## 1. Theories of Experience



For our purposes, a theory of perceptual experience aims to identify a
feature that is *constitutive* of perceptual experience: it is
shared by all perceptual experiences, and identifies at least part of
their nature. In this section, we will consider various potential
links between theories of experience and the epistemology of
perception that can be captured with the following template:



Epistemology-Mind Link
  

If experiences justify beliefs about the external world, then
experiences have property \(P\).



The idea here is that experiences have to be a certain way in order to
justify beliefs. Now, philosophers might accept a particular instance
of the E-M Link, but disagree about whether experiences are the way
they need to be in order to justify beliefs about the external world.
For example, Davidson (1986) and McDowell (1994) agree that
experiences justify beliefs about the external world only if
experiences have contents that can be assessed for truth. Davidson
(1986) argues that experiences do not justify beliefs about the
external world on the grounds that they lack truth-assessable
contents, whereas McDowell (1994) argues that experiences must have
truth-assessable contents given that they justify beliefs about the
external world (more on their dispute in
 subsection 1.2).



We can organize our discussion of such agreements and disagreements
around the following trio of claims:



Epistemology
  

Our experiences justify beliefs about the external world.



Epistemology-Mind Link
  

If our experiences justify beliefs about the external world, then our
experiences have property \(P\).



Mind
  

Our experiences do not have property \(P\).



If Epistemology and Epistemology-Mind Link are true, then Mind is
false. Something will have to go. Approaches will vary according to
their verdict on what exactly must go.



In what follows we survey the most prominent instances of the trio. We
will start with sense-data theories, then turn to raw feel theories,
and theories on which experiences have propositional contents. We will
close the part by considering the conscious character of
experiences.



Our survey of theories of experiences will not be exhaustive, but I
will briefly discuss an approach that complicates my framing of the
debates in terms of "visual experiences". Some have argued
that, when the ordinary shopper observes the lemon in the supermarket,
her visual mental life is not as simple as it seems. In particular,
rather than having a unitary visual experience, perhaps she has a
visual sensation and a visual seeming (Lyons 2005; Tucker 2010;
Brogaard 2013; Reiland 2015; also Bengson 2015 as a fellow traveler).
Call this the "hybrid" picture of experience.



To get a feel for the hybrid picture, consider a contrast between an
expert bird-watcher and an ordinary perceiver, both observing a
northern bobwhite. The hybrid theorist would say that they have the
same rudimentary visual sensation in some way involving colors and
shapes, with only the expert has a visual seeming specifically to the
effect that a northern bobwhite is present. Here the visual sensation
shared by the expert and novice is sensory in character, but the
seeming had only by the expert is itself not sensory. (For further
examples, see the opening of Tucker 2010).



The seeming might even be sharable in principle with subjects who lack
visual consciousness altogether (Tucker 2010, also Lyons 2005 with
different terminology, Brogaard 2013 however disagrees that visual
seemings can be detached so far from visual sensation). That seemings
are not sensory does not obviously entail that they are perceptually
amodal entirely, Lyons for instance seems to tie down his
"nonexperiential looks" to different perceptual modalities
such as vision or audition.



The example of the novice vs. the expert is suggestive, but what we
have said so far leaves open the respective natures of sensations and
seemings, as well as of how visual experiences are to be understood in
relation to them. Given all of this indeterminacy, as well as the room
for debate about whether we even have good reason to complicate the
structure of visual experience in this way (see Chudnoff and
Didomenico 2015 for criticisms), the discussion below will be framed
simply in terms of visual experiences. That said, the discussion
should remain applicable to experiences understood as combinations of
some sort of sensations and seemings. The discussion should also in
principle be adaptable to apply individually to sensations only or to
seemings only, depending on the reader's preferred category. At
some key stages we will explicitly highlight where the distinction
might be especially useful to apply and explore.


### 1.1 Sense-datum Theories



On sense-datum theories, whenever you have a visual experience as if
there is something present that is red, there really is something
present that is red--a sense-datum. Now, in many cases of
illusions and hallucination, there won't be any ordinary red
thing around for you to experience even if there seems to you to be a
red thing present. So sense-data are either going to be mental objects
or strange non-mental objects. Sense-datum theories usually depart
from the following principle:



The Phenomenal Principle
  

Whenever you visually experience it to be that case that something is
\(F\), then there is something \(F\)
that you experience (Robinson 1994).



Let's first examine an epistemological case for sense-datum
theories. Here the direction of flow is from epistemology to the
philosophy of mind. We can find it in the following famous quote from
H.H. Price:



> 
> 
> When I see a tomato there is much that I can doubt ... One thing
> however I cannot doubt: that there exists a red patch of a round and
> somewhat bulgy shape, standing out from a background of other
> colour-patches, and having a certain visual depth, and that this whole
> field of colour is presented to my consciousness ... (Price 1932:
> 3).
> 
> 
> 



On Price's line of thought, perceptual experiences do afford us
with some certainty. When Price sees a tomato, he may be certain that
there is something red and round present. According to critics of the
argument, Price is not entitled to be certain of any such thing. For
example, his experience might merely represent that there exists
something red and round present, where such representation can occur
even if nothing red and round is present (for more on this objection
see the entry on
 the problem of perception
 (section 3.1.2).



Let's now turn to the status of beliefs about ordinary objects
in the external world, and the flow from the philosophy of mind to
epistemology. We can organize our discussion under the following
instance of the trio:



Epistemology
  

Experiences justify beliefs about the external world.



Epistemology-Mind Link 1
  

If experiences justify beliefs about the external world, then
experiences are not relations to sense-data.



Mind 1
  

Experiences are relations to sense-data.



In principle, a sense-datum theorist might accept E-M Link 1 and Mind
1, and conclude that Epistemology is false. For example, she might
take up a coherence theory of justification, on which our beliefs
about the external world are justified by their coherence with each
other and not by experiences (see the entry on
 sense-data
 (section 3.2).



In the usual line of discussion, philosophers affirm Epistemology and
E-M Link 1, and conclude that Mind 1 is false (see Berkeley 1710/2008:
sect 18 or Reid 1764/1997: ch. 1). Sense-datum theories tell us that
the things we are directly aware of in perceptual experience are not
ordinary external objects. As the common metaphor has it, sense-data
theories draw a *veil of ideas* over the world. The usual
objection holds that this veil makes it impossible for us to gain
knowledge or justified belief from experience about the external
world. Philosophers such as Berkeley and Reid reject sense-datum
theories on the grounds that we do have epistemic access to the
world.



In response, the sense-datum theorist might deny E-M Link 1. In
particular, the theorist might say that experiences justify beliefs
about the external world when complemented with reflection on how they
are best explained (Russell 1912). Call this the IBE approach since it
concerns Inferences to the Best Explanation of our experiences (see
Vogel 1990 for more contemporary discussion). Setting aside debate
about how such an explanation might go, and why it might be the best,
the response might not go far enough.



To see why the IBE approach might not go far enough, consider the idea
that experiences provide *non-inferential* justification for
beliefs about the external world. If experiences provide
non-inferential justification for beliefs about the external world,
they justify beliefs through a route that does not involve further
beliefs. Compare how your sharp pain might justify you directly in
believing that you are in pain, without further beliefs playing any
role. Contrast how your thermometer might justify you in believing you
have a fever only in conjunction with your having reason to believe
the thermometer works. Non-inferential justification is justification
that does not involve auxiliary beliefs (see Pryor 2005 for more
detail).



On the IBE approach, it seems that experiences at best give us
inferential justification for beliefs about the external world.
That's because they justify us only in conjunction with whatever
beliefs their best explanation brings in. Experiences arguably do
better (Johnston 2006). The veil of ideas objection might then be
better put as follows:



Epistemology1
  

Experiences give non-inferential justification for beliefs about the
external world.



