DOES REFORMED EPISTEMOLOGY ESCAPE CARTESIAN SKEPTICISM?
The past fifty years have witnessed the emergence, and now the flourishing, of externalist
theories of knowledge:
first naturalistic ones and, more recently, theistic ones.
Reformed
epistemology, and especially that version of it developed by Alvin Plantinga, is currently one of the
most visible theories of the latter sort.
The motivations for externalism in epistemology are, of course, various. Perhaps the oldest,
clearly visible in Reid's response to Hume, is the desire to elude the snares set by the skeptic. Why
demand that the knowing subject have access to all of those factors that determine the truth, or
probable truth, of a belief? Why should that be a necessary condition for a belief's having positive
epistemic status, or even for knowledge?
A more recent, but related motivation is the desire to construct a theory of knowledge that is
proof against Gettier counterexamples.
Here again, externalism seems hopeful as a rescue
maneuver, as the mischances that generate such cases are characteristically beyond the subject's
ken. A reliable belief-generating process would be one either immune or by and large immune to
such vicissitudes. Nevertheless (and in tension with the goal of eliminating Gettier cases), most
externalist epistemologies are fallibilist with respect to knowledge: S may know that P even when
P is produced by a belief-forming mechanism that is fallible, provided it is sufficiently reliable.
Both of these goals are clearly evident among the aims of Plantinga's proper-function
externalism. It would be fair, I think, to say that Plantinga regards achievement of them as criteria
for the success of a theory of knowledge, and he has devoted considerable attention to trying to
show that his epistemology meets them. I have argued elsewhere that Plantinga has so far failed to
1
answer the Gettier problem;1 here my purpose is to investigate whether his epistemology succeeds
in escaping Cartesian skepticism, specifically, skepticism with regard to sense perception. Does
Plantinga have an adequate response to the Evil-Demon Argument (as concerns the senses)? Can
someone who accepts Plantinga's epistemology (and his metaphysics), and who is aware of and
understands the Evil-Demon Argument (EDA), have perceptual knowledge? Although properfunction epistemology is designed to provide an escape from skepticism, it turns out not to be a
straightforward matter whether it succeeds. If it does not, then a large measure of the motivation
for it disappears.
According to proper-function epistemology, a subject S has warrant - indeed, warrant
sufficient for knowledge with respect to a proposition P - if the cognitive faculties operative in the
generation of the belief that P are 1) well-designed in a way that is successfully aimed at truth, 2)
functioning properly in a congenial environment (i.e., the sort of environment for which they were
designed), 2 and 3) the belief is accompanied by a certain kind of doxastic experience. This
experience must produce a firmness of conviction concerning P that is commensurate with the
reliability of the judgment, i.e., is a good measure of the objective probability, given the
circumstances, that P is true. The objective probability must, for warrant to be at the level required
for knowledge, fall between some value r (>> .5) and 1.
Plantinga distinguishes between properly basic beliefs, beliefs non-inferentially generated
by reliable cognitive mechanisms, and inferential beliefs, which must acquire their warrant, at least
1
See Evan Fales, "Critical Discussion of Alvin Plantinga's Warranted Christian Belief," Nous 37
(2003), 353-370.
2
At the risk of some confusion with non-teleological reliabilist epistemologies, I shall, for
brevity, call cognitive faculties and processes that satisfy these two conditions reliable.
2
in part, in virtue of being inferred from properly basic ones. Inference is understood to be a
conscious process, "downstream from experience,"3 that is the output of the cognitive faculty of
reason. Skepticism with respect to perceptual beliefs is held at bay because, although we may have
very little knowledge, or none, of the mechanisms producing such beliefs (and although attempts to
establish the truthfulness of perceptual experience will, as the skeptic insists, be viciously circular),
nevertheless, ordinary perceptual beliefs will be properly basic, so long as they are in fact produced
by reliable faculties operating in a congenial environment, and are accompanied by an appropriate
degree of confidence that they are true.
Now the initial warrant for both basic and inferential beliefs can be defeated. The warrant S
has for a basic belief B can be defeated in two ways: either by some external factor that undermines
or degrades the reliability of S’s belief-producing mechanisms, or by evidence that S acquires, that
counts against B’s being true. Defeaters of the second kind are rationality defeaters, and they can
defeat either by rebutting or by undercutting a belief B. B is rebutted by evidence that it is false; it
is undercut by considerations that show that the evidence for it is bad.
Defeaters of the first kind are the stock in trade of Gettier cases.4 Defeaters of the first kind
arise when the prima facie warrant of a properly basic belief is neutralized by circumstances that,
though unknown to S, destroy reliability. Thus, my belief that this is a lovely barn might be
defeated by there being lots of paper-maché barn facades in the vicinity of which I am unaware.
