## 1. The Problem of the External World



The question of *how* our perceptual beliefs are justified or
known can be approached by first considering the question of
*whether* they are justified or known. A prominent skeptical
argument is designed to show that our perceptual beliefs are not
justified. Versions of this argument (or cluster of arguments) appear
in Rene Descartes's *Meditations*,
Augustine's *Against the Academicians*, and several of
the ancient and modern skeptics (e.g., Sextus Empiricus, Michel de
Montaigne). The argument introduces some type of skeptical scenario,
in which things perceptually appear to us just as things normally do,
but in which the beliefs that we would naturally form are radically
false. To take some standard examples: differences in the sense organs
and/or situation of the perceiver might make them experience as cold
things that we would experience as hot, or experience as bitter things
that we would experience as sweet; a person might mistake a vivid
dream for waking life; or a brain in a vat might have its sensory
cortices stimulated in such a way that it has the very same perceptual
experiences that I am currently having, etc.



All this suggests a "veil of perception" between us and
external objects: we do not have direct unvarnished access to the
world, but instead have an access that is mediated by sensory
appearances, the character of which might well depend on all kinds of
factors (e.g., condition of sense organs, direct brain stimulation,
etc.) besides those features of the external world that our perceptual
judgments aim to capture. Paraphrasing David Hume (1739: I.2.vi,
I.4.ii; 1748: sec 12.1; see also Locke 1690, Berkeley 1710, Russell
1912): nothing is ever directly present to the mind in perception
except perceptual appearances.



But if our only access to the external world is mediated by
potentially misleading perceptual appearances, we ought to have some
assurance that the appearances we are relying on are *not* of
the misleading variety. And here is where all the trouble arises, for
it seems that there is no way we could have any evidence for the
reliability of perception (i.e., perceptual appearances) without
relying on other perceptions. We have empirical reason, for example,
to think that science is not yet capable of stimulating brains in a
very precise way, but appealing to this to rebut the possibility of
brain-in-a-vat scenarios seems blatantly question begging. At the
heart of the problem of the external world is a skeptical argument
referred to here as "PEW," one possible reconstruction of
which follows. The premises are named, as we will want to discuss them
individually.


1. Nothing is ever directly present to the mind in
perception except perceptual appearances. (**Indirectness
Principle**) Thus:
2. Without a good reason for thinking perceptual
appearances are veridical, we are not justified in our perceptual
beliefs. (**Metaevidential Principle**)
3. We have no good reason for thinking perceptual
appearances are veridical. (**No-Good-Reason
Claim**)
4. Therefore, we are not justified in our perceptual
beliefs.



A few comments on the logic of the argument are in order.
 (2)
 and
 (3)
 make up the meat of the argument; together they entail
 (4).
 This means that
 (1),
 which is motivated by the skeptical scenarios mentioned above and the
associated veil of perception view, would be unnecessary for deriving
the skeptical conclusion, as are those skeptical scenarios, were it
not for the fact that
 (1)
 is commonly taken to render perception *inferential* in such a
way as to lend support to
 (2).
 If
 (1)
 is true, then, plausibly,
 (2)
 is: if our access is mediated by potentially nonveridical
appearances, then we should only trust the appearances we have reason
to think veridical. And no other reason to endorse
 (2)
 is immediately apparent (although an additional motivation for
 (2)
 will be discussed below, in
 section 3.1.1).
 (1) is therefore an important component of the traditional
problem. The plausibility of
 (3)
 derives from the idea that our only means of verifying the
veridicality of appearances would itself depend on perception, in the
question-begging manner sketched above.



Notice that PEW addresses justification rather than knowledge. On the
reasonable assumption that knowledge requires justification,
 (4)
 implies that our perceptual beliefs do not count as knowledge. One
who denies this assumption could easily rewrite PEW in terms of
knowledge rather than justification with little or no reduction in
plausibility. PEW has been reconstructed here in a way that is
supposed to be intuitively compelling. Were we to get specific about
the implicit quantification involved (we have no good reason for
thinking that *any* perceptual appearances are veridical? that
perceptual appearances are *in general* veridical? that
*this* perceptual appearance is veridical?), the argument would
get a lot more complicated. The simpler version presented above is
sufficient for our current purposes.



The problem of the external world should be distinguished from what is
typically called the problem of perception (see the entry on the
 problem of perception),
 even though they are motivated by similar considerations, in
particular, by the Indirectness Principle. The problem of perception
is the problem of how *perception* is possible--how it is
possible, for example, to *see* mind-independent objects,
rather than inferring them from awareness of sense-experiences, in
light of the claim that only appearances are ever directly present to
the mind. The problem of the external world is a distinctively
epistemological problem, and it focuses on the normative status of
perceptual judgments about external objects; it matters little for
these purposes whether and how such judgments might amount to
*seeing*. What matters is whether such judgments are or could
be justified.



PEW illustrates the central problem of the epistemology of perception:
if many or any of our perceptual beliefs are justified, PEW must have
gone wrong somewhere. But where? Several subsidiary problems in the
epistemology of perception arise in the efforts to solve this central
problem.


## 2. Metaphysical Solutions to the Central Problem



The Indirectness Principle is a *metaphysical* principle: it
says something about the nature of perception. The Metaevidential
Principle and the No-Good-Reason Claim are *epistemic*
principles: one lays down specifically normative requirements for
justified belief and the other denies that these requirements are
satisfied. Because PEW can be challenged by denying any of the
premises, there are two main classes of solution to the central
problem: metaphysical solutions, which challenge the Indirectness
Principle; and epistemological solutions, which challenge the
Metaevidential Principle and/or the No-Good-Reason Claim. This section
addresses the first class of solutions to the central problem.
 Section 3
 addresses the second class.



PEW starts with the Indirectness Principle, and it has often been
thought that the central skeptical worry is due to a metaphysics of
perception that holds that, although worldly objects do exist outside
of the mind, they are never directly present to the mind, but only
indirectly so, through mental intermediaries. Thomas Reid, for
example, held that "Des Cartes' system, which I shall beg
leave to call *the ideal system*, ... hath some original
defect; that this skepticism is inlaid in it, and reared along with
it" (1785: 1.vii). Consequently, a great deal of philosophy
since Descartes has involved various attempts to block PEW by doing
away with the intermediaries between the mind and the objects of
perception, by offering a metaphysics of perception that puts these
objects directly before the mind. If perception is direct in the
relevant sense, then the skeptical problem never even gets off the
ground.



There are two main branches to this tradition. The more obvious and
commonsensical one originates with Reid (1764, 1785) who insists that
physical objects and their properties can be directly present to the
mind as well as mental objects can. This is the direct realist option.
Earlier on the scene, however, is a tradition tracing back to George
Berkeley (1710, 1713), which agrees with Descartes that only mental
items are directly present to the mind but which holds that the
objects of perception--tables, rocks, cats, etc.--are really
mental items after all. This is the idealist/phenomenalist option.
Despite the manifest differences between realist and idealist
metaphysics, both branches of the "direct presence"
tradition are united in rejecting the Indirectness Principle,
insisting that tables and such are indeed directly present to the mind
in perception. If perception is thus direct, the Indirectness
Principle is false, and support for the Metaevidential Principle is
undercut, and PEW ceases to pose a threat to knowledge.


### 2.1 Varieties of Direct Presence



Whether in the realist or idealist tradition, the direct presence
theorist rejects the Indirectness Principle, insisting that when one
perceives a cat, for example, the cat is directly in view, directly
present to, simply *there* before the mind. But what is meant
by these spatial metaphors? The metaphors can be unpacked in several
importantly different ways, having different implications for the rest
of PEW. The spatial/metaphorical terminology has been so vastly
prevalent in the literature that it is very often hard to tell which
author intends which conception(s) of directness. Consequently, it is
difficult to pin particular conceptions of directness on particular
authors, and the presentation here won't try except where
it's quite obvious. Instead, the next five subsections aim to
map out the more salient possibilities. Later, in sections
 2.2
 and
 2.3,
 these distinctions will be used to examine how the traditional
metaphysical theories of perception bear on the epistemology of
perception.



