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The Inevitability of Intelligent Life?

Thus far, 2018 has been a terrific year for popular science books and two stand out in particular for confronting head-on some of the biggest and most difficult questions scientists confront. In his new masterpiece, The Equations of Life: How Physics Shapes Evolution, biophysicist Charles S. Cockell wades with admirable fortitude into the waters of how the laws of physics and mathematics place constraints—and find solutions—to the great challenges of survival. How inevitable was it that life would land on DNA as the repository of genetic information? Why have the vast majority of species settled on two biological sexes? What’s so special about phospholipids that all living cells use them for their membranes? How do ladybugs regulate their temperature? These are just a few of the incredibly complicated biological questions that actually have quite simple mathematical answers, as Cockell demonstrates.

Biologist Kenneth R. Miller tackles questions no smaller than the human intellect itself in his fourth book, The Human Instinct: How We Evolved to Have Reason, Consciousness, and Free Will. In it, Miller gives a brief but comprehensive summary of the most important scientific and philosophical work aimed at explaining if and how humans have a true and autonomous inner self. As Miller astutely acknowledges, even the language we use to address this question—words like autonomy, individual, thought, perception, intention, awareness, and conscience—cannot be taken for granted. If these words are to have any meaning whatsoever, that meaning must be created in the very instrument they are meant to describe, the human mind. It is not difficult to tie oneself into rhetorical knots while attempting to discuss the nature of consciousness, yet Miller nimbly walks us through the minefield.

If The Equations of Life attempts to provide simple answers to complicated questions, The Human Instinct does the opposite, helping us see just how complicated these questions really are and how divergent the answers could be. These books pair together perfectly because they both strike blows against the prevailing notion that human beings are the most unlikely of species. As Cockell explains, “there is nothing uncanny about life’s ability to land on the same solutions.” While anyone with basic knowledge of biology is aware of the many examples of convergent evolution, Cockell seasons those examples by deriving the mathematical relationships that underlie the convergence. Even if things like building a cell, storing genetic information, and swarming towards food might be easily reduced to physical forces, surely reason and consciousness are in a different realm altogether. Hardly, says Miller. Channeling the eminent paleontologist Simon Conway Morris, among others, Miller aggressively defends the claim that, “It is possible, perhaps even likely, that the appearance of humanlike intelligence is part of the deep structure of nature probed again and again by the evolutionary process.”

Life’s Equations

In The Equations of Life, Cockell introduces us to a unique pedagogical exercise that he has utilized for many years at the University of Edinburgh. Each semester, he challenges teams of students to explore biological processes or life forms and derive the physical equations that underpin them. Of course, he brings his own expertise to the exercise as he and his students unite the fields of classical physics and modern biology. His fascinating book is the result of many years of engaging students in this way. This should serve as inspiration to all of us in the academy charged with not only teaching science, but encouraging students to appreciate science and what it can and should do for our society.

The striking unity of life has long been considered to be one of the most compelling arguments for common ancestry, and for good reason. Cells could have utilized any number of molecules to store genetic information. What are the odds that all life would have ended up with DNA for our genes if we hadn’t inherited it from a common ancestor? Our basic biochemical energy metabolism, with pyruvate, glucose, and glutathione in such crucial positions, seems incredibly arbitrary. Why would these pathways be so strictly conserved were all living cells not related to one another?

The evolutionary biologist Stephen Jay Gould proposed that if we were to rewind the tape of history and then let it run again, life would play out on earth differently every time and the organisms we’d find would be unrecognizable to us today. Cockell skeptically concludes the opposite. From phospholipid membranes that solve “the problem of dilution” to pyruvate as the central node of biochemical energy conversions, the solutions life came up with are anything but arbitrary. Like an electron settling into its lowest energy state, the trillions upon trillions of cells on earth toyed around with all feasible solutions to life’s great challenges. Pyruvate wasn’t an arbitrary choice. If we replayed the tape, we’d almost certainly end up with pyruvate again.

