On Teaching Evolution in U.S. Public
Schools
Consider the following statement:
All life on Earth was produced by impersonal forces,
without any overriding design or purpose.
Is this statement "true," and should it be taught as fact to public school
students?
Core Questions
In my opinion, the so-called evolution/creationism "debate" revolves
around this statement (or something similar) and these two questions. That
is, the question is not whether or not organisms evolve, whether or not
creationism should be considered scientific, or any of the other host of
issues that are generally associated with the evolution/creation conflict.
The question is whether or not public school science students should
be taught that the only reasonable belief is that God played no significant
role in the creation of life.
On one side of the debate, many religious parents feel that "godless
science" is trying to teach their children that there is no God, or at
best that God may exist but is irrelevant. Their concerns about the
teaching of evolution are largely derivatives of this primary concern. On
the other side, science is by definition dedicated to finding natural explanations
for observations, explanations that have no reference to supernatural phenomena.
Most scientists are therefore understandably opposed to any attempt
to bring supernatural explanations of the origins of life into the science
classroom.
Is there a middle ground that can satisfy, or at least mollify, both
groups? I believe that there is. In a nutshell, I believe that
the key is to teach students the current scientific consensus and to also
teach them about the limits of the scientific method to determine "truth."
Scientific Consensus
It would seem to be stating the obvious to say that when scientists have
reached a consensus on some topic of research, this consensus should be taught
concerning that topic in public school science classrooms. However,
when it comes to teaching biological evolution, on which there is tremendous
scientific consensus, look out! Some creationists have gone so far
as to essentially claim that the teaching of evolution in U.S. public schools
is the result of a conspiracy among atheistic scientists who know that evolution
is bad science but are nonetheless determined to undermine the faith of religious
students through the teaching of evolutionary theories. Therefore,
the reasoning goes, even though there appears to be a consensus, it is not
a scientific consensus. This justifies teaching "true"--creationist--science
alongside "pseudo-scientific" evolutionary theories.
Notice that this line of reasoning hinges on the belief that (some) scientists
are trying to use science to attack the religious convictions of students,
stirring a visceral response in many parents. Thus, to the extent that
science education circumscribes any supposed attempt at attacking students'
convictions, the response of these parents may be significantly blunted,
and many of their objections to teaching the scientific consensus could be
expected to dissipate. But can science education perform such a role,
and should it?
Science Has Limits
Let's return to the statement above. The first phrase--all life
on Earth was produced by impersonal forces--is tautological from a scientific
perspective. That is, scientific inquiry begins with the premise
that all natural phenomena have natural explanations. In particular,
since life is a natural phenomenon, the scientific assumption is that life
has a natural explanation. This might seem to be an attack on certain
religious beliefs, but it is not. It is simply an assumption made
for the purpose of seeing how far naturalistic explanations can be carried
and for comparing various naturalistic explanations with one another.
In particular, notice that evolution, or any other scientific theory,
can never "prove" that life was produced by impersonal forces, since the
scientific process begins by assuming this and no theoretical process can
prove its own assumptions (assuming that no assumptions are redundant, which
we can assume in this case). In fact, science cannot rule out the possibility
of supernatural intervention in any process even if the process is explained
by what is considered a well-established theory (a "law"). The framework
of science ignores the possibility of supernatural events, so if such an event
was to occur it would be viewed scientifically as a problem for the theory,
spurious data, etc., but not as a supernatural event. However, assuming
for the sake of scientific study that such possibilities do not exist is
not a proof that such possibilities do not exist, no matter how well theory
fits observations. Again, there is simply no valid way to prove the
assumptions of a theoretical framework within that framework.
Another limitation of the scientific process is that it can never arrive
at the conclusion that "there is no possible theory" for some set of observations.
The most negative conclusion it can produce is that "none of our current
theories is fully satisfactory" in accounting for the observations. But
there is always the possibility that someone will develop a clever new theory
that is more satisfactory.
So, is it "true" that all life on Earth was produced by impersonal forces?
Well, if you believe (philosophically, and not just for purposes
of scientific inquiry) that every natural observation has a natural explanation,
the answer is "yes, of course!!" I suppose that one could even claim
that "science" believes that this claim is true. But it cannot be
claimed (honestly) that science has "proved" this statement in the normal
sense of the term "proof." The most that might be said along these
lines is that science has produced a theory--biological evolution based on
random mutation plus natural selection--that seems to generally fit well
with observation and that provides the best naturalistic explanation currently
for life's development from single-celled organisms to present forms. That
is, the theory of biological evolution has been "proved" in the scientific
sense of being the best current naturalistic explanation. However,
science is incapable of proving more generally that biological evolution
is the correct ("true") explanation, or even that it is the most rational
explanation.