Notice that what is metaphorical about "direct presence"
is the notion of presence, not of directness. To be *directly*
present is to be present, but not in virtue of the presence of another
thing (that would be *in*direct presence). Directness is merely
unmediatedness, but what kind of mediation is at issue will depend on
what kind of presence is intended.


#### 2.1.1 Phenomenal Directness



One dimension of directness, emphasized by Reid (1785), notes that
perceptual judgments are phenomenally noninferential, in the sense
that they do not result from any discursive or ratiocinative process;
they are not introspectibly based on premises. This noninferentiality
is usually understood loosely enough to allow for perceptual
beliefs' being based on things other than beliefs (in
particular, on experiential states, as we will see below) and also to
allow for the possibility of unconscious or subpersonal inferential
involvement in the formation of perceptual beliefs, so long as the
*agent* is not deliberately basing these perceptual beliefs on
other *beliefs*. Without these two allowances, claims of
noninferentiality would quickly run afoul of standard views in
epistemology and psychology, respectively. To claim that perception is
phenomenally direct is to claim that it is noninferential in this
sense.


#### 2.1.2 Referential Directness



Another way that perception might be direct is if perception
represents external objects, as such, without that representation
being mediated by representation of other things. Contrast this with
the classical empiricists' opposing view, that the only way to
represent external objects is as the cause of our sensations (Locke
1690, Berkeley 1710). One might worry, however, that unless perception
puts objects directly before us, we are in danger of not genuinely
being able to think about the objective, external world at all, but
only about ourselves. To say that perception is referentially direct
is to say that the ability of perceptual states to represent does not
depend on the ability of other states to represent.


#### 2.1.3 Perceptual Directness



One version of *in*directness claims that we perceive outer
things by *perceiving* (or standing in a quasi-perceptual
relation to) inner things--usually sense-data (see below and the
entry on
 sense-data).
 This makes it sound as if what we thought was ordinary direct
perceiving of tables and rocks and such is really more like
"perceiving" that someone has broken into your
house--indirectly, on the basis of actually perceiving the broken
window, empty area where the TV used to be, and so on. It is easy to
see how such perceptual indirectness may invite the semantic and
epistemological worries we have been seeing. To claim that perception
of external objects is perceptually direct is to claim that it is not
mediated by the *perception* (or quasi-perceptual apprehension
or awareness) of something else.


#### 2.1.4 Direct World-Involvement



One could endorse phenomenal directness and perceptual directness
while still holding that perceptual contact is mediated by experience,
where experience is conceived as something in virtue of which we have
perceptual contact, though it is not the perceptual contact itself. An
alternative is a relational metaphysics of perception according to
which elements of the perceived world are literally parts of the
perceptual experience. On idealist versions of this view, the mental
states whose immediate apprehension constitutes perceptual experience
*just are* the objects of perception (or parts of these
objects). On (direct) realist versions of the view, perceptual
experiences are not internal mental states of the agent but are
relations between the agent and some external objects or states of
affairs. Thus the agent is in a different type of mental state in the
case of veridical perception (the "good case") than in the
case of hallucination (the "bad case"). Veridical
perception is a certain kind of relation to a distal array, while
hallucination or dreaming is an introspectively indistinguishable but
metaphysically distinct relation to something else entirely.


#### 2.1.5 Epistemological Directness



Finally, one might hold that perception is direct in the sense that
one's perceptual beliefs about external objects, like rocks and
cats and such, enjoy a kind of justification or knowledge that does
not depend on--is not mediated by--any other justification
or knowledge. Such beliefs are said to be "epistemically
noninferential", or "epistemologically basic" and
the normative status is sometimes referred to as "immediate
justification/knowledge" or "basic
justification/knowledge". This possibility will be explored in
more detail below, in
 section 3.
 Epistemological directness will be treated separately from the
previous senses of direct presence, which can all be viewed as
metaphysical senses of direct presence. The relation between
metaphysical and epistemological directness will be addressed below,
in
 section 2.4.



With these distinctions in hand, we can better situate the traditional
theories of perception that are often thought to bear on the skeptical
problem.


### 2.2 Idealism and Phenomenalism



Idealism and phenomenalism are views that hold that ordinary objects
(tables, clouds, rocks, etc.) are really collections of or constructs
out of actual and/or possible mental states, especially perceptual
experiences. (I won't try to distinguish phenomenalism from
idealism but will use "idealism" to include both.) There
are several varieties of idealism and several motivations for holding
the view. But one motivation is that it promises to solve the
skeptical problem of the external world. Berkeley (1710) held that
idealism was a cure for skepticism. Transcendental idealism (Kant
1781) aims to split the difference with the skeptic by distinguishing
the phenomenal objects of perception--which are collections of
appearances and about which we can know something--from the
noumenal objects--which are things in themselves and not mere
appearances, and about which skepticism is true.



Idealism promises to solve the skeptical problem by attacking the
Indirectness Principle. If the problem of the external world starts
with the gap between the proximal and the distal objects of perceptual
experience, then idealism would avoid skepticism by simply closing
that gap. The idealist can embrace direct world-involvement while
retaining the claim that nothing is ever directly present to the mind
but its own mental states, by holding that the world is fundamentally
mental, that, e.g., tables are just collections of ideas. Although
metaphysical solutions are usually aimed at the Indirectness
Principle, idealism might, additionally, undermine the No-Good-Reason
Claim. Hume (1739) argued that we couldn't reasonably posit
external objects as plausible causes of our experiences without first
observing a constant conjunction between external objects and
experiences; but we can't "observe" external objects
unless we justifiedly believe in their existence, which we could only
do if we could reasonably posit them as plausible causes of our
experiences. Thus, a vicious circularity. On the other hand, if the
objects of perception are not external after all, we are in a better
position to infer causal relations between them and individual
experiences.



The main difference between idealism and an indirect realism concerns
not so much the metaphysics of perception as a larger metaphysical
view about what else exists outside of the mind. Berkeley and
Descartes agree about the direct objects of perception, but Descartes
posits an additional stratum of mind-independent external objects in
addition. The idealist denies that there is a veil of perception not
because Descartes was wrong about the nature of perception, but
because he was wrong about the natures of cats and rocks.



Idealism has a few contemporary defenders (e.g., Foster 2008, Hoffman
2009, Robinson 2022), though it is nowhere near the dominant view that
it had been for almost two centuries after Berkeley. Most responses to
PEW in the last century have endorsed some kind of realism instead,
insisting that ordinary objects are indeed mind-independent.


### 2.3 Realisms, Direct and Indirect



The problem of the external world, especially the Indirectness
Principle, sees its modern renaissance in Descartes's
representative realism, which was offered as an alternative to both
the commonsense view of naive (aka direct) realism, and the
hylomorphic theory standard among Scholastics. This latter doctrine
holds that objects are combinations of primordial matter and forms
impressed upon them, which determine the objects' properties;
these objects then cast off forms that can enter the mind through the
sense organs. A red thing is simply something that has the form of
RED, which it can transmit, making the receptive, perceiving mind
also--though presumably in a different sense--red.



Both theories have difficulty handling error. Science frequently
teaches us that things are not in reality the way they appear to the
senses. The sun, for example, perceptually appears as a small disk
rather than the large sphere that it is (Descartes 1641). This
perceptual experience cannot involve either the transmission of forms
(since the sun doesn't have those forms), or the "direct
pick-up" of objective properties (again, those properties
aren't there to pick up). Nor could we simply be picking up
relational properties, like *looking small from here*,
Descartes argues, because I could have the very same perceptual
experience in a vivid dream (where even the relational properties are
not instantiated) as I do in waking life. Therefore, perceptual
appearances must be entirely mental and internal, rather than
relational. Insofar as external objects are at all present to the
mind, it is only because of these appearances, which thus serve as
inner stand-ins, or proxies, for them. As John Locke puts it,



> 
> 
> the understanding is not much unlike a closet wholly shut from light,
> with only some little openings left, to let in external visible
> resemblances, or ideas of things without. (1690: 163)
> 
> 
> 



It is this notion of standing in that the term "representative
realism" is supposed to capture. The representative realist may,
but need not, hold that these proxies are also
*representations* in the sense of having semantic contents,
i.e., truth- or accuracy-conditions. In fact, the most recognizable
form of representative realism denies that experiences are in this
sense representational.


