Re: Adaptationism again

Bryant (
4 Sep 1996 17:29:23 -0600

In article <>,
Len Piotrowski <> wrote:

>My reading of the above:
>Hypothesis: a trait is adaptive if it is not caused by allometry, pleiotropy,
>random gene fixations, linkage and indirect selection.

A fine reading, Lenny.

>Lewontin's apparent conclusion: this is not a testable hypothesis.

Exactly! One cannot readily falsify assertions of pleiotropy, random
historical processes, or indirect selection.

>How does this then imply that "adaptationist hypotheses are more readily

Because when you hypothesize an evolved function for a trait, you can
generate predictions about what else must also be true if your hypothesis
is correct. Test those predictions. The answer will generate more
testable predictions. Test them.

You may be more creative than I, but with most of the traits we would
find interesting enough to study, I do not see how one would test non-
functionalist hypotheses without first falsifying functionalist alternatives.