knowledge. At root, all our empirical knowledge is grounded in how we
see, hear, touch, smell and taste the world around us. In section 1, a
distinction is drawn between perception that involves concepts and
perception that doesn't, and the various epistemic relations that
there are between these two types of perception are discussed–our
perceptual beliefs and our perceptual knowledge. Section 2 considers
the role of causation in perception and focuses on the question of
whether perceptual experience justifies our beliefs or merely causes
them. Sections 3 and 4 further investigate the epistemic role of
perception and introduce two distinct conceptions of the architecture
of our belief system: foundationalism and coherentism. It is shown how
perceptual experience and perceptual beliefs are integrated into these
systems. Finally, section 5 turns to the externalist view that
thinkers need not be aware of what justifies their perceptual beliefs.
1. Perception and Belief
a. Seeing That, Seeing As and Simple Seeing
Perception is the process by which we acquire information about the
world around us using our five senses. Consider the nature of this
information. Looking out of your window, you see that it is raining.
Your perception represents the world as being like that. To perceive
the world in this way, therefore, it is required that you possess
concepts, that is, ways of representing and thinking about the world.
In this case, you require the concept RAIN. Thus, seeing that your
coffee cup is yellow and that the pencil is green involves the
possession of the concepts COFFEE CUP, YELLOW, PENCIL and GREEN. Such
perception is termed "perceiving that," and is factive; that is, it is
presupposed that you perceive the world correctly. To perceive that it
is raining, it must be true that it is raining. You can also, though,
perceive the world to be a certain way and yet be mistaken. This we
can call, "perceiving as," or in the usual case, "seeing as". A stick
partly submerged in water may not be bent but, nevertheless, you see
it as bent. Your perception represents the stick as being a certain
way, although it turns out that you are wrong. Much of your
perception, then, is representational: you take the world to be a
certain way, sometimes correctly, when you see that the world is thus
and so, and sometimes incorrectly, when the world is not how you
perceive it to be.
It also seems that there is a form of perception that does not require
the possession of concepts (although this claim has been questioned).
It is plausible to claim that cognitively unsophisticated creatures,
those that are not seen as engaging in conceptually structured
thought, can perceive the world, and that at times we can perceptually
engage with the world in a non-conceptual way. You can tell that the
wasp senses or perceives your presence because of its irascible
behavior. When you are walking along the High Street daydreaming, you
see bus stops, waste bins, and your fellow pedestrians. You must see
them because you do not bump into them, but you do not see that the
bus stop is blue or that a certain pedestrian is wearing Wrangler
jeans. You can, of course, come to see the street in this way if you
focus on the scene in front of you, but the claim here is that there
is a coherent form of perception that does not involve such conceptual
structuring. Let us call such baseline perceptual engagement with the
world, "simple seeing". This perception involves the acquisition of
perceptual information about the world, information that enables us to
visually discriminate objects and to successfully engage with them,
but also information that does not amount to one having a conceptually
structured representation of the world. (Dretske, 1969, refers to
simple seeing as "non-epistemic" seeing, and refers to 'seeing that'
as "epistemic" seeing).
You can, then, simply see the bus stop, or you can see that the bus
stop is blue, or you can, mistakenly, see the bus stop as made of
sapphire. These are all forms of perceptual experience, ways you have
of causally engaging with the world using your sensory apparatus and
ways that have a distinctive conscious or "phenomenological"
dimension. Seeing in its various forms strikes your consciousness in a
certain way, a way that you are now experiencing as you look at your
computer screen. This article investigates the causal and epistemic
roles of this perceptual experience.
A little more terminology: the term "sensation" can be used to refer
to the conscious aspect of perception, but note that one can have such
sensations even when one would not be said to be perceiving the world.
When hallucinating, for example, one is having the sensations usually
characteristic of perceptual experience, even though in such cases
one's experience would not be described as perceptual.
Consider how these various kinds of perceptual experience are related
to our perceptual beliefs. Perceptual beliefs are those concerning the
perceptible features of our environment, and they are beliefs that are
grounded in our perceptual experience of the world. The content of
such beliefs can be acquired in other ways: You could be told that the
bus stop is blue, or you could remember that it is blue. Right now,
though, waiting for the bus, you acquire this belief by looking
straight at it, and, thus, you have a perceptual belief concerning
this particular fact. Just how your perceptual beliefs are grounded in
your perceptual experience is a contentious issue. There is certainly
a causal relation between the two, but some philosophers also claim
that it is perceptual experience that provides justification for our
perceptual beliefs. This foundationalist claim is denied by the
coherentist (see sections 3 and 4 below).
