The Brain Evolved!... Didn’t It? 11/09/2007 Evolutionary neurologists are so absolutely sure the human brain is a product of evolution from lower primates over millions of years, they are able to talk openly and frankly about problems with the particulars. But in reading some of their own reviews of current ideas, it is not clear which has been evolving: the brain or evolutionary theory itself. Here are a few recent cases where Darwinian boldness and anxiety exhibit a kind of left-brain, right-brain split.
Disappointed Darwinist: A book review this month in Psychiatry Online, a publication of the American Psychiatric Association, is our first split-brain case study in theoretical Darwinism. Lewis A. Opler reviewed The Evolving Brain: The Known and the Unknown by R. Grant Steen. To begin with, he cheered Steen’s knockout blow to the contender, intelligent design:
The author of this book, a neurophysiologist in the field of psychiatry, has superbly described breakthroughs in basic neurobiology, debunked “intelligent design,” and both argued and demonstrated the need for cross-disciplinary collaboration to address issues such as consciousness, creativity, and self-knowledge.
Nevertheless, when it came to explaining brain evolution, Opler came away hungry:
Paradoxically, given its title, the only area that I felt was not handled expertly was in its handling of how and why evolution had chosen us—Homo sapiens, with our large prefrontal cortex and our increased plasticity and capacity for learning and communicating—to be the rulers of planet Earth. Possible answers include intelligence, language, communication, theory of the mind, and activation of pleasure circuitry because of affiliative behavior—all lead to collaboration and sociality of our species. But what external changes emerged 50,000 years ago allowing this to give us a selective advantage?Evolutionary theory itself has evolved, and this is not addressed. Specifically, whereas early models suggest that individual traits gradually take over because of their conferring an increased chance of procreating by their host, punctuated equilibrium argues convincingly that speciation confers stability, with new species emerging only when external factors throw ecosystems into disequilibrium. A clear example of this, supported by the fossil and geographic record, is the sudden end of the dinosaurs after a meteor hit Earth rendering it uninhabitable by dinosaurs and giving mammals a selective advantage. So what factors gave us, the intelligent afilliative communicator, a leg up? Did a planet lacking an adequate food supply select us because we, by virtue of our ability to collaborate, could hunt in tribes and follow game, as well as develop societies where agriculture and breeding of other animals could occur? I do not know. But I had hoped that Dr. Steen’s book about the evolving brain would answer such questions.
At the end of the review, the contrast could not be more stark: “Steen unequivocally delivers a slam-dunk victory for evolution over intelligent design. But I kept waiting for cutting-edge neurobiology and psychology to meet cutting-edge evolutionary theory, and this did not occur.” Opler joked that “if great science is revolutionary, it follows that good science should be at least subversive—the book is at least subversive” [selah]. What would Opler think of the recent development that his clearest example of disequilibrium producing punctuated change—the death of the dinosaurs by a meteor—is now being seriously challenged? (10/31/2007, bullet 6). That might subvert the revolution itself.
The ancient brain: A glaring Toumai skull (04/14/2005) decorated two book reviews in Nature earlier this month.1 Dean Falk was so confident of evolution she did not mention any non-materialistic alternatives except as historical anecdotes; nevertheless, both her reviews contained ample seeds of doubt. Falk was sure that On Deep History and the Brain, by Daniel Lord Smail, had rendered creationist stories to the dustbin of intellectual history:
He first describes how the discovery and implications of deep time2 by geologists, biologists and naturalists in the mid-nineteenth century were the undoing of the sacred idea that humankind began relatively recently in the Garden of Eden. Historians then shifted from a sacred to a secular beginning – the rise of civilization in Mesopotamia. Thus, laments Smail, the Palaeolithic continued to receive short shrift and still needed to be ‘historicized’. After all, humans who did not keep records still had a past. He has a point.
But how would we, today, know that humans who did not keep records existed? This could seem like proposing that the space aliens who once lived on earth, but did not keep records, still had a past. Would that have a point? A past must be demonstrated with some kind of evidence, not merely asserted. Was Smail able to historicize a missing record, to bring a lost history into our cognizance? What data would he use?
Smail examines the rupture that continues to separate prehistory from recorded history, together with the historiographical, epistemological and theoretical obstacles that have kept them apart. He explores the importance of biology in shaping cultural evolution, offering an interesting take on the nature/nurture dichotomy with his suggestion that lamarckian mechanisms displaced darwinian ones when human culture started to develop.
