Reading Scott Turner’s Purpose and Desire: What Makes Something “Alive” and Why Modern Darwinism Has Failed to Explain It

Dr. J. Scott Turner grew up in coastal California and studied biology at the University of California, Santa Cruz (graduating in 1976) before earning his Ph.D. in zoology and entomology at Colorado State where he wrote his dissertation on heat exchange and blood flow in reptiles—something that Turner continues to think about in his latest book as he points out that “the body temperature of a lizard is not so much the outcome of a machine regulating it, but is a kind of cognitive state” (70). Since 2019, Scott Turner has been an emeritus professor of biology, retiring from a career that included three books—two of these with Harvard UP—and three decades of teaching at the SUNY College of Environmental Science and Forestry in Syracuse, New York (where he started in 1989 and earned a full professorship in 2009). The ESF Undergraduate Student Association awarded the Distinguished Teacher Award to Dr. Turner in 2004, and his love for teaching is apparent even in retirement, as he continues to develop online lecture materials including some free public resources. His first two books were more technical: The Extended Organism (The Physiology of Animal-Built Structures) in 2000 and The Tinkerer’s Accomplice (How Design Emerges from Life Itself) in 2007.

Writing at a more popular level, his third book was published with HarperOne in 2017 and is the focus of my review here. The 2018 Nautilus Book Awards recognized Purpose and Desire as “gold” within the science and cosmology category. I found the book’s most interesting aspect to be Turner’s outline of his best hunch regarding the origins of life on earth as well as his concern to see science restored to a full and healthy place within human culture. The book’s most delightful aspect, however, was Turner’s uncontained enthusiasm for the stories of great scientists. In fact, I thought that I could detect a pattern whereby Turner wore himself down (or his editors) over the course of the book so that a certain consistency with the consignment of scintillating narrative details to footnotes was slowly abandoned as the book progressed. Well into the book, we are treated to the story of how the skull of Edward Drinker Cope ended up in “a velvet-lined reliquary” constructed by American photographer and documentary filmmaker, Louie Psihoyos, who “took the skull around the country so that he could photograph herpetologists and paleontologists with the precious relic.” At every level of knowledge, Turner is extraordinarily well-versed in the history of evolutionary theory and engages with its many dynamic figures (from all sides of the various contentious debates) with an infectious delight in each of their special insights and colorful personalities.

On his website, Scott Turner describes himself as “a heterodox thinker about evolution, ecology and physiology” and says that “nothing arouses my suspicion more readily than consensus: by the time wisdom has become conventional, it’s a safe bet that it has accumulated sufficient baggage to hold some interesting errors in there somewhere.” Purpose and Desire unfolds Turner’s story of having fully embraced the standard mechanistic view of nature as a young scientist only to slowly undergo a process of questioning that brought him to his current heterodox position by the end of his career. As an undergraduate, Turner can “vividly remember being swept up in the seductive beauty of Hutchinson’s ‘new ecology’” (278) which melded with evolutionary theory so that every specific ecological niche in existence must eventually be filled by the work of natural selection to have its own particular species or two. After over thirty years, however, Turner now sees this scenario in reverse:

[Evolution] is not the memory tokens of the genetic organism that thrusts life into [every open ecological niche], but the other way round. It is the striving of cognitive individuals that reach into the future and drag the memory tokens along in their wake. (222) …Birds fly, not because they were the beneficiaries of lucky exaptations that enabled them to fly, but rather because, in a deep sense, the ancestors of birds wanted …to glide from tree to tree, or chase after a tasty lunch, or launch themselves up trunks of trees to avoid being lunch themselves. And those wants have dragged the genes into the future in their tumultuous intentional wake. And this makes evolution at root a phenomenon of cognition, of intentionality, of purpose, of desire—of homeostasis. (289)

Not only does life (defined by Turner as the intentional maintenance of homeostasis) seek its way intentionally into every niche, but life also starts to modify each niche:

Earthworms modify soils to help with their water balance, but the tendency extends broadly. Termites build massive lungs out of soil, beavers dam streams to promote the growth of trees they favor as food. These are examples of organisms not just “fitting into” niches, but actively building them. Meld the notion of a “constructed” niche to the Wright adaptive landscape, and you now have an entirely different way to think about adaptation and evolution. Now, the adaptive landscape is under the direct control of the organisms supposedly adapting to it. Now, it becomes an open question: what is adapting to what? Are organisms adapting to the environment, or are environments being made to adapt to organisms? This way of thinking about adaptation and evolution is called niche construction theory. (281-282) [See Niche Construction: The Neglected Process in Evolution (Princeton UP, 2003) by John Odling-Smee of Oxford University, Kevin Laland of St. Andrew’s University, and Marcus Feldman of Stanford University.]

