Philosophy Is Essential to the Intelligent Design Debate
(June 2002 Physics Today)
Mano Singham
Predictably, the attempts by advocates of intelligent design (ID) to
persuade Ohio's state school board to overrule the state's science
advisory board and insert ID ideas into the Ohio science standards
have sparked a controversy. Inevitably, the usual combatants in the
science‚religion wars have rushed to their respective barricades.1
ID advocates argue that scientists are somehow conspiring to suppress
ID ideas. They accuse scientists of practicing censorship by
arbitrarily excluding ID ideas from journals and science textbooks,
thus not giving the ideas a fair chance to gain adherents. To
overcome this perceived injustice, ID advocates have appealed
directly to political power structures such as school boards and
legislative bodies to mandate what should be included in science.
Although such bodies may have the authority to tilt science curricula
toward religion, history has not looked kindly on such efforts. The
attempts in Louisiana and Arkansas in the 1980s to mandate the
teaching of creation science, and the more recent attempt in Kansas
to eliminate the teaching of evolution, were debacles for their
proponents. They invited dismal comparisons with the Roman Catholic
Church's attempt in 1616 to ban Copernican theory or the Soviet
Central Committee's attempt in 1949 to dismiss Mendeleevian genetics
as pseudoscience. One wonders why this dubious strategy is still
being pursued.
What is interesting about this battle is that both pro-ID and anti-ID
sides casually toss around terms like the "verifiability,"
"testability," and "falsifiability" of theories, as if the meanings
of the words were self-evident. Both sides display little awareness
that historians and philosophers of science created and have
exhaustively studied the terms in the quest to understand the nature
of science. These scholars find that all such concepts fail to
satisfactorily explain how science progresses.2‚6 The problem of how
to unambiguously distinguish science from nonscience is an extremely
difficult one.6 It even has a venerable name, "the demarcation
problem." This rich scholarly tradition should play an important role
in this discussion, and there is no excuse for ignoring it.
For example, ID advocates claim that "empirical science" consists of
those disciplines in which the merits of competing theories can be
evaluated by running controlled experiments to "test" them. However,
ID advocates also claim that "origins science" (like evolution of
life or the cosmos) cannot be investigated empirically because the
experiment cannot be run again with controlled initial conditions.
Hence they propose, as an alternative methodology for evaluating
origins science, that all competing hypotheses be applied to see
which one gives the best explanation. They further assert that the
only sound hypotheses for the evolution of life are natural selection
or ID, and that since natural selection fails in certain situations
(referred to as "irreducibly complex" systems7), then, by the rules
of "falsifiability,"3,4 ID must be the correct theory.
This argument has four flaws. First, although the tools of analysis
may be different for so-called origins science and empirical science
(consisting mainly of observations for origins science and
experiments for empirical science), the ways in which competing
theories are evaluated are the same for the two cases. Second, it is
never the case that only two explanations exist for any scientific
phenomenon. Scientists are creative people. They can generate
plausible alternative explanations with little effort. Third, ID
theory does not satisfy the criteria to be considered part of
science. Fourth, "falsifiability" is not the rule by which scientific
theories are evaluated.
Although research in the history and philosophy of science
convincingly demonstrates that there are no simple and unambiguous
methodological rules for deciding which of two (or more) competing
theories are better,2,4,5 theories must meet two criteria if they are
to be seriously considered at all. The first criterion is that any
scientific theory must be naturalistic. No serious scientific theory
in modern times has invoked explanations that appeal to
inscrutability or the miraculous. As the paleontologist George
Gaylord Simpson put it,
The progress of knowledge rigidly requires that no nonphysical
postulate ever be admitted in connection with the study of physical
phenomena. We do not know what is and what is not explicable in
physical terms, and the researcher who is seeking explanations must
seek physical explanations only.8
The second criterion is that the theory must be predictive. No
scientific theory is ever just an explication of the currently
inexplicable. It must also postulate some mechanism that can be used
to predict new phenomena that could not have been conceived under
older theories. If a new theory is used to explain result a in
situation A, then that same mechanism must be able to predict result
b in situation B, predict c in situation C, and so on. This feature
of producing new and interesting areas of exploration attracts
adherents to a new theory, enabling it to become a serious competitor
to the existing dominant theory.4 It is a theory's predictive aspect
that leads to new and important discoveries. These two criteria
comprise necessary (but insufficient) conditions for a theory to be
considered a part of science. ID fails to satisfy either criterion,
and that alone is reason enough for its exclusion.
ID advocates respond that these are philosophical rules, as if that
were a disqualification. But just because a rule is philosophical
does not mean that it lacks value. In fact, these particular rules
have been key to the tremendous advance of science. While scientists
may accept that some problems are unsolved--or cannot be solved until
new technology or data become available--they never accept that a
scientific problem is inherently insoluble. This belief that only
their own ingenuity or effort stands between them and success is what
makes them persevere for years and leads to great breakthroughs. But
when ID is invoked as an explanation for something, its advocates are
essentially stating that the problem is inherently insoluble and the
solution is inscrutable. Research in that area would presumably come
to a halt.