This sounds like a mere suggestion, and a controversial one at that. As if lamarckism were any help, it seems additionally unhelpful that Smail next proceeded to debunk evolutionary psychology. Then, he offered only alternatives that “may” have explained evolution: “Palaeolithic societies, for example, may have developed a range of mood-altering practices such as song, dance, ritual, and ingestion of mind-enhancing substances.” Maybe humans expanded their minds with drugs, in other words. Students may like this suggestion, but it may not sit well with their parents. But if our ancestors developed these practices, and by this point possessed the physical equipment for intelligence, could not these practices be considered a form of “intelligent design” that evolutionary theory somehow snuck under the radar? Where did it come from? Falk did not explore this paradox, but was disappointed that the book provided so little hard evidence for brain evolution: “Although this is an enjoyable and creative book, it is not quite what I expected,” she said. “There are no endocasts or sulcal patterns here, no Brodmann’s area 10, or debates on brain size versus cortical reorganization (although Hobbits receive a brief mention).” Its value was only in its “suggestion” that “neurophysiological underpinnings of moods, motivations, and so on, were important during hominin cultural and neurological evolution,” even if these people left no records for us to ever know.
If that book left Falk feeling unfulfilled, the next was even more starved for evidence. James R. Hurford’s The Origins of Meaning: Language in the Light of Evolution walked into the “intellectual minefield” of the evolution of language. Falk thought that Hurford did a great job, but problems were evident from the outset. Chief among them were the reliance on suggestions rather than hard evidence. In the treatment of animal cognition, “Hurford shows that the seeds are there, and were probably present in our ancestors, providing fodder for natural selection” even if the details are sketchy or non-existent. The doubt-words may, might and suggests pepper the review. Did the ability of many animals to infer animacy in objects lead to our theory of mind? Perhaps. Did simple two-way communication among hominins lead to grammatical complexity later? Maybe. Was the mother-infant interaction asymmetrical enough to be the focus of intense selection? Possibly. Whether these “suggestions” postdict what happened to hominids, they leave unexplained why animals in similar situations did not develop complex language. It seems all that Hurford was able to deliver was a kind of intellectual peep show, not rigorous explanation:
There are some titillating nuggets in this book, such as a discussion of how the FOXP2 gene was mistakenly accepted as the ‘magic bullet’ responsible for language evolution. Even better is the extent to which academics from different countries use language competitively to show off – guess where Americans rank?
It is not clear how these nuggets contribute to the evolutionary savings account. Many evolutionists have championed the FOXP2 gene as a magic bullet; now, Hurford is yanking that prop. And if academics are merely showing off with language, what does that say about the reliability of their truth claims?
The social brain: One more example from Science3 (Sep. 7) shows that theories of brain evolution struggle with real-world budgeting. Advocates begin to sound like the loyal accountant, stuck with a depressing profit-and-loss statement, trying to accentuate the positive while simultaneously staying realistic. R. I. M. Dunbar and Susanne Shultz considered social factors that might have contributed to brain evolution, but again, may and might seasoned an article of rampant suggestions and few certainties. One particularly damaging oversight in the evolutionary budget was admitted early on:
....Although it is easy to understand why brains in general have evolved, it is not so obvious why the brains of birds and mammals have grown substantially larger than the minimum size required to stay alive. Traditional explanations for the evolution of large brains in primates focused either on ecological problem solving or on developmental constraints.... On closer examination, most of the energetic explanations that have been offered identify constraints on brain evolution rather than selection pressures. In biology, constraints are inevitable, and crucial for understanding evolutionary trajectories, but they do not constitute functional explanations—that is, just because a species can afford to evolve a larger brain does not mean that it must do so. Proponents of developmental explanations seem to have forgotten that evolutionary processes involve costs as well as benefits. Because evolution is an economical process and does not often produce needless organs or capacities, especially if they are expensive to maintain, it follows that some proportionately beneficial advantage must have driven brain evolution against the steep selection gradient created by the high costs of brain tissue. In this respect, most of the ecological hypotheses proposed to date also fail. None can explain why primates (which have especially large brains for body mass, even by mammal standards) need brains that are so much larger than, say, squirrels, to cope with what are essentially the same foraging decisions.
