Does Practical Rationality Constrain Epistemic Rationality

8/11/2019 Does Practical Rationality Constrain Epistemic Rationality

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Does Practical Rationality Constrain Epistemic Rationality?

(Forthcoming in Philosophy and Phenomenological

Researchsymposium on Fantl and McGrath Knowledge in

an Uncertain World)

I The Direct Argument

An issue that looms large in contemporary

epistemology concerns the relationship between knowledge

and practical rationality. Jeremy Fantl and Matt McGrath

provide the most in-depth and rigorous discussion of this

issue. Their book is an impressive achievement and Ilearned much from studying it.

Fantl and McGrath (F&M) defend a general principle

linking knowledge and rational justificationboth practical

and theoretical:

KJ: If you know that p, then p is warranted enough to justify

you in !-ing, for any !. (66)

For F&M, the justification component of knowledge is

carrying the theoretical load. Thus they endorse

JJ: If you are justified in believing that p, then p is warranted

enough to justify you in !-ing, for any !.(99)

While I am unclear about whether KJ is true, I am

inclined to think JJ is false. Most of the discussion of these

issues has centered on cases that pull intuitions in one

direction or the other. To their credit, F&M set out to move

the discussion beyond intuitive judgments about cases.

They construct a principled argument in defense of JJ.


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The direct argument" attempts to derive JJ from

fundamental principles, some of which are analogues of the

principles used in their argument for KJ. The principle I will

focus on is central to the argument for KJ and JJ:

The Unity Thesis: If p is warranted enough to be a reason

you have to believe that q, for any q, then p is warranted

enough to be a reason you have to !, for any !.

It is uncontroversial that theoretical reasons can

constrain practical reasons. But according to the Unity

Thesis, practical reasons can constrain theoretical reasons.

F&M begin by commenting on how we do in fact reason:

"On a hike, you come to a frozen pond. Do you walk across

or walk around the frozen pond? Walking around will take a

while, but you don't want to fall though the ice. How do you

decide? The crucial issue is whether the ice is thick enough

to hold you. Suppose you do some checking (you call the

park authorities) and come to know that the ice is thick

enough. So the ice is thick enough becomes a reason you

have to believe other things (e.g. that it is perfectly safe to

cross it). It would then be very odd not to allow this

knowledge into your practical reasoning" (73-4)

F&M argue that as a matter of fact we do not typically

segregate our reasons for believing and our reasons for

acting. But they concede that, as a psychological matter, it

might be possible to do so, e.g., for you to count the ice is

thick enoughas a reason to believe you will cross safely,

while at the same time not treating the ice is thick enoughas

a reason to cross the ice. In their view, however, segregating

your reasons in this way would be irrational:


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When p becomes available as a basis for theoretical

conclusions, it is 'barmy' to ignore p in one's decision-making

and planning".

While I agree that in general, reasons for believing will

(in the relevant sense) be reasons for acting, matters are

somewhat different when we consider cases with massively

asymmetrical stakes:

Suppose crossing the ice rather than walking around the

pond would save at most a few minutes (and saving the few

minutes counts for almost nothing). Suppose further that the

water is deep enough so that if you break through the ice,

you will certainly drown. When the stakes are so

asymmetrical, the Unity Thesis seems to run into trouble.

Consider the proposition:

Thick: The ice is enough to support your weight.

On the basis of the testimony of the park authorities, is

sufficiently warranted to be a reason you have to believe that

if you cross the ice, it will not break.1But is Thicksufficiently

warranted to be a reason you have to cross? It would seem

not. You have everything to lose, and virtually nothing to

gain. Why risk your life in order to gain a few minutes?2

The preceding strikes me as the correct way to

describe the case. The testimony of the park authorities

makes it rational for you to believe that if you cross, the ice

1If reasons must be true, we can stipulate that is true.2Note that one cannot hold that Thick issufficiently warranted to be a reason you have to

cross, but that it is not a good enough reason to justify crossing. Given the specifications

of the case, Thick is certainly a strong enough reason. Were you certain of Thick, itwould be rational for you to cross. So the problem has to be that it is insufficiently

warranted to be a reason for you to cross.


