Evolution of living organisms, at least for life as we know it, is a fact.
I'm so tired of hearing people who have little-to-no understanding of evolutionary biology or who "feel" like evolution
debases their religion who staunchly claim that we have no evidence for
evolution or that scientists are debating whether evolution occurs.
"Evolution is just a theory" is one of the worst things these people say. What
they mean to say is "evolution is just a cheap guess", yet they
misuse the term theory, substituting the lay connotation of that term instead
of the scientific and philosophical meaning. Saying "evolution is just a
theory" in an attempt to slander the study of biology and evolution is
less than half-witted and exemplifies the sincere necessity better education
programs across the globe.
Indeed, evolution is a theory. But evolution is an accepted fact as well.
That seems counterintuitive to most people at first, but that's usually
more due to their own ignorance rather than a lack of specificity in the
Evolution is a Fact.
This means that we know for certain, 100% guaranteed, that evolution occurs. We
can observe evolution occurring on the small scale; indeed, some of the best
undergraduate biology labs are those which allow young students to see
microorganisms evolve due to selective pressures over short periods of time.
With the mountainous body of evidence, coming from several different
lines of empirical evidence and reasoning, that we have have for evolution we
know for certain that it is occurring. Evolution is a fact.
Evolution is a theory.
In the sciences, a theory is an accepted explanation for some natural phenomena.
It usually consists of a body of evidence that support some hypotheses
for why we observe a certain occurrence or set of occurrences. Theories
must always consider exceptions and other theories. There are some
theories which are very well supported, but are not as strongly able to explain
exceptions and so we generally utilize those theories until we can find
evidence/information which allows us to rationally fix the theory or, if the
theory proves falsifiable, then we discard the theory.
As Stephen Hawking said, "A theory is a good theory if it satisfies two requirements:
It must accurately describe a large class of observations on the basis of a
model that contains only a few arbitrary elements, and it must make definite
predictions about the results of future observations. Any physical theory
is always provisional, in the sense that it is only a hypothesis; you can never
prove it. No matter how many times the results of experiments agree with some
theory, you can never be sure that the next time the result will not contradict
the theory. On the other hand, you can disprove a theory by finding even a
single observation that disagrees with the predictions of the theory."
This means that theories may be generally or even universally accepted,
yet if the theories fail to explain evidence within their realm then we have to
consider evaluating or updating the theories, and if some line of evidence
emerges that falsifies the theory then the theory is moot and a new theory must
be developed to explain the natural phenomena we observe.
Evolution is one of those extremely strong theories that explains the natural phenomena
we see (like the diversity of life on Earth and how life interacts from local
to global scales). Evolution also takes into considerations exceptions to
the rule and quite beautifully explains those exceptions. Indeed, the theoretical
nature of evolution comes from the continual revision to the field of
evolutionary biology by seeing the many various modes through which evolution
acts and the humility of scientists in our objectivity in light of evidence and
reason. We can see evolution occur gradually, like Charles Darwin
hypothesized, and we also see evolution occur in bursts, like the punctuated
equilibrium hypothesized by Stephen J. Gould. We have many hypotheses for
how evolution occurs, such as natural selection, artificial selection, and
sexual selection, and each of these explains many natural phenomena as well as
possible exceptions. Indeed, evolution is probably one of the strongest
and most acceptable theories we have in all of modern science and is indeed the
binding theory for all of biology. As Theodosius Dobzhansky said,
“Nothing in biology makes sense except in the light of evolution."
Theories in modern science.
There are many accepted forms of thought that are "just theories" as the
nay-sayers would explain them. These include the theory of gravitation,
the theory of relativity, the theory of atoms, the theory of electromagnetism,
the theory of plate tectonics, molecular orbital theory, and the germ theory of
disease. Notice that all of these theories are pretty much accepted as
explanations for why we see the universe function in the way that it does.
