I didn't intend to jump in but you did it, Alex, with the remark about
circularity.  Isn't this idea circular precisely because the only meaning
"fitness" has must be discovered in the continuation of the species?  That
is, a species is fit if and only if it continues but, and herein lies the
circularity, it continues if and only if it is fit.
 
> -----Original Message-----
> From: A Menez [SMTP:[log in to unmask]]
> Sent: Friday, May 14, 1999 8:38 PM
> To:   [log in to unmask]
> Subject:      Fitness
>
> I feel that what I wrote may have gone unnoticed! The problems in relating
> to
> the idea of fitness in evolution are easily solved if you use correct,
> constraining, meaning. As I have already said, fitness is NOT related to
> physical fitness etc. You cannot say, for example, " this animal died out
> because it was no longer fit" (re: the famous dodo). Circularity is only
> manifest if you use fitness in the everyday sense of the word.
>
> Natural selection operates whenever genotypes differ in fitness. In an
> evolutionary context fitness is measured ONLY by a genotype's rate of
> increase
> relative to other genotypes. (Thus what I said about the reproductive
> success
> and number of progeny from an individual).
>
> Alex