3
If by 'downstream' Plantinga means causally downstream, then he seems to be ignoring the fact
that there is good reason to believe that there are information-processing, or, if you will, quasiinferential processes that take perceptual experience as input but of which we are not consciously
aware. This, however, can be set aside for present purposes.
4
Plantinga, Warranted Christian Belief (New York: Oxford University Press, 2000), p. 359.
3
Finally, the warrant for an inferential belief may be defeated, either because the warrant for
one of the properly basic beliefs from which it is inferred is, or because (for nondeductive
inferences) additional basic beliefs destroy the original justification. Plantinga calls this last kind of
defeater an internal rationality defeater.5 For ease of discussion, I propose also to call reasons
which defeat a properly basic belief, internal defeaters. The EDA, then, is a kind of whole-sale
internal, undercutting defeater for perceptual beliefs and inferential beliefs based upon them.
Suppose, now, that Plantinga encounters the EDA. What sorts of defenses can he mount
against it? What he needs, evidently, is a defeater defeater, something which restores warrant to his
perceptual beliefs by destroying the force of the skeptic's reasoning. The natural place to look is to
reason itself: perhaps reason can supply an internal defeater defeater, an argument that shows the
EDA to be self-defeating or unsound in some other way. But Plantinga himself does not have such
an argument on offer, and the history of this kind of response to the skeptic does not give much
scope for optimism.6 Indeed, Plantinga thinks that there can in principle be no successful reasoned
5
My summary here of Plantinga's classification of types of defeaters is not entirely accurate.
Plantinga's usage is a bit unclear, but, as I read him, every defeater is a warrant defeater. Among
warrant defeaters, some defeat by intervening in the cognitive processes that lead a subject to
believe that B, and others (like paper-maché barn-facades of which the subject is unaware) are
environmental. Among the former, which Plantinga calls rationality defeaters, he distinguishes
external and internal rationality defeaters. The former occur "upstream from experience;" they
concern the malfunctioning of relevant cognitive modules. The latter are beliefs that the subject
comes to acquire and to recognize as constituting reasons for giving up B. The EDA is, of course, a
defeater of this last kind. It is, further, an undercutting defeater, one which removes the grounds for
thinking perceptual beliefs to be true, while not providing reasons for thinking them to be false.
6
Plantinga himself suggests that not even God could answer the Cartesian skeptic: once he calls
into doubt His own cognitive faculties, then it will be circular for him to rely upon them to
extricate Himself (Plantinga, Warranted Christian Belief, p. 125). To this, the proper Cartesian
response is that for us - and by extension for God - certain judgments are indubitable and infallible;
with respect to them, skepticism cannot gain a foothold. The Cartesian project is then to show
how the epistemic credentials of other judgments, ones initially under the shadow cast by
4
defense against global skepticism. And as I said, it is just this situation that makes externalist
approaches to epistemology so attractive. But the attraction will last only so long as it appears that
externalism can offer a genuine way out. As we shall shortly see, it is not clear that proper-function
externalism can do so.
We should note in passing that the EDA begins by challenging the claim to know that there
are such things as dressing-gowns and fireplaces. But it quickly moves - as does Descartes'
response - to contested territory of a more properly philosophical nature, viz., to the question how
we can know that our perceptual and other cognitive faculties are trustworthy. It is this that lies at
the heart of the skeptical challenge; and it is this that epistemology has traditionally understood
skepticism to require us to face.
In what other quarters might a defeater for the EDA be found? My perceptual-beliefproducing faculties might be in excellent shape, operating in an environment for which they are
perfectly well-suited; but once I encounter and understand the EDA, how am I rationally to discount
the fact that, having no rebuttal, I have no way of knowing all of this, and hence no reason to think
it even moderately probable that my perceptual beliefs are true? If there is no way to neutralize the
force of the EDA as an undercutting defeater, then surely, if my doxastic-experience-generating
faculty is under these circumstances operating up to snuff with respect to any perceptual belief P, it
will, in response to the dictates of reason, undermine my confidence in the truth of P. And surely, I
can't just "walk away" from the EDA's implications for my supposed knowledge of P - or can I?
Before we consider that question, it will be helpful to take note of two points. The first is
that those whose cognitive faculties are in good working order, and who are in normal
skepticism, can be rescued, given the fulcrum supplied by the indubitable propositions.
5
surroundings, know (say externalists) about their surroundings if they are fortunate enough not to
have encountered (and been shaken by) the EDA (or other skeptical arguments). They, the
philosophically naive, are, ironically, in a better epistemic condition than we who have met and
been impressed by the skeptic. Knowing less is knowing more.