This explains Dunbar and Schulz’ predilection for social explanations for brain evolution instead of ecological explanations: i.e., “The SBH [social brain hypothesis] proposes that ecological problems are solved socially and that the need for mechanisms that enhance social cohesion drives brain size evolution.” So how do social explanations fare, by comparison? Can they balance the selection budget, drive brain evolution forward, and make a profit? Bad news: hoped-for income is offset with rising expenses: “Nonetheless, whatever its advantages, group living incurs substantial costs, both in terms of ecological competition and, for females, reproductive suppression.” The complexity of any evolutionary accounting just went up accordingly. The SBH was conceived for primates; correlations of theory with data for other groups have produced “somewhat mixed results,” they admitted. The relationship between brain size and sociality, if anything, is qualitative, not quantitative. “These findings suggest that it may have been the cognitive demands of pairbonding that triggered the initial evolution of large brains across the vertebrates” was one proposal. Another interesting anecdote, mentioned almost as a distraction for faithful couples to flirt with, is that monogamous pairs seem to have bigger brains. So far, though, all these suggestions are post-hoc attempts to infer causes from measurements of living animals based on circumstantial evidence. Worse, they merely assume evolution rather than demonstrate it in a way that would convince a skeptic. Dunbar and Schulz puzzled over why only anthropoid apes and humans have a robust relationship between social group size and brain size. Is it because there are complex ways for them to bond with one another? “This suggestion merely adds to the puzzle of social bonding,” they admitted, wondering, “What is it about social bonds that is cognitively so demanding?” Is it that monogamy is a risky commitment? Is it that post-natal care requires loyalty by both parents? As if no other explanations were on the table, they forfeited: “Which of these two has been the key driver for brain evolution, or whether both have been equally important, remains to be determined,” they said. “It has become apparent that we lack adequate language with which to describe relationships, yet bondedness is precisely what primate sociality is all about.” Yet it would seem that without adequate language in which to pose an explanation, no explanations can be forthcoming. They delved into other issues and puzzles, which we do not need to explore in detail here, but fitness advantages for larger brains seem hard to explain socially and neurologically. They entertained a few recent suggestions about specific neurotransmitters and genes, but then ended in complete exasperation and called for a time out:
Each of these has been seen by their respective protagonists as the holy grail for understanding both social cognition generally, and, in particular, for explaining the differences between humans, apes, and monkeys. There is no question that these are individually important and novel discoveries, and they undoubtedly all play a role in the nature of sociality. However, there is a great deal more to how and why humans are different from other apes, or why apes are different from monkeys. We will need better studies of cognition and behavior to answer these questions. More important, perhaps, is one key point: Species differences in a handful of very small neuronal components do not explain the apparent need for massive species differences in total brain size. Most of these studies fall into the same trap as the developmental explanations for brain size did in the 1980s: They mistake mechanistic constraints for evolutionary function. It is unclear why this point continues to be ignored, but we will still have a lot of explaining to do about volumetric differences in brains.
At this point it would be overkill to ask what relevance brain size has to intelligence in the first place. Not only does this hark back to the discredited assumptions of Paul Broca and other 19th-century racists, it seems to be irrelevant based on observations of living people with diminutive brains (e.g., 07/22/2007). Consider that the world’s largest and smallest dogs were photographed together recently. Despite the tiny dog’s diminutive brain compared to that of the big dog, both seem to have all the required hardware for dog operations (see Daily Mail). Crows and other birds with much smaller brains seem to outperform chimpanzees at tool use. And the power of computer chips has paralleled their miniaturization – by intelligent design, uncontrovertibly, in this case. If it’s quality rather than quantity that counts, it would seem the preoccupation with brain size as a marker of evolutionary progress is vastly overblown. Abort, retry, fail?
Given the standoff in evolutionary explanations,4 how about a radical alternative? It’s not really radical; in fact, it is time-tested, logically coherent and self-evident. It enjoyed epistemic priority throughout the classical, medieval and Enlightenment periods. It is the non-reductionist position that the mind is non-material; the brain is an instrument of a spiritual reality that, while constrained by matter, cannot be reduced to its material components. A new book has dusted off this long-accepted truism and explored it within the findings of modern neurobiology. Written by neuroscientist Mario Beauregard and journalist Denyse O’Leary, The Spiritual Brain: A Neuroscientist’s Case for the Existence of the Soul is getting lively and enthusiastic reviews on Amazon.com. Perhaps the soul of science tomorrow will be the science that welcomes back the soul.
1. Dean Falk, “Delving into the ancient brain,” Nature 450, 31-32 (1 November 2007) | doi:10.1038/450031a. 2. In his book The Great Turning Point, Dr. Terry Mortensen examined the historical roots of old-age geology. He provides quotes that Hutton, Lyell and others did not ‘discover’ long ages but stipulated them a priori by overtly discounting from their method any reliance on Biblical history. 3. R. I. M. Dunbar and Susanne Shultz, “Evolution in the Social Brain,” Science 7 September 2007: Vol. 317. no. 5843, pp. 1344-1347, DOI: 10.1126/science.1145463. 4. Readers may wish to review the 09/09/2007 entry on this topic.
