> When events are not repeatible, we can still use science to learn about
> them by studying multiple lines of evidence. The point that creationists
> seem to ignore (or not respond to or it goes over their heads or...) is
> that multiple lines of evidence support the current theory of evolution.
> Dan Ashlock, one of the talk.origins regulars put it this way once, (loose
> paraphrase) "There are about 100 lines of independent evidence that support
> the currently accepted theory of evolution. Even if 95 of them were
> totally bogus, the probability that the theory is correct is still 1 -
> 2^(-5) = about 97 percent."
Held at arms length, this argument appears very impressive. There are, however,
some implicit assumptions that warrant closer investigation. The calculations
assume that all lines of evidence are independent of each other and it assumes equal
a-priori probability that each line of evidence is true or false (p=0.5). I would,
for the sake of good science, challenge both these assumptions, but for the moment,
we let them stand. What is more important is that it is claimed that the theory of
evolution is supported by 100 *potentially confirming* testable hypotheses.
On the other hand, if it were possible to test the theory of evolution by
constructing 100 *potentially falsifying* hypotheses, then even if the theory
successfully PASSES 95 of them, using the same a-priori assumptions as before,
the probability of the theory being correct is only about 3%. Of course neither
of these calculations have much bearing on reality, but they draw attention to
an important fact: The theory of evolution, as it is currently framed, whether
by intent or by circumstance, is not falsifyable. This is what lead science
philosopher Karl Popper to criticize the theory of evolution in the same way
he challenged other theories in vogue, such as Marxist economics and Freudian
psychology. To Popper, the most impressive scientific theories were those that
could be subjected to daring, potentially falsifying experiments, like Einsteins
theory of relativity. In stead, what Karl Popper found were investigators intent
only on seeking evidence to *confirm* the theory. One may wish to argue that
falsifying experiments DO exists, but only after surrendering the above
probability estimates.
-jpt
--John P. Turnbull (jpt@ccfadm.eeg.ccf.org)Cleveland Clinic FoundationDept. of Neurology, Section of Neurological ComputingM52-119500 Euclid Ave.Cleveland Ohio 44195Telephone (216) 444-8041; FAX (216) 444-9401