The second point concerns Plantinga's own main argument against metaphysical naturalism
in Warrant and Proper Function. 7
Metaphysical naturalism – the view that there are no
supernatural beings – is closely allied with epistemological naturalism, understood as proposing an
externalist, reliabilist theory of knowledge of the Goldman variety. Plantinga argues that the only
account the metaphysical naturalist can provide for the existence of organisms such as we is a
Darwinian one, and he proceeds to argue that the probability, relative to the Darwinian story, that
nature will have selected reliable cognitive mechanisms, is either low or (at least) unknowable. But
then, if the naturalist believes his mental faculties to be the product of the Darwinian mechanisms
of random variation and natural selection, he ought to have no confidence in the reliability of those
faculties (and hence, moreover, none in the Darwinian theory whose warrant depends on them).
Darwinism, therefore, supplies its own undercutting defeater.
The Christian theist, by way of contrast, is in better shape: she can be confident that a
Christian God will have designed her cognitive faculties in such a manner that, functioning as
designed, they will be successfully aimed at truth (including true theistic beliefs).
What's a poor naturalist to do?
Plantinga’s argument is an internal defeater for the
naturalist's perceptual (and hence, scientific) beliefs - and perhaps much else. Unless the naturalist
7
See Alvin Plantinga, Warrant and Proper Function (Oxford: Oxford University Press, 1993),
Chapter 12.
6
can find a rebutter, he is in the same sort of difficulty as that caused by the EDA. Perhaps, given
the EDA, this is just overkill. The naturalist's externalist epistemology is designed to fend off evildemon skepticism. Can it also protect the naturalist against Plantinga’s challenge? And on the
other hand, if the EDA supplies a genuine internal defeater, does it not defeat the naturalist and the
Christian theist equally - provided they are equally aware of, and impressed by, the argument?
Consider an externalist naturalist who remains constitutionally unimpressed by the EDA.
Such a philosopher - Quine, let us say - might nevertheless find Plantinga's anti-naturalist argument
disturbing, in the absence of a good rebuttal. This, moreover, could destroy confidence in his
cognitive abilities, removing warrant even if his (God-given?) cognitive faculties are in excellent
order. Plantinga clearly thinks Quine's confidence should be undermined. He implies that even a
quite unsophisticated theist studying elementary logic will know more logic than Quine under the
following condition, namely, that Quine's confidence in his logical ability comes to be undermined
by an encounter with Plantinga's argument, with the result that one of the conditions for warrant - at
least warrant sufficient for knowledge - is not met; Quine's logical beliefs are no longer attended by
the requisite degree of certainty.
Quine's claim to know logic will be undermined in two ways. First, he will have an
undercutting defeater, delivered by reason functioning as best it can. Second, the having of this
defeater will influence the doxastic experience that accompanies Quine's contemplation of his
logical beliefs; if the faculty that produces his doxastic experiences is functioning as it should,
recognition of the presence of a defeater will generate significantly weaker feelings of confidence;
more properly, these feelings should be ones of decided uncertainty. So, ironically, Quine's
knowledge of logic will be destroyed, but not that of the philosophically savvy theist, though she be
7
a beginner in logic.8
Now let us return to the EDA, and the response to it that Plantinga is in fact prepared to
offer. Here, as Plantinga has put it, salvation must be by grace, not by works.9 What he means is
that the destructive effects of the EDA cannot be overcome by our own efforts; that is, through the
exercise of reason. Rather, they must be, and are, overcome through the graciously benevolent
intervention of God. While not explicit about the details, Plantinga appears to be suggesting that,
confronted with radical skepticism, we manage somehow to just dismiss the EDA and kindred
arguments, in spite of recognizing their rational force.
How is it that we are able to do this? We are able to do it - so I presume Plantinga would
reply - in virtue of the fact that God has graciously so designed our cognitive faculties. He has
given us a faculty of reason powerful enough to understand many important things, and hence
powerful enough to invent and understand the EDA. But He has so designed our cognitive
constitution that reason is not, in certain cases, sovereign over doxastic experience. In particular,
when reason declares the EDA unrefuted, the cognitive module that generates the doxastic
experiences attending formation of perceptual beliefs does not respond as it ordinarily would (and
should) when a perceptual belief is undermined by an undefeated internal defeater.
Ordinarily, reason's recognition of an undefeated defeater generates a suspension of belief,
or at least diminution of confidence. That is because the presence of a defeater for a belief B
reduces the epistemic likelihood that B is true. The doxastic-experience generating system, when it
8
Here we have all the theological ingredients for a kind of Christian intellectual triumphalism.
In a response to William Talbott, "Naturalism Undefeated," read at the "Nature of Nature"
Conference held at Baylor University in April, 2000. See also Warrant and Proper Function, p.
237.
9
8
is functioning properly, is aimed at truth; hence, so long as epistemic probabilities are a guide to
truth, a doxastic-experience generating system that tracks epistemic probability will be properly
aimed at truth. Thus, insofar as reason is a faculty designed to determine epistemic probabilities,
the proper exercise of its functions includes dictating the strengths of the doxastic experiences
accompanying non-basic beliefs.