b. Perceptual Beliefs
First, one does not necessarily come to acquire perceptual beliefs in
virtue of simply seeing the world. Simple seeing is something that
cognitively unsophisticated creatures can do, creatures such as wasps
that do not have more sophisticated beliefs, propositional beliefs. It
is plausible, though, that if one sees a certain object as a bus stop,
then one would also come to believe that there is a bus stop being
seen. In many cases, this is, of course, true, but it is not in all. A
famous example is the Muller-Lyer illusion:
muller-lyer
The two horizontal lines above look as though they are of different
lengths, the upper line being longer than the lower. If we have seen
the illusion before, then we do not believe our eyes. Instead, we
believe that the lines are the same length (which they are). Here is
another case: a habitual user of hallucinogenics may doubt the
veracity of all his perceptions; he may not believe anything he sees.
His perception, however, amounts to more than simply seeing; he sees
the moon as being made of cheese and his cup of tea as grinning up at
him. Yet, because of the doubt fostered by his frequent
hallucinations, he does not move from seeing the world as being a
certain way to believing that it is. In most cases, though, if one
sees the world as being a certain way, then one also believes that it
is that way. Last, let us return to the notion of "perceiving that."
Such perception has a closer relationship with the acquisition of
perceptual belief. If one is described as perceiving that the world is
a certain way, it is implied that one also believes that the world is
so. Here, there isn't room for perception to come apart from belief.
Thus, we have seen that we can be perceptually engaged with the world
in various ways. Such engagement can amount to the mere acquisition of
perceptual information, the experience of seeing the world as being a
certain way, or the possession of the cognitive states of perceiving
and believing that it is so. If all goes well, such perceptual beliefs
may constitute perceptual knowledge of the world. According to the
traditional account, this is when those beliefs are true and when they
are justified. Perceptual knowledge consists in knowledge of the
perceptible features of the world around us, and it is that which is
grounded in our perceptual experience. Again, the nature of this
grounding is controversial. Perceptual experience is certainly
causally related to perceptual knowledge; foundationalists, however,
make the further claim that such experience provides the justification
that is constitutive of such knowledge (see section 3). Others,
though, including Armstrong (section 2a) and the coherentists (section
4), do not believe perceptual experience plays this justificatory role
with respect to perceptual knowledge. The next section considers this
key issue of justification.
But consider the issue of skepticism. The skeptical arguments of
Descartes (1641) have had an enormous influence on both the history
and practice of epistemology. He suggests certain scenarios that
threaten to undermine all of our empirical knowledge of the world. It
could be that right now you are dreaming. If you were, everything
might appear to you just as it currently does; dreams are sometimes
very real. It is also possible that a powerful demon might be
deliberately deceiving you; there may not be an external world at all,
and all your perceptual experience and perceptual beliefs may be
simply planted in your mind by this evil entity. Given such scenarios,
it is not clear how our perceptual beliefs can be justified and thus,
how we can have perceptual knowledge. Any reasons you have for
thinking that such beliefs correctly represent the world are
undermined by the fact that you could have such beliefs even if the
external world did not exist. Since the seventeenth century,
epistemology has been trying to find a solution to this Cartesian
scepticism. This article simply assumes that we can have justification
for our perceptual beliefs and that perceptual knowledge is possible.
Given this assumption, the focus is on how we should conceive of such
justification.
2. Perception, Justification and Causation
Perceptual experience provides both causal and justificatory grounding
for our perceptual beliefs and for our knowledge of the passing show.
In this section, we shall start to look at the causal and
justificatory relations between perception, belief and knowledge. As
was discussed above, our perceptual experience can be conceptually
structured: we can see the world as being a certain way, or we can see
that it is thus and so. Thus, such experience could be seen as
providing justification for our perceptual knowledge in that you could
be justified in taking things to have the properties you see them as
having. The fact that perceptual experience is conceptual, however, is
not sufficient to ensure that your perceptual beliefs are justified.
Dave, a friend of yours, sees every tackle made against a player of
West Ham United Football Club as a foul. He is not, however, justified
in taking this to be true. Often these clashes are simply not fouls;
Dave is wrong, and even when he is correct, when he really sees that a
foul has been committed, it would seem that his prejudiced observation
of the game entails that in these cases he only gets it right through
luck, and thus, he is not justified in his belief. The fact, then,
that our experience is conceptual does not entail that we have
justified perceptual beliefs or knowledge. Section 3 considers what
else needs to be said, and investigates an account of how perceptual
experience is seen to provide epistemic justification. First, though,
consider an account of perceptual knowledge that does not make use of
the notion of justification.
a. Armstrong's Causal Account of Perceptual Knowledge
Armstrong (1961 / 1973) claims that perceptual knowledge simply
requires that one's perceptual beliefs stand in lawlike relations to
the world.