Far from undercutting the unity of life, our common physics binds us together even more tightly. For example, the genesis of spots, whether on ladybugs, leopards, or Dalmatians, follows a very simple equation involving just two physical factors, pigments and inhibitors. This equation operates independently of the precise molecular mechanisms, which are of course quite different in those three animals. As Cockell explains, the pigment-inhibitor gradient phenomenon is a Turing pattern. From striking simplicity springs breathtaking complexity requiring little more than overlapping gradients. Whether those gradients are made of molecules, organisms, weather fronts, or solar systems, we get spots, vegetation patterns, storms, or the spiral arms of galaxies.

Cockell does not limit his interrogation to why things are, but also why some things aren’t. For example, the wheel is a human invention that made so much physical and mathematical sense that it transformed every culture it touched. So why didn’t life come up with a wheel with all its many advantages over other means of locomotion? As Cockell explains, it has! The bacterial flagellum turns very much like an axle and crankshaft, with all the efficiency those innovations bring. However, that efficiency breaks down rapidly when brought to larger scales as gravity takes over for buoyancy as the dominant force. When eukaryotic cells, hundreds of times larger than prokaryotic ones, developed their own flagellum, there is a reason they opted to extend and flex their cytoskeleton rather than employing the crankshaft design. Each type of flagellum does well for its scale. Also, as Cockell also reminds us, wheels are only useful if you first pave smooth surfaces for them to run on.

Instinctively Human

Roads and wheels did emerge on earth but they required human ingenuity to emerge first. In The Human Instinct, we turn our gaze inward and ask how humanity could have evolved such remarkable intellectual capacities. As one who often writes about the continuity of human and animal minds, this book was a great reminder for me of the truly stunning leaps our species has made. Miller takes us through a tour of recent research on the uniqueness of human nature, and does so humbly and with an objective distance that makes it sometimes hard to know what his own position is. I recently sat on a panel with Miller at the Boston Public Library on the evolution of human nature. When challenged on his claims of human exceptionalism, Miller conceded, quoting Henry Gee from The Accidental Species, “It’s easy to come in first when we’re the one awarding the prizes.”

But, humans are indeed unique if for no other reason than the fact that we can think about our uniqueness. No other species can do that, even those we have exhaustively taught to communicate through sign language. The contemplation and introspection that Carl Sagan famously referred to as “a way for the cosmos to know itself,” cannot simply be dismissed as anthropocentric self-congratulation. Miller elegantly expands upon this point by reminding us that, on the evolutionary tree of life, “one branch, and one alone, produced a creature with the potential… to reconstruct the very tree of which it is a part.”

Miller goes beyond musing about whether or not we are special and asks if we are improbable, as so many have said we are. While Gould insisted that it’s hard to imagine anything like Homo sapiens emerging even if we “replay the tape a million times,” Miller asks more poignantly whether something as intelligent as us would emerge, even if we didn’t. He makes a very strong case that something would.

Self-awareness, as defined by versions of the mirror test, has been documented in countless species, as has rudimentary metacognition. Many lineages have evolved perspective-taking and empathy, and many use true referential communication using sounds or gestures, in what is clearly the beginning of language. It appears that some animals really are aware of their own mental contents and that of others. Consider how long multicellularity took to emerge after cells first appeared on earth: 2.5 billion years. Now consider that vertebrates with a true brain have existed for only one-fifth of that time and yet, here we are. Clearly, the jump from one cell to many cells was more improbable than the jump from no brain at all to the discovery of relativity theory. Human beings have been on a unique evolutionary path, distinct from other extant apes, for a mere 7 millions years. That seems to have been plenty of time for hominids such as Barbara McClintock and Neil de Grasse Tyson to evolve from otherwise run-of-the-mill primates. Quoting Robert Wright, Miller implores the likes of Gould and Gee to “have some patience.”

