Reply to Kvanvig on the Swamping Problem for Reliabilism
Erik J. Olsson
1. Introduction
Most contemporary epistemologists agree that knowledge is more valuable
than mere true belief, and many argue that process reliabilism is unable to
account for this fact. In Goldman and Olsson (2008), we suggested that
there is a weak sense of “knowing”, in which knowing simply consists in
believing truly. In this weak sense, knowing isn’t more valuable than
believing truly. We also conceded, of course, that there is a stronger sense
of “knowledge” that involves more than true belief and is more valuable. In
the article, we explored two ways in which process reliabilism can account
for the extra value of knowledge. First, we observed that reliabilist knowing
has greater value than mere true belief because it makes future true belief
more likely. We concluded however that on this approach, which we called
the “conditional probability solution” for reasons that will be clear as we
proceed, the greater value is only attained normally, not in every single
concrete case. We offered a psychological explanation of why some people
think that knowledge attains its distinctive value always, appealing to a
general psychological process of value autonomization whereby a reliable
process comes to be regarded as valuable in itself.
In a new paper entitled “Further thoughts on the swamping problem” (to
appear), Jonathan Kvanvig targets both our approaches to the value
problem. My aim in this paper is to assess the force of Kvanvig’s objections
to the conditional probability solution, which is the solution that I happen to
1
prefer.1 I will be concerned with responding to Kvanvig in a way that
exhausts the resources of that proposed solution.
2. The swamping problem
According to process reliabilism, a subject S knows that p if and only if (1)
p is true, (2) S believes p to be true, (3) S’s belief that p was produced
through a reliable process, and (4) a suitable anti-Gettier clause is satisfied.
Recently a number of authors have argued that process reliabilism cannot
account for the greater value of knowledge over mere true belief. Here is a
representative quotation from Richard Swinburne (1999):
Now clearly it is a good thing that our beliefs satisfy the reliabilist
requirement, for the fact that they do means that … they will probably be
true. But, if a given belief of mine is true, I cannot see that it is any more
worth having for satisfying the reliabilist requirement. So long as the
belief is true, the fact that the process which produced it usually produces
true belief does not seem to make that belief any more worth having.
(58).
Thus, the value of reliability seems, in a sense, to be “swamped” by the
value of truth. Once the latter is in place, the former adds no value, so that
the combination of truth and reliable acquisition is no more valuable than
truth itself. Similar swamping arguments have been presented by Ward
Jones, Linda Zagzebski (1996,
2000, 2003), Wayne Riggs (2002),
Jonathan.Kvanvig (2003), Ernest Sosa (2003) and others.
One could of course respond that it is satisfaction of the anti-Gettier
clause that gives knowledge is unique value, not satisfaction of the
1
Cf. Goldman and Olsson (to appear), section 3.
2
reliability clause. But chances are that a reliabilist would not be very happy
with a defense along these lines. After all, the characteristic feature of the
reliabilist approach is precisely the insistence on reliable acquisition, and it
would therefore be unfortunate if this very feature failed to add value in the
presence of true belief. This is the rationale for focusing the following
discussion on so-called “simple reliabilism”, i.e., reliabilism without an antiGettier clause.
Thus the swamping argument, as endorsed by Swinburne and others, may
be presented schematically as follows:
(S1) Knowledge equals reliably produced true belief (simple reliabilism).
(S2) If a given belief is true, its value will not be raised by the fact that it
was reliably produced.
(S3) Hence: knowledge is no more valuable than unreliably produced true
belief.
Since (S3) is a highly counterintuitive conclusion and the argument appears
valid, one of the premises must be false. As we have seen, (S2), the
characteristic swamping premise, is taken to be obviously true by many
authors writing on this subject. It derives support from an appeal to the
following further principle:
(Veritism) All that matters in inquiry is the acquisition of true belief.