What makes…a belief a case of knowledge? My suggestion is that
there must be a lawlike connection between the state of affairs Bap
[that a believes p] and the state of affairs that makes 'p' true such
that, given Bap, it must be the case that p. (Armstrong, 1973, p. 75)
Crudely, since causal relations are lawlike, if our perceptual and
cognitive apparatus is such that it is buzzing flies that cause us to
have perceptual beliefs about buzzing flies, then it will be the case
that we will have perceptual knowledge of this annoying aspect of our
environment when the bees cause the belief. Armstrong calls his
account a "thermometer model" of knowledge. We can come to have
knowledge of the world just as a thermometer can come to represent its
own temperature. In both systems, there is simply a lawlike relation
between a property of the world and a property of a representative
device (the level of mercury in a thermometer or the state of certain
internal cognitive mechanisms of a thinker).
Highlighting the role of perceptual experience, Armstrong claims that:
"perception is nothing but the acquiring of knowledge of, or, on
occasions, the acquiring of an inclination to believe in, particular
facts about the physical world, by means of our senses," (Armstrong,
1961, p. 105)
He does, however, claim that there is a "contingent connection between
perception and certain sorts of sensation," and that this, "may help
to explain the special 'feel' of perception," (Armstrong, 1961, p.
112). Conscious sensation, then, is not essential to perception. I
could be correctly said to see the road ahead as I drive late at night
on the motorway, even though I have "switched off," and appear to be
driving on "autopilot." I can see the road because I am still causally
acquiring beliefs about the world in front of me by way of my senses.
Similarly, cases of blindsight are also bonafide cases of perception.
Blindsight patients claim to have a complete lack of visual experience
on, for example, their left side, yet they can make reliable reports
about shapes and objects that are presented to this side of their
perceptual field (they themselves, however, claim that they are merely
guessing). They do, then, seem to be acquiring correct beliefs about
their environment via a causal engagement between the world and their
senses, and thus, they perceive the world even though in such cases
the contingent connections with sensation are lost. Thus, on
Armstrong's account, perceptual experience is not necessary for
perceptual knowledge. When one does have conscious perceptual
experiences, these do not play a justificatory role; they are simply
causally related to perceptual belief and knowledge. Many, however,
find such an account too sparse, in that one's experience does not
play any justificatory or epistemic role in the acquisition of
perceptual beliefs or knowledge. It is claimed that a more satisfying
theory of perception should include an account of why perceptual
experience justifies our perceptual beliefs and that we should not be
content with simply an account of why we are caused to acquire them.
The following theory of perception attempts to include just such an
account of justification.
3. Perception and Foundationalism
Foundationalists claim that the superstructure of our belief system
inherits its justification from a certain subset of perceptual beliefs
upon which the rest sits. These beliefs are termed "basic beliefs."
Our belief system, then, is seen as having the architecture of a
building. Later, in section 4, we shall see that coherentists take our
belief system to be more akin to an ecosystem, with our beliefs
mutually supporting each other, rather than relying for their
justification on certain crucial foundation stones. There are various
versions of this foundationalist approach, two of which are discussed
in the next two sections.
a. Traditional Foundationalism
Traditionally the foundations of knowledge have been seen as
infallible (they cannot be wrong), incorrigible (they cannot be
refuted), and indubitable (they cannot be doubted). For empiricists,
these foundations consist in your beliefs about your own experience.
Your beliefs are basic and non-basic. Your basic beliefs comprise such
beliefs as that you are now seeing a red shape in your visual field,
let us say, and that you are aware of a pungent smell. In order to
justify your non-basic belief that Thierry Henry is the best striker
in Europe, you must be able to infer it from other beliefs, say that
he has scored the most goals. The traditional foundationalist claim,
however, is that this sort of inferential justification is not
required for your basic beliefs. There may not actually be a red
object in the world because you may be hallucinating, but,
nevertheless, you cannot be wrong about the fact that you now believe
that you am seeing something red. Justification for such beliefs is
provided by experiential states that are not themselves beliefs, that
is, by your immediate apprehension of the content of your sensory,
perceptual experience, or what is sometimes termed, "the Given". It
is, then, your experience of seeing red that justifies your belief
that you are seeing red. Such experience is non-conceptual. It is,
though, the raw material which you then go on to have conceptual
thoughts about. This conception of the relation between knowledge and
experience has had a distinguished history. It was advocated by the
British empiricists–Locke, Berkeley and Hume–and by the important
modern adherents C. I. Lewis (1946) and R. Chisholm (1989). However,
this conception of how your perceptual beliefs are justified has been
widely attacked, and the next two sections address the most
influential arguments against traditional foundationalism.