#### 2.3.1 Sense-data



This best known, though now widely rejected, form of representative
realism incorporates a *sense-datum theory* (see the entry on
 sense-data),
 which holds that every perceptual experience as of something's
being *F* involves the subject's awareness of something
that really is *F*. My having a perceptual (veridical or
hallucinatory) experience as of something's being blue requires
there to be a nonphysical, inner, mental object--a
sense-datum--that is blue. Sense-data are not normally taken to
be true or false, any more than rocks or tables are; nonetheless,
sense-data constitute the inner rocks and tables in virtue of which we
perceive external rocks and tables and are in that sense the
latter's representatives. Two important features of this theory
are worth highlighting: (i) that sense-data really do have the
properties that external objects appear to have, and (ii) that the
relation one stands in to one's sense-data is a perceptual, or
quasi-perceptual, relation: one is perceptually aware of objects due
to a more fundamental awareness of one's sense-data.



Any version of representative realism is indirect in the sense of
denying direct world-involvement. The sense-datum theory further
denies perceptual directness, as it has us perceive objects by way of
perceiving our sense-data; and it is typically fleshed out in such a
way as to be incompatible with referential directness as well, holding
that we can think about mind-independent objects only as the external
causes of these sense-data. It is, however, compatible with phenomenal
and epistemological directness. For example, one could deny that the
"inference" from sense-data to external objects is
conscious and deliberate and insist that only such deliberate
inferences would render a belief epistemically inferential (i.e.,
nonbasic) in the sense of
 2.1.5
 above.


#### 2.3.2 Intentionalism and Adverbialism



*Intentionalism* holds that to perceive (or hallucinate)
something as being blue is to be in a state with a distinctively
*semantic* property of *meaning* blue, of referring to
or predicating the property of blueness (see the entry on
 consciousness and intentionality).
 On this view, the inner states are not just representatives but
represen*tations*; they have semantic values. Such
representations typically lack the properties they depict external
objects as having. Furthermore, the relation one stands in to
one's perceptual representations is not necessarily a
quasi-perceptual one: it is normally held that one simply
*has*, or *tokens*, the representations; they are not in
any sense *objects* of perception or awareness in the ordinary
course of events, but the *vehicles* of perception (Huemer
2001). They might, of course, become objects of awareness if we
reflectively attend to them; and certain theories of consciousness
hold that a perception only becomes conscious when it is the object of
a higher order quasi-perceptual state, but in general, being in the
perceptual state does not require *perceiving* one's
perceptual representations.



Sense-datum and intentionalist views both see perceptual experience as
a two-place relation between perceiver and inner representative.
*Adverbialism*, on the other hand, holds that perceptual
experience itself is monadic; it doesn't involve the perceiver
standing in a *relation* to something (see the entry on the
 problem of perception).[1]
 Different kinds of perceptual experiences are simply different ways
of sensing: one "senses greenly" or "is appeared to
horsely", and such locutions do not commit us to the existence
of either sense-data or representations. Adverbialism is sometimes
offered as an ontologically neutral way of talking about experiences
(Chisholm 1957), sometimes as the more contentious claim that
perceptual experience is primitive and unanalyzable.



Intentionalism and adverbialism deny direct world-involvement but are
compatible with the other varieties of directness. They are also
compatible with any of the corresponding varieties of
indirectness.


#### 2.3.3 Direct Realism



Proponents of intentionalist and adverbialist theories have often
thought of themselves as defending a kind of direct realism; Reid
(1785), for example, clearly thinks his proto-adverbialist view is a
direct realist view. And perceptual experience is surely less indirect
on an intentionalist or adverbialist theory than on the typical
sense-datum theory, at least in the sense of perceptual directness.
Nevertheless, intentionalist and adverbialist theories render the
perception of worldly objects indirect in at least two important ways:
(a) it is *mediated* by an inner state, in the sense that one
is in perceptual contact with an outer object of perception only
(though not entirely) in virtue of being in that inner state; and (b)
that inner state is one that we could be in even in cases of radical
perceptual error (e.g., dreams, demonic deception, etc.). These
theories might thus be viewed as only "quasi-direct"
realist theories; experiences still screen off the external world in
the sense that the experience might still be the same, whether the
agent is in the good case or the bad case. Quasi-direct theories thus
reject the Indirectness Principle only under some readings of
"directness". A fully direct realism would offer an
unequivocal rejection of the Indirectness Principle by denying that we
are in the same mental states in the good and the bad cases. In recent
years, direct realists have wanted the perceptual relation to be
entirely unmediated: we don't achieve perceptual contact with
objects *in virtue of* having perceptual experiences; the
experience *just is* the perceptual contact with the object
(Brewer 2011).This is the view that perceptual experience is
constituted by the subject's standing in certain relations to
external objects, where this relation is not mediated by or analyzable
in terms of further, inner states of the agent. Thus, the brain in the
vat *could not* have the same experiences as a normal veridical
perceiver, because experience is itself already world-involving.



The type of direct realism that has received the most attention
recently is disjunctivism (e.g., Snowdon 1980, McDowell 1982, Martin
2002, Haddock & Macpherson 2008; see the entry on the
 disjunctive theory of perception).
 There are many different versions of disjunctivism, but a common
thread is the claim that the experiences involved in the veridical
case are ipso facto of a different type than those involved in the
hallucinatory cases. The theory of appearing (Alston 1999) is a type
of disjunctivism but one that emphasizes the direct world-involvement
in the veridical case rather than the radical difference between the
cases.



Some forms of behaviorism, functionalism, and embodied mind are also
direct realist views. If, for example, having a certain perceptual
experience constitutively involves being disposed to act on worldly
objects and properties in certain ways--that is, if behavioral
dispositions are themselves individuated as world-involving--then
this would render the experience relational in the way required by
direct realism; disembodied brains in vats could not have the same
experiences as we have in normal, veridical cases. Similar
consequences follow if perceptual experience is understood in terms of
"skilled coping" (Dreyfus 2002) or "sensorimotor
know-how" (Noe 2004), again, provided that these terms are
read as requiring certain interactions with real, external objects.
Any such theory implies that brains in vats couldn't have the
same experiences we do, because they're causally disconnected
from the physical world. Such a view need not be a form of
disjunctivism, however; depending on the details of the theory, a
hallucinating subject who is nevertheless embedded in and disposed to
act on the world in the right ways might have the same experience as a
veridically perceiving subject.



Direct realism is compatible with all the metaphysical species of
direct presence listed above. As such, it allows for an unequivocal
denial of premise
 (1)
 of PEW, while quasi-realist views only reject that premise under
certain understandings of direct presence.


### 2.4 Comments on Metaphysical Solutions



If representative realism is the cause of the central epistemological
problem for perception, then perhaps direct realism or idealism will
be the solution. Some philosophers have thought that these
metaphysical views resolved the epistemological problem by closing the
gap between appearance and reality, by making ordinary objects (e.g.,
tables and rocks) directly present to the mind.



On further reflection, however, it is clear that the metaphysical
account will be, at best, a *part* of the solution.



Consider again PEW:


1. Nothing is ever directly present to the mind in
perception except perceptual appearances. (**Indirectness
Principle**) Thus:
2. Without a good reason for thinking perceptual
appearances are veridical, we are not justified in our perceptual
beliefs. (**Metaevidential Principle**)
3. We have no good reason for thinking perceptual
appearances are veridical. (**No-Good-Reason
Claim**)
4. Therefore, we are not justified in our perceptual
beliefs.



Most metaphysical solutions attack the Indirectness Principle as a way
of undercutting the Metaevidential Principle. But they only attack
metaphysical readings of the Indirectness Principle, and while the
various metaphysical theories of perception from sections
 2.2
 and
 2.3
 may have certain intuitive affinities with the Metaevidential
Principle or its denial, it follows from Hume's "no
*ought* from *is*" dictum that none of them
immediately implies either premise
 (2)
 or its negation. Epistemological directness does straightforwardly
entail the rejection of
 (2),
 but epistemological directness is compatible with *any* of the
metaphysical theories of perception glossed above and is entailed by
none of them. At best, a metaphysical theory of perception will block
one avenue of intuitive support for
 (2),
 but it will not imply that
 (2)
 is false.



