THE
STRUCTURE OF C.S. LEWIS’S SELF-CONTRADICTION-IN-NATURALISM ARGUMENT
(1) Naturalism implies that all of beliefs can be completely
explained as the result of irrational causes.
(2) If a belief is wholly explicable in terms of irrational
causes, then it is unreasonable.
(3) If it were reasonable to believe Naturalism, then it
would be reasonable to believe its consequences.
(4) If it were reasonable to believe Naturalism, then would
be reasonable to believe that the belief in Naturalism itself can be completely
explained as the result of irrational causes. [(1),(3)]
(5) If it were reasonable to believe Naturalism, then it
would be unreasonable to believe Naturalism
[(2),(4)]
(6) It is unreasonable to believe Naturalism. [(5)]
The Genetic Fallacy (a species of ad hominem): An arguer commits the
Genetic Fallacy if they reply to an argument (or a claim) by asserting that the
conclusion is believed by the arguer just because of some event, state or
psychological predisposition that does not depend on the actual reasons
given.
Comment: This is a fallacy because the arguer is assuming, perhaps
falsely, that the argument given (or the claim being made) is not justified by
the reasons offered (or that could be offered). Commonly it is also
implicit in the charge that the conclusion or claim in question is false, and
this is asserted without offering any reasons to dispute the argument
presented. The reasons given (or that might be given) by the initial
arguer may in fact be quite sufficient to justify the proposition being argued,
even if the belief was caused, or partly caused, by the factors mentioned.
Examples:
1. “You only believe that abortion is not morally permissible
because you are a man.”
2. “Your defense of the free market is just another example of your
bourgeois capitalist mentality”.
3. “Your resistance to Freudian theory reveals a deep-seated
Oedipus complex.”
4. “You believe in God because of the way you were trained […
your need for a protective father-figure, your fear of death, etc,
etc.].”
5. “People’s beliefs are always just rationalizations and in
fact result from their training and the influence of their peer group.”
Objection to this formulation of Lewis’s “Anti-Naturalism”
argument:
Premise 2 of the argument is very questionable. It perhaps draws its
initial appearance of plausibility from an equivocation on
“because”. It may even involve the Genetic Fallacy. My
beliefs may just be physical states or events that have physical causes and yet
may also be justified by the reasons that I have for them.* We would be
justified in concluding that the belief in question is “worthless”
only if those causes were the only factors that bear on my having the
belief. I may also have excellent reasons.
*See Paul Meehl and Herbert Feigl, “The Determinism-Freedom and Mind-Body
Problems” in C. Anthony Anderson and Keith Gunderson (eds.), Paul E.
Meehl. Selected Philosophical and Methodological Papers (Minneapolis, Oxford:
University of Minnesota Press, 1991).
AGAINST EVOLUTIONARY-NATURALISM: ANOTHER FORMULATION OF C. S. LEWIS’S
ANTI-NATURALISM ARGUMENT (AFTER ALVIN PLANTINGA)
(1) Naturalism and the claim that our brains evolved solely
by the process described by evolutionary theory (N&E) together imply that
we have no good reason to believe that our perceptions or beliefs are likely to
be true.
(2) If the belief (N&E) were reasonable, then whatever it
implies would be reasonable.
(3) If the belief (N&E) were reasonable, then it would be
unreasonable.
Therefore:
(4) The belief (N&E) is
unreasonable – it is “self-defeating” to belief that
Naturalism together with the evolutionary explanation of the development of our
brains and belief-system is correct.