Epistemology-Mind Link 2
  

If experiences give non-inferential justification for beliefs about
the external world, then experiences are not relations to
sense-data.



So,



not-Mind 1
  

Experiences are not relations to sense-data.



Even still, it is unclear why sense-datum theories should rule out
getting non-inferential justification from experiences. Perhaps if a
sense-datum theory is true, we at best see external objects
indirectly, by means of seeing sense-data. But this is only a point
about seeing. Our justification for beliefs could still be
non-inferential (Moore 1953; Silins 2011). The crucial question for
non-inferential justification is about the role of background beliefs,
and the mental process of indirect perception need not make use of
background beliefs. For instance, whether you indirectly perceive
objects by means of sense-data might instead just be a matter of how
the sense-data are caused, leaving open the possibility that you gain
non-inferential justification for beliefs about the external world
from sense-data.



Let's now zoom out to a big picture assessment of the epistemic
implications of sense-datum theories.



The thought driving the veil of ideas worry is that if experiences
fail to put us in direct contact with reality, then they cannot
justify beliefs about external reality. This thought is meant to get
us to the conclusion that sense datum theory is false. But it might go
too far.



The first ramification concerns seeing objects. According to many
views, we see ordinary extended objects by seeing their surfaces,
rather than seeing them directly (see Moore 1918 or Broad 1952, and
Clarke 1965 or Campbell 2004 for dispute). As far as seeing objects
goes, their facing surfaces play the same role as sense-data did on
many versions of the sense-datum theory--intermediaries not
identical with objects that still permit us to see objects by seeing
them. But now, if we endorse the veil of ideas objection, there is a
risk that the facing surfaces of objects will be a veil over the rest
of external reality. Call this the *veil of surfaces*. Our
experiences might fail to give us access to whether we live in a world
of ever shifting facades or instead a world of three-dimensional
objects as they are ordinarily conceived. Descartes arguably states
this problem when he writes:



> 
> 
> I remember that, when looking from a window and saying I see men who
> pass in the street, I really do not see them, but infer that what I
> see is men, just as I say that I see wax. And yet what do I see from
> the window but hats and coats which may cover automatic machines? (PW,
> p. 21 )
> 
> 
> 



If the veil of ideas objection succeeds against sense-data theories,
it might also rule out the theory that we directly perceive only
surfaces. It is not clear whether the objection can get us that
far.



The veil of ideas objection also has controversial ramifications for
cases of illusion or hallucination. When something looks red to you
when it isn't, or when you have a hallucination of a bloody
dagger in front of you, your experience fails to put you in direct
contact with reality as it is. According to many approaches, your
experience might still--misleadingly--justify you in
believing that reality is the way it visually appears to be. However,
if the thought driving the veil of ideas objection is correct,
experiences only justify in those cases when you are seeing things as
they are. This is quite a demanding view, one that rules out
justification in a wide range of cases where many think it is present.
(For more discussion of views that exclude perceptual justification
from cases of illusion or hallucination,
 see section 2.2.).


### 1.2 Raw Feel Theories



According to sense-data theories, all visual experiences relate us to
objects with the properties attributed by our visual experiences. At
an opposite extreme, one might hold that experiences are "raw
feels", failing to present the world to us in any way. To get a
feel for this line of thought, consider the experience of
"seeing stars". According to some views, your experience
here is a mere sensation, failing to present your surroundings to you
(cf. Smith 2002: 130-1). On these views, the expression of
"seeing stars" is extremely misleading here, as you do not
literally see stars, and do not even figuratively see anything
else--it is not as if your experience is of anything in the
scene. According to raw feel theory, all visual experiences are in
fact like this, not just exceptional ones. As Bonjour puts it, we
capture what our visual experiences are like "in terms of
patches of color arranged in two-dimensional visual space"
(2001: 32). (For a survey of views that could fall under the heading
of "raw feel theory" as used here, see entry on
 contents of perception
 (section 2.1).



In a passage from "A Coherence Theory of Truth and
Knowledge", Donald Davidson can be read as using raw feel theory
to argue for a skeptical epistemological conclusion:



> 
> 
> The relation between a sensation and a belief cannot be logical, since
> sensations are not beliefs or other propositional attitudes. What then
> is the relation? The answer is, I think, obvious: the relation is
> causal. Sensations cause some beliefs and in this sense are the basis
> or ground of those beliefs. But a causal explanation of a belief does
> not show how or why the belief is justified. (1986: 310)
> 
> 
> 



By itself, the view that experiences are raw feels is silent about
whether experiences are able to justify beliefs about the external
world. To get to conclusions about epistemology, some sort of linking
principle is needed. Davidson's idea is that a source can supply
justification only if it has propositional content, so that the source
is assessable as accurate or inaccurate, depending on whether the
relevant proposition is true. On this way of setting up the issues, an
experience has "propositional content" by having content
that is assessable for truth (for further elaboration of the idea that
experiences have propositional content, see the entry on
 the contents of perception).
 Given Davidson's demand, experiences would be unable to justify
beliefs if they were merely raw feels or sensations. (For important
precedents to Davidson here, see Sellars 1956 and Popper 1959: chapter
5. For further contemporary discussion, see Bonjour 1985; McDowell
1994; Brewer 1999; and Pryor 2005.).



We can sketch the issues raised by Davidson with the following
instance of our trio:



Epistemology
  

Experiences justify beliefs about the external world.



Epistemology-Mind Link 3
  

If experiences justify beliefs about the external world, then
experiences have propositional content.



Mind 2
  

Experiences are raw feels without propositional content.



The Davidsonian response to the trio is to accept E-M Link 3 and Mind
2, but to deny Epistemology.



A different response to the trio accepts E-M Link3, but uses
Epistemology to reject Mind 2. This position was occupied by McDowell
1994 and Brewer 1999 (although they later revised their views in
Brewer 2006 and McDowell 2009).



Let us focus on debate about E-M Link 3, the common ground between
Davidson, McDowell and Brewer. It can be resisted by raw feel
theorists, as well as by non-raw feel theorists who fall short of
attributing propositional contents to experiences.



Why believe E-M Link 3 at all? Davidson's own case appeals to
the claim that, in order for an experience to justify a belief, the
experience must make more probable or entail the content of the belief
(he also uses the further assumption that only propositional contents
can do any such thing). It's not clear why all raw feel
theorists must accept the demand. Think back to the experience of
"seeing stars", and suppose that the experience is indeed
a raw feel. The experience might still justify the belief that you are
having that particular experience. Analogously, if pains are best
understood as raw feels, they arguably could still justify you in
believing that you have them. Now, if experiences could lack
propositional contents and still justify you in believing you have
them, why couldn't they still also justify beliefs about the
external world? In particular, at least if background beliefs are
allowed to play a role, it seems perfectly possible for beliefs about
the external world to be justified thanks to the availability of
inferences linking particular raw feels with particular conditions of
the external world. The justificatory structure here would look like
this:



\[ \begin{array}{ccc} \left. \begin{array}{ccc} \text{raw feel} &
\rightarrow & \text{self-ascription of raw feel} \\ & & +
\\ & & \text{auxiliary belief}\end{array} \right\} &
\rightarrow & \text{external world belief} \end{array} \]


(For a contemporary view with this sort of structure, see Bonjour
2001).



One also might try to meet the spirit of the demand that justifiers
increase probability or entail without attributing propositional
contents to experiences. Here it's important to note the rich
range of ways in which experiences might be directed at the world.
Many of these ways need not involve propositional content.



