Larry Moran put up this video of Elisabeth Lloyd discussing the problem of assuming adaptation in evolutionary studies. I think it’s excellent and makes points I wish more people would consider…but strangely, most of the comments over there are expressing extreme distaste while failing to mention any specifics about what they dislike.
Maybe some of you can watch it and explain lucidly what you object to…or what you don’t find objectionable. I get the impression that a lot of people rather rabidly turn their brains off at the merest mention of the word “spandrel”.
In case you didn’t watch it, here’s the main point.
She’s criticizing methodological adaptationists. This is a style of thinking that assumes that only adaptation and selection are important or interesting, and as a philosopher she objects to the replacement of a reasonable null hypothesis (that is, that no selective evolution is occurring for a trait) with the pretense that selections is the null hypothesis…and that if analysis of a trait reveals an absence of evidence for selection, then they will move on to consider other hypotheses.
But they don’t. As she demonstrates with the example of the evolution of the female orgasm, several prominent evolutionary biologists are so fixated on selection that they just make endless chains of adaptive hypotheses, and don’t even consider other explanations (such as drift, genetic hitchhiking, architectural constraints, or developmental mechanisms) as legitimate answers to the question of evolutionary function. It’s a new kind of teleology — they are reluctant to consider that some features of our history were completely purposeless.