Methodological vs. philosophical
                            naturalism,
            or why we should be skeptical of religion
                        By Massimo Pigliucci
    Is religion a legitimate area of inquiry for skepticism? The
  humanist community answers with a resounding œyes,� while the
  skeptic one is a lot more doubtful (interesting discussions in:
      Holden 1999; Krauss 1999; Pigliucci 1999; Singham 2000;
  Weinberg 2000). This essay has been inspired by conversations I
  have had with a couple of friends who happen to be prominently
  on opposite sides of this divide. Since similar discussions are
  endlessly carried out between skeptics and humanists as well as
among theistic and atheistic scientists, I thought it may be good to
      summarize the two positions and see where their logical
                    consequences would carry us.
The two main characters whose position I would like to discuss
are Dr. William Provine, a historian and philosopher of science at
Cornell University, and Dr. Eugenie Scott, an anthropologist and
executive director of the National Center for Science Education. I
met them both at the 1998 edition of œDarwin Day� at the
University of Tennessee, which set the stage for precisely the
discussion on which this essay is based.
Methodological vs. philosophical materialism
While both Provine and Scott are declared non-theists (the term
preferred by Scott) or atheists (Provine™s favorite), their positions
on the degree of clash between science and religion could hardly
be more different. Scott™s argument is that science simply does
not have anything to say about religion, case closed. Therefore,
scientists should go about their business of investigating natural
phenomena, and not concern themselves with religious matters of
any sort. Needless to say, Scott suggests that this should a fortiori
be any science educator™s behavior in the classroom. As I said,
however, Scott is indeed an atheist and materialist (in the
philosophical sense). So, how does she reconcile her theoretical
positions with her call for a separation of the two issues in
everyday practice?
Scott espouses the view that there is a distinction between
methodological and philosophical naturalism. The first
corresponds to what any practicing scientist would do. We assume
that the world is made of matter (and energy), and if indeed there
is something else out there, this is simply beyond the scope and
reach of the scientific method. The position of philosophical
naturalism, on the other hand, is rational, but not strictly speaking
scientific. It concludes (albeit provisionally) that there is only
matter out there, even though we cannot prove this beyond any
doubt (Pigliucci 2000).
One problem with Scott™s dualism is that, even though technically
correct, it sounds too much like the easy way out, it lacks
philosophical courage. When asked how she came to be a
philosophical materialist, Scott admitted that this was the result of
her knowledge of science. In other words, a scientific
understanding of the world leads (not necessarily, but in Scott™s,
Provine™s, and my own case) one to provisionally reject any
supernatural force or entity. I think the qualification of
œprovisional� is important because I do agree with Scott that
science cannot deny the existence of the supernatural. In fact,
more than that: science cannot prove the non-existence of
anything at all. All scientists can do is to support positive
statements with circumstantial evidence (Lakatos 1977), or
disprove them by refutation (Popper 1968). So, we are left with
the rather unsatisfactory position that science throws a little bit of
light in the abyss of the unknown, but not enough to answer
perhaps the most important philosophical question of them all: is
there something beyond matter and energy?
Soul? Evolution says no!
Not so for William Provine. His answer is clear: there is nothing
out there, we die in the most definitive sense of the word, and
there is no point in even asking the question of the ultimate
meaning of life. Where does he get this conclusion? From the
Darwinian theory of evolution by descent with modification, or so
he maintains. According to Provine, not only there is no evidence
for anything beyond matter, but the whole essence of evolutionary
change should tell us that it is irrational to even look for it. After
all, there is an uninterrupted, historical continuity between
humans and the rest of the living world. If that is so, we are left
with only two possibilities for granting the existence of something
immaterial: either we go back to Rene` Descartes™ dualism (all
living organisms are machines, except humans, which possess not
only the res extensa but also the res cogitans “ not only we have
physical bodies, but we possess consciousness); or we assume that
every living being is made of matter and of spirit, a position that
would make even the Pope rather uncomfortable (though it is an
integral component of some eastern philosophies and of animism,
and was in fact endorsed by none other than Aristotle: Thomas
1998).