This latter point is subtle but crucially important. Science has
been so successful in so many areas of inquiry that it is tempting to believe
that the scientific method is the only rational method for producing explanations.
After all, since it has worked so well in the past in so many areas,
how could we rationally believe that it will not work well in all areas
of inquiry and do so forever more? Put in such strong terms, you may
see the problem: how can we possibly know that the scientific method will
always work well? Obviously, we can't prove that it will. We
have a tendency as humans to believe that past observations are indicative
of future behaviors, but we have no proof that this will be the case. All
we have is our belief, which is not necessarily rational.
Let me put the problem another way. The scientific method is based
on the inductive method: from specific observations we induce a general
explanation that agrees (at least most of the time) with the observations.
And why do we think that the scientific method is a good way to produce
explanations? Because we have observed that it seems to have worked
well in the past. That is, our belief that it is good is based on
inductive reasoning! In other words, based on inductive reasoning,
we believe that inductive reasoning is a good way to produce explanations.
This is, of course, a circular argument, and therefore not valid (deductive)
reasoning. In short, we have no proof even that science produces the
most rational explanations of observations, let alone that it produces the
correct explanations. (For a fuller treatment of this line of thinking,
which originated with the Scottish philosopher David Hume several centuries
ago, I suggest the book "The Foundations of Scientific Inference",
by Wesley C. Salmon).
Now let's turn to the second phrase of the original statement, dealing
with purpose and design. It seems to me that many who believe philosophically
that every natural phenomenon has a natural explanation also believe that
there is no ultimate purpose or design for the universe. But notice
that these are two separate beliefs. One could, for example, rationally
believe that impersonal laws govern this universe, but also believe that
these laws were designed for some purpose by a personal intelligence. In
fact, I would go so far as to say that science itself is mute on the topic
of origins of the laws that it presumes exist. While there have been
some philosophical hypotheses about apparently naturalistic ways in which
our universe's laws could have arisen, these musings are not science per
se since they do not offer testable hypotheses. Besides, any
attempt to produce naturalistic (law-based) explanations for the origin
of the laws of our universe simply begs the question of the origins of the
supposed meta-laws. Ultimately, the questions of origins of natural
laws are philosophic and not scientific. This implies that no one
origins philosophy can claim to be more scientific than any other.
What Students Should Be Taught
It would seem, then, that there are two key points on which both sides
in the evolution/creation conflict can and should agree:
- The public school science classroom is not the place to teach various
beliefs about supernatural phenomena in general, and beliefs about possible
supernatural interventions in the origins of life in particular. These
topics are outside the scientific fields of inquiry.
- The public school science classroom is also not the place to disparage
beliefs about supernatural phenomena, for exactly the same reason: these
topics are outside the scientific fields of inquiry! To ensure that
students are not confused about the role of science in arriving at beliefs,
it is vital that students be taught explicitly and implicitly in science
classrooms that:
- The scientific method is not the only reasonable way to arrive
at beliefs about our world, or even necessarily the most rational way.
- Science assumes that naturalistic explanations exist for all
observations, not because this is the "right" assumption to make, but because
it is the way science operates as a discipline. In fact, this assumption
imposes some severe limitations on science, including:
- No law of science can ever be proved "beyond reasonable doubt"
because it is always proved in the context of the naturalistic assumption,
which is open to reasonable doubt. Put another way, the existence
of a scientific, naturalistic explanation for observations does not at all
preclude the possibility that the observations were actually produced by
supernatural phenomena.
- The scientific method can never arrive at the conclusion "there
is no natural explanation" even if this is in fact the case for some observations.
- All beliefs about the origins of the laws that science purports
to discover are equally non-scientific. This does not mean that these
beliefs are not important, or that some beliefs might not be more rational
than others. It does illustrate some of the limitations of science
even as an aid to developing beliefs.
I suppose that one could argue that what I advocate teaching in the second
point is some of the philosophy of science, not science itself, and so
does not belong in the science curriculum. But this would be a disingenuous
argument: to teach science without examining its assumptions is essentially
to teach science as if it makes no untrue assumptions, that is, to teach
that supernatural phenomena either do not exist or can always be safely ignored.
In other words, teaching science in this way is essentially teaching
not only the scientific method but also teaching a certain philosophical
viewpoint. Again, I believe that it is the implicit teaching of this
viewpoint that is at the heart of much of the rancor creationists express
concerning the current approach to teaching evolution.