First, even if experiences lack contents that are assessable for
truth, experiences might still have contents that are assessable for
accuracy. Burge 2010 suggests that experiences have non-propositional
contents of the form 'that \(F\)', and are
accurate just in case the referent has the property \(F\).
Alternatively, consider how a map or picture might
be accurate or inaccurate without being true or false. When
experiences are accurate in either of these ways, other contents of
beliefs will be true. So experiences could lack propositional
contents, but still count as close enough to entailing the contents of
beliefs or to increasing the probability of the contents of
beliefs.



Second, experiences might lack contents altogether, and not be
assessable for truth or accuracy, but still be related in important
ways to relations to the world such as seeing (Campbell 2002; McDowell
2009; Brewer 2006, 2011). According to these approaches that resist
the ascription of content to experiences, your experience justifies a
belief about the world only when your experience is a case of seeing
the world as it is. You can see the world as it is only if it is in
fact that way. Here many of your experiences might be supremely
positioned to justify whether or not they have any content. (For more
about such approaches,
 see subsection 2.2.).



In sum, raw feel theorists might be in a good position to reject E-M
Link 3. Moreover, even if experiences are not raw feels, they might
also lack propositional contents, and still be directed at the world
in a way that helps them to justify beliefs.


### 1.3 Perceptual Content



Let us now turn to more fine-grained connections between contents of
experience and perceptual justification, focusing on contents of
experience that can be assessed for truth.


#### 1.3.1 Necessity of Content



First, is having specifically the content that \(p\)
necessary for an experience to justify believing that \(p\)?
Here is a first pass at capturing the issue:



Epistemology-Mind Link4
  

If your visual experience \(e\) gives you justification
to believe some external world proposition that \(p\),
then \(e\) has the content that \(p\).



A challenge comes from cases when you use an experience and background
beliefs to extrapolate far beyond any content the experience might
have. For example, when I have an experience in New York with the
content that the traffic light is red, my background beliefs enable
the experience to justify me in believing that cars might still be
permitted to turn right. But this legally informed belief is in a
content that most likely does not figure in my experience.



To accommodate extrapolation beyond experience thanks to auxiliary
beliefs, the simplest response is to focus on non-inferential
justification that does not involve auxiliary beliefs.



Epistemology-Mind Link5
  

If your visual experience \(e\) gives you
non-inferential justification to believe some external world
proposition that \(p\), then \(e\) has
the content that \(p\).



If Link5 is true, it allows for rich connections between theories of
perceptual experience and theories of perceptual justification.
Consider for instance the debate about "high-level"
content. Very roughly, this debate is about whether our experiences
merely represent colors, shapes and locations, or whether they
represent thicker properties or relations such as causing an
explosion, being a fake Louis Vuitton bag, being virtuous, or being
glad to see you (for more see the entry on
 the contents of perception).
 If Link5 is true, and we have non-inferential justification for
belief in high-level contents, it will follow that some of our
experiences have high-level contents as well. But how to establish
that our experiences give us non-inferential justification for some
high-level beliefs?



One route is to try to leverage the psychological immediacy of our
formation of some high-level beliefs. When the fashionista sees the
droopy bag marked "Louis Vuitton" in a cheap Shenzhen
mall, she does not need to pull out her lighter to test whether the
material melts likes plastic. Instead she forms her belief that the
bag is a fake Louis Vuitton without any conscious reflection.
Likewise, we don't need to puzzle out whether our loved ones are
present when we see them--we seem to recognize them on the basis
of our experiences without reasoning. Still, it may be that auxiliary
beliefs are playing a role in all these examples while remaining
unconscious. The psychological immediacy of belief formation
needn't go along with non-inferential justification (see
McDowell 1982).



For further discussion of how to show we have non-inferential
justification from experiences for some beliefs in high-level
contents, and of whether the experiences themselves would need to have
high-level contents to do so, see Millar 2000, McDowell 2009, or
Silins 2013.



For further defense of the claim that an experience justifies a belief
only if it has a content identical with that of the belief, see
McDowell 1994 and Brewer 1999. For critical responses, see Speaks 2005
and Byrne 2005.


#### 1.3.2 Sufficiency of Content



Is having the content that \(p\) enough for an
experience to justifying you believing that \(p\)? Here
is a first pass at capturing the idea:



Sufficiency First Pass
  

If you have an experience \(e\) with the content that
\(p\), then \(e\) gives you
justification to believe that \(p\).



The Sufficiency thesis is not formulated in terms of non-inferential
justification. For all it says, whenever an experience justifies a
belief, it does so only in a way involving the assistance of an
auxiliary belief. Still, the picture does mesh well with views on
which experiences give non-inferential justification, and we may
understand it in those terms in what follows.



Our thesis does need to be qualified. For example, suppose that you
gain convincing evidence that you are the victim of an illusion, as
when you learn that the lines of the Muller-Lyer illusion are the
same in length even though they look to be different in length:



![[A set of three horizontal lines vertically aligned with the first and third having simple two line arrow heads at each end and the middle having inverted arrow heads. Sighted people tend to perceive the middle line as longer in this set. Below is the same set with the horizontal lines in red and a dashed line on each side showing that the lines are actually identical in length. ]](figure1.png)

Figure 1. Muller-Lyer
 illusion[1]




Your experience does not give you justification to believe that the
lines are different in length once you have gain the evidence they are
the same in length. Such cases are ones of "defeat", where
further evidence opposes or otherwise disrupts your receipt of
justification from your experience (some cases may be like someone
writing over the graffiti drawn by experience, other cases may be like
someone erasing the graffiti drawn by experience, and perhaps there
are further variants of defeat as well). To take account of such
cases, the fan of Sufficiency can say that



Sufficiency
  

If you have an experience \(e\) with the content that
\(p\), then \(e\) gives you defeasible
justification to believe that \(p\).



Here the core idea is that your experience gives you justification
unless you have gained evidence that your experience is
misleading.



For defenses of theses along the lines of Sufficiency, see Pollock
(1974), Pryor (2000) or Huemer (2001, 2007). Their strategies put much
weight on what it is like to have an experience (see more in
 section 2.4
 on this sort of strategy). A different approach tries to exploit the
way that experiences come to have their contents, for example by
arguing that experiences are likely to have true or accurate contents
given the way they come to have their contents. For examples of this
strategy, see Burge 2003, Peacocke 2004, Sawyer and Majors 2005, and
Setiya 2012: ch. 3.



The Sufficiency thesis also promises to establish rich connections
between epistemology and the philosophy of mind. Consider again the
debate about high-level contents of experience. If one is able to
establish that experiences have high-level contents, one could then
use the Sufficiency thesis to reach the conclusion that experiences
justify beliefs in high-level contents as well.



Assuming that experiences with the content that \(p\)
will give non-inferential justification for a belief that \(p\),
we could then have an answer to an important
question for foundationalist views in epistemology. These are views on
which our inferentially justified beliefs about the external world are
inferred from a foundation of non-inferentially justified beliefs (for
more see the entry on
 foundationalist theories of epistemic justification).
 Which beliefs get to be in the foundation? This question for
foundationalist views is pressing. As Nozick remarks, it is of little
use to have a foundation for our knowledge that is only one brick wide
(1981: 3). In general, the more restrictive foundationalist views are
about the breadth of our foundational beliefs, the harder it will be
to build up to everyday beliefs about the world. However, if beliefs
concerning causation, emotions, or morality get to be foundational,
the foundationalist project can look much more promising (Masrour
2011).



As helpful as the Sufficiency thesis could be for foundationalists, it
faces much criticism. Many objections proceed by proposing
requirements for justification that are not always satisfied when one
has an experience with a given content. For example, one might demand
that the experience be a case of seeing
 (section 2.2 of this entry),
 or demand that the experience be suitably free of top-down influence
from one's own mind
 (section 2.4 of this entry).
 (For further objections, see McGrath 2017 or Chudnoff 2018).