If S’s belief is true all that matters in inquiry is the acquisition of true belief,
then learning that S’s belief was reliably produce does not add value, just as
(S2) says. Hence, the swamping problem can be seen as arising from
combining reliabilism with veritism. Instead, the most common reaction is
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to reject (S1), that knowledge equals reliably acquired true belief. But do we
have to be so negative? I think not.
3. The conditional probability solution
The main idea behind the conditional probability solution is that a true
belief that was reliably produced is a better indicator of future true belief
than a mere true belief is. In other words, the probability of S’s having more
beliefs (of a similar kind) in the future is greater, given that S knows that p
in the reliabilist sense, than it is, given that S merely believes truly that p.
This is a claim about conditional probability, whence the name “conditional
probability solution”. Probability should here be interpreted objectively.
We illustrated this solution in connection with a modern version of
Plato’s Larissa example:
Suppose you are driving to Larissa but are at loss as to which turns to
take at various crossroads. On the way to Larissa there are two forks. If
you choose correctly on both occasions, you will get to Larissa on time.
If not, you will be late at best. Your only assistance in forming beliefs
about the right ways to turn is the on-board computerized navigation
system. We consider two situations differing only in that the navigation
system is reliable in Situation 1 and unreliable in Situation 2. We
assume that in both cases the navigation system tells you correctly how
to turn at the first crossroads. In the first scenario this is to be expected,
because the system is reliable. In the second it happens by chance.
Suppose the correct information at the first crossroads is “The best route
to Larissa is to the right”. Hence in both situations you believe truly that
the road to Larissa is to the right (p) after receiving the information. On
the simple reliabilist account of knowledge, you have knowledge that p
in Situation 1 but not in Situation 2. This difference also makes Situation
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1 a more valuable situation than Situation 2. The reason is that the
conditional probability of getting the correct information at the second
crossroads is greater conditional on the navigation system being reliable
than conditional on the navigation system being unreliable.
How does this approach solve the swamping problem for process
reliabilism? The proposal obviously does not deny (S1), the premise that
knowledge is reliably acquired true belief. On the contrary, it purports to
show how that premise can be retained in the face of the swamping threat.
And it also does not deny (S2), the characteristic swamping premises, for it
does not deny that the value of a true belief is not raised by assuming that it
was reliably produced. What it does deny is the validity of the inference
from (S1) and (S2) to the conclusion that knowledge is no more valuable
than mere true belief. What it proposes is that knowledge can be more
valuable than mere true belief even if the constituent belief is not thereby
made more valuable. This is so because a state of knowledge can be more
valuable than a state of mere true belief: a state of knowledge is also a state
of reliable acquisition and as such it is valuable not only as an indicator of
the truth of the belief thus acquired but also as an indicator of the production
of further true beliefs (of a similar kind), namely true beliefs resulting from
reapplications of the reliable method in question. This is the reason why
knowledge is more valuable than mere true belief even if the truth of both
the premises employed by the swamping argument is granted.2
What is the basis for the higher probability of future true belief
conditional on knowledge as opposed to conditional on mere true belief?
How can the truth of this conditional claim be explained? It is true, we
2
For the record, I happen to believe that (S2) is false for reasons that are not directly related
to the conditional probability solution. See Olsson (2007) where I argue that a reliably
acquired true belief is more valuable than an unreliably acquired true belief in virtue of
being more stable. Stability of true belief, moreover, promotes successful practical action
over time.
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maintained, in virtue of certain empirical regularities which we referred to
as non-uniqueness, cross-temporal access, learning and generality. By nonuniqueness, the same kind of problem will tend to arise again and again.