The theories may not fully explain everything, which is why we always
search to expand the theories and we allow for the theories to be changed as
needed so that they truly explain what we observe. If I ask someone on
the street why a tennis ball thrown upward will fall back down again, they will
likely say something like, "because of gravity." Most people
won't say, "because of the theory of gravitation, which states that matter
is attracted to other matter through gravitation which can be modeled by
Newton's laws of gravitation, Einstein's theory of relativity, and quantum
mechanics. By the way, to understand this requires that we understand the
theory of atoms and the theory of electromagnetism." Of course they
won't answer this way. Well, maybe not. I guess maybe there are a
few of us who would try to explain why the tennis ball falls with a little more
than just "because of gravity." Notice though that when someone
says, "because of gravity" you will understand what they mean.
You will most likely agree because gravitation is our understanding of
how matter is attracted to other matter. Likewise, evolution is our
understanding of how the great diversity of life on Earth has come to be and
how life as we know it interacts from miniscule to grand scales. Yet, if
I ask someone on the street (at least in America) why giraffes have such long
necks there is only a slight chance that they will say, "because of evolution".
Indeed there are a good many who will say, "because god made them
that way" and chances are the great majority will say, "I have no
The need for the end of religion?
Why all the disparity amongst the general public over our understanding of evolution?
One of the greatest reasons that evolution is still obscured by ignorance
and hatred is due to religious fundamentalism and religious dogma.
Religion, unlike science, has little-to-no humility and indeed is full of
fear. Religion drives fear of life and death, fear of the unknown, and
fear of other ideas and people. I find religion fantastic and I believe
we should study religion for its rich history and for how it moved humans
throughout history, but we have long since entered a time in modern
civilization where religion is unnecessary and, indeed, is driving a wedge of
ignorance. The acceptance of christianity into roman society and the
beginnings of the roman catholic church drove the movement of ignorance, caused
the murder of intellectuals and the burning and destruction of libraries and
schools across the Mediterranean regions, and caused the beginning of what we
now call the Dark Ages. Science, reason, and artistic expression brought
western civilization out of the dark ages. The Renaissance, the
enlightenment movements, and the end of empirical civilization has given us the
drive to a purposeful society. And yet, we are hindered by religion's
presence. Now is truly the right time for us to shed the shell of
ignorance called religion and give way to our acceptance of understanding and
rationality and to pursue a deeper understanding of human spirituality.
Evolution is a fact.
Once society can begin to look past the narrow-sighted "conclusions" of
religion, which are not based in observation or rationality, then I like to
think that evolution will be as accepted as gravitation and electromagnetism.
Martin Luther once said of Nicholas Copernicus (who gave Europe it's
first recorded heliocentric model of the solar system since the beginning of
the ignorance movements of christianity), "This fool wishes to reverse the
entire science of astronomy." Much has similarly been said of
Charles Darwin and all of those many evolutionary biologists and free thinkers
who have followed him in relation to our understanding of life. But we
now know that the sun is at the center of our solar system, just as we know
that evolution is a fact and explains the diversity of life we see on Earth.
I consider those who call evolution "just a theory" (with
a pejorative intended, even though, as I mentioned, they really
aren't appropriately slandering evolution in this way) to be the same as those
who believe the Earth is still flat and lies at the center of our solar system.
It's not that they cannot understand. Indeed, ignorance can be
surpassed and consciousness can be raised. Everyone can understand
evolution. Indeed, if everyone attempted to learn about what evolution
really says without letting their supernatural beliefs drive them to fear, then
the answer to why a giraffe's neck is long will almost always be, "because
of evolution". Also, evolution as a theory is not perfect. As
a theory it never can be, and so the theory can be updated and new modes and
facets of the theory can be resolved. If more people tried to understand
biological evolution, I think the model itself would benefit as new rational
thoughts and processes of reasoning shed light on all the ways in which
evolution has driven the diversity of life on this planet Earth. Evolution
is a theory, but it's not "just a theory". Indeed, for the
purposes of the general public, we must consider that evolution is a