Evolution vs. Naturalism  -  Why they are like oil and water
						by Alvin Plantinga

http://www.christianitytoday.com/bc/2008/004/11.37.html
	As everyone knows, there has been a recent spate of books 
attacking Christian belief and religion in general.  Some of these 
books are little more than screeds, long on vituperation but short on 
reasoning, long on name-calling but short on competence, long on 
righteous indignation but short on good sense; for the most part they 
are driven by hatred rather than logic. Of course there are others 
that are intellectually more respectable - for example Walter 
Sinnott-Armstrong's contribution to God? A Debate Between a Christian 
and an Atheist1 and Michael Tooley's contribution to Knowledge of 
God.2  Nearly all of these books have been written by philosophical 
naturalists. I believe it's extremely important to see that 
naturalism itself, despite the smug and arrogant tone of the 
so-called New Atheists, is in very serious philosophical hot water: 
one can't sensibly believe it.
	Naturalism is the idea that there is no such person as God or 
anything like God; we might think of it as high-octane atheism or 
perhaps atheism-plus. It is possible to be an atheist without rising 
to the lofty heights (or descending to the murky depths) of 
naturalism. Aristotle, the ancient Stoics, and Hegel (in at least 
certain stages) could properly claim to be atheists, but they 
couldn't properly claim to be naturalists: each endorses something 
(Aristotle's Prime Mover, the Stoics' Nous, Hegel's Absolute) no 
self-respecting naturalist could tolerate.
	These days naturalism is extremely fashionable in the 
academy; some say it is contemporary academic orthodoxy.  Given the 
vogue for various forms of postmodern anti-realism and relativism, 
that may be a bit strong.  Still, naturalism is certainly widespread, 
and it is set forth in such recent popular books as Richard Dawkins' 
The Blind Watchmaker, Daniel Dennett's Darwin's Dangerous Idea, and 
many others.  Naturalists like to wrap themselves in the mantle of 
science, as if science in some way supports, endorses, underwrites, 
implies, or anyway is unusually friendly to naturalism.  In 
particular, they often appeal to the modern theory of evolution as a 
reason for embracing naturalism; indeed, the subtitle of Dawkins' 
Watchmaker is Why the Evidence of Evolution Reveals a Universe 
Without Design.  Many seem to think that evolution is one of the 
pillars in the temple of naturalism (and "temple" is the right word: 
contemporary naturalism has certainly taken on a religious cast, with 
a secular priesthood as zealous to stamp out opposing views as any 
mullah).  I propose to argue that naturalism and evolution are in 
conflict with each other.
	I said naturalism is in philosophical hot water; this is true 
on several counts, but here I want to concentrate on just one - one 
connected with the thought that evolution supports or endorses or is 
in some way evidence for naturalism.  As I see it, this is a whopping 
error: evolution and naturalism are not merely uneasy bedfellows; 
they are more like belligerent combatants.  One can't rationally 
accept both evolution and naturalism; one can't rationally be an 
evolutionary naturalist.  The problem, as several thinkers (C. S. 
Lewis, for example) have seen, is that naturalism, or evolutionary 
naturalism, seems to lead to a deep and pervasive skepticism.  It 
leads to the conclusion that our cognitive or belief-producing 
faculties - memory, perception, logical insight, etc. - are 
unreliable and cannot be trusted to produce a preponderance of true 
beliefs over false.  Darwin himself had worries along these lines: 
"With me," says Darwin, "the horrid doubt always arises whether the 
convictions of man's mind, which has been developed from the mind of 
the lower animals, are of any value or at all trustworthy.  Would any 
one trust in the convictions of a monkey's mind, if there are any 
convictions in such a mind?"3
	Clearly this doubt arises for naturalists or atheists, but 
not for those who believe in God.  That is because if God has created 
us in his image, then even if he fashioned us by some evolutionary 
means, he would presumably want us to resemble him in being able to 
know; but then most of what we believe might be true even if our 
minds have developed from those of the lower animals.  On the other 
hand, there is a real problem here for the evolutionary naturalist. 