b. Sellars and the Myth of the Given
Sellars (1956) provides an extended critique of the notion of the
Given. There are two parts to Sellars' argument: first, he claims that
knowledge is part of the "logical space of reasons;" and second, he
provides an alternative account of "looks talk," or an alternative
reading of such claims as "that looks red to me," claims that
traditionally have been seen as infallible and as foundations for our
perceptual knowledge. According to Sellars, no cognitive states are
non-inferentially justified. For him:
"The essential part is that in characterising an episode or a
state as that of knowing, we are placing it in the logical space of
reasons, of justifying and being able to justify what one says."
(Sellars, 1956, p. 76)
Whether we are talking about perceptual or non-perceptual knowledge,
we must be able to offer reasons for why we take such claims to be
true. To even claim appropriately that I have knowledge that I now
seem to be seeing a red shape, I must be able to articulate such
reasons as, "since my eyes are working fine, and the light is good, I
am right in thinking that I am having a certain sensory experience."
As Rorty (1979, chapter 4) argues, justification is essentially a
linguistic or "conversational" notion; it must consist in the reasoned
recognition of why a particular belief is likely to be true or why one
is rightly said to be having a certain experience. If such an account
of justification is correct, then the notion of non-inferentially
justified basic beliefs is untenable and non-conceptual perceptual
experience cannot provide the justification for our perceptual
beliefs.
Surely, though, "this looks red to me," cannot be something that I can
be wrong about. Such a foundationalist claim seems to be undeniable.
Sellars, however, suggests that such wording does not indicate
infallibility. One does not say, "This looks red to me," to
(infallibly) report the nature of one's experience; rather, one uses
such a locution in order to flag that one is unsure whether one has
correctly perceived the world.
… when I say "X looks green to me"…the fact that I make this
report rather than the simple report "X is green," indicates that
certain considerations have operated to raise, so to speak in a higher
court, the question 'to endorse or not to endorse.' I may have reason
to think that X may not after all be green. (Sellars, 1956, p. 41)
Thus, Sellars provides a two-pronged attack on traditional
foundationalism. The way we describe our perceptual experience does
indeed suggest that we have infallible access to certain private
experiences, private experiences that we cannot be mistaken about.
However, we should recognize the possibility that we may be being
fooled by grammar here. Sellars gives an alternative interpretation of
such statements as, "this looks red to me," an interpretation that
does not commit one to having such a privileged epistemological access
to one's perceptual experience. Further, a conceptual analysis of
"knowledge" reveals that knowledge is essentially a rational state
and, therefore, that one cannot claim to know what one has no reason
for accepting as true. Such reasons must be conceived in terms of
linguistic constructions that one can articulate, and thus, the bare
presence of the Given cannot ground the knowledge we have of our own
experience or, consequently, of the world. This, then, is a rejection
of the traditional foundationalist picture, or what Sellars calls,
"the Myth of the Given."
One of the forms taken by the Myth of the Given is the idea that
there is, indeed must be, a structure of particular matter of such
fact that (a) each fact can not only be noninferentially known to be
the case, but presupposes no other knowledge either of particular
matters of fact, or of general truths; and (b) such that the
noninferential knowledge of facts belonging to this structure
constitutes the ultimate court of appeal for all factual claims,
particular and general, about the world. (Sellars, 1956, pp. 68-9)
c. Concepts and Experience
According to traditional foundationalism, the content of perceptual
experience, the Given, is not conceptual in nature. It has been
argued, however, that experience should not be seen in this
traditional way. The phenomenon of "seeing as," suggests to some that
experience should be interpreted as essentially conceptual in nature.
What is this a picture of?
duck-rabbit
You perhaps see a duck. I can, however, alter the character of your
visual experience by changing the beliefs that you have about this
picture. Think RABBIT looking upward. The picture now looks different
to you even though you are seeing the same configuration of black
marks on a white background. This picture is usually referred to as
"the duck-rabbit." Originally, you saw the drawing as a duck; now you
see it as a rabbit (or, as Wittgenstein would say, you notice
different "aspects" of the picture). You have, then, distinct
perceptual experiences dependent on the particular concepts "through
which" you see that picture. Some take this to prove that perceptual
experience is not pre- or non-conceptual but that it is essentially a
conceptual engagement with the world. Such experience does not only
consist in our having certain retinal images: "There is more to seeing
than meets the eyeball," (Hanson, 1988, p. 294). It is, rather, the
result of a necessary conceptual ordering of our perceptual engagement
with the world. This is a theory of experience that is at odds with
that of the traditional foundationalist.