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will hold you. But the asymmetrical stakes makes it irrational

for you to cross. If so, then the Unity Thesis fails. Of course

F&M would resist this description of the case. They would

agree that Thickis not sufficiently warranted to be a reason

for you to cross. But they would also hold that neither is

Thicksufficiently warranted to be a reason for you to believe

that if you cross, the ice will not break. On their view, it

would be barmy for you to appeal to Thickas a reason to

believe but not to appeal to it as a reason to act. F&M point

out (in correspondence) that the situation as I describe it,

would license your saying (or simply believing) seemingly

crazy things.

To see this, we need to make the familiar distinction

between there being a reason for you to do !, and your

having that reason to do !. In the case we have been

discussing, Thickis a reason for you to cross the ice. This

remains true whether or not you possess Thickas a reason

to cross the ice. On my description of the case, you are

justified in believing Thick. Now suppose, as F&M suggest,

we stipulate that you justifiably believe that Thickis a reason

for you to cross the ice. Finally, if as I hold, Thickis not a

reason you have to cross the ice, then this is something you

could recognize. But that means you could be justified in

believing:

Strange: The ice is thick enough, and that is a reason for me

to cross, but I do not have that reason.

Admittedly, this result is somewhat jarring. How could you be

justified in believing Strange? I will argue that independently

motivated principles about the structure of reasons can

explain how.

Jonathan Weisberg has defended the following


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principle:

No-feedback: If one reasons from premise P to conclusion C

via lemma L, then if p does not by itself support C, the

inference from C to L is unjustified.3

This is a very plausible principle. The main idea is that you

cannot increase the justificatory power of your evidence

simply by making inferences from it.4Suppose your evidence

supports some lemma to just above the threshold for rational

justification. Even if that lemma is a good inductive reason

to believe some further conclusion, inferring the conclusion

from the lemma could result in that conclusion having a level

of justification below the threshold. This means that we

cannot allow that any inductively good inference from a

lemma we justifiably believe yields a justified conclusion.

According to No-Feedback, the conclusion will be justified

only if the original evidence supports it.

Note that as a consequence of No-Feedback, the

following situation could arise. On the basis of some P, you

are justified in believing some lemma L, where L is a reason

to believe C. If you are justified in believing L is a reason to

believe C, then you will be justified in believing L, and that L

is a reason to believe C. But you may still be justified in

believing that you do not have that reason. This is an

epistemic analogue of (Strange). For example, suppose you

justifiably believe, on the basis of the muddy footprints

matching his shoe size, that the butler did it. But the muddy

footprints just barely justify you in believing this. Suppose

further that the butler did it is a good inductive reason to

3Bootstrapping in GeneralPhilosophy and Phenomenological Research 81, 2010. I

have simplified the statement of the principle for current purposes.4Weisberg argues, correctly I think, that the principle blocks bootstrapping reasoning.

Unfortunately, the Dogmatist is committed to rejectingNo-feedback.


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believe that the maid knows who did it. You might

nonetheless fail to be justified in believing that the made

knows who did it. That is to say, you could be justified in

believing

Strange-epistemic: The butler did it, and that is a reason for

me to believe that the maid knows about it. But I do not

have that reason.

You do not have The butler did it as a reason because it is

not sufficiently warranted to justify you in believing that the

maid knows who did it. So when there is epistemic feedback,

one can end up with justification for epistemic analogues of

Strange.5

In No-Feedback, the conclusion C is a belief. But we

also reason to practical conclusions--intentions or actions. I

see no reason why we should not generalize NF to apply to

practical conclusions as well:

Practical No-Feedback: If one reasons from premises P to

an intention to act I via lemma L, then if P does not by itself

support I, then the inference from L to I is unjustified.6

Practical No-Feedbackshould be as plausible as

Theoretical No-Feedback. The point of No-Feedbackis that

if one's initial premise does not support one's practical

conclusion, then neither does any lemma one might infer

from one's initial premise. This remains true whether the

conclusion is a belief inferred directly from the lemma, or

whether it is an intention inferred from the lemma in

5This also demonstrates the failure of F&Ms principle (J

KR for belief) p98

6We can remain neutral on whether the conclusion of a practical inference is an intention

or an action.


