(another own goal, of course.)
There he goes again. Creationist neurosurgeon Michael Egnor’s latest post over at the Discovery Institute’s Why’s Everybody Always Picking On Me blog may have actually reached a new standard for missing the point. And, as both my loyal regular readers know, that’s not an easy mark for Egnor to hit.
The current contender is his latest post in a back-and-forth that he’s been having with PZ and Orac. Once again, Egnor is attempting to argue that evolutionary biology has not provided any useful insights to the field of medicine. That much is familiar ground. What’s new this time is the hypothetical that he’s dredged up in an attempt to prove his point. His hypothetical is long and involved, which should provide you with your first warning that the argument is perhaps not as sound as he believes:
What I’m arguing is that the truth or falsehood of Darwinian stories is of no tangible value to medicine. Consider the following example.
I would suspect that careful epidemiological studies of the British population would show that the prevalence and incidence of spina bifida increased following World War One. To my knowledge, this has not been investigated, but it would make sense if it were true, for the following reasons:
Britain suffered enormous casualties during the Great War, as did many other European nations. (I’m just using Britain as an example). It has been said, with asperity, that Britain lost a generation of men on the Western Front. Britain suffered 2,300,000 war casualties – forty four percent of mobilized men, with 703,000 men killed in battle or by disease. On just one day – July 1,1916 – 19,240 British soldiers died in the battle of the Somme. The young men who died were the best of their generation – healthy, and by definition capable of meeting the rigorous physical standards required for military service.
Of course, other British men with debilitating genetic disorders, such as men with spina bifida (which renders the afflicted congenitally paralyzed), were not in the trenches that day, because they were physically unfit for military service, or at least service on the front lines as infantrymen. It’s safe to say that military age British men without spinal bifida were at greater risk of death in the war than were military age British men with spina bifida. Whatever the impediments faced by people with spina bifida – and they face many impediments – they were not called to serve and die in the trenches.
Spina bifida would then be a fine example of an environmental adaptation; it was protective against “acute lead poisoning” – protective against being mowed down by German machine gun fire on the Western Front. So, assuming for argument’s sake that my hypothesis about the post-war epidemiology of spina bifida is true, the genes that give rise to spina bifida conferred a selective advantage on young British men in the period 1914 to 1918, and the differential survival (and reproduction) of that age cohort would explain a (hypothetical) increase in the incidence and prevalence of spina bifida in England in the post war period.
Where to begin?