Table Of ContentTHE AQUINAS LECTURE, 2011
PERCEPTION AS A CAPACITY
FOR KNOWLEDGE
JOHN MCDOWELL
MARQUETTE
UNIVERSITY
PRESS
© 2011 Marquette University Press
T PREFATORY
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www.marquette.edu/mupress/ Tau, the International Honor Society for
Philosophy at Marquette University, each
Under the auspices of the
year invites a scholar to deliver a lecture in honor of
Wisconsin-Alpha Chapter of Phi Sigma Tau
St. Thomas Aquinas. The 2011 Aquinas Lecture,
LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Perception as a Capacity for Knowledge, was delivered
McDowell, John Henry. on Sunday, February 27, 2011, by John McDowell.
Perception as a capacity for knowledge / by John
Prof McDowell is a Distinguished University Pro
McDowell.
fessor of Philosophy at the University of Pittsburgh.
p. cm. - (Aquinas lecture; no. 75)
Includes bibliographical references.
ISBN-13: 978-0-87462-179-2 (hardcover: alk.
JOHN MCDOWELL
paper)
ISBN-I0: 0-87462-179-8 (hardcover: alk. pa Prof McDowell studied at the University College
per)
of Rhodesia and Nyasaland and at New College,
1. Perception (Philosophy) 2. Knowledge, Theo
, I
ry of I. Title.
B828.45.M43 2011
121:34-dc22
2010051475
Printed in the United States of America.
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The A.ssodation of J~suit LJnivp-rsily PreSl;H~l'
6 JOHN MCDOWELL Perception as a Capacity for Knowledge 7
Oxford, and taught at University College, Oxford reception of premodern philosophy, of a conception
from 1966-1986. He is an Honorary Fellow of Uni of nature that reflects an understanding, in itself
versity College. He joined the Philosophy Depart perfectly correct, of the proper goals of the natural
ment at the University of Pittsburgh in 1986. Prof. sciences. In a number of contexts, he has argued
McDowell's research and teaching fields include that we can free ourselves from characteristic sorts
Greek Philosophy, Philosophy of Language, Phi of philosophical anxiety by recalling the possibility
losophy of Mind, Metaphysics, Epistemology, and of a less restrictive conception of what it takes for
Ethics. Prof McDowell translated Plato's Theaetetus something to be natural.
for the Clarendon Plato series (Oxford University
Press, 1973). He is author of Mind and World (Har To Prof McDowell's distinguished list of publica
vard University Press., 1994), and his essays have tions, Phi Sigma Tau is pleased to add: Perception
been collected in several volumes: Mind, Value, and as a Capacity for Knowledge.
Reality (Harvard University Press, 1998), Meaning,
Knowledge, and Reality (Harvard University Press,
1998), Having the World in View: Essays on Kant,
Hegel, and Sellars (Harvard University Press, 2009),
and The Engaged Intellect: Philosophical Essays (Har
vard University Press, 2009).
Prof. McDowell has held visiting appointments
at Harvard University, the University of Michigan,
UCLA, and Princeton University. He was invited to
give the John Locke lectures at Oxford University
in 1991 and the Woodbridge Lectures at Columbia
University in 1997. He is a Fellow of the British
Academy and a Fellow of the American Academy
of Arts and Sciences. He is an Honorary Doctor
of Humane Letters of the University of Chicago.
A central theme in much of his work is the harm
ful effects, in modern philosophy and in modern
PERCEPTION AS A CAPACITY
FOR KNOWLEDGE
JOHN MCDOWELL
1. My topic is perception as a capacity for knowl
edge. But there are different things one could mean
by describing perception in those terms. I want to
consider perception as a capacity for knowledge of
a distinctive sort.
At one point in his classic investigation o£ among
other things, the epistemology of knowledge
through perception, "Empiricism and the Philoso
phy of Mind': Wilfrid Sellars famously says this:
[IJn characterizing an episode or a state as that of
knowing, we are not giving an empirical description
of that episode or state; we are placing it in the logi
cal space of reasons, of justifying and being able to
justify what one says.l
In this remark Sellars is implicitly equating, on
the one hand, reason, the faculty or family of facul
ties that, in an ancient tradition, distinguishes ra
tional animals (animals that can occupy positions
in "the logical space of reasons") from the rest of
1 "Empiricism and the Philosophy of Mind'; in Sel
lars, Science, Perception and Reality (Atascadero, Cali
fornia: Ridgeview, 1991), §36.
