Question:

I read with interest your article on the ID debate in which you say
that ID is not a scientific theory because it is not falsifiable. You also
state that evolution as a good theory. My question is this: Is evolution
falsifiable? Personally I do not think so because some say it happened
slowly while others indicate it happened in quick bursts whenever it did
occur (punctuated equilibriumists). We cannot use experimental evidence of
microevolution as proof of macroevolution. All groups, including ID,
creationist, and evolutionists agree microevolution happens. The question
remains, doesn’t macroevolution lack falsifiability?

Answer:

The answer is that evolution is indeed falsifiable, although it is a
special case. What is interesting is that when Darwin proposed the theory
of evolution by natural selection it was not really falsifiable. However,
neo-Darwinism is in fact falsifiable. Allow me to explain.

One of the fundamental tenets of modern evolution theory (also known as
neo-Darwinism) is that heredity of traits is through passing on of the DNA
from parent to offspring. Species which evolve into new species have DNA
which changes one nucleotide at a time. The cumulative change in the DNA
is what produces change of traits and new species. An clear implication of
this is that species which are related to one another by descent from a
common ancestor should have very similar DNA. In fact, one should be able
to predict to within a certain amount of experimental error how much
change should take place over time.

The point of this detail is that the relative similarity of species in
their DNA is something which can be checked by experiment. For example
the DNA of humans and chimpanzees is between 98 and 99% identical, while
the DNA of humans and goldfish has much greater difference. If experiment
showed that goldfish and humans had 99% similarity in their DNA but humans
and chimps had only 60% similarity in their DNA, that would falsify
evolution. Yes, evolution is falsifiable.

In fact, I believe that the fossil evidence we have tends to falsify the
grand claims of evolution. The Cambrian explosion, with its sudden
appearance of all five animal phyla in virtually zero geological time is
evidence which strongly argues against evolution of these phyla. It is
probably too strong to say that it absolutely falsifies evolution, but it
is suggestive. The point is that the main evidence for evolution on a
grand scale: bacteria-to-humans, is supported by two main strands of
evidence. The two main categories of evidence underlying evolution are DNA
and the fossil record. Both make evolutionm falsifiable.

Having said that, I know where you are coming from on this question. At
first glance, evolution seems non-falsifiable. The fact is that evolution
on a grand scale, if it happened, occurred in the very distant past. We
obviously cannot do an experiment in the past. Any theory which is about
the past, which is by definition not repeatable in the laboratory is a
special case. Such theories are inherently more difficult to falsify.
Another important theory in this category is the Big Bang theory. This,
too, involves a one-time event in the very distant past, which makes it
hard to confirm by experiment. Despite the limitation for testing both
the Big Bang and evolution, both are in fact falsifiable. If the universe
were not expanding, or if the background radiation were missing, the Big
Bang theory would be falsified. If the fossil record showed radical
departure from what it predicted from evolution (it does) or if the DNA
evidence was in dramatic contradition with the predictions of evolution
(it is not), then the theory of evolution is falsifiable.

John Oakes, PhD