Once you encounter a problem of a certain type, you are likely to encounter
a problem of the same type at some later point. In the Larissa case, the
question of what is the best turn for driving to Larissa was raised more than
once. By cross-temporal access, a method that was used once will tend to be
available also when the same type of problem arises in the future. In the
example, the navigation system which was used at the first crossroads was
available also when the same type of navigation problem arose at the second
cross roads. By the learning assumption, if a particular method solves a
problem once, and you have no reason to believe that it did so
unsuccessfully, then you will tend to use the same method again, if
available. In the Larissa case, the navigation method was available also at
the second crossroads, and since you had no reason to believe that it failed
at the first crossroads, you used it again. Finally, by the generality
assumption, if a method is reliable at time t, it will tend to be reliable also at
a later time t´, as was also the case in our Larissa story. On the basis of these
empirical regularities, which we claim hold normally in the actual world,
knowledge will tend to promote future true belief in a way that mere true
belief will not.
In our paper, we added that while the conditions of non-uniqueness,
cross-temporal access, learning and generally normally hold, they do not do
so always. Thus there will be cases where a problem arises only once, where
a method that was available once, is available no more, where a method that
was unproblematically employed is nevertheless not used again, and so on.
This does not affect our general claim that knowledge enhances probability
of future true belief any more than the fact that there are sick birds affects
the general claim that birds fly. But it does mean that there will be particular
cases in which knowledge is no more valuable than mere true belief. In our
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view, this is as it should be: the claim that knowledge is more valuable than
mere true belief is a defeasible claim in the sense that the claim is true even
though there are special cases in which knowledge fails to attain its
distinctive value. Let us now turn to Kvanvig’s objections.
4. Kvanvig’s critique
Kvanvig’s critique centers on another version of the swamping argument.
Consider the following example:
Suppose I want chocolate. I google to find places close to me. I get two
webpages: one entitled “places that sell chocolate in Waco”; the other
“places likely to sell chocolate in Waco”. We may assume accuracy for
both lists, and that the second list is generated from correlations: places
that sell food are likely to sell chocolate, places that sell hard candy are
too, etc. … We then note [that] … [i]f all I care about is chocolate, it
would be no better to use the list of places that both sell chocolate and
are likely to than to use the list of places that sell chocolate.
By the same token, Kvanvig thinks that it would be no better to believe in
the list of places that both sell chocolate and are likely to than to believe in
the list of places that sell chocolate. In other words, it would be no better to
believe that the first list is accurate and that the second list is accurate than it
would to believe that the first list is accurate.
Kvanvig concludes this part of the argumentation by observing that
“truth plus likelihood of truth is not preferable to truth alone” (21). Hence a
standard justified true belief (JTB) theory of knowledge that identifies
justification with likelihood of truth will be subject to a swamping problem.
Therefore, “one better not identify justification with statistical likelihood of
truth” (21).
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But how is this relevant to process reliabilism? It would be relevant were
such a theory to identify “being reliably acquired” with “being likely to be
true”, but, as Kvanvig is well aware, no known reliabilist theory does make
that identification. Kvanvig thinks that his reasoning raises a problem for
reliabilism nonetheless:
After all, if objective probability itself succumbs to the swamping
problem, why would the fact that there is an etiological relationship to a
process or method responsible for that probability relieve the theory of
the problem? Such a causal relationship to methods or process doesn’t
seem to be the kind of feature that adds value beyond the value of true
belief, so there is no apparent reason here to think that ordinary process
reliabilism is in a better condition with respect to the swamping problem
than is the simple objective probability theory [i.e. the theory that
equates knowledge with true belief that is objectively likely to be true].
