The Best American Science and Nature Writing 2010

by Tim Folger

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  In On the Origin of Species (1859), Darwin showed how new species could evolve through a process of blind variation and selective retention. He transformed at a stroke our understanding of natural design. Living things manifest complex design but can be produced by a mindless process, one that does no more than passively register, in terms of survival and reproduction, the advantages of particular variations. In The Blind Watchmaker (1986), Richard Dawkins explains how nature is like a watchmaker who builds intricate mechanisms without forethought, and he thereby overturns the famous argument of the theologian and naturalist William Paley. Paley opens his Natural Theology: or Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature (1802), with these words:

  In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that, for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer which I had before given, that, for anything I knew, the watch might have always been there...[The precision and intricacy of its mechanism would have forced us to conclude] that the watch must have had a maker; that there must have existed, at some time, and at some place or other, an artificer or artificers, who formed it for the purpose which we find it actually to answer; who comprehended its construction, and designed its use.

  Nobody could reasonably disagree, Paley adds, yet this is tantamount to what an atheist does, for "every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater and more, and that in a degree which exceeds all computation." As Dawkins notes, we now know that the complexities of natural organisms surpass those of the most intricate watch by far more than science could guess in Paley's time; yet he goes on to show how simple processes of variation and selective retention can, over many cycles, create products with even this degree of design.

  Other processes working within natural selection have been found to follow the same principle: the human immune system; the synapses in the young human brain (in the neural Darwinism of Gerald Edelman and others); culture (in the work of David Sloan Wilson and others); and invention (in the work of Donald Campbell and David Hull). Such "Darwinian systems," "Darwin machines," or, in Dawkins's term, "universal Darwinism," allow genuine novelty to be achieved without advance knowledge of what will work best in an unpredictable and open world. The common principle of blind variation and selective retention allows for a deeply indeterministic process that explores patches of possibility space in multiple directions and pursues any direction provisionally more promising than others. It tracks through the vastness of the possible in ways that surprisingly often lead to rich solutions by compounding immediate advantages and retaining achieved complexity in the next round of variations. Such Darwinian processes might well occur anywhere we find deeply original novelty.

  Darwin's explanation of evolution by natural selection shocked, and still shocks, because it appears to deny purpose. We think of purpose as something prior to decision and action: I want to raise my arm and, unless I am paralyzed or restrained, I do. But in fact purpose emerges slowly, in the species and in the individual. My capacity to move my arm in as many ways as I can depends on things like the evolution of forelegs into arms early in the primate line, the evolution millions of years later of a rotating socket in the shoulder of great apes, to enable swinging in trees, and the further freeing up of arm movements after early hominids became fully bipedal. Babies flail their arms uncontrolledly and purposelessly for months before they can direct them in a particular way for a particular purpose.

  Paley's example of the watch assumes a purpose we already understand: the intricate integration of material objects into instruments for telling the time. But humans did not evolve to be capable of constructing multipart mechanisms until within the last 50,000 years or so. Until their manual control reached a high level and their stone toolmaking had had more than 2 million years of refinement, they would have been unable to conceive of such mechanisms or, if confronted with them, unable to recognize anything of their construction or purpose. The idea of telling the time precisely would have been unknown and meaningless to our human ancestors even at the end of the Stone Age.

  Purposes can emerge only piecemeal; problems cannot even define themselves until many of the elements are already in place. The position of the sun in its daily sweep can indicate the phases of the day, but nothing more precise. Sundials and the sticks in the ground that preceded them afforded more finely determined divisions of time during daylight and made it possible to imagine coordinating common actions in advance. The first water clocks and sand clocks enabled even tighter coordination. Mechanical clocks and bells to chime the hour or even the quarter-hour took social synchronization still further. Not until European navigation and mapping flourished in the fifteenth century did anyone consider devising a portable clock to ascertain longitude, yet maritime clocks remained highly inaccurate for another three centuries. The first watches, in the early sixteenth century, could register only the hour; and it took more than another century to tell the time down to the minute on a portable mechanism. By Paley's day, the recent invention of the duplex escapement had made it possible to keep time accurately on a pocket watch, but it was only over the course of the nineteenth century that highly accurate timing made possible new degrees of precision measurement, and hence new research options in physics and in psychology. Not until well into the twentieth century did cesium clocks attain the exactitude and reliability of timekeeping needed for quantum physics or space flight.

  In the development of both instruments and ever finer standards for measuring time intervals, new purposes have been discovered, each inconceivable a stage or two previously. Purposes arise not in advance, but as possibilities materialize. Of course, when the purpose becomes established, it can then be implemented in advance of any particular manifestation: I can choose to move my arm in such a way as to put on a sweater, or to time mental responses down to the millisecond in a psychology laboratory as a measure of the complexity of the neural processing involved. But each of these purposes, although it precedes a definite action, has a long history that precedes it in the species, the culture, and the individual, a history of prior trials and errors, before the purpose could be conceived and fully defined, let alone specified in advance.

