Abstract

Should medical educators clutter the busy course schedule that medical students must master with additional instruction in evolution? The clamor to do so is not new. While many physicians surely believe in evolutionary claims, most don’t find that those beliefs enhance their day-to-day ability to care for sick people in any practical sort of way. Recently there has been some media attention directed to those who crusade to make medical students learn not only how everything in the human body works but also the evolutionary history of how each human innovation evolved through the ages. Will teaching medical students more evolutionary beliefs, if it ever catches on, produce better physicians?


Introduction

Evolution is not emphasized in most medical schools. Medical educators have a great deal to teach to budding physicians in a short time. (The time spent in actual instruction upon entering medical school is a bit of a shock to many students fresh from their college undergraduate programs.) Therefore, in the packed curricula of medical schools, the most expendable item is evolution.

Why We Get Sick: The New Science of Darwinian MedicineThis 1994 book by psychiatrist Randolph Nesse, according to atheist Richard Dawkins, could help turn all physicians into believers in Darwinian evolution. Image: books.google.com

The Dean of Yale Medical School, Robert Alpern, explains these priorities, saying, “I think evolutionary biology could be taught to a much greater extent, but as a dean who has many passions about education, there are many competing priorities for the time in the curriculum.” Asked whether additional training in evolution would improve the way doctors treat patients or conduct research, Alpern says, “I don’t think they’d change a lot.”1

Others disagree. Psychiatrist Randolph Nesse, who teaches evolutionary biology at the University of Michigan, has been crusading for decades to get medical schools to give evolution a prominent place. He wrote Why We Get Sick: The New Science of Darwinian Medicine in 1994. Evolutionist Richard Dawkins, when accepting an award from the British Humanist Association, recommended people give copies of Nesse’s little book to their physicians to transform all into Darwinian doctors. Dawkins thinks that knowledge of the evolutionary basis for disease would keep doctors from making common mistakes.2

“It’s not too hard to demonstrate that doctors are ignorant about real fundamentals of evolution,” Nesse says. “They’d flunk their first quiz in an evolution course. A doctor who has a deep foundation in evolution will think different about disease. Instead of just seeing disease as some screw-up in the machine, they will ask of every disease, why didn’t natural selection make the body more resistant to this particular problem?”1

Making the Case

Nesse, along with Yale evolutionary biologist Stephen Stearns, Dean of Harvard Medical School Jeffrey Flier, and a host of others, co-authored “Making Evolutionary Biology a Basic Science for Medicine,” which was published in the 2009 Proceedings of the National Academy of Sciences. In this eight-page essay, the authors claim that evolutionary biology “is an essential foundation for a biological understanding of health and disease.”3

To explain the absence of evolution in the thoughts and practices of modern medical practitioners, the authors noted that, “When Nazi horrors were publicized at the end of World War II, scientific publications on evolution and medicine ceased suddenly.”3 They recalled that twentieth century applications of evolutionary biology to medicine resulted in movements focused on “eugenics, supposed racial superiority, and fears of degeneration.”3 But they offered reassurance that the application of evolutionary principles to the arena of public health is not now to be feared because, they write, “new evolutionary approaches to medicine are almost entirely unconnected with these earlier movements.”3 The authors base their claim for a prime-time spot in the basic science requirements taught in medical school on the need to use evolutionary methodology to understand population genomics, pathogen evolution, and “why natural selection leaves bodies vulnerable to disease.”3

Room for Examination

In examining the claims in the essay, it is notable that, other than a mention of the fact that we know a good deal about genetics nowadays, the essay really doesn’t contain new information compared to Nesse’s 1994 book. Perhaps by publishing the essay in a prestigious journal the authors hoped to have an effect on a more academic audience than Nesse’s original book.

