The attractive force between these two objects is such and such.
OR
The amino acid sequence for this protein is such and such.
OR
These two amino acid sequences are 99% identical.
OR
This fossil is found in such and such layer.
Even the universal gravitational law is an inductive generalization. It's
not a fact--only the measurement of the force between two objects at such
and such a distance is a fact.
Likewise, by this strict definition, evolution is not a fact.
However, I'm not sure that this is a helpful distinction. By this
definition, we could not say that the proposition that matter is made of
atoms is a fact. In fact, I often say this to my students. And we do call
it atomic theory and not atomic fact. But does this mean that it's
unreasonably to act if we know for certain that matter is made of atoms--to
treat it as if it were a fact. Most of science is theory in this sense.
Here's how Gould puts in his famous (or infamous) "Evolution as Fact and
Theory" article.
"Moreover, "fact" does not mean "absolute certainty." The final proofs of
logic and mathematics flow deductively from stated premises and acheive
certainty only because they are *not* about the empirical world.
Evolutionists make no claim for perpetual truth, though creationists often
do (and then attack us for a style of argument that they themselves favor).
In science, "fact" can only mean "confirmed to such a degree that it would
be perverse to withhold provisional assent." I suppose that apples might
start to rise tomorrow, but the possibility does not merit equal time in
physics classrooms."
Notice that Gould accepts "facts" by this definition only provisionally.
Gould goes on to distinguish between common ancestry as fact and natural
selection as theory. Perhaps more cautiously he could have distinguished
between hierarchical relationships among living things at the macro and
biochemical level and the pattern found in the fossil record as facts and
the phrase common ancestry, although by Gould's definition (and his
definition of perversity-oh, what a quagmire already) common ancestry would
be a fact.
Perhaps we've been through all this--I haven't followed this thread as
closely as I should have--but I've never been convinced that fact/theory
distinctions are all that helpful. The broader scientific consensus is
what it is and it is rooted in certain lines of evidence and arguments.
There may be alternative interpretations but if a well-entrenched
macro-theory is in place, those alternative interpretations have their work
cut out for them if they will be taken seriously as an alternative. (This
all sounds horribly Kuhnian--which is fairly unusual for me.)
My own take on this is that the evolutionary framework is alive and well
among practicing biologists and biochemists. There is no reason under the
sun to think that its influence is waning. To think that intelligent
design folks are convincing anyone but themselves and people who are
already anti-evolutionist in their thinking is dreaming. This is not to
say that they aren't pointing out some very interesting questions, but very
few people think that those questions can't be answered within the general
evolutionary framework. Even such neo-Darwinian critics as Kaufmann and
Shapiro and Stanley are not turning to intelligent design or any other
brand of creationism, but rather are seeking to modify or extend the
neo-Darwinian idea of evolution.
TG
_____________________________________________________________
Terry M. Gray, Ph.D. Department of Chemistry and Biochemistry
Calvin College 3201 Burton SE Grand Rapids, MI 49546
Office: (616) 957-7187 FAX: (616) 957-6501
Email: grayt@calvin.edu http://www.calvin.edu/~grayt
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