Here we will focus on objections that turn on the character of
perceptual content. The objection here is known as "the problem
of the speckled hen" (see Chisholm 1942; Sosa in Sosa and
Bonjour 2003; Markie 2009 for different versions of the problem).



To get a feel for our problem, suppose you get a look at a speckled
hen in good light, but without enough time to carefully count the
number of speckles on it.



![[A Speckled Sussex chicken mostly black with lots of white speckles.]](figure2.jpg)

Figure 2. "Speckled Sussex Hen
named Mata
 Hari"[2]




The objection to Sufficiency can be put as follows. First, your
experience does have a verdict about how many spots face you--say
to the effect that \(H\) has 17 spots. Second, your
experience does not justify you in believing that \(H\)
has 17 spots. After all, forming a belief that \(H\)
has 17 spots without carefully counting might manifestly seem no more
likely to be right than a guess. So, the critic concludes, some
experiences have the content that \(p\) without giving
you justification to believe that \(p\).



In response, some argue that your experience is actually silent about
the exact number of speckles facing you on the hen (see Tye 2009; for
more on experience and numeracy, see Beck 2012).



One can raise the core challenge to Sufficiency in other ways. Another
source of examples can be found in Block's (2007) empirically
informed work on "phenomenal overflow" (drawing on
Sperling 1960 and Lamme 2003). Consider for example the Sperling
paradigm, in which subjects are flashed a grid of letters, and only
subsequently given a tone that indicates which row to report (high for
the top, medium for the middle, etc). Subjects are able to report any
row singled out without being able to report them all. (For an online
demo without sound, see
 Other Internet Resources).
 Arguably subjects experience all the letters as they are without
being able to report them all (but see Stazicker 2011 or Phillips 2011
for criticisms of Block, also Odegaard et al 2018). The objector may
add that we do not have justification from our experience to believe
the proposition that enumerates all the letters present. (For a
further way to set up the speckled hen problem, using the example of
highly determinate colors, see Smithies 2019: ch. 11).



Even if one allows that some experiences have enough determinacy to
set up the speckled hen problem, the option remains of maintaining
that the experiences do give you justification to believe the relevant
determinate proposition. For example, perhaps your experiences do give
you justification to believe the determinate proposition, even though
you are unable to take advantage of the justification you have by
forming a belief on their basis (see Smithies 2012a for a view with
this structure).



Alternatively, perhaps speckled hen cases are compatible with
Sufficiency since they turn out to be cases of defeat. Given that we
are generally aware of our poor ability to make snap judgments about
the details of the scene before, perhaps we have defeasible but
defeated justification to believe detailed propositions about the
scene before us.


#### 1.3.3 Intentionalism



So far we have focused on the ramifications for epistemology of the
view that experiences have propositional contents. Intentionalism is a
more ambitious view in the philosophy of mind that aims to find
necessary connections between the conscious character of an
experience--what it is like to have it--and the content of
that experience. According to intentionalists, at a minimum,



Minimal Intentionalism
  

If experiences \(e\_1\) and \(e\_2\) have the same content, then what it
is like to have \(e\_1\) is the same as what it is like to have
\(e\_2\).



In a slogan, "same content, same character" (for
discussion of further variations in the camp, see Chalmers 2004). On
this picture, if two experiences present the same testimony about the
world, there is no room for any difference in what it is like to have
those experiences. Whether there is such a tight link between content
and conscious character is controversial, consider the frequently
discussed possibility that your shifting attention could vary the
conscious character of two distinct experiences without varying their
testimony about the world.



Here we will point to some epistemological ramifications of the
view.



One way to defend Intentionalism examines how we become
introspectively aware of what it's like to have our experiences.
Arguably we become introspectively aware of what it's like to
have our experiences only by being aware of what we are experiencing.
Perhaps awareness of the world is the sole route to introspective
awareness of what it's like to have a given experience. And
perhaps this point about introspection supports at least a minimal
version of Intentionalism. For further discussion of this broadly
epistemological argument for intentionalism, see the entry on
 qualia
 (section 6), also the entry on
 representational theories of consciousness
 (section 3.3).



Another defense of Intentionalism examines how we become able to think
about certain properties by having experiences. Perhaps experiences
are sufficient for certain cognitive abilities, and perhaps
Intentionalism gives the best explanation of how experiences are
sufficient for certain cognitive abilities. For an exposition of this
broadly epistemological line of argument for Intentionalism, see Pautz
2010.



For an epistemological argument against some versions of
Intentionalism, see Kriegel 2011. He targets versions of the view that
aim to find what constitutes experience in terms of awareness of
properties (or a suitably similar relation to properties). According
to Kriegel, just as sense-data theories are unable to provide an
adequate epistemology because of the "veil of appearances"
they impose between perceivers and the world, the targeted versions of
Intentionalism fail to provide an adequate epistemology for the same
reason. As we saw in
 section 2.1,
 sense-data theorists have ways to respond to veil objections. Perhaps
intentionalists do as well.


### 1.4 Consciousness


#### 1.4.1 Does consciousness play a justifying role?



An uncontroversial theory of perceptual experiences holds that they
all have a conscious character--for any experience \(e\)
there is something it is like to have \(e\).
Further, part of what it is for something to be an
experience is for it to have a conscious character. There is much
debate about how to explain the nature of perceptual consciousness,
but there is little debate about whether something is an experience
only if it has a conscious character.



There is much more room for debate about the importance of
consciousness for the epistemology of perception. One strategy of
explaining how experiences justify beliefs focuses on their conscious
character. We may call it the phenomenal approach.



To see why this approach is a contender, consider subjects who have
"blindsight". They have visual representations of
what's in their blind field without having conscious visual
experience of anything in their blind field (see Weiskrantz 2009 for a
survey, and Phillips and Block 2016 for a debate about whether there
really is unconscious perception). Now these subjects are better than
chance at identifying objects in their blind field, but they have to
be prompted to make a guess. For our purposes, imagine a hypothetical
blindsighted subject who does not need to be prompted to form a belief
that there is an \(X\) to the left. Now compare that
subject with an ordinary sighted subject who forms a belief that there
is an \(X\) to the left on the basis of visual
experience. There are various questions here whose answers might
support the phenomenal approach (see Smithies 2012a, 2019: ch. 3 for
more).



First, is the blindsighted subject completely unjustified in believing
that there is an \(X\) to the left? If you think the
answer to this question is yes, and you're not a skeptic about
the sighted subject, you arguably should be sympathetic to the
phenomenal approach. What else would explain this difference between
them?



Second, is the blindsighted subject at any rate less justified than
the sighted subject in believing that there is an \(X\)
to the left? If you think the answer here is yes, again you arguably
should be sympathetic to the phenomenal approach. What else would
explain this epistemic difference between them?



In response, one might deny that the epistemic differences obtain (see
Lyons 2009, also Berger 2020). Even if one accepts that the epistemic
differences obtain, one might still insist that they are equally or
better explained by alternative candidates than consciousness. For
example, perhaps the blindsighted subject does not count as seeing the
\(X\), and perhaps the sighted subject is more
justified than the blindsighted subject simply thanks to seeing the
\(X\) (as an \(X\)). Here the
explanatory burden would be borne by bearing a perceptual relation to
the thing, rather than having an experience with a certain
character.



Here it might help to compare the sighted subject with a conscious
subject for whom things are just the same from the inside, but who
fails to see any \(X\) because she is hallucinating. If
the sighted subject and the hallucinating subject are equally
justified in believing there is an \(X\) to the left,
visual experience might be a better candidate than seeing to explain
the epistemic symmetry between the sighted and the hallucinating
subjects.