But, so Plantinga will say, reason goes awry when it encounters the EDA. It goes awry, not
by failing to discover a refutation to the EDA (perhaps there is no refutation), but in trying - if it
does try - to dictate the strength of our perceptual beliefs, via the doxastic-experience generating
system. It goes awry - on Plantinga's account - because one who doubts his perceptual beliefs
wholesale is one whose cognitive system is not successfully aimed at truth. Like Descartes,
Plantinga believes that God designed our cognitive faculties to aim, and aim successfully, at truth.
And the truth is, in large measure, what our ordinary perceptual beliefs capture. They are, therefore,
deserving of credence.
Anticipating, no doubt, that human reason would sooner or later discover skepticism, God
gave us a defense. That defense consists just of a natural inclination - in fact, a nearly irresistible
natural inclination - to discount skeptical arguments, even in the face of failure to find any rational
refutation. As we engage in our regular human activities, even we philosophers will just find
ourselves confidently accepting sensory information. In effect, God has inserted a "disconnect
switch" between the outputs of our reasoning faculty, and the input to the doxastic-experience
generating module, a switch that is triggered by skeptical outputs, at least of the radical and general
9
kind.10
Moreover, this is, from the point of view of our cognitive makeup, a good thing. It is true
that it involves ignoring reason, something that ordinarily constitutes a serious malfunction of one's
cognitive system, and therefore something that ordinarily destroys warrant. But here, we see (or at
any rate, God sees) that the effect of reason is destructive. The goal of the cognitive system's design
plan is to achieve true belief, and even if sometimes other goals may legitimately override that one
from the perspective of human well-being, 11 radical skepticism clearly has no legitimate claim
along these lines. So a human being's well-being, and in particular, her cognitive health, is bestserved by a design that refuses the skeptic's ploy. That being so, it can be argued that dismissal of
the EDA, unlike ordinary dismissals of the dictates of reason, does not undermine warrant.
A bit paradoxically, then, awareness of the EDA puts one in an epistemic environment in
which a kind of systemic malfunction - specifically, the failure of reason to exercise its normal
rights over belief - is the price to be paid in order that the total system remain aimed at truth, and so
that it be capable of acquiring knowledge with respect to many matters of importance.
I have been constructing what I take to be a plausible spelling-out of Plantinga's defense
against the EDA. I hope I have succeeded in capturing at least the spirit and essential form of the
10
Unfortunately, the disconnect switch, if there is one, seems often to malfunction: often, our
confidence in a belief is not undermined when it ought to be. Reason tells us that a belief B is not
strongly supported by the evidence, but the doxastic-experience generating system fails to pay heed.
11
As, for example, when a true belief is so depressing or paralyzing as to undermine the general
flourishing of a human life.
10
defense, even if Plantinga would disagree with respect to some detail or other. I want, then, to
examine the adequacy of this response.
Is a response of this kind intrinsically satisfactory? And, does it preserve the presumed
advantages, with respect to disarming skepticism, of externalism over internalism? It seems, in the
first place, that Plantinga can accommodate his reaction to skepticism to the general framework of
his proper-functionalist analysis of knowledge. What is essential here is that warrant accrues to a
belief so long as it is produced by mechanisms which, taken as a whole, are well-designed and
successfully aimed at truth, given a suitable environment. The account would fail, of course, if it
were a necessary condition for a belief to be warranted that every part of the cognitive processes
that produced it were operating in the normal fashion specified by its design plan. But Plantinga is
prepared to allow that malfunctions or abdications in one portion of a system might be compensated
for by "malfunctions" in another, with the result that the system as a whole is functioning well, and
warrant is preserved.12 So Plantinga’s response to Cartesian skepticism amounts to claiming that
our over-all design plan handles the difficulty inasmuch as God has so constituted us that, although
reason is capable of generating skeptical doubts, these are effectively squelched by other features of
our psychic makeup, with the happy result that we believe, correctly, the propositions reliably
That, at least, seems a reasonable inference to draw from Plantinga’s discussion in Chapter 2,
Section C of Warrant and Proper Function. It is, in any case, imperative for Plantinga to allow that
warrant can be uncompromised by canceling malfunctions, at least so long as this mode of
operation is built into the design plan, and not accidental. Otherwise, his defense against the EDA
straightforwardly fails. One could say that reason, confronted by the EDA, does not malfunction,
inasmuch as it has been designed by God to truncate its normal operation when radical doubt
looms. But clearly, it does malfunction in so doing, from the perspective of reason itself.
12
11
prompted by our perceptual faculties.
An initial reaction to Plantinga’s response to skepticism is that, if the goal of our cognitive
mechanisms is true belief, and if God has seen fit to achieve this aim by subverting reason, if need
be, when a person is confronted by skeptical doubts, then surely God would subvert reason in other
cases in which it led to false beliefs. It is, after all, common enough that a person finds herself in
epistemic circumstances in which the rational thing to believe is something false.