  Life could become established only when matter organized itself in a way complex enough to sustain and reliably reproduce itself. Maintaining such a highly improbable and functional arrangement of matter became life's first purpose. As species continued to evolve, so did the purposes of their organs and behaviors. New behaviors, like new organs, begin uncertainly, with slight modifications of existing structure, but become defined over time, and their function or purpose specifiable in advance: a certain kind of spider will spin a certain kind of web to catch a certain range of insects under certain conditions, and so on.

  As creatures began to act in more complex and flexible ways, nature evolved emotions to motivate better decisions. Satisfying these emotions—escaping fear, appeasing hunger, fulfilling desire, sustaining love, and so on—became important purposes in themselves for much of the animal kingdom.

  As behaviors standardize, as purposes define themselves, social animals can learn to understand not only the actions of other members of their species but even their desires and intentions before they act. Not only do we learn to infer others' intentions but, in social species that benefit from cooperation, we also evolve to empathize with or emotionally react against others' purposes. (Without this, stories would be impossible.)

  Yet we should not forget that despite our thinking of purposes as prior to actions, they have emerged over long stretche
s of evolutionary and individual time. Intentions are efficient routes to objectives clearly defined only after many preliminary stages of variation and selection within animals' evolutionary and individual pasts. Like design, purpose emerges rather than precedes, except in the case of purposes that have developed long enough to become standardized. Only in that sense can purpose be said to precede the particular instance, whether the function of an organ or the intention of an action.

  Purposes evolve, and Darwinian processes extend them. Intelligence and creativity are purposes that have emerged over the course of life on Earth. Stephen Jay Gould famously argued that if we could rewind and replay the tape of evolution, humans and human intelligence would not reappear. Quite possibly not; no one disputes that contingency strongly inflects evolution. But as Simon Conway Morris has stressed, certain capacities have evolved again and again, because of the singular advantages they offer: senses, locomotion, minds, emotions, sociality, intelligence, creativity, cooperation, to name those that concern us most. Let's consider two of these, intelligence and creativity.

  Intelligence allows us to respond flexibly to circumstances, to solve problems not only according to successful old routines (prior purposes, if you like) but in novel and more or less context-sensitive ways. Because it can sometimes find new solutions, intelligence is highly advantageous—yet not at all easy for evolution to evolve. Although minds have been necessary for all motile creatures, more advanced intelligence has emerged in relatively few lineages, although quite diverse ones: invertebrates like octopi and cuttlefish; vertebrates like crows and parrots among birds and cetaceans and primates among mammals.

  Intelligence has large benefits, but it also incurs costs. Out of the pressure to develop social intelligence, humans have grown in self-awareness, so that we can imagine ourselves as others see us in competitive and cooperative scenarios. That ability offers real benefits in anticipating others' actions and reactions, but among its costs is the fact that we can also envisage our own death and absence from the ongoing world. For humans this has raised the question of our purpose in the face of our ultimate lifelessness, one we have answered most frequently by concluding that we continue in some form after death. To judge by grave rituals dating back at least 70,000 years, and the evidence of the fear of death and the hope of immortality in the records of early civilizations, preoccupation with death has loomed large ever since the appearance of a distinctly human culture.

  Creativity is the capacity to develop significant and valuable novelty. This seems the most difficult capacity of all for evolution to evolve, and for good reason. Significant and valuable by what criteria?

  Human creativity matters for human beings. But creativity hardly matters for evolution. Single-celled organisms reproduce themselves readily, and life can go on—did go on, for billions of years on Earth—with barely more complexity. Life persists through reproduction, through transmitting accumulated complexity to subsequent generations. If inherited design were radically changed each time an organism reproduced, the hard-won gains of natural selection would rapidly be lost. Life can evolve new possibilities only slowly, through variations small enough not to threaten existing evolved functions, accreting functional novelty generation by generation from minor and undirected variation. But although evolution has thereby spawned many new species and even major new forms of life, it does not need or aim for creativity.

  Yet organisms vary, even if only through imperfections in reproduction, and conditions change. Over enough time conditions will always alter, including competition with other organisms in the environment. Since any organism can become a source of energy for others, each has to find ways of exploiting others more efficiently and to avoid being exploited by others, including predators, parasites, and pathogens. In species with a wide range of variations, some individuals will be able to exploit changing opportunities or to avoid changing threats more effectively than others. Variation in itself—considerable enough to gain advantage, but not so large as to imperil existing design—therefore offers a measure of security against unpredictable circumstances. For this reason, sex has evolved many times as a way of recombining genes unpredictably but reliably, and hence of generating a range of initially viable variations from which conditions will select. Some species even toggle between reproducing sexually or asexually according to the degree of environmental instability. Sexual recombination therefore ensures a wide and unpredictable range of genetic variation that can cope better with unpredictable circumstances.

