance of values. One who has done so is the philosopher Mark Bedau, who notes explicitly that going back through the history of philosophy makes transparently clear this point about the necessity of a value-analysis. “It has ancient roots in Plato and Aristotle, and its modern exponents include Leibniz and Kant.”23
Interestingly, but perhaps not surprisingly, those whom Bedau lists from today’s thinkers who have sensed the need of a value-analysis have, like the practicing biologist and sometime Dominican priest Francisco Ayala,24 a strong grasp of the history of philosophical thought. Obviously, if we are in a natural world, rather than in God’s world, there has to be a change in how we are to approach the problem of value. But this can be seen and tackled. The right move here is to distinguish “value” from “evaluation.” What the modern scientist denies is any kind of absolute or overall (externally conferred) value to the world—the scientist acting as scientist, that is. (Often this is referred to as an implication of “methodological naturalism,” as opposed to “metaphysical naturalism,” which would deny any such value under any perspective.) This does not mean that the modern scientist cannot make value judgments in a comparative sense. He or she might judge one kind of internal combustion engine as a great deal more efficient than another. That is obviously a value judgment—not absolute because you might judge that in this day and age, internal combustion engines are never a good thing—but comparative in the context. Pushing the argument, a biologist might argue that a group of organisms was able to take over from its rivals because it developed a mode of movement or of internal functioning a great deal more efficient than that of its competitor. This again is a value judgment—not absolute because the newly successful organism might do horrendous damage overall. Think of rabbits in Australia. It is a comparative judgment and in the circumstances fully legitimate.25
Conflict over Progress
Turn now to purpose in history. You might think that this is going to be a very short discussion. Natural selection is opportunistic. What works in one situation does not necessarily work in another. There is no reason to expect a forward direction to evolution, even one interrupted by reversals and sidestepping. Moreover, Mendelian/molecular genetics is adamant. There is no direction to the new variations—the building blocks—of evolution. No “higher” or “lower.” That is an absolute. There is no value in the course of evolution. Stephen Jay Gould was eloquent. There is no direction and so evolution apparently can go whichever way. Progress to humans is just not on. “A noxious, culturally embedded, untestable, nonoperational, intractable idea that must be replaced if we wish to understand the patterns of history.”26 Making facetious reference to that celestial body that hit the earth sixty-six million years ago, wiping out the dinosaurs and making possible the Age of Mammals, Gould wrote: “Since dinosaurs were not moving toward markedly larger brains, and since such a prospect may lie outside the capabilities of reptilian design … we must assume that consciousness would not have evolved on our planet if a cosmic catastrophe had not claimed the dinosaurs as victims. In an entirely literal sense, we owe our existence, as large and reasoning mammals, to our lucky stars.”27
Yet for all the sepulchral warnings one hears on the subject, thoughts of progress have a nasty way of creeping back in. My favorite was the American Museum of Natural History in New York City a year or two back. Down in the basement was a display about human evolution with all sorts of careful caveats about not believing in biological progress. The floor above had the Hall of Mammals, going from the shrew at one end to the great apes at the other. The Muséum National d’Histoire Naturelle in the Jardin des Plantes on the left bank of the Seine in Paris is even less circumspect. The top floor has a display of human culture and technology, going progressively from the primitive to the present. The floor below has a happily progressive display of evolution, ending with the visitor, him- or herself, on the television screen on exiting. Who is about to deny progress under these circumstances?