The theory has Kantian roots. For Kant, one cannot experience the
world without having a conceptual structure to provide the
representational properties of such experience. In Kant's terms, the
intuitions received by the sensibility cannot be isolated from the
conceptualization carried out by the understanding. As he states,
"Intuitions without concepts are blind, concepts without intuitions
are empty" (Kant, 1781, A51 / B75). Intuitions, or what we might call
bare perceptual experience–that which does not have a conceptual
structure–cannot be seen as experience of a world, and therefore, such
a conception of our perceptual engagement with the world cannot be
seen as experiential at all; it is "blind". The second clause of
Kant's aphorism claims that concepts that are not based on information
received through the senses can have no empirical content. The Kantian
claim, then, is that thinking about the world and experiencing it are
interdependent. This is an attack on the distinction drawn in section
1a between simple seeing and conceptually structured forms of
perception such as seeing that and seeing as. Kant claims the notion
of simple seeing is incoherent since such a non-conceptual engagement
with the world isn't experiential.
Not everyone accepts that the phenomenon of seeing as entails this
picture of experience. Dretske (1969) argues that simple or
non-epistemic seeing is independent of epistemic seeing; that is, it
is independent of seeing that is conceptually structured.
Non-epistemic seeing amounts to the ability to visually differentiate
aspects of one's environment such as the bus stop and the waste bin,
and one can do this without seeing these items as anything in
particular (although, of course, one usually does). Further, "seeing
as" presupposes simple seeing. One has to have some bare experience to
provide the raw materials for our conceptually structured experience
or thought. We may be able to see the picture above as a duck or as a
rabbit, but we can only do this if we have a non-conceptual experience
of a certain configuration of black marks on a white background. One's
experience of the basic black and white lines in the figure is
independent of any concepts one may have that may then allow one to
see these lines in a certain more sophisticated way, that is, as a
duck or as a rabbit. In reply, however, it could be claimed that even
such a basic experience as this relies on the contingent fact that one
has the concepts of, for example, BLACK and WHITE. Perhaps if one did
not have these concepts, then one could not even see this basic
figure.
We have, then, looked at two problems faced by the traditional
foundationalist, both of which center on the alleged non-conceptual
nature of perceptual experience. Two responses have been made by those
who feel the force of these objections: some modify foundationalism in
order to take account of some of the considerations above, and others
reject it altogether. The first of these responses is the topic of the
next section.
d. Modest Foundationalism
Some foundationalists agree that the Given is in some ways
problematic, yet they still attempt to maintain a "modest" or
"moderate" foundationalism. Audi (2003) and Plantinga (2000) promote
this view. First, our perceptual beliefs concerning both the world and
our own experience are not seen as infallible. You can believe that
you see red or that you seem to see red, yet either belief could turn
out to be unjustified. Second, non-conceptual perceptual experience
does not play a justificatory role. Perceptual beliefs are simply
self-justified; that is, it is reasonable to accept that they are true
unless we have evidence to suggest that they may be untrustworthy.
Such a view of perception remains foundationalist in nature because we
still have basic beliefs, beliefs that are non-inferentially
justified. Thus, the justification possessed by perceptual beliefs is
defeasible. You may, for example, have good evidence that your cup of
tea has been spiked with an hallucinogen, and, therefore, the
justification for your perceptual belief that a pig has just flown
past the window is defeated. More controversially, your belief that
you seem to see red could be defeated by psychological evidence
concerning your confused or inattentive state of mind. However, in the
absence of any beliefs concerning such contravening evidence, your
perceptual beliefs have prima facie justification.
Modest foundationalism avoids a dilemma that faces traditional
foundationalism. It is certainly plausible that beliefs about your own
perceptual experience are infallible and that you can't be wrong when
you claim that the cup looks red. It is not clear, however, how such
beliefs can ground your perceptual knowledge since they are about your
own mental states and not the world. The fact that the cup looks red
to you does of course relate to the cup, but primarily it is a fact
about how that cup strikes your experience. Recoiling from such a
picture, you could claim that your foundational beliefs concern the
color of the cup and not merely your experience of the cup. However,
it is not plausible that your beliefs about the color of the cup are
infallible, and therefore, such beliefs cannot play a foundational
role according to the traditional account. The modest foundationalist
can avoid this dilemma. For a perceptual belief to be justified, it
does not have to be infallible. You can, therefore, have beliefs about
the properties of objects in the world playing the requisite
foundational role rather than those that are simply about your own
experiences.