There are two arguments you can make right off the bat with a believer in brain evolution, even with no knowledge of neurons or hominids. One is an adaptation of Gödel’s theorem: a system cannot be proved within its own axioms. A system, like mathematics, requires external presuppositions for verification. Any reductionist theory of mind that invokes only particles in motion is doomed to failure. You can study all the electrons in a cathode ray tube till the cows come home, and never discern that a story is being projected from a writer’s mind to a receiver’s mind. C. S. Lewis argued that to “see through” something is not the same as to see it. Similarly, we can study neurons forever in finer detail than ever, and fail to see what is really going on. Sure, the neurons react in response to whatever is moving them, but you cannot find the mover in the physical components. Only by inferring the presence of an agent external to the system are you able to uncover the true explanation for the system. The second argument is that evolutionary explanations for the brain are self-refuting. Recall the Yoda Complex from the 09/25/2006 commentary. A Darwinist cannot sneak outside his brain and propose a theory he expects to be taken rationally as something that might be true, if he or she is claiming that the brain is only molecules molded by evolutionary forces. It matters not whether the forces are ecological or social; as long as they are materialistic, evolutionary rationality collapses under its own assumptions; it vanishes into smoke. Only by proposing the external existence of immaterial realities like Truth and the laws of logic can anyone propose a rational proof of anything. Christians, naturally, have such assumptions as their preconditions of argument. Evolutionists have none, and must be rebuked when caught plagiarizing the axioms of their opponents. If that point is conceded, the Christian view has its own challenges. Why are humans not perfectly rational, and why do individuals vary in rationality? Why does our intelligence and rationality age with our bodies? Why can an injury, a drug, or dementia turn a rational person into a vegetable? What is mental illness? An analogy may help approach these difficult questions. Picture a wild wolf, roaming free and in full possession of its capacities – the master of its turf. Then imagine a captive wolf, tied to a tree, distracted by pheromones from a she-wolf, occupied with scratching fleas, catching diseases, and having to sleep a lot and be fed. Its capacities are constrained from what they could be. Or imagine a private helicopter tethered to its parking block. The engines can run, the blades can turn, the instruments will register, and it might even be able to hop a few feet off the ground before its tether pulls it back. In the same way, our human souls are constrained by our physical ties to the Earth (and Christians would add, to our sinful natures). Beware, also, any hidden assumption that all souls are created with equal abilities even if they were freed of bodily constraints; we are, after all, finite. Limited as our rational are, the fact that we respond to social pressures and appetites is no argument that the soul is an illusion, or that rationality evolved from its physical components. Evolutionary stories about how our brains evolved from animal ancestors are speculative flights of fancy that strain credibility. We all know that recorded civilization only goes back a few thousand years, yet evolutionists propose that physically modern humans have existed for at least 100,000 years – maybe four times that. They expect us to believe that something happened around 50,000 years ago that was like the proverbial light bulb over the head, and man suddenly became rational, artistic, and capable of abstract thought. But even then, they expect us to believe another 20,000 years or more passed before any of these people learned how to ride a horse, plant a garden, write on a piece of pottery or build a city. Such imaginary eons are multiples of the length of all recorded history, during which time comparably-equipped humans have advanced from grass shacks to lunar excursion modules. How can anyone swallow such a tale? Remember, evolutionary biology is searching for natural laws, and laws have to apply to all animals. How come no other creatures on earth, including those with comparably sized brains relative to body size, and capable of tool use (like crows), developed abstract reasoning, art and true semantic language? On top of that, they try to ascribe these Eureka moments, in which virtual miracles occurred, to genetic mutations—mistakes! Anybody who tries to argue that rationality is a mistake should be considered rashly mistaken. Darwinian explanations for the brain are about as comforting as those of hijackers who, having bound and gagged the pilot and crew, get on the intercom and assure the passengers everything is under control. They laugh and celebrate their triumph over the flight crew, whom they hated and judged were unworthy of operating the plane. Almost simultaneously, practical issues assert themselves, and they begin whispering to one another, “Anybody know where this plane was headed? Do any of you know how to land this thing?” The solution is obvious: untie the pilot and let him apply his intelligence to a highly intricate, functional, and clearly designed machine. Then go to flight school like he did. The interpretation of this parable is left as an exercise. He who has a brain to think, let him think.