Suppose the blindsighted subject and sighted subject are equally
justified--is the phenomenal approach then doomed? Speaking
loosely, even if the blindsighted subject has the same epistemic
effect as the sighted subject, it's not entirely clear that
there must be the same cause (or perhaps there is a common unconscious
cause present even in the sighted subject).



To support the claim that consciousness doesn't supply
perceptual justification, one might look to other real-life cases of
unconscious visual representation. One sort of case is that of
unconscious priming. Here you are exposed to a stimulus too quickly
for it to register in visual experience, but for all that it still
does affect your behavior. For example, an unconsciously registered
numeral might improve your ability to report that a subsequently seen
numeral is greater or lower than 5, depending on whether the priming
one is itself greater or lower than 5 (Naccache and Dehaene 2001). Now
this sort of case is arguably not one in which unconscious visual
representations justify. The subjects concerned plausibly do not form
beliefs that are good candidates to be justified by their unconscious
visual representations. But consider people with visual hemi-neglect,
who seem to lack conscious visual experience of their neglected
field.



Some neglect patients seem to take in information about the neglected
stimuli, and to form beliefs about it. For instance, some of them,
when presented with a burning house in their neglected field and a
normal house in their normal field, prefer the one that isn't on
fire (Marshall and Halligan 1988; Bisiach and Rusconi 1990). Here they
do form a belief that is a candidate to be justified by their
unconscious visual representation. Their belief that the house in
their neglected field isn't preferable might be justified by the
information they take in, even if the intake is through unconscious
perception. If this case is one in which the subject is justified, and
justified to the same degree as in ordinary cases of conscious
perception, one might then start to wonder whether consciousness must
play a role even in ordinary cases of perceptual justification.
Perhaps it is side-stepped by unconscious visual representations even
then.


#### 1.4.2 What aspect of consciousness plays a justifying role?



If the conscious character of experiences does play a justifying role,
a further question remains about why it does so. One might hold that
there is no further explanation to be provided here. Perhaps the
capacity of consciousness to justify is a fundamental fact of
epistemology. According to another proposal, consciousness justifies
thanks to being introspectively accessible. On this internalist
conception of justification, a special kind of access to a source is
necessary for the source to provide justification, and consciousness
stands out for allowing this sort of access (see e.g. Smithies 2012b,
2019).



Here we will focus on a particular aspect of the conscious character
of experiences, one highlighted by Pryor (2000) among others. To get a
feel for this feature if you are sighted, first look away from this
surface and imagine a black circle in front of you. Now look at this
surface and have a visual experience of the black circle in front of
you constituting the period ending this sentence.



In the former case, you were not justified in believing that there is
a black circle in front of you. In the present case, you are. One
candidate way to explain the epistemic difference is to focus on a
difference between what it is like to imagine and what it is like to
have a visual experience (see Martin 2002 for more).



The salient feature of experience here is not easy to pin down. The
rough idea is that, when you visually experience, as opposed to when
you visually imagine, things are presented to you as actually being
the case. How this feature of experience is best to be understood is
open to debate. For now let us leave open its exact nature and simply
use the term "presentational phenomenology" as a
place-holder for whatever it is (for more elaboration see Chudnoff
2012 or Bengson 2015, and see Teng 2018 for a challenge to privileging
presentational phenomenology).



Even if presentational phenomenology is epistemically privileged,
there remains an important question about its scope. Suppose you see a
cow through a picket fence. There is arguably some way you
perceptually "get" that there is an extended cow there.
For a dramatic contrast, start by considering Damien Hirst's
 Some Comfort Gained From the Acceptance of the Inherent Lies in Everything,
 that consists of a cow vertically sliced into a series of boxes
arranged like dominos. Now suppose you know you are seeing the Hirst
sculpture through a picket fence, where the segments align exactly
with the gaps in the fence. Here you arguably would not perceptually
"get" that there is an elongated cow there.



In the ordinary case of seeing a cow through a picket fence, it is
debatable whether presentational phenomenology includes the presence
of an extended cow, or whether it includes only those regions of the
cow not occluded by the fence (see Noe 2005 for further discussion).
If your presentational phenomenology includes only the non-occluded
regions, and only presentational phenomenology supplies perceptual
justification, the rational powers of experience threaten to be
limited. You would not have justification to believe that an extended
cow is present just by taking your experience of the cow through the
slats at face value. Analogously, if only the facing surface of an
object is phenomenally present, you might have justification to
believe only that the facing surface is present by taking your
experience at face value. Here we might find ourselves back at the
"veil of surfaces" discussed in
 section 2.2.



Some might accept this prediction. In his 2018a and 2018b, Chudnoff in
effect does. He compares seeing an ordinary occluded dog with seeing
an unfamiliar occluded blob, and claims that our visual experience in
such cases has presentational phenomenology only with respect to what
is not occluded, and gives us immediate justification for beliefs with
respect to only what is not occluded. On his view, our background
information about dogs picks up the slack to enable us to have a
justified belief about the full shape of the dog, whereas no
background information is available for us to have a justified belief
about the full shape of the occluded blob. In response, Helton and
Nanay 2018 in effect argue that Chudnoff's view threatens to
lead to skepticism about ordinary beliefs about occluded objects, and
underestimates the powers of visual experience with respect to novel
occluded objects. To avoid potential skeptical problems, some may
prefer to take a more expansive view of presentational
phenomenology.


### 1.5 Degreed Perception



We have spoken so far about experiences justifying beliefs in an all
or nothing way. As Munton 2016 reminds us, visual experiences can
justify the same belief to differing degrees. For example, suppose you
are looking outside at the park on a foggy and snowy morning, and
gradually get a better view of a new snowman as the fog clears. Here
your successive visual experiences of the snowman justify your belief
that there is a snowman in the park more and more as the fog clears.
Perceptual justification comes in degrees.



A caution about how to set up the issue is in order. If you think that
perceptual justification is only binary and does not come in degrees,
you should avoid the following common formulation of that sort of
view: either your experience justifies a belief that there is a
snowman in the park or it does not. We can all agree that the law of
excluded middle applies to perceptual justification, that
doesn't yet rule out the possibility that perceptual
justification comes in degrees. For example, perhaps your experience
justifies a belief when the degree of justification it gives is
sufficiently high, and otherwise not. This is a scenario in which your
experience either justifies a belief or it does not, as well as a
scenario where perceptual justification comes in degrees.



According to Munton, we can now draw a conclusion about the nature of
visual experiences, in effect using the template we have surveyed so
far (I focus on Munton's argument because she puts epistemology
front and center. A related argument by Morrison 2016 instead focuses
on variations in what happens when we form opinions by completely
trusting our experiences, but this argument departs from psychology
rather than epistemology).



As a first pass we can try the following:



Epistemology2  
 Our experiences justify beliefs about the external
world to varying degrees.



Epistemology-Mind Link6  
 If our experiences justify beliefs about the
external world to varying degrees, then our experiences are themselves
degreed.



So,



Mind3  
 Our experiences are themselves degreed.



The conclusion that experiences are degreed is striking and important,
but it can be elaborated in quite different ways.



One choice point is where to locate potential variation in degrees.
One option would be in the contents of the experiences, another would
be in the mental relation we bear to contents or to the world in
having an experience (variation in principle could be located in the
vehicles of experiences as well or somewhere else). A further choice
point is about how to understand variations in degrees of experiences.
A tempting option is to piggyback on probabilistic theorizing about
credences or degrees of belief (but bear in mind that in principle
experiences could be degreed without being degreed in a probabilistic
way). The idea here is to cash out the idea that experiences are
degreed in a similar way to how philosophers cash out the idea that
credences are degreed (without necessarily saying that experiences
simply are credences). So just as you might have a higher credence
that the 4-sided die will land 4 than the 6-sided die might land 4,
perhaps you also have a higher visual credence that there is a snowman
out there when the fog is lighter, as opposed to when the fog is
heavier. Now, how to understand credences themselves is open to
dispute, where again dimensions of variation might be located in
differing mental relations to the content that the die will land 4, or
potentially instead in different contents concerning 1/6 probabilities
as opposed to 1/6 probabilities. Also, even if credences are
themselves best understood in probabilistic terms, that is not yet to
say that credences are best understood specifically in Bayesian terms.
So degreed views of experience aren't forced to commit
specifically to Bayesian views of perception (for more on
probabilistic views of perception, often focusing more on the
processes leading to perception rather than what is generated by those
processes, see Hohwy 2013, Rescorla 2015, Siegel 2020, or Vance 2021).
Understanding degreed experiences along the lines of credences opens a
wide menu of options. 



