T. Ryan Gregory
Science 286: 414.
According to Hogg, a physicist, the empirical
support
for evolution is limited to a few experiments on fruit flies and is
altogether
lacking in predictive tests and falsifiable hypotheses. This raises the
question, what is the nature of science? Put briefly, scientific
theories
are postulated to explain scientific facts (observations so thoroughly
confirmed that they are considered "true"). Evolution is no different
in
this regard from, say, the theory of relativity. Gravity is a
scientific
fact that relativity seeks to explain. That organisms share a common
evolutionary
history is as much an established fact as any other in science, and the
theory of evolution seeks to elucidate the mechanism or mechanisms by
which
this has occurred. (This includes, but is not limited to, Darwin's
concept
of natural selection.) Thus, Hogg's complaint that evolution has not
been
"validated" is unfounded. But can evolution (the theory, not the fact)
make testable predictions? The results of countless
laboratory and field experiments strongly suggest that it does.
Moreover,
these tests are similar in principle to those in physics (has anyone
actually
traveled at the speed of light to test relativity?). It is also easy to
imagine potential falsifiers of evolutionary theory--the discovery of
genetic
mechanisms not compatible with natural selection, for example. Not only
has evolution been overwhelmingly "validated" as a fact, but
evolutionary
theory has been greatly supported in its specifics. The past 150 years
of biology cannot be ignored. Until evolution (both as fact and as
theory)
is better understood, trends such as those illustrated by the
educational
developments in Kansas are likely to continue.
Note: Hogg's original letter, a response to an editorial
by
Stephen Jay Gould (Science
284: 2087), is found in Science
285: 663. Other replies to his letter were printed in Science
286: 413-414. Hogg accepts our criticisms and attempts to
clarify
his original position in a follow-up letter in Science
286: 1679.