It is absurd for some scientists to defend Darwinian natural
selection by saying that there is no feature of life that cannot be
explained by it. No scientific theory has ever explained all the
phenomena that fall within its domain.2,4,5 Unexplained problems will
always arise that resist solution for a long time. In fact, a good
theory is one that keeps generating new problems that scientists can
work on and that lead to new discoveries and insights. ID advocates
will never run out of cases in which Darwinian natural selection has
not yet provided an explanation. But the presence of such anomalies
has never been sufficient, by itself, to prompt the scientific
community to abandon a dominant theory.2,4,5
For example, the motion of the perigee of the moon was a well-known
unsolved problem for over 60 years after the introduction of
Newtonian physics.2 It constituted a serious problem that resisted
solution for a longer time than the problems in evolution indicated
by ID advocates. Yet no supernatural explanation was invoked.
Eventually, the problem was solved, and the result was seen as a
triumph for Newtonian theory. Similarly, the stability of the
planetary orbits was an unsolved problem for more than 200 years.5
These two examples successfully illustrate why simple methodological
rules like falsifiability do not explain science's progress. If such
a rule were rigorously enforced, then Newtonian physics (and indeed
every scientific theory ever proposed) would have been falsified and
rejected at birth and we would not have had any science at all.
Clearly, scientists make judgments about which theories to keep and
which to reject for reasons that are far more complex and subtle than
suggested by simple rules like falsifiability.
Scientists consider the merits of competing theories only when
science enters a period of crisis--that is, when a dominant theory,
despite repeated attempts by its most seasoned practitioners, fails
to explain something that should be explainable using existing
knowledge, technology, and techniques.2 The biological science
community apparently does not perceive that natural selection is in
such a state of crisis. But even if natural selection were in crisis,
biologists would not accept ID as a worthy rival. Instead, they would
look for alternative naturalistic and predictive theories. If the
history of science is any guide, biologists will find and agree on an
acceptable theory. That is the way science has evolved.
The last philosophical question about ID involves the role of
"truth." ID advocates argue that it is wrong to keep ID ideas out of
science by appealing to naturalistic and predictive rules because the
goal of science is to seek "the truth." How, they ask, will we know
if ID is the true explanation for a phenomenon if it is not allowed
to compete?
But there is no reason to think that "truth" plays a major role in
this discussion.2 Science constantly produces new theories and
discoveries that are powerful, useful, and enlightening. But does
that imply we are approaching "the truth"? Alas, no--although many
scientists would like to think so.2,9
Given the continuing success of science, this limitation is not an
easy idea to grasp, especially for scientists. To better understand
it, compare the progress of science with that of biological evolution
itself. Organisms evolve; new ones emerge from the old, which results
in the impressive array of living systems around us that are, for the
most part, wonderfully adapted to their present environments. Does
this mean that the process of evolution was directed toward a goal?
That the present living forms were preordained in the primeval soup?
Of course not. The life forms that exist now just happen to be the
ones that arose from a vast number of initial possibilities.
Likewise, scientific theories evolve according to how well they
answer, at any given time in history, the immediate questions of
interest to scientists. As a result, the present impressive array of
theories has developed to satisfactorily answer the questions that
interest us now. But that does not mean that science is goal-directed
and thus progressing toward the "truth." The present theories were
not predetermined to be discovered, any more than the first
amphibians that crawled out of the oceans many years ago had the
concept of humans encoded for future emergence. Science works--and
works exceedingly well--because of its naturalistic approach,
predictive nature, and methods of operation. To be valid, science
does not have to be true.9
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Mano Singham teaches physics at Case Western Reserve University in
Cleveland, Ohio. He is also a member of Ohio's science advisory
board, which drafted the guidelines for the state's science standards.
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References
1. M. Singham, Phi Delta Kappan 81, 424 (February 2000).
2. T. S. Kuhn, The Structure of Scientific Revolutions, U. of Chicago
Press, Chicago, Ill. (1970).
3. K. R. Popper, Conjectures and Refutations: The Growth of
Scientific Knowledge, Harper and Row, New York (1963).
4. I. Lakatos, The Methodology of Scientific Research Programmes,
Cambridge U. Press, New York (1978).
5. P. K. Feyerabend, Against Method, Verso, New York (1993).
6. L. Laudan, Science and Relativism: Some Key Controversies in the
Philosophy of Science, U. of Chicago Press, Chicago, Ill. (1990).
7. M. J. Behe, Darwin's Black Box: The Biochemical Challenge to
Evolution, Free Press, New York (1996).
8. G. G. Simpson, Tempo and Mode in Evolution, Columbia U. Press, New
York (1944), p. 76.
9. M. Singham, Quest for Truth: Scientific Progress and Religious
Beliefs, Phi Delta Kappa Educational Foundation, Bloomington, Ind.
(2000).
© 2002 American Institute of Physics
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