The Human Instinct opens with a concise but erudite defense of evolution, that is, the scientific claim that Homo sapiens evolved from ape ancestors over the last few million years. Miller has no doubt honed his airtight arguments through years of sparring with creationists since the Dover, PA “intelligent design trial,” at which he was a key witness. In the final chapters, however, Miller courageously takes on the subject of free will and determinism. Understandably, Miller’s writing posture is a defensive one in these sections, as he is fully aware that the notion of free will is currently facing considerable headwinds among scientists. Nevertheless, Miller argues that the claim that our universe and the common human experience is fully deterministic undermines the scientific process itself and implies that all the great strides we’ve made to examine, probe, and describe our universe were pre-destined, as was the rejection of scientific evidence by too many. Like Stephen Hawking before him, Miller finds this conclusion not only incongruous but self-defeating.

Lessons from Science on Inevitability

One important lesson taught equally by The Equations of Life and The Human Instinct is that when you have billions of years and trillions of trials, fantastically unlikely events become not just possible, but inevitable. For so long, popular science writing has underscored the assumption that life is ultimately improbable and that human beings are the most unlikely creatures of all. Maybe not. Though they would seem to hail from separate magisteria, as it were, both of these books come to the rather surprising conclusion that life and humanity, as we know them, may not be so implausible after all. Many of the strange quirks of our world really aren’t so strange.

A common trope in science fiction is to depict extraterrestrial sentient life as basically humanoid, right down to two eyes, ten fingers, and one narrow tube for eating and breathing. Many of the aliens encountered by the various incarnations of the USS Enterprise can even interbreed. Mr. Spock, arguably the first extraterrestrial that Western culture became intimately familiar with, was just such a hybrid. Here on 21st century earth, contrarian scientists like myself reliably (and pedantically) respond that life on other planets would likely have evolved to be radically different, possibly to the point of being incomprehensible to us. Everything we find familiar is arbitrary, we would say, and life on other planets could be altogether unrecognizable to our subjective sensibilities.

Cockell and Miller teach us that, in fact, if we ever encounter extraterrestrials, they might not be so different than the life forms we find familiar here on earth. The common animal body plan—meaning eyes, paired limbs, guts with polarity and unidirectional flow, and sensory-perception cephalization at one end of the body—is so advantageous that multicellular creatures are likely to evolve that way anywhere, just as they have multiple times here on earth. And as long as eating, surviving, and reproducing are important to a species, selecting for advanced cognition seems inevitable as well.

Science fictions writers may be correct after all. Extraterrestrial life may be strikingly similar to terrestrial life. In fact, I would further argue that alien species are sure to have their own versions of the quirks and flaws that I describe in my book Human Errors. Cockell even takes down the Horta, one of the few examples of truly “alien” life from the original Star Trek series, featured in the episode “Devil in the Dark,” one of the best stories from that era. The Horta are a species whose chemistry is based on silicon instead of carbon. However, as similar to carbon as silicon is, the covalent bonds it forms are weaker, making impossible the kinds of large complex biomolecules necessary for cellular life.

Similarly, Miller argues that the mental abilities we know as human reasoning are also not arbitrary, or at least, they are no more arbitrary than mathematics itself. Humans didn’t invent arithmetic, algebra, trigonometry, or even calculus. We discovered them. While the scientific method is a purely human endeavor, at least on earth, it does not follow that science is a construct the way that literature or the arts are constructs.

We know that science is more than just a human invention because it works independently of us. Certain principles are elevated as “logic” because they are objectively unassailable. There cannot be a world, at least not in this universe, where a species evolves to understand that two plus two is five. As Cockell demonstrates, from something as simple as two plus two can emerge the forces that propel a dolphin through the water or a naked mole-rat through the earth. It can hardly be any other way. And creatures that learn to carefully observe their surroundings will one day attempt to understand them. How else will they test their understanding but by making predictions and testing them through observation?

If his goal is to show how the beauty and complexity of life spring from the logic and simplicity of math, Cockell succeeds enormously. If you agree with Miller, as I do, that science is the ultimate expression of human reason, logic, and curiosity, you will find The Human Instinct and The Equations of Life to be scholarly, delightful, and utterly satisfying. Perhaps they were pre-determined to be so by the laws of physics.

