Elliott Sober

Oxford, 1993.

Biologists who may have wondered about philosophy can get a good look at what goes on in that department in Sober's detailed guide to theoretical issues arising from the study of evolution. Conversely, philosophers can be led to appreciate biology as a ripe subject for philosophical scrutiny.

Part of the matter is philosophy of science, and there is some discussion of Popper's falsifiability criterion, the suggestion that what makes a statement scientific is that some evidential statement could count against it. Claims that could not conceivably be refuted cannot really be saying anything about the world. Sober repeats one criticism of this criterion (p.48), which is that there is something peculiar about the fact that the negation of a falsifiable generalization is not falsifiable. So, negating "All As are B" gives us "There exists an object that is both A and not-B." The latter existential statement is not subject to refutation, since no amount of observations could falsify it.

Sober thinks that this shows that there is something amiss with the criterion. But once the original statement is negated, the resultant statement is clearly not equivalent to the first, so why would it be expected to retain the property of falsifiability? The equivalent would surely be "There is no object that is both A and not-B", and this would be refuted by producing such an object.

There is more to be said for his assessment of creationism (the belief that there has been no evolution, as everything was divinely created, supposedly in 4004 BC):

"Research traditions are tested in the long run by seeing if they progress: do problems get solved, or do theories come and go with no net gain in understanding? It is important to realize that creationism is defective not only in its current theories but in its historical track record: its current theories are unsuccessful and its long-term track record has been dismal. It is no surprise that biologists have come to regard 'creation science' as a contradiction in terms." (p.56)

A distinction is made between adaptation and adaptive which may clarify some kinds of evolutionary explanation:

"A trait is adaptive now if it currently confers some advantage. A trait is an adaptation now if it currently exists because a certain selection process took place in the past... A trait can be an adaptation now without currently being adaptive. And it can be adaptive now, although it is not now an adaptation (for example, if it arose yesterday by mutation)." (p.84)




Paul Taylor 2001