The central hero of Turner’s book is Charles Darwin’s French contemporary, the great physiologist Claude Bernard (1813–1878) and his concept of homeostasis. Bernard says that “the constancy of the internal environment is the condition for a free and independent life” (14). Turner returns to this quote throughout the book as he develops the ways in which this idea offers us a “process vitalism” in the place of all the various (and notorious) vitalisms of the past whereby the intentionality of life came from the soul or from any one of a number of proposed life-giving elements. This process vitalism defines life as that which must maintain a constancy of the internal environment (the dynamic disequilibrium of homeostasis). Much of this is set out in pages 20 to 40, although its significance was not clear to me until much later. By identifying “the essential nature of homeostasis” with “life as a persistent dynamic disequilibrium” (20), Turner is offering what he twice calls a “middle path” (44, 298) between pure mechanism (of which life is nothing but an especially complex example) and the appeal to transcendence (whereby life is the gift of some higher truth or power).

Bernard’s process vitalism, as expounded by Turner, simply maintains that life is the process of an internal dynamic disequilibrium that persistently seeks out means for its own maintenance. This claim makes no assumptions about any God or gods or any soul or other special life elements or forces. It is just a self-maintaining process that includes the capacity to seek out its own maintenance and flourishing. Here Turner undertakes some more careful definitions to use the term “cognition” as his name for life’s capacity to seek out its own good. Turner says that cognition must include purpose, desire, and even some form of self-awareness but not self-awareness that would rise to the level of self-consciousness. As Turner distinguishes “cognition sharply from consciousness,” he says:

I feel compelled to do so because the two are often conflated, with the result that neither can be spoken of sensibly. While the two arguably are related to one another, cognition is relatively straightforward compared with consciousness, which is deep, perhaps unfathomably so. It’s clarity I’m aiming for here, not profundity, and conflating the two only muddies the waters. …It’s probably unreasonable to speak, as some of the more far-out advocates of Gaia theory sometimes do, of the Earth’s “global consciousness”; but it’s not so unreasonable to speak of there being a “global cognition.” (181, 221)

This reference to a “global cognition” and to Gaia theory brings us to what I found to be the most interesting aspect of the book: Turner’s best guess as to the way in which life originated on our planet.

Much of the book is taken up by fairly demanding examinations (considering its lay audience) of the most recent theories about the origins of the first living cells on earth. This includes a tour of the fascinating proposal by Lynn Margulis (1938–2011), called the serial endosymbiosis theory, which suggests that the eukaryotic cell emerged from a series of symbiotic associations and cell mergers between various types of prokaryotic ancestors. Turner takes us earlier than this, however, to the first possible moments when the simplest elements of the prokaryotic cells could have come to be. As Turner works through the many theories proposed for the assembly of the first cellular structures (including a fascinating one involving clay crystals), he says that we must tend to get one of two interrelated capacities ahead of the other. What might be achieved first, the ability for metabolism (as with the release of energy from sulfur reactions) or the ability for hereditary memory (as with gene structures)? Turner inclines toward the metabolism-first camp (229) but considers all of the proposed options at some length, including those that suggest ways for both capacities to have shown up in sync.

All of these theories, however, continue to flounder against truly imponderable odds when imagined as playing out within any known conditions on planet earth. Here, Turner asks a question:

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. 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. 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. (252)