Provine goes even further, by accusing scientists who cling to a
dualistic view either of intellectual dishonesty or of intellectual
schizophrenia. Let us see why. The schizophrenic attitude can be
traced back to Descartes himself. Although credited with nothing
less than the invention of the scientific method (Descartes 1637),
the French philosopher recoiled from the implications of his own
thesis, thereby introducing the above mentioned dualism between
the two res . Yet, a schizophrenic truly believes in the separation
of his two personalities. Where does the dishonesty come into
play? The answer, according to Provine, lies at least in part in the
federal funding of biological research. His thesis is that one of the
fundamental reasons that compel most biologists to look the other
way and not engage in disputes with religious overtones is simply
the fact that the evolution = atheism equation is potentially very
dangerous for their pockets (as well as their peace of mind). After
all, most evolutionary biology research is funded through federal
agencies such as the National Science Foundation (NSF). This is
taxpayers™ money. What would happen if the taxpayers found out
that their money is going to foster atheistic beliefs? Especially
given the current conservative (reactionary would be a better
word) political climate, it does not take a huge leap of the
imagination to see Republican senators and representatives crying
foul and axing the already meager NSF budget. Indeed, it is true
that NSF does not have a division of œevolutionary biology,�
while clearly a large portion of its funding for the biological
sciences goes to evolutionary research projects under the
euphemism of œpopulation biology.� Regardless of repeated
statements to the contrary, this is both a scientific and a political
war, and the stakes are as high as the future of education in the
most powerful country in the world, make no mistake about it.
On the other hand, Provine™s views are an example of
philosophical, not methodological, materialism. Scott is correct
when she says that you can infer, but not demonstrate, that there is
no God, no afterlife, and no cosmic meaning to our existence.
Therefore, the real question seems to me to be: what is the limit of
science? Does science truly confine itself to methodological
materialism, and it is therefore silent on everything else? Or, can
we use scientific results to make inferences that go beyond a
pragmatic approach and allow us to probe into ultimate questions?
You can™t have it both ways: methodological naturalism implies
philosophical naturalism
I will try to argue that:
1. It is true that science cannot prove the inexistence of
supernatural phenomena or entities; but that,
2. It is perfectly reasonable to provisionally reject such
phenomena or entities on scientific grounds.
The first point acknowledges Scott™s distinction between
methodological and philosophical materialism. As I mentioned
above, science cannot prove the inexistence of something. In fact,
there are even more strict limits on what science can do. These
limits derive from the indispensability of falsifiable hypotheses
(not always easy to formulate), and from the necessity of enough
empirical evidence to actually test such hypotheses. For example,
in the case of the origin of life, or the origin of the universe itself,
the questions may be scientifically approachable, and it certainly
is possible to derive falsifiable alternative hypotheses. However,
we may never have sufficient data to actually test and reject (or
provisionally accept) some reasonable hypotheses. Unfortunately,
the universe is not constructed in such manner to leave abundant
clues for the scientific version of Sherlock Holmes, that we like it
or not.
The second point is, obviously, the most controversial. My
reasoning (as well as Provine™s) is that you cannot pick and
choose your philosophy depending on the situation. A
methodological materialist who is not a philosophical materialist
is basically saying that he believes in matter and only matter...
most of the time! But if you grant the possibility of a God messing
around with the universe once in a while, where do you get the
assurance that that God is not doing it every day, every minute, in
every place of the universe? Furthermore, science is not about
proving things; it is about constructing workable causal models of
reality. For a scientist to reject the supernatural, God, and
(therefore) ultimate meaning in life is a perfectly logical
consequence of the current state of scientific findings. The reason
for this is that all such rejections are implicitly understood as
provisional, and they are necessary in order to construct the best
hypothesis consistent with the data. Since there is no evidence of
any God or supernatural design in the universe, the scientific
conclusion has to be that there is none. Unless and until such
conclusion is falsified by the available evidence.
Once one understands that science is not about definitive proofs,
but about reasonable working models (or proof beyond currently
reasonable doubt), the distinction between methodological and
philosophical materialism gets very much blurred. And by the
way, falsification of the naturalist paradigm is indeed possible
(contrary to what creationist Phillip Johnson Johnson 1997
maintains). The ongoing controversy over the so-called anthropic
principle is a case in point (Leikind 1997; Stenger 1996;
Weinberg 1999). Should we conclusively determine that the
probability of existence of our universe is infinitesimally small,
and should we fail to explain why physical constants have
assumed the quantities that we observe, the possibility of a
designed universe would have to be seriously considered.
The peculiar thing is that most practicing scientists and educators,
including Scott, apply exactly this reasoning every day of their
lives. Suppose you have a graduate student who comes in with the
results of an experiment and a series of alternative explanations
for the observed data. If one of the explanations is œGod did it,�
you will reject it on the grounds that there is no evidence of such
supernatural intervention, as well as because it is no explanation
at all. In other words, it is a characteristic of the scientific method
to reject explanations based on unnecessary hypotheses, as well as
hypotheses which carry no explanatory power. Such rejection, of
course, does not equate to saying that there is no God. It simply
means that our provisional model of the universe is consistent
with the idea that there is no God, and we will go with that for
now. Should new evidence emerge, a true scientist would
reconsider his working model and, if so compelled by the nature
of reality, would change it accordingly.