\
10 JOHN MCDOWELL Perception as a Capacity for Knowledge 11
the animal kingdom, and, on the other hand, mas This applies to knowledge in general something
tery of language, and in particular language with Sellars has been claiming, in the immediate con
which one can give expression to one's credentials text, about observational knowledge in particular.
for saying things ("being able to justify what one And that brings us to my topic, perception as a
says"). That is, he is suggesting that to be a rational capacity for knowledge. Observational knowledge
animal is to be a language-using animal. We might is knowledge one has through the operation of
frame the suggestion like this: human beings are perceptual capacities. And Sellars considers obser
born with a potential for rationality, and that po vational knowledge as a kind of knowledge whose
tential is brought into first actuality, in the guise of instances are self-conscious rationality at work.
a capacity available for exercise in second actuali I will not go into detail about Sellars's treatment
ties that we might call "acts of reason'; by initiation of observational knowledge. But I can sketch its
into a linguistic practice. basic shape quite quickly.
Against that background, Sellars is indicating Given that he is considering observational
that the topic of his epistemological reflections is knowledge as a form of the kind of knowledge that
knowledge of a sort that is distinctive of rational is self-conscious rationality at work, and given the
animals-that is, given his assumption, knowledge connection he assumes between rationality and
of a sort that is distinctive of language-using ani language, it is unsurprising that he approaches
mals. An instance of knowledge, of the sort Sellars observational knowledge by considering linguis
is concerned with, is an act of reason. And part of tic moves that express it, speech acts that he calls
what that amounts to is that someone who has a "reports". He puts two conditions on observational
bit of knowledge of the sort Sellars is concerned reports: first, a report must have an authority that
with is self-conscious about its credentials: in Sel consists in its issuing from a reliable capacity to
lars's terms, she occupies a position in the space of speak the truth, in appropriate circumstances,
being able to justify what one says. If someone has about the matters it concerns (consider, for in
a bit of knowledge of the sort Sellars is concerned stance, the capacity to know the colours of things
with, she can state not only what she knowledge by seeing them, an example Sellars makes much
ably believes, but also how her believing it is ratio of); and, second, that authority "must in some sense
nally grounded in a way that shows the belief to be be recognized by the person whose report it is"
knowledgeable.
12
JOHN MCDOWELL Perception as a Capacity for Knowledge 13
(§35).2 Someone who knows something by obser is green, or perhaps from her being inclined to say
vation, according to Sellars's conception, must be that it is green, with the cogency of the inference
self-consciously aware of the authority with which underwritten by the reliability she needs to be able
she speaks if she expresses what she knows, an au to ascribe to herself according to the second of Sel
thority her position has by virtue of its being the lars's two conditions.
upshot of a reliable capacity to be right about the But it seems bizarre to suggest that the thought
relevant kind of thing. Spelled out in connection that something she sees is green is warranted like
with the capacity to know the colours of things by that for the subject herself. Moreover, the idea is
looking at them, the requirement is that someone out of line with one of Sellars's fundamental con
who gives expression to such knowledge by saying, victions, that knowledge through perception is not
for instance, "That's green" must be able to vindi inferential.
cate the authority with which she speaks by saying 1 do not believe Sellars is even flirting with such
something like "I can tell a green thing when 1 see an idea when he sets out the two conditions. No
IL one". doubt someone else could exploit the reliability the
This might make it seem as if Sellars is flirting subject ascribes to hersel£ to license an inference
with the idea that the warrant by virtue of which from her saying that something is green to the con
an utterance of "That's green" counts as expressing clusion that it is green. But Sellars is not implying
knowledge has an inferential structure, like this: that the subject's own warrant for her belief that
what warrants the subject in believing that the thing the thing is green consists in such an inference.
she is talking about is green is the cogency of an He requires that she be able to claim reliability for
inference to its being green from her saying that it hersel£ but he does ~~eive her claim of reli
ability as formulating the principle of an inference
2 The distancing note sounded by Sellars's qualifi that captures her warrant for believing the thing is
cation "in some sense" is there because he thinks the green. Her warrant for believing the thing is green
second condition is difficult to accommodate; he is that she can see that it is. The reliability she must
goes on to make heavy weather over the credentials be able to claim is a condition for her to be able to
a reporter can have for counting as knowing that she
have experiences in which she sees that things are
has that authority. I think the difficulty Sellars makes
green; it is such experiences that warrant her in
for himself over this is misplaced, and I am going to
, believing, and saying, that things are green.
ignore the qualification.
