Positivism in evolutionary science

James Francis Lyons-Weiler weiler at ERS.UNR.EDU
Wed Dec 3 09:18:03 CST 1997

On Wed, 3 Dec 1997, Tom DiBenedetto wrote:

> explanation for this pattern (ever since Darwin at least) is descent;
> i.e. genealogical relationship. Are you proposing that this
> explanation is in doubt, and if so, then what other causal factor(s)
> could result in such patterns?

        Organisms do not only acquire traits from their parents
        and species do not only aquire traits through geneaology
        that are informative of shared ancestry - they also
        aquire traits through descent that are misleading.  It is
        a positivistic position to state that most of the
        traits that organisms aquire through genealogy will
        have remained informative about shared ancestry.  it's
        a matter of signal:noise, and to focus only on what we
        perceive as signal without (adequately) measuring the
        noise is positivistic.  Relying on (parsimony) trees
        to tell us about the reliability of the information
        in the distribution of character states among organisms
        is like trying to receive instructions on how to construct
        an antenna through the antenna you're trying to construct.
        Some parts of the information may come through, but other
        parts are jumbled.  It's even worse than this analogy, because
        at least with radio or television signals we can immediately
        recognize the noise (scatter).  It would be as if the antenna
        would organise the noise into coherent sentences about the
        contruction of the antenna that were misleading - and we
        would have no independent means of checking the quality of
        the reception, because the antenna is making "sense" out
        of "nonsense".

        Of course, in every case, this problem will exist more or
        less, so it's a matter of degree.  Let's keep the baby and
        clean up the bathwater and get the job done (I think I
        avoided a truly mixed metaphor ... whew!).

        James Lyons-Weiler

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