The implications of Evolution

Well, this is all a little vague, so in reply here are some general thoughts, for what they are worth.First of all, trying to find the adaptive merits of biological features is in fact a good idea. When we take such a feature and ask "what is it for?" (i.e. what benefits does it confer on the organism possessing it or the gene that produces it) we often find an answer which is not only plausible but utterly undeniable. If there wasn't a good fit between the features of an organism and its way of life, no-one would have thought of evolution --- or, if it comes to that, of ascribing life to a wise creator.This is not to say that such an adaptationist program will always succeed. Indeed, the theory of evolution itself tells us that it shouldn't, because evolutionary pathways are constrained by historicity --- one thinks here of the blind spot of the vertebrate eye, the recurrent laryngeal nerve in tetrapods, the olfactory pseudogenes of whales, and so on. In fact some of the most compelling arguments for evolution lie precisely in those cases where we can point out that adaptation is not the answer but history is, since these points distinguish it from the only rival hypothesis to attain any measure of popularity.Then there is neutral mutation. We know, I would say beyond doubt, that it is the explanation for certain characteristics of genomes (thanks to the work of Shimura and others); to what extent can it account for observable features of the phenotype?We might go on to mention sexual selection; or we might discuss "spandrels", i.e. cases in which an adaptation brings with it side-effects that are not adaptive, as a result of the non-modularity of phenotypes.The theory of evolution, then, is not strictly adaptationist, but that said, faced with any given biological phenomenon, an adaptationist hypothesis is a good place to start.

Well, you can always add an is to an ought to get another ought. For example, if you already think "I ought not to poison people" then when scientists tell you "Arsenic is poisonous", you would conclude that "I ought not to feed people arsenic". And if you had been doing so up to that point, then you would also conclude: "My behaviour ought to change in the light of this scientific finding".Blind faith in infallibility doesn't come into it. No-one in the whole world thinks that scientists are always right, but given their track record it's the right way to bet.