In describing the effect of genetic variation on populations, the essay offers a catalogue of the genetic mechanisms that can affect the fitness and overall makeup of population. Genetic variants, mutations, population bottlenecks, genetic drift, inbreeding, and migrations all have their influence, the authors indicate. And those most able to survive and reproduce are those most likely to produce the populations of tomorrow. Therefore they conclude, “Natural selection and these other evolutionary mechanisms change species, and, equally important, keep them the same via stabilizing selection that disfavors individuals with extreme traits.”3

Natural selection within the human species has nothing, however, to do with the supposed biological evolution of complexity. All of these mechanisms are important genetic mechanisms that affect the traits found in a population, but they have nothing to do with molecules-to-man evolution. In fact, biblical creationists commonly cite these very factors when explaining how various people groups developed after the global Flood and the subsequent dispersion from the Tower of Babel. Biblical creationists also commonly cite these factors to explain the profusion of animal variety that has developed in the few thousand years since the global Flood. None of these mechanisms involves the evolution of new, more complex kinds of living things. These observable genetic mechanisms are the here-and-now tools that have long been applied by doctors concerned about the studying the occurrence and spread of traits and disease in populations. Teaching physicians to accept evolution would not make them better able to use these tools.

“Resisting” the Facts

When Dawkins recommended Nesse’s 1994 book, he said, “If doctors had been wise to natural selection we wouldn't have the problem we now have with antibiotic resistance evolving by natural selection by bacteria.”4 Yet, antibiotic resistance has nothing to do with evolution. In fact, the assumption that resistance traits have to actually evolve in pathogens is erroneous. Antibiotic resistance, as we discussed recently, involves natural selection and the genetic shuffling of genes that bacteria already possess. That’s why antibiotic resistance in a population of bacteria can develop rapidly, without requiring millions of years like evolutionists must postulate in their efforts to explain the evolution of biological complexity.

A recent editorial published in the Point/Counterpoint forum of OneHealth, a coalition of veterinarians and medical doctors dedicated to cooperating to improve health care for animals and humans, derided the lack of evolutionary teaching in veterinary and medical schools.5

Those writers raised the same concerns as Nesse regarding the need to be schooled in evolution in order to understand antibiotic resistance, microbial pathogenicity, genetics, and anatomical problems. They predicted planetary-wide catastrophes in health if vets and docs don’t develop an evolutionary mindset to deal with medical and veterinary problems. Yet, they also failed to distinguish between the observable effects of natural selection and other genetic mechanisms and the unobservable notions of shared evolutionary ancestry. Comparative anatomy, for instance, allows a student to compare the common designs found in animals and humans. These common designs have nothing to do with a shared evolutionary past—nor do they need to. Likewise, medical applications of population genetics and epidemiology (the spread of disease) deal with observations in the present, not conjectures about “deep time.”

The essay’s authors cite the importance of understanding evolution to explain the development of pathogenicity (the disease-causing nature of microbes). But, as many articles on this website (listed below) have discussed, microbial pathogens can be best understood by realizing the beneficial roles of microbes in the original, good, disease-free creation and then examining the changes brought about since sin and death entered the world. Understanding how microbial pathogenicity can develop through mechanisms like the horizontal transfer of genomic components (one bacterium passing genetic material directly to another) has nothing to do with evolutionary dogma.

“Feverish” effort

Dawkins, borrowing some of Nesse’s “evolutionary tips” for doctors, said, “Is [running] a temperature a Darwinian adaptation by the body to make life difficult for the pathogen? If so, giving someone a drug to bring the temperature down is the very last thing a doctor should be doing.”4 There is no need for evolutionary concepts to understand that the fever associated with an infection may, under some circumstances, inhibit the growth of some bacteria. But to point to fever as the obvious result of millions of years of evolutionary adaption in the animal kingdom—as Nesse does in his book6—is not only unverifiable but dangerously simplistic. Fever can be helpful, harmful, or sometimes both at the same time. And the human body’s homeostatic mechanisms (the things that keep all sorts of things, like body temperature, in “balance”) are remarkably complex.