About the Author

Nathan H. Lents is professor of biology at John Jay College, CUNY, and the author of Not So Different: Finding Human Nature in Animals and Human Errors: A Panorama of Our Glitches, From Pointless Bones to Broken Genes. He also maintains The Human Evolution Blog.

This article was published on September 11, 2018.


15 responses to “The Inevitability of Intelligent Life?”

  1. Paul Topping says:

    Mathew Goldstein: “That our behavior is fixed does not interfere with our ability to evaluate when behavior is harmful or destructive and to appropriately react accordingly.”

    Many would say that you have just described everyday free will. If we are able to consider and react, then we have free will. Even if determinism is true, we have no access to what is determined. I think physicist Sean Carroll has it right. Determinism and everyday free will are at different levels of description and human discourse.

  2. Joe says:

    Been trying to post the following message for a couple days but, for reasons unknown, it isn’t posting. I’d included 9 websites to support what I’d written. Perhaps the site monitor here won’t allow links to other sites? Or doesn’t wish to permit me the choice of adding them to my response?

    I’ll try to send them in a separate response and see if that will work. Meanwhile here is my response stripped of the links, and we’ll see if it posts:

    Appeals to authority are fine, so far as they go, but what to do when other authorities disagree with your authorities? In addition to Kenneth Miller (one of the authors reviewed above), many others are finding fault with the notion that free will does not exist in humans. Clearly, there is yet much we do not know about human existence, and absolute declarations about matters such as free will are premature.

    (9 links were listed here originally.)

    Read any or all of these as you freely choose. Or maybe you’ll have no choice in the matter?

    As far as involvement of the supernatural, I’m not so sure of the necessity or not of that. First, we’d have to define what exactly we mean by “natural” and then “supernatural”. As with human existence, I believe we still have much to learn about the “natural” world and beyond.

  3. Mathew Goldstein says:

    Lots of neuroscientists and biologists consider free will to be counter-evidenced and improbable. Conscious cognition, regardless of quantity and duration, does not suffice to demonstrate free will. There is probably no way to get to free will from any combination of determinism and stochasticism, free-will appears to require supernaturalism. Someone wrote a book claiming that life surfs the expansion of the universe in a way that grants life free-will, but I have not heard that his argument is persuasive to other cosmologists.

  4. Joe says:

    Mathew Goldstein, thank you for the explanation. Someone I was discussing this matter with a while back cited the same or similar experiment with electrodes monitoring brain activity. I’m sorry to say that I found both your explanation and his unconvincing.

    Who’s to say that the delay between response in the brain and action isn’t simply recording the lag time between brain activity and body activity? Could it be that brain activity occurs merely from weighing the option to move the finger, before the decision to move the finger is actually finalized and the finger itself is moved?

    What (or who) initiates the activity within the sector of the brain prior to the movement occurring?

    If I’m told to move a finger but stop moving the finger when I hear a tone, what (or who) is determining that my finger will move until a tone is sounded? Is it the tone that decides to stop my finger moving or is it the person moving the finger who determines that they will stop upon hearing the tone?

    I can pretty much guarantee that were I given such a test and prior to its administration I wrote on a piece of paper that I would only stop moving my finger on every third tone, my finger would continue moving on tone #1 and tone #2 and I would stop the movement on tone #3. BUT it is entirely possible (or I wouldn’t be at all surprised) that the area of my brain responsible for finger movement and stopping would be active during tones #1 & 2 due to the nature of the experiment.

    I am skeptical of drawing any conclusions about free will or consciousness based simply on whether electrodes indicate activity in a particular region of the brain.

    Even you seem a little uncertain in your last line: “Therefore, the generation of awareness occurred afterwards, or in parallel, to action, and it was probably not the cause of the movement.” as to the “probable” cause of the movement.

  5. Mathew Goldstein says:

    Experiments show that decisions to act precede self-awareness of the decision.