An idealist, for example, will allow that we sometimes dream and that
there is a real difference between hallucination and veridical
perception, even though in both cases the direct object of awareness
is a collection of ideas. The standard view (Berkeley 1710) is that a
hallucinatory table is a different *sort* of collection of
ideas than a real table; certain counterfactuals are true of the
latter that are not true of the former (e.g., that if I were to will
certain movements, my visual perceptions would change in certain ways,
etc.). But this reopens the gap between perceptual experiences and
ordinary objects. Tables are not just experiences; they are larger
entities of which experiences are parts, and those parts can be shared
by hallucinations. So what is directly present to the mind is
something common to hallucination and veridical perception. So my
perceptual experience would seem to be neutral with respect to whether
I am seeing or hallucinating a table. So to be justified in believing
there is a table in front of me, I will need some reason to think this
particular experience is veridical, and PEW is back in business
(Alston 1993, Greco 2000).



Direct realism precludes this particular relapse into skepticism by
denying that the experience is the same in the good and the bad cases.
If our perceptual evidence includes the experience, then our evidence
in the good case is different from our evidence in the bad
case--they are different mental states. It does not follow,
however, that these two bits of evidence have differing evidential
import; both may--for all we've been told so far--be
evidentially neutral with respect to, e.g., whether there is actually
a chair in front of me or whether it merely appears so. Even if they
are very different mental states, it doesn't follow that they
license different inferences; nothing prevents the direct realist from
holding that both only license beliefs of the form 'I'm
either seeing or hallucinating a table'. Additionally, the
direct realist is free to impose a metaevidential demand on justified
perceptual belief, a demand that we know which kind of experience we
are having before that experience can serve as evidence.
Unsurprisingly, direct realists often endorse some kind or other of
epistemological directness
 (section 3.3
 below), though some endorse the Metaevidential Principle, and in any
case, the metaphysical view is by itself silent on this
epistemological issue.



Even with the metaphysical premise
 (1)
 removed, a purely epistemological version of PEW, consisting of
 (2)
 through
 (4),
 still challenges the justification of our perceptual beliefs. A
satisfying solution to the problem of the external world requires the
articulation of some plausible epistemic principles, one that explains
which of the two crucial premises
 (2)
 and
 (3)
 of PEW are being rejected, and provides an epistemological context
which renders that rejection plausible. An entirely metaphysical
solution to the problem of the external world will not suffice. An
epistemological solution to this epistemological problem will be
needed in addition or instead.


## 3. Epistemological Solutions



Any satisfactory, non-skeptical epistemology of perception is going to
deny one or more of the epistemological premises of PEW. But that
denial will have to be situated within the context of a larger
epistemological theory of perceptual belief--or better yet, of
belief more generally. There are three broad, not necessarily
exclusive, approaches to this question:


* an **evidentialist** approach, which holds that
perceptual beliefs are justified when held on the basis of (or when
the agent is in possession of) something that counts as a *good
reason* for holding that belief;
* an **etiological** approach, which holds that
perceptual beliefs are justified when formed in an appropriate way
(i.e., when the psychological processes by which the beliefs are
produced are the kind that generally conduce to justification);
and
* a **world-involving** approach, which holds that
perceptual beliefs are justified when the agent is appropriately
related to the worldly truthmaker for that belief (e.g., the
perceptual belief that *p* is justified when the agent
*sees* that *p*).



The first two are normally defended as parts of and continuous with a
more general epistemological view, encompassing not just perception
but also testimony, introspection, memory, inductive and deductive
inference, and so on. The world-involving view, on the other hand, is
formulated specifically to handle perception, though one could imagine
it being extended to some of these other sources.



An important difference among these approaches is the way they handle
perceptual experiences. On nearly any evidentialist view,
experiences--construed as internal, nonfactive (i.e.,
non-factively-individuated) mental states of the agent--play a
central role in the epistemological story, although not necessarily an
*evidential* role; indeed what that role is will differ
considerably for the different evidentialist views. For an etiological
view, experiences matter if and insofar as they are links in the
causal chain by which perceptual beliefs are formed, but they are no
more or less important than the other, nonexperiential, links. The
world-involving views bring experiences back to a position of
centrality, but only with a very different understanding of
experiences: not as inner states of an agent but as factive,
relational phenomena holding between a perceiving agent and a worldly
state of affairs.



These three are quite general approaches, and there is much room for
disagreement within each. Thus there are internalist as well as
externalist varieties of each as well as disagreement within each as
to which of the epistemological premises of PEW is to be rejected.


### 3.1 Evidentialist Approaches



For most of the history of philosophy, epistemologists have assumed a
framework that is both internalist and at least weakly evidentialist.
Since the mid-1960s, both the internalism and the evidentialism have
become controversial views, rather than common ground that can simply
be assumed without argument, though they are still very much live
options.



The traditional framework is internalist in both of the two main
senses of *mentalism*, holding that all the factors relevant to
justification supervene on the nonfactive mental states of the agent;
and *accessibilism*, requiring that the presence of these
factors is knowable by the agent on the basis of mere reflection (see
entry on
 internalist and externalist conceptions of epistemic justification).
 The framework is weakly evidentialist in requiring--at least for
any proposition that is not directly (i.e., immediately)
justified--that its justification derives from and is a function
of an actual or potential basing relation to some ground, or reason,
in relation to which that proposition is a reasonable one to believe.
Contemporary evidentialists tend to espouse a stronger kind of
evidentialism, according to which *all* justification, and not
just indirect justification, is a function of the agent's
evidence. But this is a later development. There's no hint in
Descartes or Locke, for example, that experiences serve as
*reasons* for appearance beliefs; rather, their occurrence is
partly constitutive of the reflectively transparent infallibility of
those introspective judgments, which gives these judgments the highest
degree of epistemic certainty.


#### 3.1.1 Classical Foundationalism



Foundationalism is the view that some beliefs are epistemologically
direct, or "basic"--i.e., their justification does
not depend on evidential support from other beliefs--and all
other justified beliefs ultimately derive their justification from
these. (Basically justified beliefs are sometimes referred to as
"immediately justified" as well.) *Classical
foundationalism* is the view that (i) it is *appearance
beliefs*--i.e., beliefs about perceptual
appearances--that are basic, and perceptual beliefs about
ordinary objects, events, and properties are based at least partly on
these, and (ii) perceptual justification requires us to have good
reason to think that the relevant current appearances are veridical.
Basing is a relation of *epistemic* dependence and does not
imply explicit inference, although particular theories might hold that
the relation is satisfied only when inference occurs.



(i) is defended in one of several ways. Here are brief versions of
some of the more common, often implicit, arguments:


* The empirical foundation must consist of the most highly justified
contingent beliefs, and these are appearance beliefs.
* In order for perception to give us genuine knowledge of the
external world, perceptual knowledge must be grounded in direct
acquaintance with something; we are not directly acquainted with
physical objects, but only with our experiences, so beliefs about
these experiences must serve as the foundations of perceptual
knowledge.
* We can and do articulate beliefs about our experiences in defense
of our perceptual beliefs when challenged; so these appearance beliefs
must be at least part of our evidence for the perceptual beliefs.
* Perceptual beliefs about external objects are not self-evident (if
they were, they would be justified whenever held), so they must be
based on some other belief; the only candidates are appearance
beliefs, which plausibly are self-evident.



(ii) includes an endorsement of the Metaevidential Principle. We have
looked at representative realism as one motivation for that principle,
but there are others. Classical foundationalists have traditionally
endorsed it because it follows from two other claims they find
plausible. The first is (i) above, that our perceptual beliefs are
based on appearance beliefs. The second is the claim that in order to
be justified in believing hypothesis *h* on the basis of
evidence *e*, one must be justified in believing that
*e* makes *h* probable (or that *e* entails
*h*, or *e* is good evidence for *h*, etc.) This
second claim is a version of Richard Fumerton's "Principle
of Inferential Justification" and is often defended by citing
examples (Fumerton 1995; see the entry on
 foundationalist theories of justification).
 My belief that you're going to die soon cannot be justified on
the basis of your tarot card reading unless I'm justified in
believing that tarot cards really do tell the future. Whether such
examples generalize to *all* inferences is an open question.
Some forms of internalism (see the entry on
 internalist vs. externalist conceptions of epistemic justification)
 would imply the Principle of Inferential Justification as well.