Nesse acknowledges that we do not understand the evolution of fever and should investigate its evolutionary origins before treating it. He doesn’t go so far as to say we should never try to bring fever down, but Dawkins at least suggests it. Furthermore, lest people actually begin trying to use his evolutionary principles to actually make real decisions about their health, in his book Nesse wrote, “A caveat is necessary. Doctors and patients, like all other people, are prone to extend theories too far. . . . Clinical principles of medicine should come from clinical research, not from theory.”7 Understanding the evolutionary origin of fever—even if it had one—would not help us know whether to give someone an antipyretic (medicine to lower fever). Only experimental laboratory and clinical trials in the here-and-now can determine when it’s best to treat fever and when it’s best to leave it alone. In other words, observable, testable science is the bedrock on which medical practice should be based, not evolutionary conjectures.

Frankly, if Nesse and friends wanted to teach a course on how our vulnerability to disease and supposed “design flaws” managed to do an end-run around the evolutionary mechanisms that should have weeded them out, they would do well to subtitle it: “Why Evolution Really Cannot Explain Medical Realities.” Both vulnerability to disease and the gradual degeneration of good anatomical and physiological designs make sense when understood in light of biblical history and sin’s curse on an original perfectly good creation.

Dawkins, continuing his Nesse-derived evolutionary tips-for-docs, said, “Lower back pain is likely because we are ancestrally quadrupedal animals turned into bipeds and this is giving us problems.”8 The interaction of many parts of the entire human musculoskeletal design contributes to making our genuine bipedal gait a marvelous design. The design of the lower back enables it to develop a springy protective curve in response to an upright posture. Nothing about this design demonstrates that it evolved from a quadrupedal ancestor. No evolutionary presumptions are needed to explain how the lower back, like everything else in a sin-cursed world, sometimes suffers from stresses and strains and degeneration.

We’ve discussed a number of these supposed “evolutionary design flaws” that seem to pop up in the popular press on a regular basis. Have a look at “Organ Recital: A Parade of Presumed Design Flaws Devoid of Truth,” “Body un-designed,” “Vestigial hiccups, folding fish-eyes, and other fables: Our fishy forebears . . . again!” and “The Evolution of Childbirth?” for more on some of these.

Cause and Effect?

Nesse and his coauthors recommend that “every trait of every organism needs two separate and complementary kinds of explanation, proximate explanations of how mechanisms work, and evolutionary explanations (sometimes called ‘ultimate explanations’) about how they got to be the way they are.”7 For instance, they consider that while it is important for a medical student to learn all about how the adrenal gland works, “Separate, and equally important, is an evolutionary explanation: the phylogeny of the adrenal gland and how it has conferred a selective advantage.”7 However, evolutionary assumptions about phylogeny—the supposed evolutionary ancestral history of the adrenal gland across many kinds of organisms—depend entirely on unverifiable worldview-based presumptions that humans evolved from less complex animals over millions of years. Similarities noted when comparing humans to various animals are easily understood as common designs created by their common Designer. What evolutionists term “selective advantage” is merely a way of reminding students that the anatomy and physiology of the human body is well-designed to cope with life’s stresses. Speculation about how the adrenal gland evolved can contribute nothing to a physician’s ability to understand how the adrenal affects the body or to diagnose and treat its malfunctions.

The authors of the essay promoting evolutionizing premedical and medical education assert that “knowledge about evolution provides physicians with an integrative framework that links otherwise disparate bits of knowledge. It replaces the prevalent view of bodies as machines with a biological view of bodies shaped by evolutionary processes.”7 As a physician, I can attest that my medical education did not consist of “disparate bits of knowledge” in need of a unifying concept. Medical schools must integrate a phenomenal amount of detailed information concerning the anatomy, physiology, histology, biochemistry, and pathophysiology of each area of the human body into a unified whole. In fact, it is that, in part, which distinguishes a physician’s education from that of most technicians and support personnel. But physicians are trained to understand how “each part” interacts with “every other part” in the here and now without any need to look back over the eons to figure out how things supposedly evolved to work the way they do. (That's why even Nesse has to include a caveat that medical judgments should be based on “clinical trials” instead of evolutionary claims.) And while I don’t doubt that many of my professors and mentors in medical school accepted evolution, they were too busy teaching us about things that mattered to waste time on it.