For a final complication, note that there is extensive debate about
the relation between traditionally conceived beliefs and credences.
One eliminativist option ultimately denies that there are beliefs,
replacing them with credences. Other approaches keep both beliefs and
credences in the picture, and understand beliefs in terms of
credences, or credences in terms of belief, or neither in terms of the
other (see section 4 of SEP entry on formal representations of
belief). Likewise, once one has admitted experiences that are degreed
somehow in the manner of credences, one might at the same time still
allow for other experiences more like traditionally understood
beliefs. So there is now room for the questions about the relation
between beliefs and credences to play out in the case of experiences
that are structured along the lines of beliefs vs. degreed experiences
structured along the lines of credences. Perhaps there only are
degreed experiences structured like credences, or perhaps there are
also experiences structured like beliefs, where we can ask whether
either of the two entities has explanatory priority in relation to the
other. 



In sum, understanding experiences as being degreed in the manner of
credences is a fascinating line of research, but also a multi-pronged
one given the extent range of questions about credences.



Now that we've seen some of the possibilities that arise if
experiences are degreed, the question remains of whether the epistemic
argument above establishes that any of them is actual.



In order to make the needed link from epistemology to mind plausible,
the linking premise and the rest of the argument need to be refined
right away. The strategy is to trace variation of degrees in
justification to variations of degrees in experience, but rival
candidates for explaining the variation need to be blocked. For all we
have said so far, the variation in degrees of justification could be
traced not to experiences, but rather to differing degrees of
justification to believe that your experiences are trustworthy
(depending on the conditions of fog).



To block a role for differences in your background beliefs, Munton in
effect focuses on immediate justification for your experiences (using
the terminology of "direct" justification). This gives us
the following



Epistemology3  
 Our experiences immediately justify beliefs about
the external world to varying degrees.



Epistemology-Mind Link6  
 If our experiences immediately justify
beliefs about the external world to varying degrees, then our
experiences are themselves degreed.



So,



Mind3  
 Our experiences are themselves degreed.



Even given these refinements, rival explanations still need to be
blocked. For example, perhaps the new version of Epistemology is
false, and experiences only provide specifically immediate
justification in optimal cases (for discussion see Munton 2016). Or
perhaps the new version of Link is false, and the variations in
degrees of justification can be explained in line with a traditional
non-degreed picture of what experiences are. For example, consider
that your experience plausibly concerns not just the potential snowman
in the park, but also the amount of fog in the park and other aspects
of your viewing conditions. And consider the phenomenon of defeat,
where information you receive can reduce or destroy the amount of
justification given by your experience. Given that your experience in
effect takes a stand on the quality of your viewing conditions,
perhaps your experiences in higher conditions of fog undermine the
degree of justification they supply specifically to believe a snowman
is there. Here we might explain the variation of degrees of
justification through variation in the experience, but through garden
variety non-degreed perceptual content concerning viewing conditions,
rather than any more striking degreed character of the experiences
(this sort of objection is discussed further in Beck 2020).



We have now surveyed the epistemic implications of some central
theories of experience. We have by no means covered all theories of
experience. Here we will simply point to further important areas to
consider. For discussion of naive realist theories of experience,
and of their interaction with issues about skepticism, see the entries
on
 epistemological problems of perception
 and
 the disjunctive theory of perception.
 For discussion of how dualist theories of experience might lead to
epiphenomenalism, where epiphenomenalism might lead to skeptical
problems, see the entry on
 epiphenomenalism
 (section 2.3). For discussion of the theory that experience is
actually a special case of belief, where that theory might affect our
understanding of how we base beliefs on experiences, see the entry on
 the contents of perception
 (section 2.2).


## 2. Perceptual Phenomena



Let us now consider the significance for epistemology of a range of
perceptual phenomena. On most views, these phenomena do not occur in
all cases of perception, but still have important ramifications for
the epistemology of perception.



The first array of phenomena are concerned with the relation between
experience and the world. Here we will consider different kinds of
perceptual error, as well as forms of perception that occur only in
the absence of error. The remaining phenomena we will consider are
characterized by the internal etiology of experience. Here we will
look at the influence of attention and of other mental states on our
experience.


### 2.1. Perceptual Error


#### 2.1.1 Illusion and Hallucination



In cases of perceptual error, we form a false belief on the basis of a
misleading experience, as when an uninformed subject concludes there
is motion below (to get the effect, let your eyes drift over the
image):



![[A visual illusion. The object looks like 18 overlapping circles with an intricate repeating pattern. For most sighted people the circles seem to rotate.]](figure3.png)

Figure 3. "Rotating
 snakes"[3]




This is a paradigm case of an illusion, where you do see a scene, but
misperceive what the scene is like. In a paradigm case of
hallucination, you have a perceptual experience, but do not perceive
anything in the scene before you.



Few dispute that there are cases of perceptual error (although some
disagree about whether perceptual error is ever properly at the level
of experience as opposed to that of beliefs formed on the basis of
experiences, cf. Brewer 2006). Many skeptical arguments use the
occurrence of perceptual error to conclude that experiences do not do
a particular job in epistemology. We can understand these arguments as
using different versions of the Epistemology-Mind Link:



Epistemology-Mind Link7
  

If experiences sometimes deceive us, then experiences do not give us
knowledge of the external world.



Epistemology-Mind Link8
  

If experiences sometimes deceive us, then experiences do not give us
justified beliefs about the external world.



For discussion of how to supplement or defend such principles, see the
entries on
 skepticism
 and
 epistemological problems of perception.



Here we will focus on a weaker principle that addresses the kind of
justification we can get from perceptual experiences:



Epistemology-Mind Link9
  

If experiences sometimes deceive us, then experiences at best give us
inferential justification for beliefs about the external world.



If our experiences sometime deceive us, there is a "gap"
between our having of the experience and the truth of the proposition
they putatively justify. On E-M Link9, some intermediate belief will
then be needed to close the gap between experience and truth, for
example a belief to the effect that our experiences are reliable.
Given the need for an intermediate belief, our experiences will then
arguably fail to give us non-inferential justification for beliefs
about the external world. This conclusion is endorsed by some
philosophers who still reject skepticism about perceptual
justification (Cohen 2002; Wright 2004; or White 2006).



E-M Link9 might still lead to skepticism. Consider an auxiliary belief
meant to bridge the gap between experience and truth, and ask whether
whatever process that lead to it might sometimes deceive us. For
example, consider your belief that your experiences are reliable, and
whatever process led to your belief that your experiences are
reliable. That process could arguably lead you to falsely believe your
experiences are reliable in a situation where you are radically
deceived by an evil demon.



We now have a gap between the occurring of the process that led to an
auxiliary belief and the truth of the auxiliary belief. So then,
according to the reasoning behind E-M Link9, we would need another
auxiliary belief to bridge the gap. Since an evil demon could
presumably deceive us yet again, a threat of vicious regress arises
here ((White 2006 articulates this line of thought without endorsing
it (or explaining where it goes wrong)).