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analogues of Strange. I can see no reason to suppose that

you could be justified in believing Strange-epistemic but not

Strange. I conclude that the Unity Thesisis false.

II Outright Belief

My argument against the Unity Thesisraises issues

about the nature of binary or outright belief. On a certain

view of outright belief, my description of the case seems to

be incoherent. F&M call it The Strong Pragmatic View of

belief:

(SPV) You believe that p iff your credence for p is high

enough for p to be your motivating reason for !-ing for all

!.(137)8

A consequence of SPVis that in the asymmetrical stakes

version of the frozen pond case, you fail to outright believe

Thick. Given those stakes, your credence for Thickis not

sufficient to motivate you to cross the ice. And if you do not

believe Thick, you do not justifiably believe Thick.

The issues concerning the nature of outright belief are

too complex for a thorough treatment in this symposium

piece. What I can do is point out a reason to be worried

about the correctness of (SPV). Then I will sketch an

alternative account according to which you do outright

believe Thickin the asymmetrical stakes case.

The reason to be worried about (SPV) is that it has the

consequence that what you believe depends on what you

prefer.9Suppose in the asymmetrical stakes case, I get

7 F&M favor SPV, though they do not explicitly endorse it. They also distinguish it from

what they call weak pragmatic belief.9 Jacob Ross and March Schroeder raise this problem in Belief, Credence, and

Pragmatic EncroachmentPhilosophy and Phenomenological Research, forthcoming.


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depressed and stop caring whether I fall through the ice and

drown.10 According to (SPV), under this scenario I do

outright believe Thick, because my new preference structure

has eliminated the massive asymmetry in the stakes. With

my new preferences, my credence for Thickis high enough

for it to be my motivating reason to cross the ice. I will save

time, and it is no longer a priority for me not to fall through

the ice. So before the change in my preferences, the

strength of my credence was insufficient for me to count as

believing Thick. After the change, even though my credence

for Thickremains unchanged--the strength of my credence

has not increased--I now count as believing Thick. The mere

fact that I have stopped caring so much about whether I

drown entails that I now believe Thick. This strikes me as

extremely implausible.

Now consider the view that part of the functional role of

outright belief is to (defeasibly) dispose one to treat P as true

in ones reasoning.11 On this account, your outright believing

disposes you to treat Thickas true in your reasoning. But

the disposition is defeasible. So while in the normal course of

events, you will treat Thickas true in your reasoning, in

cases where the risk of acting on Thickis too great, this

disposition gets defeated. In these circumstances, you will

treat Thickonly as probable in your reasoning. But the

defeasible disposition remains, even when it is defeated.

Thus, despite the fact that under these circumstances you

are not treating Thickas true in your reasoning, you continue

10 It is not clear to me whether SPVrequire rationalmotivation. If so, and we assume

depression is irrational, we can assume that the preferences change rationally, or at least,

not irrationally.11

Versions of this view have been held by various people, though I borrow this

formulation from Jacob Ross and Mark Schroeder, ibid.


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to outright believe 12

III The Subtraction Argument.

F&Ms` "Subtraction Argument" purports to derive JJ

from KJ. If the Unity Thesis fails, then so does the argument

for KJ. I do however think that KJ is more plausible than JJ

on its own terms. For this reason, it would be of interest if JJ

could be derived from KJ.

The Subtraction Argument has three steps:

(S1) If you know that p, then p is warranted enough to justify

you in !-ing for any !(KJ).

(S2) Holding fixed knowledge-level justification, while

subtracting from knowledge any combination of truth, belief,

or being ungettiered makes no difference to whether p is

warranted enough to justify you in !-ing, for any !.

Therefore

(S3) If P is knowledge-level justified, then p is warranted

enough to justify you in !-ing, for any !.

