Positivism vs Realism
James Francis Lyons-Weiler
weiler at ERS.UNR.EDU
Sun Dec 14 09:47:02 CST 1997
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:
-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
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.
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