Positivism vs Realism

[James Francis Lyons-Weiler]

On Sat, 13 Dec 1997, Byron Adams wrote:

>
>         First of all, do we agree on a definition of metaphysics?  I'm not
> referring to that associated with crystals, pyramids, the occult,
> or windham hill samplers, although your post (and an earlier one from
> James, who, in a criticism of cladistics said,  "My comments are not
> intended to place cladistics firmly into metaphysics...") hints at this.
> I'm using the term metaphysics to mean the science that deals with
> ontological reality at its most fundamental level.

        For clarity's sake, let's agree that every scientific inference
        is somewhere on a scale, like this:


        metaphysical                                    objective
        positivism                                      realism
        -7  -6  -5  -4  -3  -2  -1  0   1   2   3   4   5   6   7

        Most of the debate surrounding this thread has been
        about where on this scale do we find (or expect to
        find) cladistic parsimony.

        A Popperian would say that it doesn't matter where we think
        we find that mode of inference.

        A Kuhnian would say that a majority rule vote by practicing
        systematists and theorists would settle the issue - for the
        time being, until popular opinion changed, and then the
        relative -ism of the field of cladistics sensu stricto
        would also change.

        I rather think that anyone who asserts that the common
        opinion determines the validity of a test in a way that
        supercedes the formal logic behind the inference is more
        affined to Kuhn than to Popper.

        So, when I claimed to not wishing to place cladistics
        in the metaphysical realm, I was stating that the question
        apparently has no absolute answer; but rather, if I were
        to restrict my statement to my humble opinion, I would say
        that it (the field) falls somewhere on the negative end
        of this scale, but is not a firm -7.

        That is to say, using cladistic parsimony alone as
        a test/measure/source of evidence for congruence is
        closer to making an inference about pigs flying only
        when no one can detect the event than it is to
        experimental falsification.

        A user's guide to such a scale would come with guidelines
        about measuring the relative amount of a priorism, the
        degree to which background knowledge seeps into the
        test statements, and a good description of what constitutes
        a severe and critical test.  We instance, we don't want to
        defend hypotheses against doubt, says Popper, we should rather
        try to determine the observable consequences that would
        result should the hypothesis in fact be false - NOT the
        consequences  that we can line up as evidence in support of a
        hypothesis in support of its confirmation.

        The metaphysical attributes I keep referring to are those
        which are shared by inferences that cannot be made to
        render observable consequences.  This is NOT the same
        as pure empiricism - it just restricts the kinds of
        evidence that can be used as a test statement.  Crystal
        balls and soothsaying falls on -7. So, again, it's not
        an all-or-nothing classification - unless the field
        deserves an (absolute) score of -7 or +7.  In sum, the
        possibility for corroboration and the degree of corroboration
        upon the event of surviving a test decreases at the
        left end of the scale, and increases to 1.0 (never
        attainable) at the right end of the scale.

        James Lyons-Weiler