  Just as natural selection has evolved sex as a means for amplifying genetic variation, it has evolved art in humans as a means for amplifying behavioral variation. Art has been designed by evolution for creativity.

  The human immune system and the infant human brain naturally overproduce options to cope with as many unpredictable situations as they can. They then pare back whatever is not activated by experience and regenerate from whatever has been stimulated by experience. These second-order Darwinian processes allow an additional level of flexibility beyond first-order genetic variation, a still more sensitive adjustment to even shorter-term unpredictability.

  Art is a subsidiary Darwin machine that generates not natural but "unnatural" variations or options. By "unnatural" I mean only that art involves highly deliberate human choices, both individual and cultural, even if these are themselves ultimately the products of nature.

  Creativity as a principle, as a Darwinian process, solves no particular prespecifiable problem; but it offers an additional way of generating new possibilities that may prove to solve problems, even significant ones, provided there is a consistent pressure toward a solution—whether over generations, as in natural selection, or over weeks or months or years, as when a storyteller, say, drafts and revises a story, or in only minutes or seconds in the spreading neural activation in a poet or a scientist seeking a new image or idea, in a mind prepared over many years by many trials.

  Art did not evolve in order to foster creativity. Evolution has no foresight. It cannot evolve what has only future advantages, but can evolve only what offers benefit now. Yet art now does foster creativity. So how did it evolve and why?

  New evolutionary solutions themselves often spawn new problems. When our brains allowed us to become superpredators, to dominate our environments and earn the food we needed in much less time than our waking hours, we did not solve the "problem" of spare time, as did other top predators, such as lions, tigers, or bears, by sleeping the extra hours away to conserve energy. Even at rest our large brains consume a high proportion of our energy, and since they offer us most of our advantages against other species and other individuals, we benefit not from resting them as much as possible but from developing them in times of security and leisure. Art as cognitive play, appealing to our appetite for potentially meaningful patterned information, engages our attention in a self-rewarding way and therefore encourages us to strengthen the processing power of our minds in the kinds of information that matter most to us.

  Because it appeals to our own cognitive preferences, we have built-in incentives to generate art: its effects should be pleasing in themselves. Since the criteria for success are human preferences, since the testing mechanisms are already in our minds as we sing, or tell a story, or dance, or daub, we can readily adjust our actions to produce more satisfying effects: we can easily select from what we do, as we do it, and try out new variations, or stop when interest flags.

  In most soci eties art has been collective and active, and even in modern cities, dance and song often still remain so. Where art tends to be more individual than communal, those with talent enough to spark the interest of others have a strong extra incentive to develop their skill for the attention, gratitude, and status it can earn them. Although professional artists may not have appeared until agriculture and permanent settlement allowed resources to accumulate and labor to specialize, the quality of some of the earliest art suggests that some individuals, long before agriculture, had the lux
ury of developing singular skills. Creative concentration and feedback during composition could work like a speeded-up version of natural selection, as these artists rapidly generated, discarded, and regenerated new variations.

  Even in societies where art has become individualized and professionalized, it remains highly social. Art not only activates our private cognitive preferences but also adjusts and amplifies them through our sociality. From the first, mothers and others engage with infants in multimodal social play involving fine-grained attunement and interaction. We instinctively make learning enjoyable for young children by making it social, by making it play, and by making it art, by appealing to the cognitive preferences that art animates. Throughout life, participation in artistic activities in group settings, whether actively (in performance) or more or less passively (as audiences), continues to amplify the emotional charge of art.

  Art's social nature not only motivates our participation, but also provides ready-made models to reduce the costs of invention and increase the benefits of response. Tribal arts like weaving, classic forms like the sonnet, or modern arts like filmmaking all depend on the existence of shared norms to provide prompts and challenges. As the film theorist David Bordwell observes: "Norms help unambitious filmmakers attain competence, but they challenge gifted ones to excel. By understanding these norms we can better appreciate skill, daring, and emotional power on those rare occasions when we meet them."

  Art can engender variations through other factors present elsewhere in nature—through randomness, "an intrinsic part of brain function," and "nature's way of exploring unforeseen possibilities" in other domains too, and through copying errors—and through distinctively human factors. Art does not need to start from scratch but can recombine elements already developed in the same or a different art or tradition. Just as sex, by recombining genes, and hybridization, by recombining lineages that have had time to separate, can engender novel forms, art too can readily recombine, from the animal-human blends in cave art to the Minotaurs of the ancient Greeks or the modernist Picasso.