The classical foundationalist avoids skepticism by rejecting the
No-Good-Reason Claim, insisting that we do often have good,
non-viciously-circular, reasons for thinking that our experiences are
veridical. Two questions thus arise for classical foundationalism, one
about the nature and justification of appearance beliefs and one about
the allegedly non-circular inference from appearance beliefs to
perceptual beliefs.



Appearance beliefs are not based on other beliefs, so how are they
justified?



Appearance beliefs are a species of introspective belief, and
introspection is sometimes thought to involve a "direct
contact", or "confrontation", or "acquaintance
with", or "access to", or
"self-presentation" of certain truths. As we saw in
 section 2.1,
 regarding "direct presence", such metaphors could be
unpacked in a variety of ways. If claims about
"acquaintance" and the like (for simplicity, all of them
will be referred to indiscriminately as "acquaintance")
are given an epistemological reading, then they seem to restate or
reiterate the classical foundationalist's claim that we can have
foundational justification for appearance beliefs, rather than to
explain or argue for that claim. If they are making some metaphysical
claim, then the consequences for epistemology are indirect and
unclear. Epistemologists are sometimes less than fully explicit about
how they are understanding acquaintance. And however acquaintance is
understood, the classical foundationalist must make acquaintance broad
enough that we are plausibly acquainted with appearances (on pain of
skepticism) but narrow enough that we are not acquainted with physical
objects as well (or else endorse a very different kind of
foundationalism).



Roderick Chisholm's (1977) conception of acquaintance (he calls
it "self-presentation") is explicitly and fundamentally
epistemic--a self-presenting state is simply one such that a
person is justified in believing they are in it whenever they actually
are in it. This doesn't explain or argue for the special
epistemic status of appearance beliefs, but Chisholm denies that
argument or explanation is needed: it is self-presenting that
appearance beliefs are self-presenting.



Attempts to explicate acquaintance in non-epistemic terms fall into
one of two categories. The traditional way to understand acquaintance
is in terms of a containment relation between appearance beliefs and
appearances, with the result that appearance beliefs entail their own
truth. This is the indirect realist's analogue of the
world-involvement invoked by direct realists (above, sections
 2.1.4,
 2.3.3). Descartes (1641) held that appearance beliefs, like any
belief about one's own mental states, are infallible for this
reason, and transparently so, and thereby justified. Though some still
endorse this view (McGrew 2003), most epistemologists deny that our
self-attributions are infallible. A more modest claim is that only
*some* appearance beliefs are infallible. A certain kind of
token-reflexive concept ("direct phenomenal concepts")
might include phenomenal qualities as literal elements or constituents
(Chalmers 2003), and so introspective judgments that involve the
application of such concepts cannot be mistaken.



This does not yet fully account for the distinctive epistemic status
of appearance beliefs, as the epistemic implications of infallibility
remain unclear, especially in the context of an internalist
epistemology. One might believe some necessary truth as the result of
a lucky guess; the belief is infallible, but not justified. This seems
at least in part to result from the fact that the infallibility
occurs, in some sense, outside of the agent's perspective. (The
infallibility involved in self-attribution, however, seems intuitively
to fall *within* the agent's perspective.)



The second type of approach views appearance beliefs as justified by
something extrinsic to them, so that an appearance belief is justified
when it is accompanied by acquaintance with the experiential fact that
the appearance belief describes. Laurence BonJour (2003), for example,
understands acquaintance in terms of constitutivity, though in a very
different way from the one just seen. BonJour claims that awareness of
the sensory content of an experience is partly constitutive of what it
is to have a conscious experience. That awareness is thus infallible,
but appearance *beliefs*--which purport to describe the
experience and constituent awareness--are fallible. Though, he
hastens to point out, we are very likely to get them right in such
conditions. Similarly, Fumerton (1995, 2001) claims that acquaintance
is a nonepistemic relation, but that whenever we're acquainted
with a fact, everything possibly relevant to the truth of that fact is
unproblematically *there* before the mind.



These two views see acquaintance as a metaphysical (i.e.,
non-epistemic) relation. They lay down as a separate, further thesis
one that is not directly entailed by but is rendered highly plausible,
proponents think, by the nature of the acquaintance relation: that
when one is thus acquainted with an experience, one has a strong
*prima facie* justification to believe that one has that
experience, and furthermore, that justification does not depend on any
other beliefs. On either non-epistemic understanding of acquaintance,
it puts us in a very good position to make correct judgments about our
current experiences. Most classical foundationalists allow that all
appearance beliefs are defeasible (i.e., having a kind of
justification that is capable of being overridden or undermined by
further reasons); hence the claim made is merely for *prima
facie*, rather than *ultima facie*, justification. (To say
that a belief is *prima facie* [aka *pro tanto*]
justified is to say that it is has some positive epistemic status, in
the sense that it is justified *if* it is not defeated by
overriding or undermining considerations.) Chisholm (1977) and Timothy
McGrew (2003) endorse the stronger claim that acquaintance provides
indefeasible, *ultima facie* justification.



So far we haven't seen any talk of evidence; that will come
later for these views, in the movement from appearance beliefs to
beliefs about the external world. But a stronger kind of evidentialism
could hold that the experience (or acquaintance with it) serves not
only as a truth-maker and justifier for the appearance belief, but as
*evidence* for that belief as well. By "evidence"
is meant here not just any factor that serves to confer justification
on a belief, but something that serves as a *ground*, or
*reason*, or *rational basis*, for that
 belief.[2]
 Not all justification-conferring or justification-relevant factors
count as evidence in this sense (if they did, evidentialism [see Conee
and Feldman (2004) and entry on
 epistemology]
 would not be the controversial thesis that it is). Evidence, in the
current context, is something that an agent can *possess* and
on which they can *base* a belief; someone who possesses
evidence that *fits*, or *supports,* some belief has
(*prima facie*) propositional justification for that belief,
and doxastic justification if that belief is based on that evidence.
Not all justification-making factors fit this bill. For example,
Descartes held that all clear and distinct judgments were justified,
though certain judgments--e.g., "I think"--are
justified without evidential appeal to clarity and distinctness. It is
the *fact* that it is clear and distinct that makes it
justified, not the agent's awareness of that fact or
appreciation of that fact's epistemic significance, so clarity
and distinctness are not functioning here as evidence. Similarly,
reliabilism holds, roughly, that being reliably formed renders a
belief justified; although reliability need not--and typically
does not--figure in as the agent's evidence or grounds for
believing something.



The stronger evidentialist view holds that even directly (i.e.,
basically/immediately) justified beliefs are justified by evidential
connections, but since these beliefs are basic, their evidence must
consist of something other than (justified) belief. Hence the popular
claim that perceptual experiences are nondoxastic (i.e., non-belief)
states that nevertheless serve as evidence for appearance beliefs, in
much the way that beliefs serve as evidence for other beliefs, though
with one crucial difference: for one belief to serve as evidence for
another, the former must be justified; experiences on most views are
not susceptible to justification, thus can be neither justified nor
unjustified, but--on the standard strongly evidentialist
view--can nevertheless serve as evidence and confer justification
on beliefs. The justification of appearance beliefs on this view
depends on evidential connections to other mental states but not to
other beliefs, and because experiences need not be justified in order
to serve as evidence, the threatened regress is halted in a way that
is consistent with foundationalism. The idea of such nondoxastic
evidence raises several problems, as we will see shortly.



Classical foundationalism is sometimes objected to on the grounds that
we typically do not have beliefs about our experiences (e.g., Pollock
1986, Greco 2000), at least not consciously. This raises interesting
and difficult issues about the natures of evidence and the basing
relation. For the belief that *p* to serve as justifying
evidence for the belief that *q*, must I consciously form the
belief that *p*, or is it enough that, e.g., I have good reason
to believe that *p* and be disposed to do so if the question
arises? Surely the classical foundationalist never denied phenomenal
directness or thought our perceptual beliefs were reasoned out
explicitly. If one could show that only consciously formed beliefs
could ground other beliefs, this would be bad news indeed for
classical foundationalism, but this is a controversial claim.
Alternatively, the objection might be that we are typically not even
yet *in a position* to form justified appearance beliefs, in
some situations where we are nevertheless well justified in our
perceptual beliefs. Being in a position to form justified appearance
beliefs would require further investigation, in an
"inward" direction. This investigation is not always easy
(Pollock 1986), and it is possible that such investigation would alter
the nature of the experience. In addition, some perceivers may lack
the conceptual resources to distinguish appearances from external
objects, although they seem to be justified in their perceptual
beliefs nonetheless.