Even if
rationality is a tool well-designed to lead us to truth, it is hardly foolproof. So, why doesn't God
simply step in under these circumstances, and ensure true belief by means of some mechanism that
overrides reason?
A natural response to this difficulty has two parts. First, even though true belief is
intrinsically a good thing, it is not the only good thing, and constant intervention by God to save us
from false belief might in certain ways be harmful. If we suspected it, we might simply abandon
the hard work of reasoning, and the virtue of intellectual responsibility that it fosters.13
Perhaps the occasional error into which we fall when following reason is a fair price to pay for
intellectual independence.
Second, the harm of believing falsely is the more limited, the more limited the belief, and
the harm produced by divine intervention is the greater, the more frequently God would have to
rescue us from false beliefs. But the rescue from radical skepticism can be a singular affair, a once-
13
Rationality would, in such a world, become merely a superfluous ornament, one that might as
well be dispensed with entirely: for any true proposition P such that it is good that we believe it, a
providential God would directly cause us to believe it. Such a world would not be desirable; in it we
would be epistemic automata.
12
for-all special dispensation that preserves us from a far-reaching, distinctively destructive cognitive
defect.
Imagine a creature whose normal cognitive capacities suffer from severe malfunctioning.
To remedy the situation, God reprograms it to override its misbehaving cognitive systems and settle
for true beliefs and no false ones. One might think of such a creature as a true believer by fiat. But
surely the epistemic condition of the creature is not a desirable one. Its design plan has gone awry,
and the "fix," while ensuring true belief (and let us add, that firmness of conviction sufficient for
knowledge), leaves our creature lacking a certain kind of understanding: it lacks the understanding
that elements of its belief structure stand in certain logical and inductive relationships, ones which,
in a normal individual, organize that structure in fundamentally significant ways.
Such a creature would, by Plantinga's criteria, still possess warranted beliefs. Nevertheless,
it would be misbegotten in another sense, a sense we might describe by saying that it lacks much of
importance with respect to how well it embodies the virtues of reason.
We may consider the issues raised by this case more generally by introducing the notion of a
preempting defeater. A preempting defeater is one that is triggered under certain conditions in such
a way as to override the operation of our internal belief-generating mechanisms (those accessible to
consciousness). It does so in a way that is independent of the will.
From an internalist perspective, preemptive defeat, considered in isolation, will look like an
epistemic vice. But from God's perspective, perhaps this is the best way to neutralize the EDA.
Still, we ought to greet with skepticism the idea that endowment with a preemptive defeater is a
satisfactory response to the EDA. One question we ought to ask is whether this is the only - or the
best - recourse God has available. But we also ought to investigate more generally how operation
13
of preemptive defeaters affects warrant. Here, perhaps, intuitions will vary, but intuition applied to
illustrative cases is perhaps the only test we have.
Consider Jill, a skilled mathematician, who thoroughly understands the
requirements of proof for mathematical theorems. Oddly enough, she also is an idiot savant,
capable of infallibly generating fifty-digit prime numbers. Jill has no way of independently
checking whether these numbers are indeed prime (they are too large even for computers to test),
hence she has no inductive evidence of the reliability of her powers.14 Nevertheless, she can't help
believing the numbers are prime: once she leaves her study, her doubts just evaporate. Should we
say that Jill knows her numbers are prime? Or does she just "know" them to be prime in the
metaphorical sense in which a mechanical prime-number generator "knows" this?
It seems quite clear that we would not, and should not, have any confidence in Jill's number
picks; her beliefs on these matters would seem oddly obsessive. Even Jill herself, to the extent that
she is able to gain some rational distance from her doxastic condition, surely would - and should classify her belief states as inexplicably compulsive. Confident though she may remain, it is
unlikely that she would consider it appropriate for her prime number claims to be published in a
journal of mathematics, for they seem to be just the sorts of claims requiring proof, and not
knowable in a properly basic way.
Yet, according to Plantinga, Jill does know these numbers to be prime, so long as her design
To forestall an inductive argument from Jill’s success at picking smaller primes, imagine that
her gift works only for numbers of fifty or more digits. (I understand that computers are now
discovering Mersenne primes of more than four million digits, so my example is clearly out of
date. But let’s suppose computers can’t do that yet; they have only managed to pick out primes
of less than forty digits.)
14
14
plan includes an idiot-savant capacity reliably to generate them that is functioning properly, etc.
She retains this knowledge even in the face of the reflection that people don't generally discern large
prime numbers except by calculation, that she has no independent way of testing her beliefs, and so
on - so long as her confidence is not shaken by this defeater.
Perhaps Jill ought to distrust her prime-number beliefs, which are, we may assume, of no
great significance to her, not essential for her flourishing as a human being or mathematician. But
of course it doesn't follow that, in the absence of a refutation of the Cartesian skeptic, it would be
the correct strategy for us to follow with respect to sense perception. For here, the cognitive (and
perhaps also the practical) consequences of agnosticism are far more pervasive and pernicious - at
least if our senses are reliable.