Richard Dawkins once claimed that evolution made it possible to be an 
intellectually fulfilled atheist.  I believe he is dead wrong: I 
don't think it's possible at all to be an intellectually fulfilled 
atheist; but in any event you can't rationally accept both evolution 
and naturalism.
	Why not? How does the argument go?4  The first thing to see 
is that naturalists are also always or almost always materialists: 
they think human beings are material objects, with no immaterial or 
spiritual soul, or self.  We just are our bodies, or perhaps some 
part of our bodies, such as our nervous systems, or brains, or 
perhaps part of our brains (the right or left hemisphere, for 
example), or perhaps some still smaller part.  So let's think of 
naturalism as including materialism.5  And now let's think about 
beliefs from a materialist perspective.  According to materialists, 
beliefs, along with the rest of mental life, are caused or determined 
by neurophysiology, by what goes on in the brain and nervous system. 
Neurophysiology, furthermore, also causes behavior. According to the 
usual story, electrical signals proceed via afferent nerves from the 
sense organs to the brain; there some processing goes on; then 
electrical impulses go via efferent nerves from the brain to other 
organs including muscles; in response to these signals, certain 
muscles contract, thus causing movement and behavior.
	Now what evolution tells us (supposing it tells us the truth) 
is that our behavior, (perhaps more exactly the behavior of our 
ancestors) is adaptive; since the members of our species have 
survived and reproduced, the behavior of our ancestors was conducive, 
in their environment, to survival and reproduction.  Therefore the 
neurophysiology that caused that behavior was also adaptive; we can 
sensibly suppose that it is still adaptive.  What evolution tells us, 
therefore, is that our kind of neurophysiology promotes or causes 
adaptive behavior, the kind of behavior that issues in survival and 
reproduction.
	Now this same neurophysiology, according to the materialist, 
also causes belief. But while evolution, natural selection, rewards 
adaptive behavior (rewards it with survival and reproduction) and 
penalizes maladaptive behavior, it doesn't, as such, care a fig about 
true belief.  As Francis Crick, the co-discoverer of the genetic 
code, writes in The Astonishing Hypothesis, "Our highly developed 
brains, after all, were not evolved under the pressure of discovering 
scientific truth, but only to enable us to be clever enough to 
survive and leave descendents."  Taking up this theme, naturalist 
philosopher Patricia Churchland declares that the most important 
thing about the human brain is that it has evolved; hence, she says, 
its principal function is to enable the organism to move 
appropriately:
	 Boiled down to essentials, a nervous system enables the 
organism to succeed in the four F's: feeding, fleeing, fighting and 
reproducing.  The principal chore of nervous systems is to get the 
body parts where they should be in order that the organism may 
survive Š . Improvements in sensorimotor control confer an 
evolutionary advantage: a fancier style of representing is 
advantageous so long as it is geared to the organism's way of life 
and enhances the organism's chances of survival [Churchland's 
emphasis].  Truth, whatever that is, definitely takes the hindmost.6
  	What she means is that natural selection doesn't care about 
the truth or falsehood of your beliefs; it cares only about adaptive 
behavior.  Your beliefs may all be false, ridiculously false; if your 
behavior is adaptive, you will survive and reproduce.  Consider a 
frog sitting on a lily pad.  A fly passes by; the frog flicks out its 
tongue to capture it.  Perhaps the neurophysiology that causes it to 
do so, also causes beliefs.  As far as survival and reproduction is 
concerned, it won't matter at all what these beliefs are: if that 
adaptive neurophysiology causes true belief (e.g., those little black 
things are good to eat), fine.  But if it causes false belief (e.g if 
I catch the right one, I'll turn into a prince), that's fine too. 
Indeed, the neurophysiology in question might cause beliefs that have 
nothing to do with the creature's current circumstances (as in the 
case of our dreams); that's also fine, as long as the neurophysiology 
causes adaptive behavior.  All that really matters, as far as 
survival and reproduction is concerned, is that the neurophysiology 
cause the right kind of behavior; whether it also causes true belief 
(rather than false belief) is irrelevant.
	 Next, to avoid interspecies chauvinism, let's not think 
about ourselves, but instead about a hypothetical population of 
creatures a lot like us, perhaps living on a distant planet.  Like 
us, these creatures enjoy perception, memory, and reason; they form 
beliefs on many topics, they reason and change belief, and so on. 