The second big question for the classical foundationalist is how
appearance beliefs provide justification for beliefs about external
objects.



Cartesian foundationalism was the strictest form of classical
foundationalism, requiring a deductive metaevidential argument for the
reliability of perception. Descartes believed that he could give a
non-circular argument for thinking that some perceptual experiences
were veridical, by constructing an *a priori* argument for the
reliability of perception. He also aimed for certainty, so his
argument was a deductive one, starting with the existence and
perfection of God and concluding that any clear and distinct awareness
(including some elements of perceptual awarenesses) must be true; so
some perceptual experiences--namely, the clear and distinct
ones--are veridical. This would have licensed a rejection of the
No-Good-Reason Claim, by showing how we could have a good reason for
thinking our experiences to be veridical. However, Descartes's
*a priori* arguments for the existence of God were at best
controversial, and the theology needed to deduce the reliability of
perception from the perfection of the deity was unconvincing, so
deductive metaevidential arguments along these lines were not pursued
further.



NonCartesian forms of classical foundationalism have tried to combine
the a priority required by non-circularity with a probabilistic form
of inference, the most promising candidate being abduction, or
inference to the best explanation (Russell 1912, BonJour 2003).
According to this view, the best explanation of our experiences is the
commonsense hypothesis that there is a mind-independent external world
that conforms in some measure to these experiences and is the cause of
them. The superiority of this explanation to the alternatives
(idealism, a Cartesian demon, etc.) is held to be an *a priori*
matter, thus not dependent on assuming the veridicality of the very
experiences the argument is supposed to legitimate. There is a good
deal of intuitive plausibility to the claim that an external world
serves as the best explanation for our sense experience, but making
that case in any detail, especially enough to satisfy the idealist,
would require taking on some large and complex issues, like what makes
one explanation better than another (see the entry on
 abduction),
 and--since the commonsense view is sometimes (e.g., Russell
1912, BonJour 2010) held to be *simpler* than
competitors--what counts as simplicity, a vexed question in the
philosophy of science (see the entry on
 simplicity).
 William Alston (1993) offers an influential critique of abductive
arguments for the reliability of sense-experience.



Furthermore, if we are trying to explain how the ordinary
person's perceptual beliefs are justified, then it is not enough
that *there be* some good deductive or abductive argument for
the reliability of perception; this argument must be in some important
sense available to or possessed by the agent. Premise
 (2)
 of PEW, after all, is the claim that *the agent* must have
some good reason for thinking their experiences are veridical. Some
(e.g., Pollock & Cruz 1999) think this imposes a significantly
more onerous burden on the proponent of classical foundationalism,
although others (e.g., BonJour 2010) claim that the superiority of the
commonsense view is quite accessible to ordinary epistemic agents.


#### 3.1.2 Fundamental Epistemic Principles



Other traditional foundationalists have responded to PEW by denying
the Metaevidential Principle, rather than the No-Good-Reason Claim.
Most such views have rejected both parts of the standard argument for
the Metaevidential Principle
 (3.1.1
 above), but one important exception is worth noting. Chisholm (1966,
1977) agrees with the classical foundationalist that perceptual
beliefs are based on appearance beliefs but denies that any argument
for the legitimacy of the appearance-reality inference is needed.
Chisholm posits as a fundamental epistemic principle that if one is
justified in believing herself to be perceptually appeared to as if
*p*, then one is *prima facie* justified in believing
that *p*. The significance of insisting that this principle is
fundamental is to insist on the legitimacy of the move from
*p*-appearance to *p*-reality while denying that that
legitimacy is derived from deduction or abduction. This move is
similar to one taken by the antireductionist in the epistemology of
testimony (see the entry on
 epistemological problems of testimony).



To the classical foundationalist, this move seems illicitly *ad
hoc*. Admittedly, it gives the answer we desire--that
perceptual beliefs are justified--but it doesn't explain
how this can be so or give us any reason to think it is true (Fumerton
1995). The objection holds that the postulation of fundamental
epistemic principles licensing the inferences we like, despite our
inability to provide an argument for the legitimacy of such
inferences, has, to borrow Bertrand Russell's apt phrase, all
the advantages of theft over honest toil.


#### 3.1.3 Coherentism



The coherentist, like the classical foundationalist, endorses the
Metaevidential Principle but holds that we can indeed have good
arguments for the reliability of perception. Coherentism is the view
that at least some justification comes from mutual support among
otherwise unsupported beliefs instead of tracing back to basic
beliefs. As such, coherentists are sometimes said to endorse certain
kinds of circular (they prefer to call them holistic) argument, but a
coherentist will reject the No-Good-Reason Claim by insisting that
there is nothing viciously circular about our arguments for the
reliability of perception (BonJour 1985, Lehrer 1990). Because it
allows mutual support, coherentism can tolerate *empirical*
arguments for the reliability of perception, in principle, allowing
appeals to track records, evolution, and other scientific
evidence.



Coherentism has traditionally been propounded as a doxastic theory:
one that holds that only beliefs can serve as evidence. This is in
part because one of the major motivations for coherentism derives from
an argument due to Wilfrid Sellars (1956), Donald Davidson (1986) and
Laurence BonJour (1980) that purports to show that nondoxastic states
(e.g., experiences) cannot play an evidential role (about which, more
below, in
 section 3.1.5).
 Indeed, on this sort of view, experiences play no *epistemic*
role at all (though maybe a causal, psychological role), either
evidential or otherwise. This doxasticism is the source of one of the
most notorious problems for coherentism, however, for the internal
coherence of a belief system could result from the ingenuity of the
believer, rather than from its fit with reality. A detailed enough and
cleverly constructed fairy tale could be highly internally coherent,
but surely I am not justified in believing the fairy tale, in my
current situation and environment. This is the famous *isolation
objection* to coherentism: a belief system could be isolated from
the world and yet be fully coherent. Since those beliefs would not be
justified, coherence is not sufficient for justification.



The brunt of the isolation objection is that (doxastic) coherentism is
unable to do justice to perception, for it does not require any
genuinely perceptual contact with the world. But without perception,
the whole of one's beliefs is just another plausible story, not
the one true description of things. (Even with perception, there is
unlikely to be a *single* best belief set, but the number of
equally good contenders will be vastly reduced.) For some time,
BonJour (1985) thought that the problem could be solved with more
beliefs; he required a candidate belief system to include a number of
beliefs attributing reliability to beliefs that seem to be
involuntary, noninferential, and directly caused by the outside world.
But this solution seemed *ad hoc*, and it still didn't
require the belief set to be very highly constrained by perception; at
best it constrained the belief set by what the agent *believes*
to be perception, and even then, only those putatively perceptual
beliefs about which the agent has favorable metabeliefs would need to
constrain the rest of the system in any way. This seems to render
perception epistemically "optional", in an objectionable
way.



Although BonJour (1997) has consequently abandoned this approach in
favor of a form of foundationalism, others have sought to incorporate
experiences into a nondoxastic coherentism (Conee 1988, Haack 1993,
Kvanvig 2012, Kvanvig & Riggs 1992). If experiences are among the
relata over which the coherence relation is defined, then a fully
isolated agent won't be able to satisfy the coherence
requirement, and the isolation objection may be averted.