• I
14
JOHN MCDOWELL Perception as a Capacity for Knowledge 15
2. Sellars says knowledge is a position in the space lives of human children in whom the potential for
of reasons. And he connects the ability to occupy rationality has not yet been brought into first actu
positions in the space of reasons with the ability to ality. Sellars has no reason to deprecate the use of
use language. One might be tempted to think this epistemic vocabulary in connection with subjects
expresses a kind of human chauvinism, a position that do not count as rational animals. He has no
that would refuse to attribute knowledge in any reason to claim, for instance, that any knowledge
proper sense to non-human animals. But I think such beings are credited with is only loosely so
that would be point-missing. called.3 In the terms I have suggested, his point is
Certainly philosophers can be tempted into that just that the knowledge of such beings does not
sort of position. Consider the Cartesian idea that belong to the species of knowledge he is concerned
non-human animals are automata, beings that do with, knowledge that is rationality in operation.
not have mental states; on such a view, non-hu And that applies to Sellars's treatment of per
man animals do not have beliefs, and if we think of ception in particular. Directing our attention to
knowledge as belief with appropriate credentials, perception as a capacity for a ~J._~i~c:ri~JdE-4. of
we have to say, a fortiori, that they do not have knowledge, knowledge that is an act of reason,
anything genuinely recognizable as knowledge. need not be prejudicial to the possibility of ac
But as I understand him, Sellars is not making knowledging that perception is, on some suitable
a pronouncement about how we may properly use understanding, a cognitive capacity in many kinds
the word "know" and its cognates. He is noting of non-human animals, and in pre-rational (pre
that his topic is knowledge as an act of reason in linguistic) human children, also.
a sense that he connects with language and self In restricting his topic to knowledge of a kind
consciousness. But that need not be prejudicial to whose instances are reason in operation, Sellars is
a more liberal application of epistemic concepts, making a move that is not special to him, and it
for purposes other than his. I do not believe we is not arbitrary or unmotivated. In the Critique of
miss anything Sellars has reason to insist on if we Pure Reason, Kant makes this well-known remark:
take him to conceive his topic as a species of a ge
nus, which, for all he cares, can be recognized as 3 Compare, for instance, Robert Brandom, "Knowl
edge and the Social Articulation of the Space of Rea
being instantiated also in the lives of at least some
sons'; Philosophy and Phenomenological Research vol. 55
non-human animals, and, we might add, in the
no. 4 (1995),895-908, at 899-900, n. 3.
16 JOHN MCDOWELL Perception as a Capacity for Knowledge 17
All the interests of my reason, speculative as well as instance of the knowledge I am concerned with as
practical, combine in the three following questions: a potentially self-conscious standing in the space
1. What can I know? of reasons.
2. What ought I to do?
3. It might seem that Sellars's focus on knowledge
3. What may I hoper
as self-conscious rationality at work goes badly
The first of those questions defines what we might
with an interest in perception, in particular, as a ca
call "philosophical epistemology': The question
pacity for knowledge.
is posed in the first person, by a self-consciously
The conception of knowledge Sellars expresses
rational subject, one who asks the question as
in the remark I began with is epistemologically
encapsulating one of the interests of his reason.
internalist, in this sense: the warrant by virtue of
Sellars is more explicit than Kant in linking self
which a belief counts as knowledgeable is acces
conscious rationality with the capacity to use lan
sible to the knower; it is at least potentially known
guage. But Kant too is tacitly presupposing the ca
by her. Someone who has a bit of knowledge of
pacity to use language, at least in the shape of the
the relevant sort is self-conscious about the cre
capacity to ask questions like these. And Sellars's
dentials of her knowledge. As Sellars puts it, she
remark about what we are doing when we classify
occupies a position in the space of being able to
something as a case of knowledge, of the distinc
justify what one says.
tive sort he is interested in, lines up well with the
Now it seems obvious enough that some of the
implicit definition of philosophical epistemology
knowledge had by a rational subject is grounded
put in place by Kant's question. If! ask"What can
like that, grounded in a way that is accessible to the
I know?': I must be conceiving any instance of the
subject. Suppose I have a bit of knowledge whose
knowledge I am asking about as an achievement
warrant consists in the cogency of an inference to
whose credentials to count as such, which must
what I know from something else, my warrant for
warrant the relevant beliefs by the lights of my
which is for present purposes not under question.
reason, I can recognize. I must be conceiving anx.
I must be able to say not only what it is that I know
in that way, but also why it counts as knowledge;
4 Critique of Pure Reason, translated by Norman I must be able to cite, and if necessary defend, the
Kemp Smith (London: Macmillan, 1929), A804-5/ inferential basis on which I know it. "My neighbour
B832-3.
