This leads me to a strange thought. As I write these words, I am surrounded by a garden of grass, trees, flowers, and herbs that is visited from time to time by animals that eat the plants and (rarely) by other animals that eat the first animals in turn (I’m particularly mindful of a black cat that visits from his cosseted home next door to pick off the birds in my garden). In the soil live innumerable bacteria and fungi leading busy lives consuming what the animals have left. It is a hectic, tangled world of little lives.

  As I allow my physiologist’s mind to drift, a new picture emerges of what I see. What really surrounds me (and carries me along as well) is not quite a complex world of things, but a complex cascade of energy: a turbulent, frothy wave of electrons interposed between the sun and the rest of the universe. The wave crests first at the interception of light by green plants,* tumbles down the curl through animals, and ends with the bubbly foam of the decomposer bacteria and fungi.* If you surfed along with this wave, you would see the complex structure of the wave surface bubbling, foaming, circulating, reflecting the innumerable fractal surfaces that manage the energy flow: the folded chloroplasts, the spongy interiors of leaves, the vast surfaces of lungs and intestinal tracts, the structured soils—energy cascading through them all forward in time.

  This foamy wave of energy is a standing wave, like the wake that follows a speedboat. It exists in time and persists as long as energy is being fed into it. The standing wave is a metaphor for the open thermodynamic system I introduced in the Preface: energy flows in, does work, and then is dissipated as heat. On Earth, the standing wave has existed as long as the sun has spewed forth photons and the Earth has been present to intercept them. The standing wave exists in some form wherever any planet is close enough for the sun’s energy to do significant work on it.

  Energy flowing through open thermodynamic systems often imposes orderliness on them.27 There is nothing magical about this; the orderliness is simply the fastest way to hurry energy through the standing wave, from photons from the sun to heat that warms the universe.28 We can see this orderliness in the stately waves that roll across oceans and atmospheres, manifest as great circulation cells, by large breakaway eddies that boil occasionally here and there into chaotic storms. Such patterns are also evident on Mars and Venus, in the tumultuous weather of those planets.

  What life on Earth has wrought is a change in the wave’s form. You can see the difference if you look at it the right way. A Martian landscape and a barren landscape on Earth look disturbingly similar, shaped by physical forces of erosion and soil movement. Wind and water erosion patterns on Earth and Mars resemble one another closely, for example. So great are the similarities, in fact, that NASA uses several of these terrestrial landscapes—in the Namib Desert or the Atacama Desert, for example—as mock Martian landscapes to test rovers and other devices for deployment to Mars. Compare this to a life-rich landscape on Earth, and the difference is clear: the Earth landscape is much richer and filled with more complex shapes.29 That leaf is not so much a thing as it is an interface between photons streaming in from the sun and ultimate disorder and heat—its complex form sustained by the leaf’s ability to capture energy and funnel matter through it and shape its progress to disorder in a highly specified way.

  Although the form of orderliness might differ, the important point is that there is orderliness in the first place. Let us reflect on why. We spoke in the preface of the spontaneous orderliness of open thermodynamic systems, the Fourth Law of Thermodynamics. Orderliness in open thermodynamic systems is a form of work: it takes energy to sustain it. At the same time, orderly systems spontaneously decay to disorder, usually wrought by the disruptive power of diffusion. That is the Second Law of Thermodynamics. Orderliness in an open thermodynamic system therefore persists only when sufficient order-generating energy flows through to overcome diffusion’s disruptive power. This is why the peculiar orderliness of weather and cumulus clouds is a phenomenon of large scale. At the scale of the cell, there is no such thing as weather, only destruction.

  Let’s picture this in our metaphor of a standing wave of energy flowing through the open thermodynamic system of the Earth’s (Figure 10.4).30 The Earth intercepts a continuous stream of energy from the sun, at a rate of about 128 petawatts.* By way of comparison, the world’s fossil fuel energy consumption amounts to around 16 terawatts, roughly 0.0125 percent of the energy streaming in from the sun. The energy streaming through all life on Earth amounts to about 90 terawatts, which is also about 0.01 percent of the light energy that actually reaches the surface of the Earth, fueling plant growth. All the rest of the energy streaming in to the Earth—the other 99.99 percent—powers the orderly patterns of global atmospheric and oceanic circulation that drives global weather.

  Figure 10.4

  The standing wave metaphor for the Earth’s open thermodynamic system. Details in text. Figure taken from the Stanford Global Climate and Energy Project.

  Life, therefore, represents a tiny froth on the crest of the Earth’s standing wave of orderliness. The point is that much of the orderliness of life comes from orderliness already existing on the open thermodynamic system of the Earth.31 The signature of life amounts to a specified orderliness that shapes the crest. What life has done is to make the wave crest “foamier,” if you will, ordering it into an infinitude of nested and interlocking systems of persistent and specified energy flows, vast conspiracies of life that currently envelop our living planet.32

  Which leads us to the strange question: what law demands that life has to evolve up, from the small scale to the large? Why couldn’t it have been the other way? Why couldn’t life—homeostasis, essentially—have emerged first at the large scale, even as a planetary phenomenon, sustained at a large scale on pre-existing orderly flows of matter and energy until it could be encapsulated within the safe harbor of the cell? All that is needed is an energy source that is large enough to overcome the disruptive power of diffusion at a small scale and that is persistent enough to allow incipient conspiracies of homeostasis to piggyback on that standing thermodynamic wave. And that only occurs at large scale.