This was not a portion of the book that I was entirely able to follow. However, Turner evidently considers it most likely that the dynamics of homeostasis arose on a planetary scale first and that this intentionality or capacity to seek after “persistent dynamic disequilibrium” showed up on planet earth as simple thermodynamic processes that were more complex than the standard weather patterns induced by sunlight and that took on the characteristics of homeostasis, that is to seek after the preservation of this complexity (252-256). As I noted, I’m not able to follow the details of Turner’s connections at this point, but this intentional pursuit that came with planetary homeostasis, caused the earth’s thermodynamic patterns to literally desire and pursue conditions that were unusually favorable to the eventual rise of micro instances of homeostasis—i.e. to the advent of early celular life which then would itself begin to experience the basic cognitive realities of pursuing its own growth. If all of this sounds like a wild ride, it is. Turner is striving to define terms that would allow all biologists to speak comfortably of our planet gaining the capacity to desire and to pursue its own life before even the first cellular structures took shape. Then, once cellular structures did take shape, Turner is arguing that the process of homeostasis for them also means experiencing a desire for their own flourishing—now on a micro scale but that would continue to play into the preexistent desires of our living planet on a macro scale. All of this is language that, despite its intense connotations, is grounded in observable processes and need not suggest the existence of any God, gods, demiurges, souls, or other vital forces.

This grand summary in my own words certainly has not done any justice to Turner, but I have some hope that it is, at least, accurate as a broad outline. Before concluding, however, I want to make one final comment on motives. Why does Turner go to all of this effort with regard to these elaborate and heterodox claims near the end of his successful career as a biologist? In his preface, he alludes to the suspicion on the part of one critic that he holds such ideas simply because he himself is a theist:

He had gone on to demand that I should have made known my religious beliefs (I’m a Christian, if that matters, albeit not a very good one). This struck me as strange, even a tad illiberal. (x)

Turner insists that his case is not motivated by his faith. Instead, he gives a frank account of the motivation that is behind his work. However, he does this in full only at the very end of the book, which I found to be a frustration because he had hinted repeatedly at “biology’s impending crisis” many times throughout the book. It was some relief when he finally explained what he meant by this:

True enough, the enterprise of science continues to enjoy generous funding, support, and prestige. Biology makes dazzling advances almost daily in new products and therapies. It continues to challenge our views of our world, ourselves, and our society. So where’s the crisis? Why change? Here is my claim for why. Science is first and foremost a cultural phenomenon. …The crisis for biology right now is one of alienation: of the alienation of the science of life from life itself, but more alarmingly, of the alienation of science from the broader culture. Evolution has been the touchpoint for this alienation for a very long time. It would be nice if it could be resolved. (293)

Turner tells several stories highlighting this alienation where biology, the science of life, testifies not at all to the uniqueness and the purposefulness of life. Turner considers this cultural fracture a tragedy and believes that this will only grow worse with time. His book is offered as a source of hope:

The crisis will be averted …when biology becomes reenchanted. How, or even whether, this happens is anybody’s guess, but my candidate for the reenchanting of biology is Claude Bernard’s dangerous idea: homeostasis, the relentless striving of living systems for persistence and self-sustenance. Properly understood, homeostasis is life’s fundamental property, what distinguishes it from nonlife. In short, homeostasis is life. (292)

There can be no question about Turner’s own love for science and for the theory of evolution, specifically. For him, it is an endlessly fascinating and beautiful set of ideas and questions. In all of his assessments of various scientists across the centuries, he repeatedly insists on the various insights embedded within each approach from every direction within the disputes. He also notes, moreover, how many of these past insights have been lost to us given the limitations of later prejudices. This in no way clouds his enthusiasm for even the most recent and strictly mechanistic models of life and evolution, however. About halfway through the book, he uses the metaphor of half-court basketball to describe how he feels watching biologists work within the confines of a strictly mechanistic and purposeless understanding of life:

LeBron James will play brilliant basketball whether he is playing full-court or half-court: he will just play brilliantly within different bounds. That is largely the case for the post-Weismann epistemic closure of evolutionism. There is much brilliance in there to appreciate, but the appreciation must be tempered by the realization that we are now watching half-court basketball. (125-126)

Turner is not suggesting any change in the focused methodologies of modern science, but he is suggesting that biology would grow to be deeply in touch with human culture as well as expansive in its own vision and theorizing were it to embrace the idea that life is a distinctive process, unlike any other in its capacity for purposefulness and desire.

Clearly, this is not the book that is likely to persuade most scientists at a technical level. Turner’s earlier works likely offered more in this regard. This book is the direct and unguarded thoughts of a biologist at the end of a distinguished career who is sharing his own deepest hopes for his culture and his profession. It is colloquial and even quaint. For my part, I loved his playful style and his use of phrases like “the narrative with which modern biology prinks itself.” However, more skeptical readers will no doubt grow tired of the familiarity: “So, allow me to be the Virgil to your Dante, for there is a surprising conclusion about memory awaiting us at the threads’ terminus.”