Interestingly, Gould notwithstanding—and we shall see that he is more complex and convoluted than one might expect on first sight—many of today’s leading evolutionists are quite open about their beliefs in biological progress. The most distinguished member of the fraternity, Edward O. Wilson, Harvard professor and world-leading specialist on ants and on sociobiology (the evolution of social behavior), is unequivocal. “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—in each case farther from the nonliving state than their simpler antecedents did.”28 Adding: “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.” Elsewhere he writes of the “pinnacles” of social evolution, judging that we humans have won that competition outright.29
Part of the ongoing problem is that of defining biological progress in terms that are not flagrantly circular. If you define progress in terms of being humanlike, which is basically the move of Wilson, it is hardly surprising to find that we have won. Often complexity is thought to be the key, but here there are difficulties. In many respects, for instance, humans are a lot less complex than was once supposed. For instance, some single-celled organisms have more DNA than we do! Apart from anything else, in biology, as in real life, “Keep It Simple Stupid” is often a very good motto. The evolutionary biologist George Williams, a lifelong opponent of biological progress,30 was fond of pointing out that in principle the jet engine is far simpler than the internal combustion engine. And all of this is apart from the very difficulties in defining complexity. Always ready with an answer, Dawkins suggests that it is just a matter of description. If you write down all of the features of one organism and compare it with a like description of the features of another organism, the one with the longer list wins. “If you have a lobster and an earthworm and you wish to decide which is the more complex, proceed as follows. Write a book about the lobster, write another book about the earthworm, and count the number of words in the toolbox. The animal which needs the larger book is the more complex.”31 The trouble here is the same as what taxonomists ran into fifty years ago with the advent of computers—it all seemed so easy. Count up the characteristics, put them into the machine, and out would come objective classifications. Rapidly people saw that this approach—“phenetic” or “numerical” taxonomy—would not work because no one knew how to divide up the countable characteristics.32 Does a bald man differ from one of the Beatles by one feature or by literally thousands—hair by hair? This isn’t to say that the lobster is not more complex than the earthworm, but that it isn’t easy to say on what basis.
In the Origin, Darwin admitted candidly that paleontologists have a sense of progress. “The inhabitants of each successive period in the world’s history have beaten their predecessors in the race for life, and are, in so far, higher in the scale of nature; and this may account for that vague yet ill-defined sentiment, felt by many palæontologists, that organisation on the whole has progressed.”33 Despite Gould, many of today’s paleontologists feel the same way. The late Jack Sepkoski, one of the most highly regarded paleontologists of the end of the last century—actually they preferred to call themselves “paleobiologists” to denote the fact that they wanted to move beyond simply digging out fossils and to understanding the past in (evolutionary) biological terms—put things in a very American way, referring to the opening of the frontier. He was much interested in mass extinctions, which he saw as both creative and destructive.
Mass extinctions have probably been good for the evolving biosphere. I said, “good” and I’ve got to explain why I said “good”—in the sense that they probably promoted diversity.
Real evolutionary innovations, probably coming in during the rebound of these extinction events, clear out a lot of diversity. Clear out a lot of biomass. We’re back into semi-frontier days. Sort of environment where you don’t have to be real good to get on, so something very new and different may be able to grab hold of a piece of the ecological pie, and hold it, giving rise to new kinds of organisms.
So mass extinctions are good in that sense. They promoted evolutionary innovation.34
Generally, when talking of change, paleobiologists slip into value-impregnated language and progress-type talk. For instance, a fairly typical discussion of evolution runs: “Fish can be seen to have undergone significant morphological ‘advancement’ [for example from the chondrostean to holostean grade among Actinopterygii, or the ‘cladodont’ to ‘hybodont’ grade in Chondrichthyes].”35 Analogously, in the plant world we find distinction between primitive and advanced, with the former characterized by the leaves exhibiting “‘first rank’ leaf architecture: i.e., poor definition of vein orders, irregularity of spacing, angle of departure, course, and branding patterns of secondary and higher-order veins, and incomplete differentiation of blade and petiole, a syndrome of characters originally postulated to be primitive in dicots on the basis of comparative studies of Recent forms.”36
What is striking is how most evolutionists more or less take biological progress for granted—for all that they are prone to deny it when in public and totally sober—and go on to argue from there. There are a number of reasons for this. One is that since we are asking questions about progress, necessarily we are at the end of the evolutionary process and so there is an inclination to think that we must have won. There tends not to be much fellow feeling with warthogs at a time like this. Second, bound up with this first point is the sense that if warthogs feel that they are so very important, why don’t they speak up and say so? Because we can ask questions about progress, we tend to judge progress in these terms. Perhaps warthogs judge progress in terms of wallowing in mud and letting the world pass by except when out feeding or copulating. Would a warthogian Aristotle judge that inferior? Third, in a tradition going back to Diderot, there is a tendency to read hopes of cultural progress into the biological world and come up with confirmatory biological progress. Uniquely, scientists live in a world where—the social constructivists and other relativists notwithstanding—there is real progress. Newton was better than Aristotle and Einstein was better than Newton. Creationism is wrong and evolution is right. Why wouldn’t one expect to find biological progress, especially since we are the ones responsible for scientific progress?