    For example, a particular pattern of neural activity that can be monitored by placing electrodes on the scalp and amplifying the signal will correspond with a decision to make a particular movement a finger. Individuals are told to ocassionally so move their finger but stop moving their finger whenever they hear a tone. The electrodes showed that the intent to move started about 2.8 seconds in advance of the movement. Movement halted when the tone occurred at least 0.1 before the movement but not more than about 1.8 seconds before. The initial one second gap during which the tone did not stop the finger movement corresponds to the time when the decision to move remained unconscious. Therefore, the generation of awareness occurred afterwards, or in parallel, to action, and it was probably not the cause of the movement.

  6. Joe says:

    Herb Van Fleet, thank you for taking the time to respond and for your attempt at clarifying this point. I understand that I stand atop the various histories (biological, social, environmental, etc.) that preceded me and that they have shaped who I am now, today. I likewise understand that I had no choice in any of that but have inherited it, just as I’ve inherited my eyes or hair or predisposition for various diseases from my ancestors.

    I find it odd that neither you nor Mathew Goldstein deals directly with the example I gave of deciding which route to take to my destination “B” after leaving point “A”. Or put another way, my genetic history determined my hair color and type (brown, wavy). But today, if I choose, I can change my hair color to blonde and texture to straight. Sam Harris notwithstanding, I can decide whether I will decide to do that or choose any other color. What I don’t understand is how that decision has anything to do with any of my histories or how such a decision can be considered predetermined.

  7. Joe says:

    Mathew Goldstein, while I appreciate your responding I cannot say that your responses are offering greater clarity rather than more obscurity.

    If I may slightly paraphrase what I understand you to have written: Our behavior is fixed, but we can evaluate our behavior for the harm it represents and change our behavior (“appropriately react accordingly”). It seems to me that if I can and do change my harmful behaviors then I’m exercising my will . . . freely.

  8. Herb Van Fleet says:

    Joe, consider that each of us are the sum of our histories – our genes having come from our ancestors all the way back to the first forms of life. So we come into this world with a lot of history already made an inherent part of our selves; a history over which we had no choice. As we mature from infants to children to adults to old age, our exposure to, and our perception and processing of the external environment, adds to that history, along with any infirmities or accidents we may have along the way. We are each unique. Thus, free will is not free, it is irrevocably tied to our history; i.e., to a series of causes and effects. As Sam Harris writes in his book “Free Will,” “You can do what you decide to do, but you cannot decide what you will decide to do.”

  9. Mathew Goldstein says:

    What we are discussing is descriptive, not prescriptive. That our behavior is fixed does not interfere with our ability to evaluate when behavior is harmful or destructive and to appropriately react accordingly.

  10. Joe says:

    Mathew Goldstein, if you were responding to me, I appreciate it and thank you. However, your response, I’m afraid, has gone no further to enlighten me.

    I understand that among many scientists current thinking today suggests that “free will is inconsistent with the known laws of science and thus probably false.”
    I’m not sure which known laws of science you are referring to, and beyond telling me that my “self-perception could be misleading”, I’m not sure why my changing my mind on a course of travel is not some indication of free will (or why an adulterer ought to be given a pass on his/her adultery since: “Babe, I got no free will; I just had to do it.”
    If you’d care to expand on your earlier answer, I’d be grateful.

  11. Mathew Goldstein says:

    Yes, we are saying that free will is inconsistent with the known laws of science and thus probably false. Our decisions are made mechanically, biology has no ability to give us a supernatural free will capability. While attempting to defend free-will you are telling us a story that your mind is generating about yourself. Our self-perception of our having self-agency is not particularly good evidence for free -will, that self-perception could be misleading.

    Actions should be evaluated as better or worse, as proper or improper, etc., on a basis of benefit and harm. Actions should not be evalulated by supernatural agency because we do not have such agency.

  12. Joe says:

    Try as I might, either due to lack of sufficient education or intellectual capacity, I cannot follow the argument that there is no free will and all my actions are predetermined. Somehow, the fact that stimulating regions of the brain of patients undergoing “awake brain surgery” does not seem to translate to “real world” (i.e., non-awake brain surgery) experience.

