Re: Adaptationism again

Len Piotrowski (
Thu, 5 Sep 1996 12:41:50 GMT

In article <50l3cj$> (Bryant) writes:


>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.

This is not apparently what Lewontin means. The gist of his conclusion states
that a test of a trait's adaptiveness is not equivalent to the negative
results from a series of tests of a trait's allometry, pleiotropy, random
gene fixation, linkage, 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.

Based solely on Lewontin's conclusion, this methodology is not logically
excluded from application to questions of allometry, pleiotropy, random gene
fixations, linkage and indirect selection.

>Test those predictions. The answer will generate more
>testable predictions. Test them.

The logical relation between Lewontin's initial premise and conclusion, and
this implication is unclear.

>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.

I believe that this final point is actually logically consistent with a closer
reading of Lewontin's statement.