The crucial premise in the subtraction argument is (S2). F&M

argue for it by considering a case where you are freezing

12 I am not sure weather the right way to think of outright belief on this view is as a

defeasibledisposition. That is how Ross and Schroeder describe it. But couldnt your

having a disposition to treat P as true in your reasoning just amount to the followingcondition being defeasibily true: If P is relevant to your reasoning, you will treat P as

true? One such defeater would be massively asymmetrical stakes. So if P is relevant toyour reasoning and the stakes are massively asymmetrical, you may not treat P as true. I

confess that I am not competent enough about the metaphysics of dispositions to have aview about this.


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cold and see a barn close ahead on the right. There is

another barn much further ahead on the left. They note that

because you want to get out of the cold as soon as you can,

if you know there is a close barn on the right (and

presumably, there are no countervailing considerations),

then there is a barn on the rightis warranted enough to

justify you in heading toward the barn on the right (rather

than the distant barn on the left). This remains true even if

there is instead a barn replica on the left and so you are

gettiered and fail to know there is a barn on the right.

Similarly if there is no barn on the right but merely a facade,

you are still justified in heading toward the barn on the right.

Even if, despite your evidence, you fail to believe there is a

barn on the right, you remain justified in heading toward the

barn on the right.

These intuitive considerations are taken by F&M to

support (S2). By definition, if you know p, you have

knowledge-level justification for p. KJ says that if you know

p, then p is warranted enough to justify you in !-ing for any !.

The subtraction argument says that subtracting truth, belief

and being ungettiered, you remain warranted enough to

justify you in !-ing, for any !. Thus, knowledge-level

justification for p makes p sufficiently warranted to justify you

in !-ing for any !.

As I see it, the main problem with the subtraction

argument hinges on the notion of being ungettiered. What

is it to be ungettiered? The only way to define being

gettiered", without solving the Gettier problem, is this: You

are gettiered just in case you have justified true belief that

isn't knowledge. (Indeed the title of Gettier's paper is "Is

justified true belief knowledge?).

But this definition raises the question whether the

existence of high stakes can be a gettier condition? This


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would be ruled out only if it were impossible for the stakes to

be high enough to rule out knowledge, without ruling out

knowledge-level justification. Because the subtraction

argument attempts to derive the stakes-sensitivity of

knowledge-level justification from the stakes sensitivity of

knowledge, it would be question-begging to assume this at

the outset.

If you can be gettiered by high stakes, then in order to

subtract your being ungettiered, while holding fixed your

knowledge-level justification, we would have to assume that

the stakes are high enough to preclude knowledge, even

given your knowledge-level justification. But high stakes

undermine knowledge by blocking justification for acting.

Thus you will have knowledge-level justification for p, with

insufficient warrant for p to justify you in acting. So (S3) will

not follow.

Are there other ways of defining being gettiered" that

exclude high stakes? F&M, at different, places talk about

"Gettier luck" conditions as well as "truth-relevant"

conditions. Neither of these specifications is precise enough

to capture all the conditions discussed in the Gettier

literature, but no matter. The problem remains. The

subtraction process begins with stakes low enough for you to

know P and thus low enough for P to be sufficiently

warranted to justify you in !-ing. Now suppose we subtract,

in addition to truth and belief, all the additional truth-

relevant/no-luck conditions for knowledge. Presumably, low

(enough) stakes is not a truth-relevant/luck condition. (If it

were, the subtraction process would result in stakes high

enough to prevent P from being sufficiently warranted to

justify you in !-ing and (S3) would not follow). So after the

subtraction process, low (enough) stakes will remain. But

then all that follows is:


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(S3') If P is knowledge-level justified and the stakes are low

enough for knowing, then p is warranted enough to justify

you in !-ing, for any !.

(S3') is weaker than (S3). Just because knowledge-level

justification for p ensures that p is sufficiently warranted to

justify acting when the stakes are low enough for knowing, it

doesn't follow that knowledge-level justification ensures that

p is sufficiently warranted to justify acting when the stakes

are too high for knowing. Again, the argument assumes that

one cannot have knowledge level-justification for P when the

stakes are too high for knowing. In essence, the subtraction

argument overlooks the possibility that low enough stakes is

an independent condition for knowledge.

Stewart Cohen

University of Arizona

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Does Practical Rationality Constrain Epistemic Rationality