Arms Races
Yearning sentiments aside, is there any reason, any Darwinian reason, to think that progress will occur? Specifically, is there any Darwinian reason to think that biological processes will lead to human beings? Or, at least, is there any Darwinian reason to think that biological processes will lead to what have been called “humanoids,” that is, humanlike beings with intelligence and so forth? I don’t suppose anyone is demanding that we have five rather than six digits or white/brown/black skin rather than blue or green skin. I am not so sure about sex, in part because no one has a fixed idea about the causes of sex. It certainly seems to be the case, however, that sex makes things happen, namely, gathering good mutations together quickly in one individual, and so one suspects it unlikely that our humanoids would be sexless entirely. But there could be variations, like them all being hermaphrodites, all both capable of fertilizing and open to being fertilized and giving birth.
Humans have evolved, so obviously they could evolve. If you were to allow the hypothesis of multiverses—an infinite number of other universes, some (presumably an infinite number) like ours—then presumably (updating the argument of the atomists) somewhere, sometime, humans were going to evolve. To say otherwise is to say that they couldn’t. In fact, one presumes that an infinite number of humans are going to evolve. I remember once the late J.J.C. (“Jack”) Smart, a British-born, absolute fanatic about cricket—and a man who, incidentally, educated literally thousands of young Australians—saying with some glee that all over the universe there is an infinite number of teams capable of beating the Australians! This, one should say, was said at a time when it seemed that nothing natural was ever going to beat the Australians. Smart, incidentally, felt even more strongly on the subject of cricket played in colors other than the traditional white. Presumably, all over the universe there are teams clad in shocking-pink hot pants, capable of beating the English by an innings and several wickets.
However, even if this is so—and there are serious critics of multiverses—we hardly have anything one would be inclined to call “progress.” It starts to sound like huge arrogance to say that, in a situation where presumably one has billions of life-forms, everything in some sense bows down to us—or even to the billions of us in various galaxies. We can put the values in, if we want, but we are not reading them out of nature. There is nothing in biology itself to say we are better. Although, this said, there is equally nothing to stop us looking for Darwinian reasons for thinking that the nature of the evolutionary process is such that humanlike beings are (best scenario) necessarily going to emerge or (less attractive scenario) at least very likely to emerge. There are two popular proposals.
The first builds on the insight of Darwin about competition leading to improvement, particularly the competition between evolving lines leading to improvement. This idea about “arms races” was elaborated in most detail by Julian Huxley in a little book at the beginning of the last century. He gave a graphic description of an arms race couched in terms of the then state-of-the-art naval military technology. “The leaden plum-puddings were not unfairly matched against the wooden walls of Nelson’s day.”37 Now, however, obviously having in mind the then huge naval competition between Britain and Germany, “though our guns can hurl a third of a ton of sharp-nosed steel with dynamite entrails for a dozen miles, yet they are confronted with twelve-inch armor of backed and hardened steel, water-tight compartments, and targets moving thirty miles an hour. Each advance in attack has brought forth, as if by magic, a corresponding advance in defence.” Likewise in nature, “if one species happens to vary in the direction of greater independence, the inter-related equilibrium is upset, and cannot be restored until a number of competing species have either given way to the increased pressure and become extinct, or else have answered pressure with pressure, and kept the first species in its place by themselves too discovering means of adding to their independence.” Eventually: “it comes to pass that the continuous change which is passing that through the organic world appears as a succession of phases of equilibrium, each one on a higher average plane of independence than the one before, and each inevitably calling up and giving place to one still higher.”