#### 2.1.2 Dreaming



We have considered the significance of illusion and hallucination.
Let's now examine the case of dreams. Dreams are often
understood to be paradigms of perceptual error, for example by
Descartes when, discussing his apparent perceptions, he writes
that



> 
> 
> this would not happen with such distinctness to someone asleep.
> Indeed! As if I did not remember other occasions when I have been
> tricked by exactly similar thoughts while asleep! (PW, p. 13)
> 
> 
> 



The picture of dreaming as a case of perceptual error is challenged by
Sosa (2005).



We can frame the issue with a simplified argument for skepticism:



Epistemology-Mind Link10
  

If our experiences justify beliefs about our present surroundings, our
experiences do not frequently deceive us while we dream.



Mind4
  

Our experiences frequently deceive us while we dream.



So,



Not-Epistemology
  

Our experiences do not justify our beliefs about our present
surroundings.



Sosa responds (to a more complex skeptical argument focused on
knowledge) by defending an alternative conception of dreams known as
"the imagination model". According to the imagination
model, we actually do not form beliefs about our surroundings when we
dream, or even have perceptual experiences when we dream.



In defense of the imagination model, consider that, when I go to bed,
I form and store a belief that I am lying in bed. If I were to form a
belief while I am dreaming that I am running away from lions, I would
then have a belief that contradicts my stored belief that I am lying
in bed. Now we arguably do not have such contradictory beliefs while
we are dreaming. The view that we form beliefs while dreaming might
then be what has to go (Sosa 2005: 6).



Let's now consider the case of visual experience. On the
imagination model, when dreaming we do not even have visual
experiences with the same conscious character as those we have when
awake (we leave open whether we have "visual experiences"
while dreaming in some extended sense). The argument at this stage can
exploit the earlier conclusion that we do not form beliefs about our
surroundings while dreaming. Sosa defends the further thesis on the
grounds that, if we did have experiences when dreaming with the
conscious character of those we have when awake, we would be open to
epistemic criticism for failing to form beliefs that take our
experiences at face value. However when I dream that I am being
attacked by a lion, but do not believe while I dream that I am being
attacked by a lion, I arguably am not open to epistemic criticism.



If the imagination model of dreaming is correct, the skeptical
argument above is unsound because Mind is false. For discussion of
whether Sosa succeeds in blocking the best dreaming arguments for
skepticism, see Ichikawa 2009. For further discussion specifically of
the visual character of dreams, see Schwitzgebel 2011: ch. 1.


### 2.2 Successful Perception



Some epistemologists privilege perceptual states that you are in only
if you are not in cases of illusion or hallucination. On their views,
these states are either the only sources of perceptual justification,
or at any rate the best sources of perceptual justification. In the
terminology of Hawthorne and Kovakovich 2006, we may call these
perceptual states "success states".



To get a sense of some of the candidate states, consider the following
table:





|  | (Successful) vision | Illusion | Hallucination |
| --- | --- | --- | --- |
| Having a visual experience with the content that \(a\) is \(F\) | Y  | Y  | Y  |
| Seeing \(a\) as being \(F\) | Y  | Y  | N  |
| Seeing that \(a\) is \(F\) | Y  | N  | N  |
| Seeing \(a\)'s \(F\)ness | Y  | N  | N  |



(In setting up this table, we assume that hallucinations of a
particular object are possible. For discussion, see Johnston 2004 or
Schellenberg 2010.)




Epistemologists differ according to which success states they
privilege, what job they assign to the state, and how severely they
regard the absence of the privileged state.



For views which privilege seeing that \(p\), see
McDowell (1982, 1995) or A. Jackson (2011). For views which privilege
something along the lines of
seeing \(a\)'s \(F\)ness, see
Johnston (2006). These states are
*fact-entailing*, since as a matter of necessity, you see that
\(a\) is \(F\), or
see \(a\)'s
\(F\)ness, only if \(a\)
is in fact \(F\). For a view that
potentially favors the sort of perceptual state you find in cases of
vision and illusion rather than hallucination, see Burge (2003). This
sort of state is *relational*, since you can be in it only if
the relevant object of perception is present in your scene. Assuming
that each conscious success state has a counterpart in unconscious
perception, notice that versions of these views might focus on
perceptual states in common between conscious subjects and subjects
without conscious perception.



In principle, you might get perceptual justification from a success
state in the good case of vision or illusion, and get the same amount
of perceptual justification from a non-success state in the bad case
of hallucination (Lord forthcoming takes up a view with this structure
regarding reasons for belief). We bracket that sort of approach here.
It is more common to hold that you get no perceptual justification in
the case of hallucination (e.g., Jackson 2011), or at least a lower
degree or different kind of perceptual justification in the case of
hallucination (e.g., Schellenberg 2013).



Let's group views that privilege success states under the label
"Success Theory", and leave open how to adjudicate within
the camp.



In support of Success Theory, one can emphasize the tight connection
the approach draws between perceptual justification and truth. On many
versions of the approach, the state that gives you justification to
believe that \(a\) is \(F\) guarantees
the truth of the belief that \(a\) is \(F\).
Moreover, the source of your justification remains
mental and arguably accessible to you, thus satisfying the demands of
some "internalist" approaches in epistemology that
privilege what is inside the subject or accessible in a special way by
the subject (Prichard 2012). Moreover, Success Theory has a promising
connection with issues about skepticism. They promise to block
skeptical arguments that assume our evidence is the same between the
good case of successful vision and the bad case of radical deception
or hallucination (McDowell 1995, for a critique, see Wright 2004).



As an objection to Success Theory, many bring in demands on
justification that are not satisfied by the most versions of the view.
For instance, consider the internalist thesis that, if things seem the
same to each of two people from the inside, then those two people are
equally justified in their beliefs. More specifically, if two people
have the same conscious perspective on the world, and the same stored
beliefs, then they are the same with respect to the degree of
justification of their beliefs. This sort of thesis is often motivated
by considering radically deceived counterparts to us, and appealing to
the intuition that such subjects and us are equally justified (Lehrer
and Cohen 1983; Cohen 1984; Wedgwood 2002; for dispute, see Sutton
2007 or Littlejohn 2012). Now, if a version of Success Theory predicts
that a subject in perceptual error has less justification than a
corresponding perceiver, that version might be rejected on the basis
of its conflict with the internalist thesis.



In response, one might attempt to explain away the intuition of equal
justification as instead concerning equal blamelessness or
excusability, or at any rate as being correct only if restricted to
blamelessness or excusability (e.g. Williamson 2007 or forthcoming).
Critics often try to respond by distinguishing the sort of
blamelessness or excusability one finds in cases of cognitive delusion
or brainwashing, from the epistemic status of the beliefs of the
victim of an evil demon (Pryor 2001), or by demanding a more thorough
explanation of why the victim is indeed blameless or excusable
(Miracchi forthcoming). Recent literature also steps back to examine
whether a substantive distinction can be drawn between justification
and excusability, surveying potential distinctive explanatory roles
for epistemic excuses to play (Greco 2019).



Alternatively, someone with a "disjunctive theory of
perception" might insist that the radically deceived subject
does not have the same conscious perspective on the world as the
successful perceiver (Fish 2013, also the entry on
 the disjunctive theory of perception).
 On this line of thought, to have the conscious perspective of someone
in a case of perceptual success, you need to be in a case of
perceptual success. Here the antecedent of the internalist thesis is
not satisfied in cases of radical deception. One challenge here is
that there are many ways to be deceived. For example, when someone
sees that a lemon is yellow, they might well lack a conscious
counterpart who hallucinates, but they arguably still have a conscious
counterpart who sees a fake lemon that is yellow. If the subject in a
case of vision and the subject in a case of illusion are equally
justified, that will be trouble for approaches that give justifying
privilege to the states of seeing that \(a\) is \(F\)
or seeing \(a\)'s \(F\)ness.



