Grimm's Law and Predictability (ex Re: The Neolithic Hypothesis)

X99Lynx at aol.com X99Lynx at aol.com
Tue Apr 27 04:29:49 UTC 1999


In a message dated 4/26/99 3:32:41 PM, whiting at cc.helsinki.fi wrote:

<<Predictability and repeatability are
indeed the hallmarks of a sound scientific theory.>>

I'm happy we agree about something, more or less.

<<But they are the results of hypothesis testing, not the basis for
hypothesis formulation and testing. >>

Scientifically valid hypotheses (be they right or wrong) "predict" results
and this is the basis of experimentation.  The term "predictability" may be
somewhat arbitrary, but once again it is the common term of art.

E.g., Bayes' Theorem extends that predictability to a measure of probability:

 "Bayes' Theorem provides a way to apply quantitative reasoning to what we
normally think of as 'the scientific method'. When several alternative
hypotheses are competing for our belief, we test them by deducing
consequences of each one, then conducting experimental tests to observe
whether or not those consequences actually occur. If an hypothesis predicts
that something should occur, and that thing does occur, it strengthens our
belief in the truthfulness of the hypothesis. Conversely, an observation that
contradicts the prediction would weaken (or destroy) our confidence in the
hypothesis.

"In many situations, the predictions involve probabilities-- one
hypothesis might predict that a certain outcome has a 30% chance of
occurring, while a competing hypothesis might predict a 50% chance of
the same outcome. In these situations, the occurrence or non-occurrence
of the outcome would shift our relative degree of belief from one
hypothesis toward another."

See the neat Bayes' Theorem Calculator at http://m2.aol.com/johnp71/bayes.html

With regard to the coexistence of two contrary hypotheses, the obvious
objective for the experimenter is to generate a test which resolves the
situation. From the abstract to P.Adorján, J.B. Levitt, J.S. Lund, and
K.Obermayer.  A model for the intracortical origin of orientation preference
and tuning in macaque striate cortex., Visual Neuroscience, 16:1-16,
1999:"...In contrast to models based on an afferent orientation bias,
however, the intracortical hypothesis predicts that orientation tuning
gradually evolves from an initially nonoriented response and a complete loss
of orientation tuning when the recurrent excitation is blocked, but new
experiments must be designed to unambiguously decide between both hypotheses."

A hypothesis must predict before it can be proven false by experimentation.
E.g.: "Our results are inconsistent with the detoxification hypothesis that
predicts that a large proportion of the heavy metals passing through the gut
are absorbed and stored permanently. We found for both zinc and copper that
the quantity in the abdomen was not proportional to the concentration of
these metals in the consumed food but was, instead, relatively invariant. For
these reasons, we suggest that regulated biological availability, not
detoxification, may be the primary benefit of zinc and copper storage." -
Abstract, MeV-ion microprobe analyses of whole Drosophila suggest that zinc
and copper accumulation is regulated storage not deposit excretion. Robert M.
S. Schofield, John H. Postlethwait and Harlan W. Lefevre; Journal of
Experimental Biology v.200(24)1997

What is most relevant about the three quotes above (as well as thousands of
others) is that they all include the phrase "hypothesis predicts."  As a
matter of language the two terms very often come together in this way in
scientific usage.  And this reflects clearly an understanding that the
"predictions" of the hypothesis are what is being tested.

Whether that is philosophically right or wrong is another matter.

Regards,
Steve Long



More information about the Indo-european mailing list