4. Perception and Coherentism
Modest foundationalists attempt to keep some of the features of the
traditional foundationalist picture while conceding that their
foundations aren't infallible. There is, however, a distinct response
to the problems associated with traditional foundationalism, and that
is to reject its key feature, namely its reliance on foundational,
non-inferential, basic beliefs. Coherentism presents an alternative.
Coherentists such as Bonjour (1985) and Lehrer (1990) claim that
beliefs can only be justified by other beliefs and that this is also
true of our perceptual beliefs. Section 3.a described how Sellars
argued for such a position in that, for him, perceptual beliefs must
be supported by beliefs about the reliability of our experience. The
next two sections explain the coherentist account of justifying
perceptual claims.
a. The Basic Idea Behind Coherentism
For a coherentist, a particular belief is justified if one's set of
beliefs is more coherent with this belief as a member, and,
conversely, a belief is unjustified if the coherence of one's set of
beliefs is increased by dropping that particular belief. The basic
idea behind coherentism is that the better a belief system "hangs
together," the more coherent it is. How, though, should we conceive of
"hanging together" or "coherence"? First, one requires consistency.
Our beliefs should not clash; they must not be logically inconsistent:
we should not believe p and believe that not p. However, more than
mere logical consistency is required. One could imagine a set of
beliefs that consisted of the belief that 2+2=4, the belief that Cher
is a great actress, and the belief that yellow clashes with pink.
Although these beliefs are logically consistent, they do not form a
particularly coherent belief set since they do not have any bearing on
each other at all. For coherence, therefore, some kind of positive
connection between one's beliefs is also required. Such a positive
connection is that of inference. A maximally coherent belief set is
one that is logically consistent and one within which the content of
any particular belief can be inferred from the content of certain
other beliefs that one holds. Conversely, the coherence of a set of
beliefs is reduced if there are subgroups of beliefs that are
inferentially isolated from the whole.
b. Bonjour and the Spontaneous Nature of Perceptual Beliefs
For a coherentist, perceptual beliefs are justified, as all beliefs
are, if our acceptance of them leads to an increase in the overall
coherence of our belief system. An account, though, is also required
of how perceptual beliefs can be seen as correctly representing the
external world, a world that is independent of our thinking. This is
particularly pressing for the coherentist because the justification
for our perceptual beliefs is provided by one's other beliefs and not
by one's perceptual experience of one's environment.
To account for the representational ability of perceptual beliefs,
Bonjour focuses upon a class of beliefs that he calls "cognitively
spontaneous." These are beliefs we simply acquire without inference.
Right now, on turning my head to the left, I spontaneously acquire the
belief that the orange stapler is in front of the blue pen, and that
my glass of water is half full. These perceptual beliefs are likely to
be true when certain conditions obtain–that the light is good and that
I am not too far away from what I am looking at (these Bonjour calls
the "C-conditions"). My belief, then, that my glass is half full is
only justified if I also have beliefs about the obtaining of
C-conditions. However, for Bonjour's account to be persuasive, he
needs to provide some justification for this claim that beliefs
acquired in the C-conditions are likely to be true representations of
the world. This he does. First, we do not arrive at them via
inference; they are spontaneous. Second, the beliefs that we acquire
in this way exhibit a very high measure of coherence and consistency
with each other and with the rest of our belief system. The question
arises, then, as to why this should be so, since it is not obvious why
such spontaneous beliefs should continue to cohere so well. If, for
example, these beliefs were randomly produced by our perceptual
mechanisms, then our set of beliefs would very soon be disrupted.
Bonjour's claim is that there is a good a priori explanation for the
ongoing coherence and consistency of our set of beliefs, that is, that
it is the result of our beliefs being caused by a coherent and
consistent world. Thus, our perceptual beliefs correctly represent a
world that is independent of our thinking. Non-conceptual perceptual
experience does not play a justificatory role with respect to
perception. This experience may cause us to acquire certain beliefs
about our environment, but the justification for these perceptual
beliefs is provided by the inferential relations that hold between
these beliefs and the rest of our belief system.
There are important objections. Plantinga (1993) notes that in the
Cartesian skeptical scenarios we also have a coherent set of beliefs,
but in these cases they are caused not by a coherent and consistent
world but by an evil demon or by a mad scientist who manipulates a
brain that lies in a vat of nutrient fluid (see Descartes 1641 and
Putnam 1981). Bonjour's claim, however, is that it is a priori more
probable that our beliefs are not caused by these creatures. Plantinga
finds such reasoning "monumentally dubious."
