Theory, Experiment, and Evolution

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The word “theory” has many meanings, which makes it a rich source of confusion.  A theory might be a guess, as in “I’ve got a theory about that.”  It might be a collection of accepted practices, as in “music theory.”  And it might be a widely held general principle which explains something —one that is supported by facts—as in “the theory of relativity.”   Opponents of evolution often claim that it is a theory in the sense of “guess.” This claim commits the logical fallacy of equivocation—the substitution of an irrelevant meaning for the one that is intended, since evolution is actually a principle grounded in fact, just as Einstein’s theory of relativity is.  They also claim that one must be able to reproduce a phenomenon in the laboratory—to be able to “repeat the experiment”— before the theory which explains a phenomenon can be said to be scientific.  This isn’t true either.  And they claim that evolution has been discredited.  Another falsehood.

This is worth a moment of our time—not to refute creation science, which is easily done for it isn’t science at all (it just borrows and misuses the terminology of science), but to see how those opposing evolution craft their arguments.  They claim that evolution is a theory in the first sense—a guess.  Scientists don’t use the word in that way, and if one is questioning the claims of scientists, one must look to see what they mean by their words; after all, their meanings are what they claim to be the case.  In the formal development of scientific ideas, the closest that a scientist comes to making a guess is actually called an “hypothesis,” not a “theory,” and an hypothesis is actually a reasoned conjecture that emerges from an analysis of the relevant facts, not a mere “guess.”

Scientists know that an hypothesis is not established scientific fact, and they look for evidence to refute it or support it.  (Both are equally important to scientists!)  Only when there is very substantial evidence in its favor does it become a theory.  And when there is so much evidence that it is one of the most certain things that we know, it is still called a theory since a scientific theory is a general principle supported by facts.  Any large dictionary gives all of these meanings so the appropriate uses of the word “theory” are readily available to anyone who looks for them.  That being so, the misrepresentation of science in this way is more likely to be willful disregard of the truth than it is to be ignorance, and both are reprehensible when one is promoting an argument.  Much the same sort of thing can be said of the other claims.

It is claimed that evolution cannot be proven to be true because it cannot be demonstrated in the laboratory.  That is not a tenet of science but something made up by the opponents of evolution.  Close reasoning from facts can substitute for such a demonstration.  No one has ever seen an atom in the sense that we can see an acorn or a flea, but atomic theory explains, predicts, and makes possible everything from the microwave oven to the atomic bomb.  It works, and for it to work, atoms must exist and have the properties that are assigned to them.

The history of genetics is particularly relevant to the theory of evolution.  The concept of evolution has been around since at least the time of the ancient Greeks because it explains the astonishing similarity of the skeletons of related animals that exist now, as well as providing a framework that explains fossil remains.  Darwin’s theory of evolution by natural selection was widely accepted by scientists within a few decades of the time that it was proposed.  Nonetheless, there was no widely-accepted theory of genetics, and this was a problem because evolution requires a mechanism to pass on the characteristics that result from the natural selection process.  Darwin believed that a kind of a vague blending of characteristics must be the case, but this notion became more troublesome as the years passed and no detailed mechanism was discovered to make it plausible.  (This is one of the justifications for the bogus claims that the theory of evolution is now in trouble among scientists.)  Darwin actually had a copy of Gregor Mendel’s groundbreaking paper on inheritance which was published in 1866, but he apparently hadn’t read it, or had missed its significance.

 

In the meantime, the separation of the chromosomes in the nuclei of cells had been observed under the microscope.  Then, in 1900, three researchers simultaneously discovered the principles that Mendel had proposed.  It was now clear that the reduction division of the nucleus that had been observed microscopically, partitions the genetic material between the resulting sex cells, but what genes were—chemically and physically—was still unknown.

 

Since the 18th century, scientists had classified organisms into branching hierarchies based upon the similarity of stable features.  When evolution became widely accepted, such “trees” were recognized as being “family” trees, but there was no independent way of demonstrating what scientist knew to be true—that organisms located on these trees were closely or distantly related.  In 1953, Watson and Crick discovered the structure of the DNA molecule.  The chemical and physical nature of the genes was now known, and gene maps that plotted the sequences of the genes could be made.  As DNA testing became more refined, it was applied to various animals and plants, and the results were remarkable.  To an astonishing degree, the relationships of the animals in the traditional phylogenetic trees were verified by the similarity of their genetic makeup.

 

This history is surprising and beautiful, for it shows the gradual unraveling of a tremendous mystery.  It is somewhat like solving an intricate jigsaw puzzle, but the pieces came from different areas of inquiry, and sometimes other discoveries had to be made before their true significance became apparent.  Each piece fits cleanly into the emerging pattern, revealing a coherent undistorted picture.  Genetics—which is now a fully validated observational and experimental science—provides powerful proof of evolution.  (There are other important proofs, as well, originating, for example, from embryology and comparative anatomy.)

 

So, has evolution been discredited?  The answer is simply “No.” It has been validated to such an extent that one must agree with Julian Huxley, who said more than half a century ago that it is a fact, like digestion.  Every relevant new discovery supports it.  It is true that the concept of natural selection, as Darwin understood it, is being refined in various ways, but the basic nature of the system of inheritance is scientific fact.

 

All of this leaves us with some questions about creation science, which provides much of the ammunition for those who oppose evolution (although many of the arguments are jaded, going back to Henri Bergson and even further).  How many of the “creation scientists” are in fact top-notch scientists, people doing the cutting-edge work in discovering what the world is like?  The answer is—none, although a few have published useful papers.  A degree in science doesn’t make one a scientist.  (I have one, and have even published a useful paper, but I wouldn’t make such a claim.)  Furthermore, a job running routine scientific tests or teaching science in a bible college doesn’t prepare one to speak for science since it doesn’t require that one be alive to the significance of the ideas themselves.  What research scientists do is look for the “truths” of the world, the facts and principles that we can rely on.

It is clear from their writings that creation “scientists” are not really aware of what has happened in science over the last hundred years—or if they are aware of it, they choose to ignore it.  Both are contemptible.  Evolution is, in truth, alive and doing very, very well as the unifying theory of biology.  Why should anyone believe people who seem incapable of presenting the facts honestly?