18 JOHN MCDOWELL Perception as a Capacity for Knowledge 19
is at home'; I say. "How do you know?'; you ask. "entitlement" for a species of warrant that, as he
I must be able to make some such reply as this: explains,
"His car is in his driveway:' And if my interlocutor
need not be fully conceptually accessible, even on
responds "Maybe he went to work on the bus'; I reflection, to the warranted individual. The indi
must be able to recognize the relevance of what he vidual need not have the concepts necessary to
says. Perhaps I should then withdraw the claim to think the propositional content that formulates
know that was implicit in my first assertion. the warrant.6
But the credentials of perceptual knowledge And he maintains that the warrant perceptual
are surely not like the credentials of knowledge states provide for beliefs about the environment
self-consciously grounded in inferential connec is entitlement in that sense. Even for a subject for
tions between propositions. And it can seem that whom a perceptual warrant is conceptually acces
if we give an internalist account of warrants for sible-a subject who can justify a belief she holds
perceptual knowledge, the effect is that we cannot by citing a perceptual state she is in-the warrant
accommodate that dissimilarity. that the perceptual state itself affords to the belie£
For reasons of this sort, Tyler Burge advocates as Burge sees things, is warrant of the same sort
an epistemological externalism, in a sense that is that perceptual states provide for subjects who
a counterpart to internalism as I have found it in cannot conceptualize that warrant. So we cannot
Sellars, about the warrant that perceptual states give an acceptable account of that sort of warrant
provide for knowledge.s Burge adopts the term by saying something that is meant to be specific to
the perceptual beliefs of rational subjects.
5 Burge applies the idea of inference to "truth-and
Part of what is motivating Burge here is a
reason-preserving propositional transitions among
thought I have already considered, that perceptual
propositional attitudes" even in animals that are not
able to give expression to the warrants-which, on knowledge can b~ had by non-human animals and
this conception, may be inferential-for their beliefs.
See "Perceptual Entitlement'; Philosophy and Phe can capture the objection by saying that as Burge
nomenological Research vol. 67 no. 3 (2003), 503-48, understands him, Sellars groups perceptual knowledge
with knowledge whose title to count as knowledge
at 519. Burge's objection to Sellars ian internalism
consists in an inferential warrant that is accessible to
about perceptual knowledge cannot be put by saying
the subject.
Sellars groups perceptual knowledge with inferential
knowledge on that undemanding conception. But we 6 "Perceptual Entitlement'; 504.
20 JOHN MCDOWELL Perception as a Capacity for Knowledge 21
.
~Il) ;~
pre-rational (pre-linguistic) human children as must be wrong in an account that is supposed to
1,'
well as by mature human beings, subjects in whom fit perceptual knowledge in general. But that does ('
a potential for reason has been brought into first not sh o w. t hat 'm ternal I' sm cannot be n'gh t ab o ut a I ': , fJ'il,l l· ''f,, f'
actuality. Burge is calling for a general account of distinctive kind of warrant by virtue of which the \'/ J -rI.
perceptual warrant as such, an account suitable for perceptual knowledge of rational subjects counts i ,f:
all cases of perceptual knowledge. He writes: as the knowledge it is. If our concern is with a spe- I ~I !
I "
cies, we do not have to restrict ourselves to things I
A viable conception of warrant and knowledge must J
include both primitive and sophisticated types. A ~h~t are tr~e of all instances of the genus of which
condition of viability is that such a conception apply It IS a specIes.
to animal and child perceptual belief, and knowl
edge, as well as to mature human instances of belief 4. Such considerations perhaps undermine some
and knowledge.7 of Burge's rhetoric. But they would not be enough
As it stands, this seems to express a version of to disarm his resistance to a Sellarsian internalism
the thought I tried to discourage when I argued about perceptual knowledge, even if we stress that
that Sellars should not be accused of human chau the internalism is meant to apply only to the war
vinism. As I urged in that context, giving a special rant for a special kind of perceptual knowledge,
account of the perceptual knowledge of rational distinctive of rational subjects. Burge has an ob
animals is consistent with regarding perceptual jection that such considerations do not address. If
knowledge in rational animals as a sophisticated Burge's objection works, it tells against a Sellarsian
species of a genus that is also instantiated more internalism about perceptual knowledge even if
primitively in non-rational animals and pre-ratio the internalism is explicitly restricted to a species
nal human children. of perceptual knowledge that is held to be distinc
/ To exploit the idea of genus and species like that tive of rational subjects.
I is to accept what Burge insists on, that non-rational Burge actually considers two sorts of approach,
subjects, subjects incapable of getting their minds supposedly inspired by Sellars, to perceptual
around the warrant for their beliefs, can have knowledge.
perceptual knowledge. It follows that internalism According to the first, there is nothing of epi
stemological significance between circumstances
in a perceiver's environment and the formation of
7 "Perceptual Entitlement'; 505.