Even if such a hypothesis [that concerning the claim that our
coherent belief system corresponds to a coherent world] and these
skeptical explanations do have an a priori probability…it's surely
anyone's guess what that probability might be. Assuming there is such
a thing as a priori probability, what would be the a priori
probability of our having been created by a good God who…would not
deceive us? What would be the a priori probability of our having been
created by an evil demon who delights in deception? And which, if
either, would have the greater a priori probability?…how could we
possibly tell? (Plantinga, 1993, p. 109)
5. Externalism
The varieties of foundationalism and coherentism examined so far share
a certain approach to questions concerning epistemic justification.
They ask whether the evidence available to you is sufficient to
justify the beliefs that you hold. Questions of justification are
approached from the first person perspective. Foundationalists claim
that you have justified perceptual beliefs because of the fact that
these beliefs are grounded in your perceptual experience, experience
that is, of course, accessible to you; it is something of which you
are aware, something that you can reflect upon. Coherentists find
justification in the inferential relations that hold between your
perceptual and non-perceptual beliefs, relations that are, again,
something to which you have cognitive access. Epistemic practices can,
however, also be assessed from the third person perspective. It can be
asked whether a person's methods do, in fact, lead him or her to have
true beliefs about the world, whether or not such reliability is
something of which they are aware. Externalists claim that it is this
perspective with which epistemology should be concerned. A key notion
for externalists is that of reliability. A belief is justified if it
is acquired using a method that is reliable, with reliability being
cashed out in terms of the probability that one's thinking latches
onto the truth.
The justificatory status of a belief is a function of the
reliability of the processes that cause it, where (as a first
approximation) reliability consists in the tendency of a process to
produce beliefs that are true rather than false. (Goldman, 1979, p.
10)
One need not be able to tell by reflection alone whether or not one's
thinking is reliable in the required sense; a thinker does not have to
be aware of what it is that justifies his or her beliefs.
According to a reliabilist, then, a perceptual belief is justified if
it is the product of reliable perceptual processes. One strategy that
reliabilists have adopted is to ground their account of reliability in
terms of the causal connections that thinkers have to the world.
Roughly, for one to have a justified perceptual belief that p, the
fact that p should cause my belief that p. I am justified in believing
that Frasier is on television because its presence on the screen
causes my belief. Such accounts are developed by Goldman (1979 / 1986)
and Dretske (1981). It is important to note the difference between
this kind of account and that of Armstrong (section 2a). Armstrong
eschews all talk of justification and provides a wholly causal account
of perceptual knowledge. Many externalists, however, give an account
of justification in causal terms.
It was assumed throughout this article, except during the discussion
of scepticism, that we do have perceptual knowledge of the world, and
the article explored the multifarious epistemic and causal relations
that there are between the various modes of perception and perceptual
knowledge. Justification is the key issue, and there are four basic
stances. One stance is to agree with Armstrong and deny that
perceptual experience plays any justificatory role. Foundationalists
see perceptual experience as the justificatory basis for perceptual
knowledge, and it is such experience that ultimately provides
justification for all our knowledge of the world. Problems with the
traditional form of this position urged us to explore a more modest
form of foundationalism. Others reject foundationalism altogether.
Coherentists claim that the justification for our perceptual beliefs
is a function of how well those beliefs "hang together" with the rest
of our belief system. They too reject the justificatory role of
perceptual experience. Some externalists claim that justification is a
matter of reliability and that so long as our perceptual beliefs are
produced by mechanisms that reliably give us true beliefs, then those
beliefs are justified. Therefore, perception is of prime
epistemological importance, and it remains the focus of lively
philosophical debate.
6. References and Further Reading
* Armstrong, D. M. 'The Thermometer Theory of Knowledge' in S.
Bernecker & F. Dretske, eds. Knowledge: Readings in Contemporary
Epistemology, Oxford University Press, Oxford, pp. 72-85, 2000.
Originally published in Armstrong, 1973, pp. 162-75, 178-83.
* Armstrong, D. M. Belief, Truth and Knowledge, Cambridge
University Press, Cambridge, 1973.
* Armstrong, D. M. Perception and the Physical World, Routledge
and Kegan Paul, London, 1961.
o Included in the above is Armstrong's causal account of perception.