Making My Point
I believe that a careful treatment in the classroom of the underlying
philosophical assumptions made in the pursuit of science as a discipline
would go a long way toward relieving the concerns of many religious parents
of public school students. On the other hand, defenses against creationist
"attacks" on evolution, such as Scientific American editor-in-chief John
Rennie's "
15 Answers to Creationist Nonsense" (July 2002), seem more likely to
continue the nonsense1 than to end it. If evolution was
carefully presented in science classrooms as what it is and no more--the
scientific community's current best attempt at producing a naturalistic
explanation for life as we know it, with all of the limitations outlined
above--then it would seem that much of the pressure to "attack" evolution
(or, more to the point, attempt to defend a theistic philosophy of origins)
would be relieved.
Let me focus for a moment on Rennie's essay, since it prompted me to
write this piece. Some of his arguments, viewed through the philosophy-of-science
lens I have described above, just serve to make my point about science education.
Take his opening sentence, for example: "When Charles Darwin introduced
the theory of evolution through natural selection 143 years ago, the scientists
of the day argued over it fiercely, but the massing evidence from paleontology,
genetics, zoology, molecular biology and other fields gradually established
evolution's truth beyond reasonable doubt." I assume that Mr. Rennie
is here implying the adjective "scientific" before the words "truth" and "doubt."
That is, I assume that he agrees that a "scientific truth" is
never necessarily correct, and that it is therefore always reasonable to
doubt a scientific truth, even if it has been established beyond doubt from
a scientific perspective by showing truly remarkable agreement with observations,
being simpler than alternative theories, etc. Are these meanings of
"truth" and "doubt" clear to the typical reader of Scientific American? I
suspect not, precisely because I suspect that very few non-scientists are
ever taught to distinguish between scientific truth and unqualified truth.
So I strongly suspect that the typical reader sees this sentence as
saying that "evolution is true beyond reasonable doubt, period." But
this statement is simply not true, by the reasoning above, and I for one
think that public school science curricula need to make this clear so that
the general public has a better understanding of claims such as Rennie's.
As it is, such a statement seems only likely to further incite creationists.
For the specific case of evolution, as opposed to the discussion about
science in general given above, here's another way of seeing the absurdity
of a blanket "true beyond reasonable doubt" claim. Rennie himself notes
that some "antievolution" authors have identified certain "evolutionary problems
as unsolved and difficult (which no one disputes)." How can it be
unreasonable to doubt a theory such as evolution that has difficult unsolved
problems? Isn't it possible that these problems will never be solved
by evolutionary arguments, that the theory (or some significant portion
of it) will prove to be wrong? Well, if evolution is essentially the only
reasonable naturalistic theory explaining certain observations and
if a naturalistic theory must exist, then there is no reasonable alternative.
But if we drop the naturalistic assumption that such a theory must
exist, then there are many reasonable (although non-scientific) alternative
explanations, and it becomes not only reasonable but perhaps sensible to
entertain doubts about evolution. In terms of teaching evolution in
the classroom, while it would probably be inappropriate to present possible
non-scientific explanations, it would seem eminently appropriate to present
various problems--that no one disputes--with evolutionary theory and to point
out that it is reasonable to have doubts about at least some of evolution's
claims. After all, one of our goals in science education should be
to teach students that our scientific understanding of the world is--for
lack of a better word--constantly evolving, and that a prime way in which
we improve scientific knowledge is by identifying shortcomings in current
theories and working either to modify or supplant the theories. So
introducing science students to shortcomings in current evolutionary theory
would seem to be an excellent way to show these students that science doesn't
already have all the answers, that there is still work to do, that maybe
some of our theories--yes, even evolutionary theories--are just plain wrong.
What better way to calm creationists than to candidly admit that their
core belief that God played a significant role in the creation of life on
Earth may turn out to be correct, that no one can prove (without assumptions)
that they are wrong?
Some Humility
To summarize, it seems to me that both sides in the creation/evolution
conflict could use a little more humility (OK, so could we all, but that's
another story ;-). Creationists need to recognize that supernatural
explanations are not scientific explanations and to back off from any attempts
at forcing public school science teachers to present non-scientific explanations
in the guise of science. Evolutionists need to recognize that scientific
explanations are not necessarily equivalent to unqualified truth and to
back off from any attempts to use public school teachers to present scientific
"truth" and the scientific method as more than they are, in the process belittling
nonscientific but still feasible beliefs.
Footnotes
1. For the record, I don't believe that all of the creationist work alluded
to in Rennie's article qualifies as "nonsense," nor that he would even necessarily
make such a claim. On the other hand, I do agree with Rennie that there
is a great deal of creationist nonsense and certainly concur with his desire
to see an end to the promulgation of that nonsense.
Copyright © 2002 Jeffrey Jackson. All rights reserved.