It is unclear whether such a move genuinely rescues coherentism or
simply replaces it with a version of foundationalism. If consonance
with experience can increase the credibility of a belief, then it
begins to look as if that belief satisfies at least some
("weak") foundationalist definitions of an
epistemologically basic belief. Instead, the nondoxastic coherentist
might insist that experiences justify perceptual beliefs, but only in
the presence of the right background beliefs about which experiences
reliably indicate which distal states of affairs, where these
background beliefs are themselves justified in a coherentist manner
(Gupta 2006). This view seems to be securely coherentist, though it
threatens to render coherence with experience optional in just the way
BonJour's older view did. The crucial question here is whether
experiences--alone, and in and of themselves--affect the
coherence of a belief system, or whether they do so only in the
presence of the relevant metabeliefs. If the former, then
"nondoxastic coherentism" may not be significantly
different from some form of foundationalism. If the latter, then an
agent lacking the requisite metabeliefs might satisfy the coherence
requirements quite well but have a belief system that clashes with
their experience, and the nondoxastic coherentist would have to hold
that the agent is none the worse, epistemically, for that fact.



The very spirit of coherentism seems to dictate that perception yields
justification only because and insofar as the perceiver has
metabeliefs that favor perception, while it is central to the
foundationalist theory of perception that perceptual experience
imposes epistemic constraints on us, whether we believe it or not.


#### 3.1.4 Seemings Internalism



The epistemological views considered so far can all be considered
*egoistic theories*, for they hold that justification for
beliefs about external objects depends in part on justification for
beliefs about oneself--about one's current mental states,
about the connections between one's experiences or putatively
perceptual beliefs and certain distal states of affairs, rendering
perceptual beliefs nonbasic. *Modest foundationalism* is a
nonegoistic version of foundationalism, one that allows some beliefs
about external objects and their properties--particularly,
perceptual beliefs--to be epistemologically basic. (Both types of
foundationalism also countenance other basic beliefs, e.g., beliefs
about simple arithmetical truths.) Modest foundationalism thus denies
the Metaevidential Principle; perceptual beliefs are not based on
other beliefs and thus not based on appearance beliefs, and if they
are based on something other than beliefs (namely, experiences) the
agent need not have a justified belief about the reliability of this
connection.



Some proponents of modest foundationalism go a step further and offer
a derivative denial of the No-Good-Reason Claim: since we already have
justified beliefs about our surroundings, and introspective knowledge
of the deliverances of perception, we can construct non-circular
arguments for the reliability of perception. Indeed, if I can have
first-order knowledge about the world around me without first having
metaevidence about the reliability of perception, I should be able to
accumulate empirical evidence for thinking that I am not a brain in a
vat, that I am not dreaming, etc., without begging the question.
Whether this should count as a virtue or a vice of the theory is a
matter of debate. Proponents of a "Moorean" response to
skepticism (see the entries on
 skepticism
 and
 epistemic closure)
 will see this as a selling point for modest foundationalism (Pryor
2000). Others (Vogel 2000, 2008; Cohen 2002) have interpreted this
result as revealing a fundamental flaw of the theory: it makes
justification and knowledge "too easy". It is as if I used
an untested speedometer to form beliefs both about my speed and what
the meter indicated my speed to be, then used a number of such belief
pairs to inductively argue for the reliability of the speedometer.



Modest foundationalism endorses epistemological directness
 (section 2.1.5
 above) and could be considered a kind of *epistemological direct
realism*, for it makes the world and its elements "directly
present" to the mind in a fairly clear, epistemological sense:
perceptual justification is not dependent on any other justification;
no other beliefs are interposed between us and the world (in fact,
John Pollock's term for his [1971, 1986] modest foundationalism
is "direct realism"; cf. Pollock & Cruz 1999). Modest
foundationalism is compatible with any metaphysical view about the
nature of perception. Even a sense-datum theorist could embrace this
epistemological direct realism, provided they held that the inference
from sense-data to external objects was a kind of (perhaps unconscious
or subpersonal) inference that does not impose evidential requirements
on the conclusion belief.



Modest foundationalism is usually associated with the internalist,
strongly evidentialist versions of the theory, of the sort initially
developed by Pollock (1971) and Anthony Quinton (1973), though given
renewed visibility in recent decades by James Pryor (2000), Michael
Huemer (2001) and others. These views hold that perceptual beliefs
about external objects, events, and properties are directly justified
by the corresponding perceptual experiences; it is the experiences
themselves, rather than beliefs about the experiences, that do the
justificatory work. Thus, Huemer's (2007) "phenomenal
conservatism", Pryor's (2000) "dogmatism", and
Pollock's (1971, 1974, 1986) "direct realism" all
endorse something like the following principle:




If *S* has a perceptual experience as of *p*, then
*S* is *prima facie* justified in believing that
*p*.




Alternatively:




If it perceptually seems to *S* that *p*, then
*S* is *prima facie* justified in believing that
*p*.




That is, *S* is *prima facie* justified *whether or
not* perception is reliable for *S* and whether or not
*S* has any evidence in favor of the claim that perception is
reliable. Perceptual beliefs are justified by the experience alone, in
virtue of some intrinsic feature of that experience (its content, or
phenomenal character, or assertive force, some combination of these,
etc.). Of course, because the justification here is only *prima
facie* justification, this justification could be defeated if,
say, *S* has good enough reason to think that perception is
unreliable, or has independent evidence that *p* is false.



To have a neutral term, this view will be called "*seemings
internalism*", for it holds that perceptual beliefs are
based on "seemings", i.e., appearance states, i.e.,
experiences. (There is no fixed, established terminology here.)
Seemings internalism is attractive on the grounds that it offers
intuitively correct, nonskeptical verdicts about ordinary perceptual
belief and does so, according to some proponents, in a way that is
less intellectually demanding than other internalist views, thus more
likely to get the result that animals and small children have
perceptual knowledge, even though they're not sophisticated
enough to have beliefs about appearances.



Susanna Schellenberg's (2013, 2018) view is best classified as a
form of seemings internalism, but only about one aspect or dimension
of justification. On her view, any time it perceptually seems to you
that *p*, you have "phenomenal evidence" for
*p*. Full justification of the sort required for knowledge
requires another kind of justification in addition to phenomenal
evidence (as we'll see in section 3.3). She has a complex
externalist theory about what constitutes it seeming to you that p,
but there is no conflict between a seemings internalist epistemology
and the various kinds of semantic externalism (see entry on
 externalism about the mind).



Most seemings internalists are fairly liberal about the contents of
the seemings and thus about which perception-based beliefs are
directly justified. Others, notably Elijah Chudnof (2018) and Matthew
McGrath (2013, 2018), are more conservative. Is my belief that
there's a dog in front of me basic, or does its justification
depend on the justification of more elemental beliefs: that
there's a medium sized, 3-dimensional object of such-and-such a
shape and a furry texture, etc.? Is my belief that that's Django
on the floor in front of me basic, or does it depend on the belief
that there's a black and tan dog of a certain description, that
Django is a black and tan dog who fits that description, etc.?
Liberals will take the former options, while conservatives will go
with something like the latter. Seemings internalism requires
experiential states whose contents match the contents of the basic
beliefs, so a liberal view about direct justification requires a
liberal view about the contents of perceptual experience (see the
entry on the
 contents of perception).
 Chudnoff (2018) combines a liberal theory about the contents of
perception with a conservative view about basic beliefs by endorsing a
restricted kind of seemings internalism: not all perceptual
experiences provide *prima facie* justification, only the ones
with "presentational phenomenology", which not all
perceptual experiences do have.


#### 3.1.5 The Sellarsian Dilemma and Other Challenges



Perhaps the most important problem for internalist, evidentialist
views concerns the relevant understanding of seemings, or perceptual
experience. It is clear that seemings must be non-belief states of
some sort, as their epistemological role is to confer justification on
basic beliefs, and the latter wouldn't be basic if seemings were
themselves beliefs. The "Sellarsian dilemma" is a famous
argument, in some ways due as much to BonJour (1978, 1985) as to
Sellars (1956), which claims that "experience" and
"seemings" and the like are ambiguous in a way that
undermines the epistemological role that a strongly evidentialist
foundationalism requires of experiences. That role, of course, is to
provide justification for beliefs without being themselves in need of
it. Sellars (1956) starts with the justification of appearance
beliefs. He argues that there is a kind of noncognitive awareness of
sensations that does not involve learning or the application of
concepts; this kind of awareness accompanies all conscious sensations,
but this kind of awareness does not account for the justification of
our appearance beliefs, for one might well have this kind of awareness
without having any idea what kind of experiences one is having (or any
idea that there are such things as experiences). There is another kind
of awareness of our sensations that does involve the application of
concepts and does entail knowledge and justification. But this
awareness *just is* one's knowledge of one's
experiences (i.e., one's justified, true, unGettiered appearance
belief). But that kind of awareness cannot then serve as a nondoxastic
foundation that confers justification on beliefs without being itself
in need of justification (see Lyons 2016).