He notes, however, that both the conditional probability solution and the
solution that focuses on value autonomization “go beyond the identification
of justification with objective likelihood of truth, and thus provide some
hope of avoiding the swamping problem” (23). Even so, Kvanvig thinks
that, in the case of the conditional probability solution, this initial hope is
difficult to sustain:
Once we appreciate the nature of te swamping problem as a problem
concerning properties of belief that are non-additive of value in the
presence of true belief, it becomes hard to see how the above proposal is
helpful at all. In the analogy involving chocolate, I don’t even know
how to begin thinking about applying this idea to new businesses of the
same type, conditional on the first list (places that sell chocolate) and the
third list (places that both sell chocolate and are likely to)
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It is not difficult to see why it is difficult to apply the conditional probability
solution to Kvanvig’s chocolate analogy. In focusing exclusively on the
objective likelihood of the belief produced, that analogy abstracts from
everything about a reliable process that doesn’t amount to that process
indicating the truth of the belief to which it gave rise. Our proposal, by
contrast, seeks to identify a value in reliable acquisition that goes beyond the
value such a process has in virtue of indicating the truth of the belief it
produced. Our suggestion, again, centers on the idea of reliable acquisition
indicating not only the truth of the belief thus acquired but indicating also
the future acquisition of true beliefs (of the same kind). Since Kvanvig’s
chocolate example excludes our proposal from the start, and does so without
independent justification, far from providing a counter example to our view
it begs the question against it.
This takes us to Kvanvig’s second point which concerns the fact that the
truth of our claim that the probability of future true beliefs is greater
conditional on knowledge than conditional on mere true belief hinges on
certain contingent regularities, namely those of non-uniqueness, crosstemporal access, learning and generality. Kvanvig offers the following
interpretation of our view:
So the claim really isn’t that the conditional inequality explains the
value of knowledge over that of true belief. The claim is, rather, that
when certain contingent features are in place, we should expect the
conditional probability of future true beliefs to be higher, given that one
knows rather than one merely truly believes.
He continues:
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This response, however, fails to come to grips with the core of the
swamping problem. As we have seen, once the relevant controls are in
place, we should expect, always and necessarily, for knowledge to be a
value-enhancing characteristic of a state of true belief, not just such a
characteristic when the person is likely to use the same method in the
future and the world hasn’t changed so … what was reliable in the past
is no longer so. To uncover the special value of knowledge, we have to
control for interaction by values outside the purely cognitive sphere, but
once we do so, we should find that knowledge is special. It is not only
special when the future resembles the past and when people retain their
dispositions across time of how to find out what the world is like.
Perhaps we are stuck having to adopt such a revisionary account of the
value of knowledge, but we shouldn’t offer such an account and pretend
that it is not radically revisionary.
Rather than engaging in detailed criticism of these passages, which I
believe to some extent misrepresent the conditional probability solution, I
will focus on what I take to be the main issue. The starting point of the
whole discussion of the value of knowledge is the following observation
which was apparently first made by Plato:
(VK) Knowledge is more valuable than mere true belief.
This principle is the point of departure for most investigations into the value
of knowledge simply because it is something upon which most of us can
agree. Moreover, most epistemologists also agree on the following more
specific value principle.
(EVK) Knowledge is epistemically (intellectually) more valuable than mere
true belief.
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There is less agreement on how, exactly, EVK should be interpreted?
Kvanvig apparently thinks that the following is a proper construal of that
principle:
(KEVK) Necessarily: for all x, x being an item of knowledge (materially)
implies x being epistemically more valuable than mere true belief.
Consequently, Kvanvig thinks that any concrete item of knowledge is
epistemically more valuable than any corresponding item of mere true
belief, and that this is so not only in our world but also in other possible
worlds. He exemplifies:
There are worlds in which my coming to know one more thing makes
certain that the world will end. So suppose I just now have come to
know one more thing. In such worlds, the likelihood of my having any
future beliefs at all, true or otherwise, conditional on knowing versus
truly believing, is the same: zero. But this probability doesn’t undermine
the fact that I ended my cognitive career on a high note. I learned
something, and that is a good thing. There may be other more important
things on which to end a life: bringing about world peace, for example.
And certainly, from an all-things-considered perspective, it would have
been better had I not achieved this additional learning. But merely
acquiring a true belief wouldn’t have been as good from a purely
cognitive point of view, and we deserve an explanation of that.
