But it's "JUST a THEORY"
This is such a common complaint about evolution that it deserves a
page of it's own. This
comment is born out of misuse of the word theory. People who make
statements like: "But
it's only a theory; it's not a scientific law," or "It's a theory, not
a fact," don't really know
the meanings of the words their using.
Theory does not mean guess, or hunch, or hypothesis. A theory does
not change into a
scientific law with the accumulation of new or better evidence. A
theory will always be a
theory, a law will always be a law. A theory will never become a law,
and a law never was a
theory.
The following definitions, based on information from the National
Academy of Sciences,
should help anyone understand why evolution is not "just a theory."
A scientific law is a description of an observed phenomenon. Kepler's
Laws of Planetary
Motion are a good example. Those laws describe the motions of
planets. But they do not
explain why they are that way. If all scientists ever did was to
formulate scientific laws, then
the universe would be very well-described, but still unexplained and
very mysterious.
A theory is a scientific explanation of an observed phenomenon.
Unlike laws, theories
actually explain why things are the way they are. Theories are what
science is for. If, then, a
theory is a scientific explanation of a natural phenomena, ask
yourself this: "What part of
that definition excludes a theory from being a fact?" The answer is
nothing! There is no
reason a theory cannot be an actual fact as well.
For example, there is the phenomenon of gravity, which you can feel.
It is a fact that you
can feel it, and that bodies caught in a gravitational field will fall
towards the center. Then
there is the theory of gravity, which explains the phenomenon of
gravity, based on
observation, physical evidence and experiment. Albert Einstein's
General Theory of Relativity
replaced the less accurate gravity theory of Sir Isaac Newton, which
was the first complete
mathematical theory formulated which described a fundamental force.
There is the modern theory of evolution, neo-darwinism. It is a
synthesis of many scientific
fields (biology, population genetics, paleontology, embryology,
geology, zoology,
microbiology, botany, and more). It replaces darwinism, which replaced
lamarckism, which
replaced the hypotheses of Erasmus Darwin (Charles' grandfather),
which expanded the ideas
of Georges de Buffon, which in turn expanded upon the classification
of Karl von Linne.
(see also: Darwin's Precursors and Influences)
So there is the theory of evolution. Then there is the FACT of
evolution. Species change--
there is variation within one kind of animal. There is a predictable
range of genetic variation in
a species, as well as an expected rate of random mutations.
Creationists readily admit that a
"kind" (an ambiguous, non-scientific term) can develop into different
species (i.e. a dog
"kind" can evolve into wolves, coyotes, foxes, and all types of
domestic dogs) but they insist
that it must stop there. They never give any reason for this
fabricated limitation-- they just
deny that it can happen. They just can't accept macroevolution,
because it contradicts the
"truth" of their dogma. But in reality, there is no limit to the
degree that a species can change.
Given enough time, a fish-like species can evolve into a
amphibian-like species, an
amphibian-like species can evolve into a reptilian-like species, a
reptilian-like species can
evolve into a mammalian-like species, and an ape-like species can
evolve into the modern
human species.
The process (simply stated) involves the genetic potential of many
different types of
individuals within a species, the birth of a great many individual
organisms, and the deaths of
those individuals whose characteristics are not as well suited to the
total environment as other
individuals of the same species. The deaths of these less well suited
individuals allows for the
increased reproduction of the better suited ones, which initiates a
shift in the appearance and
function of the species. Without limitation. There is more genetic
stuff to it than that, but that
is basically how it works.
Yes, evolution is a fact, as real as gravity. The fact that all
species alive today have
descended from a common ancestor can be denied, but not refuted. We
know it happens
because we can observe it directly in short-lived species, and for
longer lived species there is
genetic and fossil evidence that is unambiguous. There is no other
scientific explanation for
the diversity of living species. Evolution is a very well established
scientific concept with a
massive amount of physical evidence for support. It is not a guess.
Evolution is the basis of
modern biology, and universities and laboratories across the world
are engaged in research
that explores evolution.
You don't have to 'believe' in evolution. You can trust that the
thousands of scientists who
study this phenomenon aren't morons, or Satanists. You can accept the
general idea that life
propagates with modifications, and those modifications can lead to
improved survival, and
that as those modifications are passed over time, many modifications
can lead to a species
that looks very different from its predecessor. Is that so hard to
accept?
I have no faith at all in evolution. (I also have no faith in algebra,
chemistry or astronomy).
Evolution either stands or falls by the strength of the evidence used
to substantiate it.
Evolutionary biology relies on factual data, physical evidence,
molecular experimentation, and
it goes hand in hand with geology.
Some people can say "Well, scientists weren't there... they don't know
what happened. It's
still faith." But that is mere blind objectionism, like an ostrich
hiding its head in the sand.
There are real reasons behind the science of reconstructing the past.
My favorite analogy is
forensic science. A man can murder someone (with no witnesses), and
scientists can
reconstruct the scene with such accuracy as to pinpoint the guilty
person-- with such accuracy
as to cause that man to receive the death penalty. For example, most
Americans are
convinced of O.J. Simpson's guilt... even though no one was there to
see him do it. The
situation with evolution is much the same-- reconstructing the past
through examination of the
evidence. It's true that not every theory withstands the test of time
and goes on to be
considered a fact by nearly all of the scientific community, but
evolution is one that has.
See also: Evolution is a Fact and a Theory
This is the statement from the National Academy of Science:
Is Evolution a fact or a theory?
The theory of evolution explains how life on earth has
changed. In
scientific terms, "theory" does not mean "guess" or "hunch"
as it does
in everyday usage. Scientific theories are explanations of
natural
phenomena built up logically from testable observations and
hypotheses. Biological evolution is the best scientific
explanation we
have for the enormous range of observations about the
living world.
Scientists most often use the word "fact" to describe an
observation.
But scientists can also use fact to mean something that has
been
tested or observed so many times that there is no longer a
compelling
reason to keep testing or looking for examples. The
occurrence of
evolution in this sense is a fact. Scientists no longer
question whether
descent with modification occurred because the evidence
supporting
the idea is so strong.
Why isn't evolution called a law?
Laws are generalizations that describe phenomena, whereas
theories
explain phenomena. For example, the laws of thermodynamics
describe what will happen under certain circumstances;
thermodynamics theories explain why these events occur.
Laws, like
facts and theories, can change with better data. But
theories do not
develop into laws with the accumulation of evidence.
Rather, theories
are the goal of science.
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