    The other day I decided (or so I thought) to walk from home to a store 8 blocks east and 6 blocks north. Numerous possible routes were afforded me, from a more straightforward one to a more zig-zag one. At one point, heading east, I’d passed a street by half a block when I remembered that that street offered more shade and it was a hot day. I stood for a moment debating whether it was worth it to back track and take the shadier route or simply continue another half block east and then turn north. Are the non-free will people saying that I had no choice then, that my hesitation, internal debate, and eventual decision were already predetermined?

    If that’s so, don’t cheating spouses now have the ultimate excuse: “Honey, there was nothing I could do; it was predetermined that I would cheat.”?

  13. Mathew Goldstein says:

    Stephen Hawking and Leonard Mlodinow, The Grand Design, Bantam Books, New York, 2010, p. 32.

    “Though we feel that we can choose what we do, our understanding of the molecular basis of biology shows that biological processes are governed by the laws of physics and chemistry and therefore are as determined as the orbits of the planets. Recent experiments in neuroscience support the view that it is our physical brain, following the known laws of science, that determines our actions, and not some agency that exists outside those laws. For example, a study of patients undergoing awake brain surgery found that by electrically stimulating the appropriate regions of the brain, one could create in the patient the desire to move the hand, arm, or foot, or to move the lips and talk. It is hard to imagine how free will can operate if our behavior is determined by physical law, so it seems that we are no more than biological machines and that free will is just an illusion.”

  14. Herb Van Fleet says:

    I have not read either of the books discussed above. And I’m not a scientist or a mathematician or an engineer. In fact, I flunked organic chemistry. I say all that so that the reader can consider my comments accordingly.

    I get from the above review that Drs. Miller and Cockell have each have taken complimentary approaches to making sense of the chemical and biological soup that can be used to explain the origins of life and its evolution. But I respectfully take issue with some of the premises as described above.

    Some time ago I wrote and published a paper titled, “SETI’s Mission Impossible” in which I argue that the complexity of any extraterrestrial life form that could evolve to the point that it could produce radio signals which could then be detected by radio telescopes on Earth is virtually impossible. (The SETI project defines “intelligence” as radio waves since they are the only signals we can detect. The screech of an extraterrestrial chimpanzee would not be loud enough for us to hear.)

    Using human beings as a proxy, I have challenged the famous Drake Equation commonly used to estimate the likelihood of civilizations on other planets with capabilities similar to ours. As opposed to the Drake Equation’s seven variables, I’ve identified 57, but use only 40, which are assumed to be sequential and thereby calculable as a factorial. The end result for succession of these 40 conditions in order for life like ours to exist on another planet would be 40!, which is 8.1647. That is to say, the chances of another alien civilization like ours is a little under one in 8.16 trillion, trillion, trillion, trillion. So, clearly, the Search for Extraterrestrial Intelligence, where intelligence is defined as having human-like characteristics is all but impossible. It’s like throwing a deck of cards in the air, remembering their arrangement after they fall, and then trying to duplicate that same arrangement with that same deck.

    But that is not to say that extraterrestrial life is impossible. On the contrary, I believe the universe is crawling (so to speak) with all kinds of critters and plants, large and small, single cell or multicellular – we could call them extremophiles. But the probability of any extraterrestrial having the capability of transmitting radio signals is close to zero.

  15. Mathew Goldstein says:

    “Miller argues that the claim that our universe and the common human experience is fully deterministic undermines the scientific process itself and implies that all the great strides we’ve made to examine, probe, and describe our universe were pre-destined, as was the rejection of scientific evidence by too many. Like Stephen Hawking before him, Miller finds this conclusion not only incongruous but self-defeating.”

    Agreed, predestination undermines or self-defeats the opposing, free-will based conclusions. If this assertion is intended as an argument for free-will then it is a misdirected, irrelevant, argument. The only valid basis for favoring one conclusion over the other is best fit with the available empirical evidence, not best fit with personal, a-priori, gut feeling, preferences.

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