On the other hand, for precisely this reason, the question of reliability is a correspondingly
more important one, and the required subversion of reason correspondingly more significant.
So, from the mere fact that this subversion of reason is a singular dispensation from God, unlike the
multiple annihilations that would be required for God to rescue us from particular cases of rational
false judgment, it does not follow that the former would be desirable but the latter not.
We can bring out the seriousness of this subversion of reason by recalling the nature of the
problem posed by Cartesian skepticism. Although that skepticism was directed initially against
such beliefs as that there are chairs and trees, it quickly emerges that Descartes' real concern is with
whether our cognitive faculties are trustworthy, or whether they are at least able to avail themselves
of sufficient resources to produce knowledge and avoid error.
As an epistemologist, then,
Descartes is really interested in the second-order question: how do I know that my faculties are
reliable? This is the principle question skeptical doubts appear to render insoluble.
15
God can salvage our confidence by getting us to ignore the doubts. But this does not defeat
Cartesian skepticism in any internalist sense; it walks away from it. It may (if there is no demon,
we are not dreaming, etc.) protect us from epistemic harms consequent upon taking skepticism
seriously, but it is also to abandon the traditional epistemological project.
To be sure, externalist epistemologies characteristically do abandon that project.
Nevertheless, there is a way that Plantinga can address the Cartesian skeptical challenge squarely:
just as my belief that I am sitting in front of a fire can be properly basic for me, why not the belief
that my eyes, brain, etc. are working properly according to their design plan? Or, if that is not
properly basic, perhaps it can be inferred from the knowledge I now supposedly have that I see
myself to be sitting before a fire (or more precisely, from the knowledge that I know this).
But that is not how Plantinga reasons. In Warranted Christian Belief, Plantinga argues that
if what he calls the Aquinas/Calvin model of Christian knowledge (including the knowledge that
we are created in the image of God) is correct, then Christians have properly basic beliefs
concerning the central claims of Christianity. He does not, however, undertake to argue that the
A/C model is correct. In Warrant and Proper Function, commenting upon Descartes' response to
demonic skepticism, Plantinga has this to say:
Of course [the theist] can't argue that in fact our beliefs are mostly true, from the premise
that we've been created by God in his image. More precisely, he can't sensibly follow
Descartes, who started from a condition of general doubt about whether our cognitive nature
is reliable, and then used his theistic belief as a premise in an argument designed to resolve
that doubt. ...Suppose, therefore, that you find yourself with the doubt that our cognitive
faculties produce truth: you can't quell that doubt by producing an argument about God and
16
his veracity, or indeed, any argument at all; for the argument, of course, will be under as
much suspicion as its source. Here no argument will help you; here salvation will have to
be by grace, not by works. But the theist has nothing impelling him in the direction of such
skepticism in the first place; no element of his noetic system points in that direction....15
So the alleged asymmetry between the Darwinian naturalist and the theist is that
Darwinism contains within itself the makings of an undercutting defeater, whereas theism (at least
Christian theism) does not. Even if that were granted, though, we have here nothing by way of a
response to Descartes' second-order doubt, his worry about the reliability of his cognitive faculties.
The Darwinian's undercutting defeater is motivated by Darwinism itself; the theist's undercutting
defeater is merely an epistemic possibility.16 But it is not one the theist can argue away.
Salvation, Plantinga insists, is “by grace, not by works.” That means, we may safely suppose,
that the theist doesn’t have to argue away the EDA. Probably it means more: namely that the theist
does best not to attempt to refute the EPA, but rather to just ignore it. The ability to do this – the
grace that saves the theist from first-order doubt about fires and dressing-gowns – presumably
applies just as beneficially to second-order doubts about the reliability of his cognitive faculties.
But if there is no God, the undisputed disposition to invariably wave aside the EDA when
we get to the practical business of life can just as easily be supposed to have evolved by Darwinian
processes. Indeed, a Darwinian explanation is the more natural, if there is a way a benevolent God
could have rescued us from the EDA without subverting our reason.
15
Plantinga, Warrant and Proper Function, pp. 236-237.
But perhaps the naturalist can avail himself of a strategy that parallels Plantinga’s theistic
optimism concerning our cognitive faculties: see below.
16
17
How, then, do matters stand? Externalist epistemologies are motivated by the apparent
inability of internalism to rationally refute various skeptical arguments. Here we have considered
two of these: the EDA, and Plantinga’s argument that metaphysical naturalism, coupled with the
Darwinian account of evolution, generate an undercutting internal rationality defeater for the
naturalist. Plantinga’s target here is naturalists who subscribe to an externalist epistemology.