This discussion about methodological and philosophical
naturalism may sound very much academic and abstract, except
that it has already had a profound impact on the US national
policy on the teaching of evolution adopted by the very influential
National Association of Biology Teachers. In 1998, the NABT
was pressured into changing its definition of evolution by
conservative Christian theologians Alvin Plantinga and Houston
Smith, an unprecedented act of interference of religion in public
education. The controversy raged around the fact that the original
NABT definition included the words œunsupervised� and
œimpersonal� to describe the process of evolution. These were
seen as unscientific statements, because nobody can prove that
evolution is indeed unsupervised or impersonal (methodological
naturalism). Yet, every textbook and professional publication in
evolutionary biology makes precisely that assumption (of lack of
supervision and impersonality), otherwise the whole (astoundingly
successful) explanatory framework of evolutionary biology (and
in fact of science itself) would be a joke!
The distinction between methodological and philosophical
naturalism, therefore, misses one important component of the
scientific method: science is an enterprise based on (reasonable)
philosophical assumptions, not just a collection of facts. Two of
these assumptions are particularly relevant to our discussion. First,
William of Ockham (1285-1349), who incidentally was a
scholastic theologian, proposed what is now known as Ockham™s
razor: It is vain to do with more what can be done with less. In
other words, supernumerary hypotheses (such as the existence of
God) are to be avoided if we can explain the same facts with
fewer assumptions. Second, David Hume (1711-1776), the arch-
skeptic, suggested that (to put it as Carl Sagan did) extraordinary
claims require extraordinary evidence (Hume 1748 / 1956). This
is exactly the position of skeptics of the paranormal, astrology,
alternative medicine, and so on. It is difficult to see why such a
basic precept of science should not be extended to religion.
I think that part of the problem resides in a matter of semantics.
When a scientist says œthere are no flying horses� she doesn™t
mean that she has exhaustively searched the entire universe to
incontrovertibly verify that fact. The sentence just means that we
assume there is no Pegasus (the flying horse of Greek mythology)
because we have a good theory of mammalian anatomy and of
flight, and the two do not make it likely for animals like the
mythical stallion to exist. There is always the possibility that we
will observe one on some remote area of the globe, or find its
fossilized remains, or discover them on another planet. Until then,
however, I bet on Provine, dollar to doughnut.
References
Descartes, R. 1637. Discourse on method. Open Court Classics
{1989}, La Salle, IL.
Greene, B. 1999. The Elegant Universe: Superstrings, Hidden
Dimensions, and the Quest for the Ultimate Theory. Norton &
Co., New York, NY.
Holden, C. 1999. Subjecting belief to the scientific method.
Science 284:1257-1259.
Hume, D. 1748 / 1956. Enquiry Concerning Human
Understanding. Gateway Editions, Chicago, IL.
Johnson, P. 1997. Defeating Darwinism by opening minds.
InterVarsity Press, Downers Grove, IL.
Krauss, L. M. 1999. An article of faith: science and religion don't
mix. Chronicle of Higher Education A88.
Lakatos, I. 1977. The methodology of scientific research
programmes. Cambridge University Press, Cambridge, England.
Leikind, B. J. 1997. Do recent discoveries in science offer
evidence for the existence of God? Skeptic 5(2):66-69.
Pigliucci, M. 1999. Gould's separate "Magisteria": two views. A
review of Rocks of Ages: Science and Religion in the Fullness of
Life by S.J. Gould, Ballantine, 1999. Skeptical Inquirer 23 (6):53-
56.
Pigliucci, M. 2000. Personal gods, deism, & the limits of
skepticism. Skeptic 8 (2):38-45.
Popper, K. R. 1968. Conjectures and refutations; the growth of
scientific knowledge. Harper & Row, New York, NY.
Singham, M. 2000. The science and religion wars. Phi Delta
Kappan 425-432.
Stenger, V. J. 1996. Cosmythology: was the universe designed to
produce us? Skeptic 4(2):36-41.
Thomas, N. J. T. 1998. Imagination, eliminativism, and the pre-
history of consciousness. Web address:
www.calstatela.edu/faculty/nthomas.
Weinberg, S. 1999. A designer universe? Web address:
www.nybooks.com.
Weinberg, S. 2000. Five and a half utopias. Atlantic Monthly 107-
114.

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