Some philosophers might attack Success Theory on the grounds that it
is too internalist rather than not internalist enough. According to
theorists such as Ginsborg 2006 or Roessler 2009, the justifiers of
perceptual beliefs are best understood to be facts about the external
world rather than facts about perceivers' mind.


### 2.3 Attention



Standard cases of perceptual justification are ones in which you
attend to what you see, as when you attend to your mail and form a
justified belief that you have mail. But are all cases of perceptual
justification ones in which attention is involved? According to the
*Attention Needed* view, only attentive experiences can provide
justification. According to the *Attention Optional* view,
inattentive experiences can provide propositional justification.



If you only experience what you attend to, as is maintained by
philosophers such as Prinz 2012, all cases of justification by
experience will trivially involve attention as well. Here we'll
pursue the issue on the assumption that we sometimes experience
something we do not attend to, as is held by theorists such as Searle
1992 and Mole 2011.



To make our discussion concrete, consider Simons and Chabris's
(1999) famous "Selective Attention Test" on youtube (see
the link in
 Other Internet Resources).
 When subjects were asked to count passes of basketballs--spoiler
alert!--a fair number failed to notice a person in a gorilla suit
who came into the scene. Given how hard it is to track the passes of
basketballs, it is natural to assume that the non-noticers were
attending only to the basketballs, and did not attend to the person in
the gorilla suit. Now suppose that some of non-noticers still did
experience a person in a gorilla suit in the scene, as a person in a
gorilla suit. According to the Attention Needed view, their
inattentive experience cannot provide them with justification to
believe that someone's there in a gorilla suit. According to the
Attention Optional view, their inattentive experience might still
provide them with justification to believe that someone's there
in a gorilla suit.



Both views have their attractions. Typically, if you look carelessly
at a scene, your experience will put you in a worse epistemic position
if you look attentively at the scene. Perhaps if attention is fully
gone but experience remains, experience no longer provides
justification.



On the other hand, you can have evidence you don't notice you
have, and this point might favor the Attention Optional view. Consider
everyday cases of "change blindness" discussed by Dretske
2004. For example, your friend gets a haircut, and asks you "do
I look different?" You are stumped. On Dretske's account,
you might still have a perfectly accurately experience of how his hair
now looks. Here your experience plausibly gives you justification to
believe that your friend got a haircut (when combined with your
background beliefs). You also fail to notice that your experience
gives you justification to believe your friend got a haircut. If
experiences provide un-noticed evidence, such cases are arguably good
precedents for the sorts of cases allowed by the Attention Optional
view. (For striking cases of change blindness, see the link in
 Other Internet Resources.)



For further discussion of the potential epistemic roles of attention,
see Campbell 2002, 2011; Roessler 2011; Smithies 2011; Wu 2014; and
Silins and Siegel 2014.


### 2.4 Cognitive Penetration



According to one empiricist tradition, experience functions as a
mirror, reflecting what is before the subject, without any
manipulation by the subject's mind. Given that experience is
supposed to not be influenced by one's theories or expectations,
it is thereby supposed to be in an optimal position to confirm or
disconfirm hypotheses about the world. According to a wide range of
philosophers and scientists, such a picture of the nature of
experience is mistaken, putting limitations on the ability of
experience to justify belief. In the philosophy of science, the
challenge has been put in terms of the "theory-dependence of
observation", and the implications thereof. In more recent
epistemology and philosophy of mind, the challenge has been put in
terms of "cognitive penetration" or "top-down"
effects and the implications thereof.



To survey the debate, we'll start with the philosophy of mind by
considering potential examples of the phenomenon, and we will then
turn to questions in epistemology.



One potential source of examples comes from ambiguous figures such as
the Necker cube (Hanson 1958; Kuhn 1962; Churchland 1979, 1988).



![[two identical squares overlapping and with lines connecting the four vertices of one to the equivalent vertex of the other]](figure4.png)

Figure 4. Necker
 Cube[4]




You can see this figure as a downward-tilted cube with the left face
closest to you, or as an upward-tilted cube with the right face
closest to you. Critics dispute whether such examples support any
thesis of *theory*-dependence of observation. An alternative
response is that you experience the figure in different ways merely
because you attend to different parts of the figure at different
times. Here the difference in your experience is not explained by
differences in what theory you hold (Fodor 1984).



Theorists such as Hanson, Kuhn and Churchland also made much of work
by so-called "New Look" psychologists such as Bruner and
Postman. Consider for instance Bruner and Postman's classic 1949
experiment involving anomalous playing cards. In this experiment,
subjects were briefly shown the following sort of card:



![[The 6 Spades playing card but red instead of the normal black]](figure5.png)

Figure 5




What did you just see? When subjects were exposed to this sort of
card, many reported it to be a six of hearts. The card is actually a
red six of spades.



One might claim that the card looked to you the way red sixes of
hearts look to you. However, there is much skepticism about whether
there is an effect here on perceptual experience itself (Fodor 1983;
Pylyshyn 1999). Perhaps the card fails to look like a red six of
hearts to you, and you simply jumped to the conclusion that it is a
red six of hearts when you form your belief. The effect might merely
have been on beliefs formed on the basis of perceptual experience.



The current debate about cognitive penetration is informed by more
recent experiments in psychology. For a case of a top-down effect in
the current literature, consider "memory color" in Hansen
et al.'s banana (2006). When subjects were asked to adjust an
image of a characteristically yellow object until it was achromatic,
they overcompensated by adjusting until the image was slightly bluish.
Subjects did not overcompensate with objects that were not
characteristically yellow. The type of case presented by Hansen et al.
is much harder to explain away as not really involving top-down
effects than those in the classic philosophy of science literature.
(For related examples, see Delk and Fillenbaum 1965 or Olkkonen,
Hansen, and Gegenfurtner 2008. For further discussion of whether and
how there might be top-down effects on perception, see Macpherson
2012, Deroy 2013, Firestone and Scholl 2016; Green 2020).



Let us now turn to the epistemology of cases of cognitive
penetration.



It's not clear whether all cases of top-down effects are
problematic for perceptual justification. Consider the possibility of
top-down effects from expertise. For example, perhaps the expert
radiologist sees more than the novice when looking at an x-ray, and
perhaps the expert chess-player sees more than the novice when looking
at a chessboard in mid-game (see the papers in Ericsson 2006 for
discussion of such examples). Further, suppose that the expertise
examples are genuine cases of top-down influence. Here the expert is
presumably at an epistemic advantage thanks to top-down effects, where
her experience justifies her with respect to those contents that her
experience has thanks to her cognitive background (Siegel 2012).



To see why some cases of top-down effects might be epistemically
problematic, consider Siegel's (2012) hypothetical case of
"Angry Looking Jack". Suppose that Jill antecedently has
an unjustified belief that Jack is angry at her. The next time she
sees him, he does look angry to her--as a result of a top-down
effect from her belief. In response to her experience, Jill then
reaffirms her belief. Is she now justified in believing that Jack is
angry at her? (Markie 2005 presents a related example of a gold
prospector whose wishful thinking makes a nugget visually seem to be
gold).



If you are inclined to deny that Jill's belief is justified, you could
appeal to an intuition that Jill is not justified by her experience in
believing that Jack is angry at her (Siegel 2012). But others may not
share the intuition.



Another strategy is to give a further argument that Jill is not
justified by her experience in believing that Jack is angry at her.
For arguments that appeal to an analogy with the unjustified formation
of a belief on an unjustified belief, see McGrath (2013) and Siegel
(2013) (Teng 2021 critically responds). For an argument that appeals
to an analogy with the unjustified formation of beliefs on the basis
of emotion, see Vance (2014).