Apropos of Mike Huckabee & Ron Paul's evolution skepticism and its relevance to their political runs Andrew Sullivan has beenposting a seriesof comments from readers about whether evolution and gravity are laws or theories. I am generally somewhat averse to these semantical debates, and more interested in the fundamental question as to whether one can be rational & informed and reject evolutionary theory. But what do readers and others ScienceBloggers think? I was taught that laws are empirically validated truths and rest upon induction. Theories are basically systems of highly validated sets of interlocking hypotheses and inferences. I also think that this sort of dichotomy makes a bit more sense in physical sciences than it does to evolutionary science. Nevertheless, I do think the last comment goes a little too far here:
"Evolution" doesn't have a law because there's just not a nice mathematical expression of it to call a law.
I don't think they're nice, and nor do they have the power of Newtonian mechanics, but the body of work produced by theoretical population geneticists isn't something that should be dismissed. Fisher's Fundamental Theorem of Natural Selection aims to characterize one parameter, while various stochastic models can handle drift and its affinal processes. These tools and heuristics aren't what anyone would wish, but they exist. Finally, just as theories of gravity have been used in practical circumstances, such as extra-planetary trajectories or projecting the arc of a cannon ball, quantitative insights premised on evolutionary assumptions lay at the heart of much of agricultural science (e.g., animal breeding and so forth). Update:John Hawks has the goods. When I see some evolutionarily influenced thinkers posit "laws" I do tend to roll my eyes thinking back to their proliferation in late 19th century biology....