  The energy needn’t come from the sun, which is what mostly drives present life. One could imagine any number of other large-scale energy sources that might do. Residual heat from the formation of the Earth, emerging, say, in concentrated form around hydrothermal vents might do.33 Natural fission reactors, like the one discovered in Gabon that generated power at a rate of about 100 kilowatts for roughly three hundred thousand years, might also serve.34 No matter what the putative energy source, this thermodynamic approach brings a distinctive perspective to the problem of the origin of life: it turns Darwin’s “warm little pond” upside down, because it is only at a large scale that life—that is, homeostasis—can arise on its own, without help from the hand-of-the-scientist-god.

  The idea of life originating at a planetary scale is odd enough, but if we follow the logic that led us here, we can follow it further to an even stranger thought. Let’s first recap where we have come. If Biology’s Second Law is true and life is at root an expression of the phenomenon of homeostasis, then the origin of life is tantamount to the origin of homeostasis. Homeostasis demands certain things, however—among them at least rudimentary forms of cognition and intentionality. This leads to the very strange thought that the origin of life is tantamount to the origin of cognition and intentionality. Even stranger, cognition and intentionality had to have actually preceded the origin of cellular life.

  We can rescue this idea from the loony bin by defining cognition very broadly and generally—as informing a state or process about its environment. Our own very complex cognition should not blind us to the fact that cognition can be framed even in very simple systems, like individual cells, or even simpler. The nerve cells that underlie our own cognitive systems are certainly cognitively aware, but they are cognitively aware in a very different and highly circumscribed way from the large-scale cognitive phenomena in which they participate. An individual nerve cell is cognitively aware of the fluid environment in the brain in which it bathes, and of the chemical signals flung at it by the myriad other nerve cells communicating their own cognitive states, and very likely many other features of its little world. Outside of brains, individual cells are cognitive entities in the same way. A photosynthetic algal cell maps the presence or absence of light onto its encapsulated catalytic milieu, altering the cell’s physiology in accordance with its environment.35

  Similarly, intentionality can be defined very broadly. As I argued in The Tinkerer’s Accomplice, intentionality can be construed as the coupling of cognition to metabolic engines that can shape the world to conform to a cognitive map.* Brains produce a very complicated intentionality. If I have a cognitive vision of my office being organized in a particular way, I can do the work to bring my office into conformity with that cognitive map. When my office degrades into inevitable chaos, I do the work again to conform it to that cognitive vision of an orderly office. There is no reason to suppose that this kind of intentionality cannot operate at different scales of life. The microbial mat, for example, is the large-scale emergence of a constructed environment that reflects the awareness of each species of microbe of its local environment, and the reshaping of that environment to bring it into conformity with the microbe’s internal cognitive map of what its surroundings should be.

  If we imagine what those first conspiracies of homeostasis must have been like, then we can envision a kind of selection operating between different persistent systems of energy and mass flow. Fitness in this instance will be equivalent to persistence, and persistence will be equivalent to robustness of homeostasis. Persistence will turn on how effectively the present and persistent state of an order-producing thermodynamic system—a kind of memory, keep in mind—can shape its broader environment to bring it into conformity with itself. Fundamentally, this is coupling work to information, which is what relates intentionality and cognition in purposeful living systems. This implies that cognition and intentionality were with life from the get-go, and before cellular life emerged from the living thermodynamic froth.

  The origin of life invites us to think differently about the nature of life and its distinction from the material world. Specifically, thinking of life as chemistry or simple mechanism has led us to ingenious insights into the origins of self-replicating chemistry and the fuzzy boundary between the twin pillars of the Darwinian idea: apt metabolism made reproducible by heritable memory. It has led us ultimately to a dead end, however, because life emerging from the small scale to the large runs up against the formidable hurdle of diffusion. Confronted with this hurdle, we are forced to turn the problem upside down. In so doing, however, we are drawn to think about life as a global phenomenon, driven by the emergence of homeostasis and the cognitive capabilities that implies.

  Among the different perspectives is that life shapes its world according to its desires and striving toward homeostasis. Life, in other words, emerged as a massive extended—an intentional—organism.

  11

  Plato Street

  On the southern outskirts of Windhoek, the capital city of Namibia, there sits a modest little neighborhood called Academia (Figure 11.1). It is so named because of its proximity to the campus of the University of Namibia, chartered in 1993, three years after Namibia’s independence. Academia’s claim to distinction is naming all its streets after famous philosophers, hoping, I suppose, to inspire the new scholars that would swarm to the new university with thoughts of Great Things.

