There may be a simpler tautology. Something like " The fittest are those who "survive" , and fitness is defined as those who have surviving offspring _ad infinitum_ or for indefinitely many generations into the future. The tautology comes with the term "survive" in subject and predicate.
Charles
* >CB: I think natural selection is an expression of Hegel's "the actual is>rational and the rational is actual" idea, too.
BLab:What do you mean by that?
CB: The surviving species are actual; and the extinct species are not actual, i.e. don't exist anymore.
The surviving species _are_ actual because their relatively superior fitness to the extinct species is rational relative to the given environment. Rational in the sense that whatever fit traits they have adapt them well to the given environment. Adaptive traits are rational relative to the environment that they adapt well to.
You can see tautology impinges from a couple of angles. Hegel's aphorism is a sort of tautology. Then "what is rational is adaptive and what is adaptive is rational" is a tautology of a sort