Where’s the Harm?

Other than the obvious problems of crowding out basic science courses that have genuine relevance to the practice of medicine, is there any harm in teaching more evolution to medical students? History would say “yes.” Erroneous beliefs that certain mysterious “vestigial organs” were useless evolutionary leftovers, for instance, led many physicians to destroy them needlessly. Countless appendixes were removed unnecessarily on the Darwinian assumption that they were useless leftovers from our ape-ish heritage, ignoring clear evidence that the appendix functions as part of the immune system. Likewise, the thymus glands of many children were needlessly irradiated by physicians who thought the thymus—an important component of a child’s developing immune system—was a useless evolutionary vestige.

While premedical students will have to be familiar with evolutionary claims in order to do well on the 2015 version of the Medical College Admissions Test (MCAT), which is being revised to include more questions about evolution, there is no necessity that they actually believe the claims. In fact, the most discerning students should be equipped to understand the difference between evolutionary conjecture and experimental, testable, clinical science on which they should base their medical decisions. And, except for those who seek a career in a scientific specialty that is specifically devoted to creating some sort of niche for “evolutionary medicine,” physicians who wish to engage in basic research should also find no use for evolutionary thinking. As Henry F. Schaefer III, the Graham-Purdue Professor of Chemistry and Director of the Center for Computational Chemistry at the University of Georgia explains:

Darwinian assumptions are not needed for the day-to-day work of science. If you look at the biochemical literature for scientific papers that try to explain how biochemical systems developed step-by-step in Darwinian fashion, there aren’t any. It’s startling. Most biologists completely ignore evolution in their work, and the ones that think about it simply look for relationships and don’t bother with Darwinism. My University of Georgia colleague in biochemistry, Professor Russell Carlson, has expressed the same sentiment to me privately.9

Dr. Benjamin Carson, who is a professor of neurology, oncology, plastic surgery, and pediatrics, the Director of Pediatric Neurosurgery at Johns Hopkins, and co-director of the Craniofacial Center there, is a creationist. He told the National Science Teachers convention, “Evolution and creationism both require faith. It’s just a matter of where you choose to place that faith.”10 Despite a flap last year from evolutionists who objected to him speaking at Emory University’s commencement on the grounds that such a non-evolutionist “did not understand science,” Dr. Carson has done brilliant work on behalf of children with craniofacial deformities. Dr. Carson’s work depends on observable science, not evolutionary conjecture. In his field, his understanding of embryological developmental errors that produce birth defects is not hampered by his “refusal” to believe that embryologic development recapitulates an evolutionary past. He understands human anatomy and development and has developed innovative ways to relieve human suffering. That’s what physicians do. They deal in the here and now.

Nesse not only pushes to have evolution consume a greater portion of time in the training of young doctors, he also pushes for his own field of expertise—psychiatry—to “become a fully fledged biological science.”11 He believes this transformation will require the development of an evolutionary understanding of how mental illness developed in Homo species. An editorial comment in response to his proposals, published in the 2010 British Journal of Psychiatry, summed up the problems with Nesse’s evolutionary goals:

I think that Nesse’s approach is as laudable as it is flawed. Evolutionary psychology proposes that most if not all human psychological traits are complex adaptations which have evolved under selective pressures. Richardson [in R.C. Richardson’s 2007 Evolutionary Psychology as Maladapted Psychology] convincingly shows that the claim that all our psychological capacities have been selected for the purpose of accomplishing a particular task is too strong and that the empirical evidence required to support this claim is necessarily historical. The problem is, however, that the required historical evidence is hard or impossible to come by – we simply do not know what psychological traits were prevalent let alone advantageous to survive in a Pleistocene environment about which we also have little information. For evolutionary psychology to be regarded as a credible theoretical framework it will have to be examined against standards of scientific enquiry used in other evolutionary fields such as evolutionary biology (emphasis ours).11

Unfortunately, the discernment expressed by this evolutionary letter-writer regarding the lack of historical documentation or objective evidence to back up Nesse’s evolutionary conjectures about the human mind does not extend to his understanding of biology. Evolutionary biology is just as lacking in historical and objective evidence.