One who has (without acknowledgment) picked up enthusiastically on this kind of thinking is Richard Dawkins. “Directionalist common sense surely wins on the very long time scale: once there was only blue-green slime and now there are sharp-eyed metazoan.”38 He too finds the key in arms races. As one who embraced computer technology early and enthusiastically, perhaps expectedly Dawkins notes that, more and more, today’s arms races rely on computer technology rather than brute power, and—in the animal world—he finds this translated into ever-bigger and more efficient brains. No need to hold your breath about who has won. Dawkins invokes a notion known as an animal’s EQ, standing for “encephalization quotient.”39 This is a kind of cross-species measure of IQ that takes into account the amount of brain power needed simply to get an organism to function (whales require much bigger brains than shrews because they need more computing power to get their bigger bodies to function), and that then scales according to the surplus left over. Dawkins writes, “The fact that humans have an EQ of 7 and hippos an EQ of 0.3 may not literally mean that humans are 23 times as clever as hippos! But the EQ as measured is probably telling us something about how much ‘computing power’ an animal probably has in its head, over and above the irreducible amount of computing power needed for the routine running of its large or small body.”40
As always, it is the analogy with human progress that is the key.
Computer evolution in human technology is enormously rapid and unmistakably progressive. It comes about through at least partly a kind of hardware/software coevolution. Advances in hardware are in step with advances in software. There is also software/software coevolution. Advances in software made possible not only improvements in short-term computational efficiency—although they certainly do that—they also make possible further advances in the evolution of the software. So the first point is just the sheer adaptedness of the advances of software make for efficient computing. The second point is the progressive thing. The advances of software, open the door—again, I wouldn’t mind using the word “floodgates” in some instances—open the floodgates to further advances in software.41
He adds, “I was trying to suggest, by my analogy of software/software coevolution, in brain evolution that these may have been advances that will come under the heading of the evolution of evolvability in the evolution of intelligence.”42
Others endorse similar lines of thinking. For instance, there is reason to think that shellfish are in arms races with predators, putting ever-greater resources into thicker, tougher shells, with the predators developing ever-more efficient methods of boring into shells and extracting the contents. However, not every Darwinian biologist is that enthused by arms races. The fossil evidence, for instance, does not show unambiguously that prey and predators have become ever faster. And even if arms races are ubiquitous, it does not follow that intelligence will always emerge. Having high intelligence means having large brains, and having large brains means having ready access to large chunks of protein, the bodies of other animals. There were no vegans in the Pleistocene. Sometimes—as cows and horses demonstrate—it is just easier to get your food in other ways, especially if you are living on grassy savannahs. Despite his enthusiasm for progress, Jack Sepkoski put matters colorfully and definitively: “I see intelligence as just one of a variety of adaptations among tetrapods for survival. Running fast in a herd while being as dumb as shit, I think, is a very good adaptation for survival.”43 So the overall answer seems to be that although arms races may well lead to intelligence, there is no guarantee that this will happen, and given that we have only the one instance (admittedly successful) to go on, it would be rash to argue with too much confidence that progress up to humans is the norm.
