Who is the postivist?

James Francis Lyons-Weiler weiler at ERS.UNR.EDU
Mon Dec 8 16:27:55 CST 1997

On Mon, 8 Dec 1997, Tom DiBenedetto wrote:

>  Richard Zander wrote:
> > Parsimony eliminates grossly unreasonable
> >trees, maximum likelihood eliminates grossly improbable trees.

Tom Di:.

> I disagree with this. Parsimony selects the tree which represents the
> set of least falsified grouping hypotheses.

        Tom, you seem to disagree with EVERYTHING.
        You needn't, because Richard didn't say HOW one decides
        that the longer trees are unreasonable.  One might use, for
        instance, tree length as a criterion for reasonableness.

        You're all over the map on the relationships between tests,
        criteria and hypothesis formulation - the effect is to
        confuse and dismay - more smoke than fire is the

> >I don't see a way to select one tree as a
> >reconstruction. Every elimination from the set of reasonable trees is an
> >ad hoc assumption of no convergence.
> "No convergence" is not an ad hoc hypothesis. An ad hoc hypothesis is
> one which addresses a particular case and seeks to explain why it is
> incompatable with a more general hypothesis.

        That's not the standard definition of ad-hoc.  Ad-hocness
        can apply to specific or general hypotheses.
James L-W

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