Conclusion

The presumptions of evolutionary biology do not need to be taught to pre-medical and medical students as if they are factual. Future clinicians do well to discern that what can be tested and observed is qualitatively distinct from evolutionary mythology. The lessons of the past—the recent past, that is—have shown how evolutionary presumptions can derail sound medical judgments. The areas in which evolutionary biologists claim to be able to contribute to medical education actually have nothing to do with evolution. Rather, the ordinary observable processes of natural selection, comparative anatomy and physiology, microbiology, molecular genetics, epidemiology, and population genomics are able to serve practicing and academic physicians without any evolutionary overlay. Evolutionary instruction can contribute nothing useful to the future of medical care nor can it equip clinicians to stop the scourge of antibiotic resistance or relieve the burden of disease on the humans and animals living on earth.

For more information:

. . . about evolution and medicine:

This information is intended for general education purposes only and is not intended as professional medical advice.  The information should not be relied upon as a substitute for medical advice from your doctor or other healthcare professional. If you have specific questions about any medical condition, diagnosis, or treatment, you should consult your doctor or other healthcare provider.

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Footnotes

  1. www.boston.com/bostonglobe/ideas/brainiac/2013/04/a_movement_to_m.html Back (1) Back (2)
  2. www.guardian.co.uk/science/blog/2012/jun/12/richard-dawkins-evolution-new-classics Back
  3. R. Nesse, et al., “Making Evolutionary Biology a Basic Science for Medicine,” Proceedings of the National Academy of Sciences (published online November 16, 2009). DOI: 10.1073/pnas.0906224106. Back (1) Back (2) Back (3) Back (4) Back (5) Back (6)
  4. Carole Jahme, “Richard Dawkins wants evolutionary science to be 'the new classics,'” The Guardian, June 12, 2012, www.guardian.co.uk/science/blog/2012/jun/12/richard-dawkins-evolution-new-classics. Back (1) Back (2)
  5. Leonard C. Marcus and James P. Evans, “Evolutionary Biology: The Scientific Basis for One Health & an Essential Part of Biomedical Education,” Clinician's Brief web exclusive, September 17, 2012, www.cliniciansbrief.com/article/evolutionary-biology-scientific-basis-one-health-essential-part-biomedical-education. Back
  6. R. Nesse and G. Williams, Why We Get Sick: The New Science of Evolutionary Medicine, (New York: Random House, 1994), p. 12. Back
  7. R. Nesse and G. Williams, Why We Get Sick: The New Science of Evolutionary Medicine, (New York: Random House, 1994), p.247. Back (1) Back (2) Back (3) Back (4)
  8. Carole Jahme, “Richard Dawkins wants evolutionary science to be ‘the new classics,’” The Guardian, June 12, 2012, www.guardian.co.uk/science/blog/2012/jun/12/richard-dawkins-evolution-new-classics. Back
  9. H. F. Schaefer, 2004. Science and Christianity: Conflict or coherence? (Athens, Georgia: The University of Georgia, 2004), p. 102, quoted in An Evaluation of the Myth That “Nothing in Biology Makes Sense Except in the Light of Evolution”. Back
  10. News to Note, May 26, 2012 Back
  11. R. Nesse, British Journal of Psychiatry 196 (2010):247–248, doi: 10:1192/bjp.196.3.247a. Back (1) Back (2)