The other favored approach to getting progress out of the Darwinian system works on the theme of ecological niches and organisms finding them and occupying them. We often think of the broad niches occupied by organisms—animals particularly—water, earth, and air. Why not just add on another—culture—and suppose that it was waiting to be occupied and finally protohumans found it and moved in? Gould of all people floated some idea like this. He thought that, if not on our earth, then somewhere in the universe this might have happened. He quoted Theodosius Dobzhansky: “Granting that the possibility of obtaining a man-like creature is vanishingly small even given an astronomical number of attempts … there is still some small possibility that another intelligent species has arisen, one that is capable of achieving a technological civilization.”44 Gould commented, “I am not convinced that the possibility is so small.” He gave an argument that evolutionary convergence (where two different lines evolve essentially similar adaptations to survive and reproduce) suggests that even though major intelligence has arisen but once on this earth, it is quite possible that elsewhere in the universe it has arisen quite independently. “But does intelligence lie within the class of phenomena too complex and historically conditioned for repetition? I do not think that its uniqueness on earth specifies such a conclusion. Perhaps, in another form on another world, intelligence would be as easy to evolve as flight on ours.”45
I am not sure that one would want to use the word “progress” here. As in the multiverse discussion, that intelligence appears over and over does not really justify one in saying it is the best or even better than other life-forms. At the least, one wants some kind of channeling or funneling toward humans. Using much the same argument as Gould, the paleontologist Simon Conway Morris (as a Christian) is very keen to argue for the inevitability of the appearance of humans. He argues that only certain areas of what we might call “morphological space” are welcoming to life-forms (the center of the sun would not be, for instance), and that this constrains the course of evolution.46 Again and again, as Gould argues, organisms take the same route into a preexisting niche. The saber-toothed, tigerlike organisms are a nice example, where the North American placental mammals (real cats) were matched right down the line by South American marsupials (thylacosmilids). There existed a niche for organisms that were predators, with catlike abilities and shearing/stabbing-like weapons. Darwinian selection found more than one way to enter it—from the placental side and from the marsupial side. It was not a question of beating out others but of finding pathways that others had not found.
Conway Morris argues that, given the ubiquity of convergence, we must allow that the historical course of nature is not random but strongly selection-constrained along certain pathways and to certain destinations. Most particularly, some kind of intelligent being was bound to emerge. After all, our very own existence shows that a kind of cultural adaptive niche exists—a niche that prizes intelligence and social abilities. “If brains can get big independently and provide a neural machine capable of handling a highly complex environment, then perhaps there are other parallels, other convergences that drive some groups towards complexity.” Continuing: “We may be unique, but paradoxically those properties that define our uniqueness can still be inherent in the evolutionary process. In other words, if we humans had not evolved then something more-or-less identical would have emerged sooner or later.”47
Does this do the trick and is this progress? One might question positive answers to both questions. Even if it exists, why should we or anyone else necessarily or even probably enter the culture niche? Life is full of missed opportunities. Maybe Gould is right and most times evolution would have gone other ways and avoided culture entirely. Warthogs rule supreme. Huxley always argued that now humans occupy the culture niche, no other animal is going to be able to enter.48 Perhaps other animals (dinosaurs) would have prevented our animals (mammals and then primates) from making their way to the door. In any case, many wonder if it is right to think that niches are just waiting out there, ready to be conquered and entered. Do not organisms create niches as much as find them? There was hardly a niche for head lice, for instance, until vertebrates like us humans came along. Should we expect that there was a niche for culture, just waiting there, like dry land or the open air? Perhaps there are other niches not yet invented. We cannot imagine something other than consciousness; but take heed of the wise warning of J.B.S. Haldane: “Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.”49 For all their talk about analogy, Christians tend to think that their God can get up to some pretty clever tricks, way beyond their ken. Perhaps these are not all supernatural abilities, but simply abilities that were omitted from our evolution. Perhaps, far from being the best, we are a short side-path and very limited in the true scheme of things. No more than in the case of arms races do we get much guarantee of either human emergence or a sense that we are in some way superior and for this reason we won.
Purpose is there in Darwinian biology, through and through. Thanks to Darwin, many enthusiasts think we have come a long, long way. We have purpose in the individual feature—the eye exists in order to see. Equally, although there are some (including myself) who are not so enthusiastic on this score, many think we have purpose in history. Humans are the destined end point, thus far. Have we arrived at the bright, Elysian shore? Many Darwinians think we have. Others—who have greater or less degrees of enthusiasm for natural selection—are not so certain, as we shall now see.