Let's suppose, furthermore, that naturalistic evolution holds for 
them; that is, suppose they live in a naturalistic universe and have 
come to be by way of the processes postulated by contemporary 
evolutionary theory. What we know about these creatures, then, is 
that they have survived; their neurophysiology has produced adaptive 
behavior.  But what about the truth of their beliefs?  What about the 
reliability of their belief-producing or cognitive faculties?
  	What we learn from Crick and Churchland (and what is in any 
event obvious) is this: the fact that our hypothetical creatures have 
survived doesn't tell us anything at all about the truth of their 
beliefs or the reliability of their cognitive faculties. What it 
tells us is that the neurophysiology that produces those beliefs is 
adaptive, as is the behavior caused by that neurophysiology. But it 
simply doesn't matter whether the beliefs also caused by that 
neurophysiology are true. If they are true, excellent; but if they 
are false, that's fine too, provided the neurophysiology produces 
adaptive behavior.
	 So consider any particular belief on the part of one of 
those creatures: what is the probability that it is true?  Well, what 
we know is that the belief in question was produced by adaptive 
neurophysiology, neurophysiology that produces adaptive behavior. 
But as we've seen, that gives us no reason to think the belief true 
(and none to think it false).  We must suppose, therefore, that the 
belief in question is about as likely to be false as to be true; the 
probability of any particular belief's being true is in the 
neighborhood of 1/2.  But then it is massively unlikely that the 
cognitive faculties of these creatures produce the preponderance of 
true beliefs over false required by reliability.  If I have 1,000 
independent beliefs, for example, and the probability of any 
particular belief's being true is 1/2, then the probability that 3/4 
or more of these beliefs are true (certainly a modest enough 
requirement for reliability) will be less than 10^-58.  And even if I 
am running a modest epistemic establishment of only 100 beliefs, the 
probability that 3/4 of them are true, given that the probability of 
any one's being true is 1/2, is very low, something like 0.000001 
(ref 7).  So the chances that these creatures' true beliefs 
substantially outnumber their false beliefs (even in a particular 
area) are small.  The conclusion to be drawn is that it is 
exceedingly unlikely that their cognitive faculties are reliable.
	 But of course this same argument will also hold for us.. If 
evolutionary naturalism is true, then the probability that our 
cognitive faculties are reliable is also very low.  And that means 
that one who accepts evolutionary naturalism has a defeater for the 
belief that her cognitive faculties are reliable: a reason for giving 
up that belief, for rejecting it, for no longer holding it.  If there 
isn't a defeater for that defeater - a defeater-defeater, we could 
say - she can't rationally believe that her cognitive faculties are 
reliable.  No doubt she can't help believing that they are; no doubt 
she will in fact continue to believe it; but that belief will be 
irrational.  And if she has a defeater for the reliability of her 
cognitive faculties, she also has a defeater for any belief she takes 
to be produced by those faculties - which, of course, is all of her 
beliefs.  If she can't trust her cognitive faculties, she has a 
reason, with respect to each of her beliefs, to give it up.  She is 
therefore enmeshed in a deep and bottomless skepticism.  One of her 
beliefs, however, is her belief in evolutionary naturalism itself; so 
then she also has a defeater for that belief. Evolutionary 
naturalism, therefore - the belief in the combination of naturalism 
and evolution - is self-refuting, self-destructive, shoots itself in 
the foot.  Therefore you can't rationally accept it.  For all this 
argument shows, it may be true; but it is irrational to hold it.  So 
the argument isn't an argument for the falsehood of evolutionary 
naturalism; it is instead for the conclusion that one cannot 
rationally believe that proposition.  Evolution, therefore, far from 
supporting naturalism, is incompatible with it, in the sense that you 
can't rationally believe them both.
	What sort of reception has this argument had?  As you might 
expect, naturalists tend to be less than wholly enthusiastic about 
it, and many objections have been brought against it.  In my opinion 
(which of course some people might claim is biased), none of these 
objections is successful.8  Perhaps the most natural and intuitive 
objection goes as follows.  Return to that hypothetical population of 
a few paragraphs back. Granted, it could be that their behavior is 
adaptive even though their beliefs are false; but wouldn't it be much 
more likely that their behavior is adaptive if their beliefs are 
true?  And doesn't that mean that, since their behavior is in fact 
adaptive, their beliefs are probably true and their cognitive 
faculties probably reliable?