Internal rationality defeaters, like Plantinga’s argument and the EPA, can be effective
against externalism because even if a belief has prima facie externally derived warrant, it can still
be defeated by encountering internal obstacles – sufficiently strong counterevidence. No externalist
wants to deny that the possession of internally accessible reasons for or against a proposition are
irrelevant to the all-things-considered warrant that proposition has for us.
The EPA is therefore one such line of reasoning that, for any epistemology, has potential to
destroy the prima facie warrant for empirical beliefs – both first-order beliefs and higher-order ones
about our cognitive faculties. I have examined the resources available to Plantinga’s epistemology
for neutralizing the threat. I have not yet considered whether naturalistic externalist epistemologies
might have comparable resources.
But I have described an additional threat to naturalistic
epistemologies, from Plantinga’s “Darwin” argument.
What can be gleaned from all this, I suggest, are the following lessons:
1) The EPA functions as a threat, in the form of an undercutting internal rationality defeater, for
both Plantinga’s and naturalistic epistemologies.
2) Plantinga has certain resources for dealing with that threat, but these come at a price.
3) If that cost is acceptable to Plantinga, then it is worth inquiring whether the naturalists has
available a parallel defense against the EPA, perhaps at similar cost.
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4) It is further worth asking whether the naturalist has, as well, a defense against the “Darwin”
argument that parallels Plantinga’s own theistic appeal to a benign and gracious God.
Let us now tackle these two questions, beginning briefly with naturalist/externalist
resources for parrying the EDA. Naturalists emphasize the reliability, rather than the proper
functioning, of our cognitive faculties. A person who is ignorant of the EDA will know that she has
two hands, provided, roughly, that the relevant cognitive faculties are operating in such a way as to
yield mostly true perceptual beliefs under relevantly similar circumstances. But what if she has
before her mind the EDA? Will this not defeat her claim to knowledge? Resort to rather drastic
measures seems necessary to thwart the threat presented by the EDA. Some externalists, for
example, reject the closure principle, the principle that if S knows that p, and S knows that p entails
q, then S knows that q. Rejection of this principle allows the externalist to accept:
1. I know that I have two hands.
2. If I know that I have two hands, then I know I am not the victim of an evil demon.
but to reject:
3. I know that I am not the victim of an evil demon.
So, the externalist can admit to having no refutation of the EDA, while insisting that she
nevertheless does know that she has two hands.
The price is drastic. The closure principle certainly seems to be a self-evident truth; indeed,
we implicitly invoke it whenever we use deduction in our knowledge-seeking efforts. Nor does
there seem to be any principled way of quarantining those violations of the principle that protect the
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externalist against the EDA. There are other strategies open to the externalist.17 I do not have time
to survey them. But all seem to me quite implausible. It is, however, not easy to judge whether any
one of them is less onerous than the strategy I have suggested on behalf of proper-function
externalism. Perhaps all that can be said at this point is that the EDA remains a serious difficulty
for every externalist view.
By way of considering, finally, whether the “Darwin” objection to naturalism can be
defeated, let us consider a further objection to Plantinga’s response to the EDA, which involves
legitimating the ascendancy of natural inclination over reason. The objection is that ceding the rule
of reason opens the door to a kind of intellectual promiscuity. For on the face of it, the response
supplies a strategy that can be deployed to support knowledge-claims on behalf of any belief toward
which we are strongly inclined, even in the absence of good confirming reasons, or the presence of
good disconfirming reasons.
Take any favored belief B, to which an individual, S, is stubbornly inclined to cling, even
though good reasons for it are unavailable, and counterevidence is: say, the belief that God exists.
An epistemologist who wishes to defend the epistemic propriety of this belief need only claim that
S's conviction is the result of proper all-things-considered cognitive function; nor need the presence
17
Perhaps the most promising of these rejects the EDA altogether as a defeater of either firstorder or second-order empirical beliefs. G. E. Moore offered this response to skepticism; a more
recent, sophisticated argument for the approach is given by Timothy Williamson in Knowledge
and Its Limits (Oxford: 2000); see esp. Chapters 8 – 9. The essential maneuver is to claim that
we do know a variety of empirical truths (e.g. that we have hands); it follows that skeptical
scenarios, such as the evil demon hypothesis, are not epistemically possible. The trouble with
this is that it clearly is possible for us to be mistaken about even such elementary empirical
truths; and sometimes we are. Further, the logical and epistemic possibility of the evil demon
hypothesis clearly appears to be a truth that, upon reflection, we can come to know a priori.
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of rationally undefeated rationality-defeaters have any force against this, since his inclination to
believe is a result of a providential cognitive-system design that overrides reason in this sort of case
on behalf of truth. (Should others be inclined to deny or doubt B, that can be explained too: their
cognitive systems are malfunctioning.)