  The layout of the streets offers some unintentional philosophical humor. For example, the neighborhood’s trunk road is Plato Street. This is sensible, I suppose, in light of Alfred North Whitehead’s famous aphorism that all of philosophy is a series of footnotes to Plato. Yet Socrates, arguably more the root of Western philosophy than his prolific scion Plato, gets allocated only a minor side street. Aristotle Street, meanwhile, is a shabby peripheral avenue that faces onto Windhoek’s noisy municipal airport. Is this a subtle commentary on the conflict between Plato and Aristotle, which Aristotle lost and which led to him decamping in sulky self-exile to Asia Minor? More germane to me, the biologist, is the short shrift given to Charles Darwin. If I had been the neighborhood’s developer, I would have named the major thoroughfare after him, not Plato. Instead, Darwin Street is an insignificant connector between Plato and Aristotle Streets, just long enough for two homes on each side of the street (Figure 11.2). One wonders whether the developers gave any thought at all to the layout of their presumptuous little neighborhood.

  Figure 11.1

  Academia.

  Figure 11.2

  Plato Street, in the Academia neighborhood of Windhoek. (a) Intersection of Plato Street and Darwin Street. (b) The view of Aristotle Street. (c) Darwin Street, looking toward Aristotle Street from Plato Street. The Windhoek Municipal Airport is visible at the end.

  Of course they didn’t, and it’s silly even to ask it. But it gives me an excuse to ask an interesting question: where, philosophically, does biology sit? Does it sit with Plato and his notion that the universe is motivated by striving toward his ethereal universe of ideals? That’s where biology sat for much of its history, from Plato himself through Linnaeus and his Platonic theory of the species through William Paley. Or would biology sit more comfortably with Aristotle? That seems more likely, as a clear thread still connects Aristotle’s notions of internal strivings with medicine, physiology, and embryology. Or perhaps biology sits with neither of these purposeful avatars, as the modern legatees of Darwin’s name would assert? If that is true, then what is Darwin Street doing bridging Plato and Aristotle Streets? Wasn’t Darwin supposed to have broken us free from all this purposefulness stuff?

  The point of my little soliloquy on streets and philosophers is that eventually life, mute and insistent, inevitably confronts us with the perplexing riddle it has always posed. To mangle a common joke, Why did the chicken cross Plato Street? The scientist’s reflex is immediately to recast the question—How did the chicken cross Plato Street?—in the hope that the rephrased question will give us a “real” answer: because its legs carried it there. Modern science has been drawn into that unfunny answer because it opens the gates to the lush landscapes of the “how”: what controls the legs’ movements, how the muscles attach, what the circuit diagram looks like for the chicken’s walking. Yet sitting just outside those luxurious depths lurks what is arguably the only “real” answer to the original question: because it wanted to.

  Wanting something is desire, and meeting wants is purpose, and both are inextricably bound up with “why.” But is it possible—permissible, even?—for a scientist (a “real” scientist) to think about purpose and desire in any other way but “how”? Certainly, for scientists, the “how” of purpose and desire has been the more scientifically fruitful question than the “why.” We have begun to map out the neural architecture of emotions, motivations, and intentions, at least for the brains of humans. We know the parts of the brain and the neurotransmitters involved; we can manipulate emotions and desires with pharmaceuticals. We can evoke remarkably vivid sensations and wants by tickling just the right parts of the brain with electrical currents. We can read the weak magnetic fields that emanate from the meat-ware computers crackling away inside our heads. We can even begin to discern the thoughts that are generating them. But has our increasingly sophisticated ability to map the three-dimensional architecture of desire brought us any closer to the “why” of desire?—which would seem to be the most important thing about it. As some wag once put it, a computer called Watson may have beaten Ken Jennings at Jeopardy,* but did Watson want to win? Did Watson know he (it) won? Even granting the dubious long shot that Watson could be said to want anything at all, Ken Jennings undoubtedly brought desire to the game in an entirely different way from Watson. So the question remains: even if we understood in the uttermost detail how the chicken crossed Plato Street, would that entitle us to say anything—anything at all—about why the chicken crossed Plato Street?

  The problem of purpose and desire is thorny enough for life as it exists, but it becomes an enormously more difficult proposition when it comes to evolution. Individuals may have purpose and desire. We know this of ourselves, undeniably, and we can guess pretty well that we see purpose and desire in fellow humans. But it is a tenet of received Darwinian wisdom that individuals die, leaving only their lineages to evolve. What role could desire possibly play there, when desires must die with the individual feeling them? Or do their desires really die? Remember, this was the sticking point between Lamarck and Darwin. Lamarck thought that the ineffable forces that drove purpose and desire in individuals could transmit through lineages. Darwin didn’t think much of Lamarck’s ineffable forces, but if his Lamarckian schemes of inheritance bear any witness, he was attuned to adaptations being transmitted along lineages. Although we might quibble that Darwin’s disagreement with Lamarck was not quite as deep as we imagine today that it was, it is incontrovertible that, with the advent of Neo-Darwinism, the break became total. Ever since, the a priori exclusion of the “why” has become so forceful that even bringing it up elicits something akin to religious warfare.*

 

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