	 This is indeed a natural objection, in particular given the 
way we think about our own mental life.  Of course you are more 
likely to achieve your goals, and of course you are more likely to 
survive and reproduce if your beliefs are mostly true.  You are a 
prehistoric hominid living on the plains of Serengeti; clearly you 
won't last long if you believe lions are lovable overgrown pussycats 
who like nothing better than to be petted.  So, if we assume that 
these hypothetical creatures are in the same kind of cognitive 
situation we ordinarily think we are, then certainly they would have 
been much more likely to survive if their cognitive faculties were 
reliable than if they were not.
	 But of course we can't just assume that they are in the same 
cognitive situation we think we are in.  For example, we assume that 
our cognitive faculties are reliable.  We can't sensibly assume that 
about this population; after all, the whole point of the argument is 
to show that if evolutionary naturalism is true, then very likely we 
and our cognitive faculties are not reliable.  So reflect once more 
on what we know about these creatures.  They live in a world in which 
evolutionary naturalism is true.  Therefore, since they have survived 
and reproduced, their behavior has been adaptive.  This means that 
the neurophysiology that caused or produced that behavior has also 
been adaptive: it has enabled them to survive and reproduce.  But 
what about their beliefs?  These beliefs have been produced or caused 
by that adaptive neurophysiology; fair enough.  But that gives us no 
reason for supposing those beliefs true. So far as adaptiveness of 
their behavior goes, it doesn't matter whether those beliefs are true 
or false.
	Suppose the adaptive neurophysiology produces true beliefs: 
fine; it also produces adaptive behavior, and that's what counts for 
survival and reproduction.  Suppose on the other hand that 
neurophysiology produces false beliefs: again fine: it produces false 
beliefs but adaptive behavior.  It really doesn't matter what kind of 
beliefs the neurophysiology produces; what matters is that it cause 
adaptive behavior; and this it clearly does, no matter what sort of 
beliefs it also produces.  Therefore there is no reason to think that 
if their behavior is adaptive, then it is likely that their cognitive 
faculties are reliable.
  	The obvious conclusion, so it seems to me, is that 
evolutionary naturalism can't sensibly be accepted.  The high priests 
of evolutionary naturalism loudly proclaim that Christian and even 
theistic belief is bankrupt and foolish.  The fact, however, is that 
the shoe is on the other foot.  It is evolutionary naturalism, not 
Christian belief, that can't rationally be accepted.

Alvin Plantinga is John A. O'Brien Professor of Philosophy at the 
University of Notre Dame.

1. Reviewed elsewhere in this issue by Douglas Groothuis, in a piece 
covering four books dealing with atheism in one fashion or another.
2. Coauthored with Alvin Plantinga in Blackwell's Great Debates in 
Philosophy series (Blackwell, 2008).
3. Letter to William Graham (Down, July 3, 1881), in The Life and 
Letters of Charles Darwin, ed. Francis Darwin (London: John Murray, 
1887), Volume 1, pp. 315-16.
4. Here I'll just give the bare essentials of the argument; for 
fuller statements, see my Warranted Christian Belief (Oxford Univ. 
Press, 2000), chap. 7; or my contribution to Knowledge of God 
(Blackwell, 2008); or Natural Selection and the Problem of Evil (The 
Great Debate), edited by Paul Draper, 
www.infidels.org/library/modern/paul_draper/evil.html.
5. If you don't think naturalism does include materialism, then take 
my argument as for the conclusion that you can't sensibly accept the 
tripartite conjunction of naturalism, evolution, and materialism.
6. "Epistemology in the Age of Neuroscience," Journal of Philosophy, 
Vol. 84 (October 1987), pp. 548-49.
7. My thanks to Paul Zwier, who performed the calculations.
8. See, e.g., Naturalism Defeated?, ed. James Beilby (Cornell Univ. 
Press, 2002), which contains some ten essays by critics of the 
argument, together with my replies to their objections.