Speaking of Dante, as a humanities and theology person myself, I was a little disappointed by Turner’s lack of connection to much at all outside of science. He mentions Aristotle positively with the briefest of passing remarks: “Would biology sit more comfortably with Aristotle? That [is] likely, as a clear thread still connects Aristotle’s notions of internal strivings with medicine, physiology, and embryology” (259). This is the book’s only positive example, however, when it comes to any schools of ancient wisdom. Of Plato, Turner writes that “the old coot keeps sneaking in through the back door” (281). Pythagoras is accused of obscuring the truth behind “the glittering curtains of a mathematical mystery cult” (279). There is the slightest hint that Turner may have more respect for Plato as he refers twice to a “nagging crypto-Platonism” (281, 288) in modern science, leaving room for there to be some value in true Platonism (although Turner never comments on this one way or the other).

Despite my own minor disappointments in such areas, it is no surprise that I loved the book and found it to be a fascinating example of how science and everyday human culture might be reconciled within a reinvigorated relationship that would be friendly and inspiring to the professional scientist as well as to the religious and the irreligious layperson in our contemporary world. Of course, I was already fully convinced of all the book’s most basic proposals for reasons entirely outside of science. To be honest, reading the wise words of a benevolent dog had already convinced me of all this and more:

It makes better sense to believe with Aristotle that there’s a mind-like rational order within nature that moves toward certain possible resolutions of evolutionary imperatives and constraints like a stream of rational thought solving problems in light of the conclusion being sought. So, yes, yes indeed, it’s far more beautiful and reasonable to see that mind indwells all things, and that life is the primordial truth of things, and that everything is alive, is luminous, shines with spirit. Divine mind, divine Sophia, the world soul in all. (Roland in Moonlight by David Bentley Hart, 185)

I learned about Turner through a comment on David Bentley Hart’s June 18 subscription newsletter essay entitled “A Politics of Life.” Someone asked in the comment if Hart would consider natural processes to be “constantly redirected by formal and final causalities that simply cannot be predicted.” Hart answered:

Oh, goodness, what a complex question. But, yes, once one rejects pure mechanism and allows for the reality of intentionality even within organic nature—and one should—many things become more coherent. I think that, for instance, Evan Thompson, Terrence Deacon, and J. Scott Turner are all good examples of thinkers who have fruitfully rethought evolutionary theory in just such post-mechanistic terms. I think only the third is free from a lingering emergentist view of consciousness, but that’s another matter. And I think the present state of physics has for a long time been irreconcilable with the mechanist prejudice.

For my part, already sold on all of this, I was delighted just to learn some details of how a genial and successful biologist such as Turner still exists who can love both evolutionary theory and the irreducible distinctiveness of life. I’m grateful to have read Turner’s plea for a science of life that could break free from the mechanist prejudice and find greater ways to strive and to flourish and, even occasionally, to frolic with the rest of human culture.

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Post Script

An astute reader in another forum asked this excellent question, and it clarified some of my own remaining questions: “What confuses me is that Hart praises this unreservedly. But it is emergentist, which is one of his greatest foes.”

Here is my initial reply to this question: Yes, I’m still trying to puzzle this out myself. Hart speaks of how critical it is that science ‘allows for the reality of intentionality even within organic nature.’ Turner certainly does that. Then Hart is speaking only of Turner when he says: ‘only the third is free from a lingering emergentist view of consciousness.’ However, Turner clearly speaks of an emerging cognitive experience of life on earth. The resolution might be in two areas.

• First, Turner is clearly maintaining that science can only study life as an organic phenomenon or process that emerges (which is obviously true), but Turner is not necessarily insisting that life is only an organic process. Turner allows for the fact that life might also be a metaphysical reality but insists that it only shows up as organic life (subject to science) within the process of homeostasis.
• Second, Turner insists that organic life can only be studied in terms of cognition and not consciousness (which Turner calls deeply mysterious and is evidently placing outside the realm of what biology can address). Perhaps Turner’s second book with Harvard, The Tinkerer’s Accomplice: How Design Emerges from Life Itself, might set these boundaries out more clearly? It is not entirely obvious to me from Purpose and Desire, but I suspect that Turner is allowing for the idea that organic life (i.e. homeostasis) participates in a transcendental or metaphysical life and consciousness while also being clear that this is a question that science cannot address.

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