* Audi, R. "Contemporary Modest Foundationalism," in Pojman, L.
ed. The Theory of Knowledge: Classical and Contemporary Readings,
Wadsworth, Belmont, CA. 3rd edition, 2003.
o A useful paper in which it is argued that modest
foundationalism has advantages over traditional foundationalism.
* Bonjour, L. The Structure of Empirical Knowledge, Harvard
University Press, Cambridge, Mass. 1985.
o A well-developed coherentist theory of justification which
includes an account of the role of perception within such a theory.
(One should note, however, that Bonjour has recently abandoned
coherentism in favour of a version of foundationalism.)
* Chisholm, R. M. Theory of Knowledge, 3rd edition, Englewood
Cliffs, New Jersey, 1989.
o A wide ranging study of various epistemological issues
including his version of traditional foundationalism.
* Descartes, R. "First Meditation," in Meditations on First
Philosophy, 1641. Reprinted in The Philosophical Writings of
Descartes, eds. J. Cottingham, R. Stoothoff & D. Murdoch, Cambridge
University Press, Cambridge, 1983.
o One of the most influential passages of epistemological
writing in the history of Western philosophy in which various
skeptical possibilities are raised that suggest that our perceptual
beliefs may not be justified.
* Dretske, F. Seeing and Knowing, Routledge and Kegan Paul, London, 1969.
o Dretske defends the claim that seeing can be seen as
non-conceptual (or non-epistemic).
* Dretske, F. Knowledge and the Flow of Information, MIT Press,
Cambridge, Mass. 1981.
o Here he presents his sophisticated version of reliabilism.
* Goldman, A. I. "What is Justified Belief?," in G. Pappas, ed.
Justification and Knowledge: New Studies in Epistemology, Reidel, pp.
1-23, 1979.
* Goldman, A.I. Epistemology and Cognition, Harvard University
Press, Cambridge, Mass. 1986.
o In the above, Goldman forwards his reliabilist account of
justification.
* Grice, H. P. "The Causal Theory of Perception," in Proceedings
of the Aristotelian Society, Supplementary Volume 35, pp. 121-52,
1961.
o A precursor to the various contemporary causal theories of
perception, presented in the context of a sense datum theory of
perception.
* Hanson, N. R. "From Patterns of Discovery," in Perception, R.
Schwartz, ed. pp. 292- 305, 1988.
o Hansen argues that the nature of our perceptual experience
depends on the concepts we possess.
* Kant, I. The Critique of Pure Reason, trans. N. Kemp Smith, 1929
edition, The Macmillan Press, Ltd. Basingstoke, Hampshire, 1781.
o One of the greatest and most influential works of modern
philosophy. Of relevance to this article are Kant's thoughts
concerning the relation between our conceptual framework and the
nature of our perceptual experience.
* Lehrer, K. Theory of Knowledge, Westview Press, Boulder, Colorado, 1990.
o Lehrer provides a critique of foundationalism and his own
developed version of coherentism.
* Lewis, C. I. An Analysis of Knowledge and Evaluation, La Salle,
Illinois, 1946.
o Amongst various other important epistemological issues,
one can find Lewis's account of traditional foundationalism.
* McDowell, J. Mind and World, Harvard University Press,
Cambridge, Mass. 1994.
o In this transcription of his Locke lectures, McDowell
argues that perceptual experience is essentially conceptual in nature.
* Plantinga, A. Warrant: The Current Debate, Oxford University
Press, Oxford, 1993.
o An excellent epistemology textbook which includes an
in-depth critique of Bonjour's coherentism.
* Plantinga, A. Warranted Christian Belief, Oxford University
Press, Oxford, 2000.
o In the context of a sophisticated discussion of the
philosophy of religion, Plantinga develops a version of modest
foundationalism which he calls "reformed epistemology".
* Putnam, H. Reason, Truth and History, Cambridge University
Press, Cambridge, 1981.
o In chapter 1, Putnam presents his contemporary brain in a
vat version of the Cartesian skeptical scenario.
* Rorty, R. Philosophy and the Mirror of Nature, Princetown
University Press, Princetown, 1979.
o A historically informed and extended attack on traditional
foundationalism.
* Schwartz, R. Perception, Blackwell, Oxford, 1988.
o A good collection of articles focused on the epistemology
of perception.
* Sellars, W. Empiricism and the Philosophy of Mind. Originally
published in H. Feigl and M. Scrivens, eds. Minnesota Studies in the
Philosophy of Science, vol. 1, University of Minnesota Press,
Minneapolis, pp. 253-329, 1956. Page numbers here refer to 1997
reprint, Harvard University Press, Cambridge, Mass.
o This includes Sellars' influential attack on the Given.
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