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Why Isn’t Evolutionary Medicine More Popular Than It Is?

You have got a fever, your body aches, and you feel dreadful. What should you do? The traditional answer is: “Take two aspirin, drink lots of fluids, get to bed and call me in the morning if you don’t feel better.” Could it be that this is just the wrong advice? That the last thing you should do is reduce your temperature with aspirin or ibuprofen or whatever? Is it, to use a phrase, nature’s way of fighting illness?

This is very much the position of a small group of biologists and medics who are pushing what has come to be known as “evolutionary medicine.” Crystallized about 20 years ago by a book – Why We Get Sick: The New Science of Darwinian Medicine – authored by the distinguished evolutionist George C. Williams and the psychiatrist Randolph Nesse, it claims that the force that caused us all, Darwin’s mechanism of natural selection, does not care about human happiness or even human health per se. What it cares about is survival and reproduction and it is prepared to go to great measures to achieve its ends.

Too long has medicine focused only on proximate causes, the physiological and other reasons for ill health. What we must do also is look at end causes, what Aristotle calls final causes and what we might call ultimate causes, and put our bodies and their functioning in perspective – a perspective that in this day and age means Darwinian evolution brought about by natural selection. If selection found that fevers increase life expectancies and consequent reproductive success, then bring them on, no matter how unpleasant they may be.

That evolution is important is probably accepted by every medical person today in some respects. As soon as a new wonder drug is introduced, the countdown is on to see how quickly nature will respond by making viruses and bacteria immune to the drug. Penicillin was introduced in the early 1940s. By about 1947 it was being made ineffective by disease-causing agents that had been selected for resistance.

That evolution is that important is far from generally accepted. How many, for instance, take seriously the idea that troubles in pregnancy might be the result of conflict between mother and fetus? It seems obvious that the mother cares for the child without reservation and the same has to be true of her biology. But according to the Darwinian medicine enthusiasts, this is not necessarily so. Apart from anything else mothers tend to have more than one child, so biologically it is in the mother’s interests to spread her attentions. The child, on the other hand, although related to its siblings, has itself as its prime concern. If it dies then it isn’t going to reproduce. It is thought that this causal infighting might be going on in such dire medical conditions as preeclampsia, where pregnant women get very high blood pressure. This could be of benefit to the fetus even if the mother is put at risk. Of course, a dead mother means a dead fetus, but sometimes natural selection is willing to gamble.

Obviously causal understanding does not at once lead to methods of amelioration, but it sure helps. Why then is evolutionary medicine not embraced by all? Why was it not embraced at once after Darwin published his Origin of Species in 1859? My suspicion is that today it is, in major part, natural conservativism coupled with reluctance to give time to such ideas. In biology departments, we know how hard it is to get in courses on evolution. There is always someone arguing for yet one more course on biochemistry. I would not be at all surprised to find that there is also a religious factor here. My experience is that if you want to find your evangelicals on campus – often, the real fundamentalists – you had best start with your medical school. Or, as I discovered from working for 35 years at the University of Guelph in Ontario, with your veterinary college. These people really worried about the dimensions of the Ark and thought that their professional training was directly relevant.

However, going back further, fascinatingly and paradoxically, the person most responsible for keeping evolution out of medical education was Thomas Henry Huxley, Darwin’s self-styled “bulldog.” Huxley was a fanatical evolutionist and preached it publicly on every occasion. But he was never that keen on natural selection and thought overall that evolution was too speculative – and of no real value – to biological education. As I discovered by looking at student notebooks, in a 165-lecture course on biology, he would give less than half a lecture to evolution, and selection got all of 10 minutes.

As a master academic politician and system builder – and as one who incidentally started life with a medical degree – Huxley saw the medics as the source of support for his science and his students. After the total muck up in the Crimean War, when most soldiers died of disease and dirtiness and not battle, the medical profession realized that the time had come to stop killing and start curing. Huxley gave them the perfect solution. “I will educate people in basic biology and then you can take them and turn them into doctors.”

Everybody was happy and it wasn’t overall a bad solution. But evolution for Huxley was always as much an ideology as a science and there was no place for it in his professionalized science education. And I suspect we still live with that legacy. But as the Nobel Prize winner H. J. Muller once wrote: “A hundred years without Darwin are enough.” And that was over 50 years ago. I would say: “A hundred and fifty years without Darwin in medicine are more than enough.” Looking back, my prediction is that in 2059, the 200th anniversary of the publication of the Origin, we will all celebrate the insights of George Williams and Randy Nesse.

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