Of course, we are bound to wonder whether someone who employs this strategy is right
about the crucial thing: are his cognitive processes, taken as a whole, in fact reliable with respect to
the production of B? Perhaps our friend S does have warrant; but it certainly doesn't look that way;
indeed, it likely doesn't look that way to S himself, given the defeaters. But of course, this question
about warrant is not one that can be answered, at least not without the appearance of begging the
question against the skeptic.18 In this sense, I think we must allow that the skeptical challenge
remains undefeated.
Still, perhaps this is exactly the upshot that Plantinga is willing to accept. We do know the
things perception ordinarily leads us to believe, thanks be to God's providential design, even though
sustaining this knowledge requires a firm intransigence when it comes to the demands made upon
our intellects by the Evil Demon Argument.
This way with the EDA, it might occur to us, is not entirely new. It is anticipated by none
other than Hume. Hume draws a more despairing conclusion. But a modern naturalist might be
more sanguine.
Indeed, many modern naturalists are more sanguine.
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Harboring externalist
Were S himself an epistemological sophisticate, he could make the argument just set forth in the
amicus brief filed by the friendly epistemologist. And if the claims upon which that argument is
based were challenged, he might claim to possess a firm conviction as to their truth - and could
postulate the same mechanisms as providing warrant for his belief that those mechanisms are
operative in him. But Plantinga himself does not seem prepared to move up levels in this way,
perhaps because the maneuver seems to invite a nonterminating regress.
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proclivities in epistemology, most of them are prepared, like Plantinga, to suppose that the "animal
faith" in the deliverances of our senses upon which Hume remarks is a felicity conferred upon us by
nature - specifically by evolution - because of its clear advantages to an organism in the struggle for
survival.
Suppose, however, that such a naturalist encounters Plantinga's argument in Chapter 12 of
Warrant and Proper Function. That argument purports to show that true perceptual beliefs do not
confer a clear advantage in the competition for survival - or rather, not one that could not equally be
achieved in several other ways. Hence, it is not particularly likely (or has a likelihood unknown by
us) that our perceptual beliefs are for the most part true. This argument provides a defeater for the
prima facie warrant possessed by the perceptual beliefs of the naturalist.
Now, a naturalist might sensibly try to counter this defeater by showing that Plantinga's
argument is unsound - as, indeed, I believe it is. 19 But suppose Plantinga's argument is not
unsound, or can't be shown to be. What recourse might there be? Remembering Hume (but
disavowing his internalism), a naturalist can emulate Plantinga. Our "animal faith" in the general
reliability of our senses is, he may say, providential.
Of course, this providence has not been
supplied by God; it is a grace conferred by Mother Nature. It is providential in that our senses in
general are reliable - even though we know of no good argument to support our belief to that effect
- and our animal faith destroys any attempt on reason's part to undermine this conviction and thus
defeat the warrant conferred upon perceptual beliefs by their sterling pedigree.
19
See Evan Fales, "Plantinga's Case Against Naturalistic Epistemology," Philosophy of Science 63,
(1996), 432-451.
22
So it matters not a whit whether the epistemic probabilities of Darwinian evolution
coughing up cognizers with reliable or properly functioning cognitive faculties is low or
inscrutable. We’ve been immunized against the EDA – both the Quinian naturalist and the
Plantingain can equally help themselves to that datum – and that suffices to preserve warrant
against the EDA, so long as that is part of the reliability/proper-function package, however it may
have arisen.
To be sure, the naturalist pays a price by adopting this strategy. He must accept that, in this
case at least, it is legitimate for Mother Nature to send Reason packing, for the sake of preserving in
her rational animals doxastic systems that are both robust and truth-conveying. But that is no
greater a demerit than the one Plantinga himself seems prepared to accept as the price of preserving
warrant. It is not a price I think we should be willing to pay. Attending to Reason, wherever she
may lead us, is too integral to our conception of what it is to have knowledge.
It is an indication of the strength of this conception that, if Reason were someday to
discover a decisive refutation of the EDA (and similar skeptical arguments), we would joyfully
abandon the Hume/Plantinga strategy. We should abandon externalism in epistemology as well:
save for a fascination with cognitive science, the dialectical advantages claimed on behalf of
naturalized epistemology are its supposed ability to provide a route of escape from skepticism, and
its alleged ability to solve Gettier problems.20
By Plantinga's lights, God has bequeathed us the Evil Demon Argument by giving us the
capacity for philosophy. He has provided a solution as well: a thick carpet of natural instinct, a
In Fales, “Review of Plantinga’s Warrant and Proper Function,” Mind 103 (1994), 391-395 and
"Critical Discussion of Alvin Plantinga's Warranted Christian Belief," Ibid., I have argued that
20
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hand to lift its corner, and a good strong intellectual broom. Perhaps that is the best God could do,
both for us and for Himself.
Evan Fales
The University of Iowa
Plantinga's epistemology continues to succumb to Gettier counterexamples.
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