Thus, Kvanvig thinks that EVK should be interpreted as expressing that
knowledge has its distinctive value necessarily. Against this proposal one
might point out that there is nothing in the surface structure of EVK that
suggests this interpretation. Moreover, EVK is not only compatible with a
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contingent reading; it is even compatible with one that admits of exceptions.
For EVK could well be taken to mean that knowledge is normally, but
perhaps not always, more valuable than mere true belief. On this
interpretation, there is an inference to be made from “x is knowledge” to “x
is more valuable than mere true belief”, but this inference will be defeasible:
it can be made in the absence of explicit reasons not to make it:
(DEVK) There is a defeasible inference to be made from “x is knowledge”
to “x is epistemically more valuable than mere true belief”.
This is the reading of EVK that is most consonant with our conditional
probability solution.
Which reading of EVK is correct? Kvanvig thinks that his interpretation
is the correct one and accordingly that other readings, such as the reading
that he ascribes to Goldman and myself, are “revisionary”. But there are
reasons to think that exactly the opposite is true. First of all, one cannot help
noticing the ubiquity of defeasible reasoning in everyday life.3 Claims like
“birds fly” are not to be interpreted in the strict sense of predicate logic as
“for all x, if x is a bird then x then x flies” (with a material conditional) but
as “normally, birds fly”. To put it otherwise: from the fact that this is a bird
you may conclude that it flies, but you may have to retract the conclusion if
you receive further evidence about the thing in question, e.g. that it is a
penguin. Countless other common sense inferences follow the same pattern.
We may go one step further and claim, with John L. Pollock, that “an
important feature of most reasoning is that it is defeasible” (2007, p. 43, my
emphasis). In fact, this was noted already by Aristotle, who studied
3
Defeasible reasoning seems to be ubiquous even in natural science. For instance, it is
difficult to find any general claim of biology that does not allow for exceptions. For more
on the ”disunity of science”, see Dupré (1993).
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defeasible reasoning at great length in his Topics and found it to be typical
of common sense reasoning.
What has been said so far will raise few eyebrows in artificial
intelligence or cognitive psychology communities. However, if most
common sense reasoning is defeasible, then there is a presumption in favor
of interpreting any particular piece of common sense reasoning as
defeasible, and there is a corresponding presumption in favor of regarding
other more demanding readings as too strong and therefore revisionary. It
follows that there is a presumption in favor of considering, as we do, the
EVK principle to be defeasible and a presumption in favor of considering
more demanding interpretations, such as the one put forward by Kvanvig, as
incorrect and revisionary.
5. Conclusion
Contrary to what Kvanvig thinks, his chocolate example is no counter
example to the conditional probability solution put forward by Goldman and
myself in response to the swamping argument against reliabilism. The
example begs the question against that solution. Moreover, Kvanvig’s
argument for a reading of the claim that knowledge is more valuable than
mere true belief according to which that claim should hold “always and
necessarily”, so that other less demanding interpretations are “revisionary”,
is unconvincing. The opposite conclusion can be reached from the
commonplace observation that pre-systematic reasoning is normally of a
less demanding “defeasible” kind, i.e. a kind that admits of exceptions.
Thus, we have independent reasons – reasons derived from the study of
the nature of common sense reasoning – to consider the Epistemic Value
Principle to be defeasible principle. It licenses an inference form “this is
knowledge” to “this is distinctively valuable”, but it doesn’t thereby also
express that every case of knowledge is also a case of extra value. This
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value inference may be defeated by showing that the situation was in
relevant respects abnormal.
The conditional probability solution explains why reliabilist knowledge
has extra value in the defeasible sense. Reliable belief acquisition is
valuable not only because it indicates the truth of the belief thus acquired,
but also because it is indicative of future true belief. This is how the
conditional probability solution solves the swamping problem. The
inference from “this is reliabilist knowledge” to “this has extra value” can
be defeated by new evidence to the effect that one or more of the conditions
of non-uniqueness, cross-temporal access, learning or generality failed, but
this is of course in line with the relevant value principle being defeasible in
nature.
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