A commenter on our ID post directed us to this supposed refutation of Karl Popper's arguement that the notion of survival of the fittest is a tautology.
The argument posits the following important premise:
This ["survival of the fittest"] is not a tautology, or, if it is, then so is the Newtonian equation F=ma [Sober 1984, chapter 2], which is the basis for a lot of ordinary physical explanation.
That is not true, however, for the two propositions are most definitely not identical in type. The Newtonian equation is a proposition that cannot be untrue; there is no alternative possibility that would explain the relationship between force, mass, and acceleration that we observe. There are, however, other possible explanations for the origin and variety of species. Just as two and two must equal four if the cosmos is to hold together, so must force, mass, and acceleration be related as Newton suggested. For the species we see on the earth to exist, however, Darwinian evolution is not a necessity, as the author of the article admits:
Recently, there have been attacks on the very notion of adaptive explanation by some evolutionary biologists themselves (eg, Gould and Lewontin ). These fall into two camps - those who think adaptation is not enough to explain diversity of form, and those who think that adaptive explanations require more information than one can obtain from either reverse engineering or the ability to generate plausible scenarios. The reason given for the former is a kind of argument from incredulity - natural selection is not thought to be a sufficient cause, and that macroevolution (evolution at or above the level of species) is a process of a different kind than selection within species. Arguments about parsimony (Ockham's Razor) abound.
Darwinian natural selection is the preferred explanation of a great many people, but that is greatly different from it being a necessary proposition. And that is why it can correctly be classified as a tautology, as Popper did.