This argument--Sellars's original argument--is aimed at a kind
of classical foundationalism, but a modified version has more general
ambitions. Sellars himself (1956) thought that there are two elements
to perception: a bare sensation, which is an inner event with
qualitative character but no representational content; and a
perceptual belief (or belief-like state, in cases where the agent does
not accept appearances at face value; see Reid 1764, 1785 for a
similar view). Recent formulations of the Sellarsian dilemma have
focused on this mismatch in content between experience and perceptual
belief, and have modified the argument to include an attack on modest
foundationalism. There are several variants of the argument; what
follows is an amalgamated version.


1. Let us say that a state is "cognitive" just
in case it has conceptual and propositional content, and assertive
force; it is "noncognitive"
 otherwise.[3]
2. If an experience is noncognitive, then it cannot justify
a perceptual belief.
3. If an experience is cognitive, then it cannot justify
any beliefs unless it is itself justified.
4. Therefore, in neither case can an experience confer
justification without being itself justified.



In defense of
 (2),
 experiences have frequently been construed as lacking
representational contents altogether (Sellars 1956, Martin 2002,
Brewer 2011), or as having nonconceptual contents (Heck 2000, Peacocke
2001).[4]
 An influential argument (e.g., McDowell 1994, Brewer 1999) holds that
without conceptual content, an experience would have to stand outside
the "logical space of reasons" and thus cannot justify a
belief. This line is perhaps most plausible if the relevant mode of
justification is assumed to be a specifically *evidential* one
(see
 section 3.1.1
 above). To serve as evidence, the experience would need to stand in
logical or probabilistic relations to beliefs, and without
(conceptual) contents, it is unclear how it could stand in evidential
relations to beliefs, or which beliefs it would serve as evidence for
(McDowell 1994). A common response is that as long as experiences have
contents of any sort, they can have truth conditions and thus stand in
entailment and probabilistic relations to beliefs (Heck 2000, Byrne
2005). One way to follow through on the original argument for
 (2)
 is to emphasize the kind of content necessary for evidence
appreciable as such by the perceiver. If experiences are
nonconceptual, then it seems that I could have a nonconceptual
experience of a cat without being in any position to appreciate the
fact that the experience is *of a cat*. In such a case, I could
fail to have any justification for believing that there is cat in
front of me. So nonconceptual experiences cannot, by themselves,
justify perceptual beliefs (Lyons 2016). Such an argument requires the
controversial assumption that an agent must "appreciate"
*e*'s evidential significance vis-a-vis
*h*, in order for *e* to supply that agent with evidence
for *h*. Some (e.g., Alston 1988) have explicitly rejected this
assumption, although some forms of access internalism require it.



As for the other horn of the dilemma, premise
 (3),
 one can argue that so-called "experiences" that have
assertive force and the same contents as beliefs are, if not
themselves beliefs, at least sufficiently belief-*like* that
they are susceptible to epistemic evaluation in much the way that
beliefs are; if so and if only the "justified" ones can
confer justification on beliefs, then these experiences will not have
filled the role foundationalism had carved out for them (Sellars 1956,
BonJour 1978, Sosa 2007).



In recent years, several authors (Lyons 2005, 2009; Bengson, Grube,
& Korman 2011; Brogaard 2013) have argued that what we think of as
perceptual experiences is actually a composite of two (or more)
distinct elements, what Chris Tucker (2010) calls the
"sensation" (an imagistic state, rich in perceptual
phenomenology) and a "seeming" (here construed as a purely
representational state, applying conceptual categories to things in
the world). Seemings understood in this way are still non-belief
states: in cases of known perceptual illusion, it might seem to me
that *p*, even though I don't believe that *p*.
Something like the above Sellarsian dilemma can be run with this
distinction in hand: sensations without seemings are insufficient to
justify beliefs; and seemings without sensations would be subjectively
too similar to mere hunches to justify beliefs (Lyons 2009). The
seemings internalist can reply by arguing that seemings alone, even
construed as just one component of perceptual experience, can indeed
justify beliefs (Tucker 2010), or by rejecting this composite view,
insisting that a seeming is a single, unified state, whose perceptual
phenomenology and conceptual content are inextricably linked (Chudnoff
& Didomenico 2015).



Seemings internalism as formulated above claims that the content of
the experience is the same as the content of the belief, thus
rejecting premise
 (3)
 of the Sellarsian argument. There may be variations close enough to
still count as seemings internalism that deny
 (2)
 instead, allowing experiences with nonconceptual contents to justify
beliefs. The standard schema would have to be modified:




If *S* has a perceptual experience as of *p\**, then
*S* is *prima facie* justified in believing that
*p*.




One would, of course, want to say more about the relation between
*p* and *p\**. Although his concern is not with
nonconceptual content, Nico Silins (2011) defends a view much like
seemings internalism, where the experiences are not required to have
the same contents as the beliefs.



A second problem is that of alien sense modalities (Bergmann 2006).
There are possible creatures with sense modalities and experiences
that are foreign to us: echolocation, electroreception, etc., and
presumably these creatures can be justified in their alien perceptual
beliefs. If metaevidential beliefs are not necessary for perceptual
justification, then these same experiences ought to justify
*us* in those same beliefs. Intuitively, however, a sudden
electroreceptive experience would not justify me in believing there
was a medium sized animal about three feet behind me. In fact, a
famous objection to a different (reliabilist) theory seems to apply
equally well to seemings internalism. Norman (BonJour 1980) has no
reason for thinking that he has reliable clairvoyant powers, but one
day he has a clairvoyant experience as of the president being in New
York; intuitively, he is not *prima facie* justified in
believing that the president is in New York, yet seemings internalism
seems to imply that he is. The clairvoyance objection is normally
pressed against reliabilist theories, not on the basis of the
reliability component, but rather on the basis of their rejection of
the Metaevidential Principle, a rejection that is shared by seemings
internalism. One might reply that Norman's experience is not
exactly perceptual; perhaps this might offer a way out, especially if
one could explain why it isn't perceptual and why that should
make a difference. Some versions of seemings internalism restrict
their claims to perception (Pryor 2000), although some (Huemer 2007)
apply to seemings much more generally.



Another potential problem is that seemings internalism is insensitive
to the etiology of the experience, although it intuitively seems that
this should matter. If the only reason Jack looks angry to Jill is
that she has an irrational fear that he would be angry, then her
perceptual experience as of angry-Jack should not carry its usual
evidential weight (Siegel 2011). This problem is sometimes framed in
terms of the "cognitive penetration of perception", a
controversial empirical issue in the philosophy of perception. In
general, experiences that result from wishful thinking, fear, and
various irrational processes should not have the same evidential
import as do experiences with a more respectable etiology (Markie
2005, Siegel 2013). But seemings internalism makes the experience
itself sufficient for (*prima facie*) justification and thus
leaves no role for etiology to play. One response to these sorts of
cases is that if it genuinely looks to Jill as if Jack is angry, then
the only appropriate thing for Jill to do is believe that he is angry
(Huemer 2013). This is compatible with there still being something
else epistemically lacking in Jill; e.g., she presumably doesn't
know that Jack is angry (even if he is). Chris Tucker (2014) argues
that cognitive penetration problems are a worry for everyone, not just
for seemings internalists.



This last concern in particular calls into question a phenomenal
determination principle, assumed by all the epistemological views
canvassed so far, which holds that the phenomenal character of an
experience completely determines which beliefs that experience
directly justifies: two agents cannot be alike with respect to their
phenomenology and yet differ in which beliefs are directly (*prima
facie*) justified for them. The phenomenal determination principle
has some intuitive plausibility, but so does its denial. Cognitive
penetration cases (Markie 2005, Siegel 2011) purport to offer cases
where two agents have the same phenomenal states but different direct
justification, and certain responses to the new evil demon objection
to reliabilism (Lyons 2012) try to undermine intuitive support for the
phenomenal determination principle.



A different worry concerns the basing relation. Doxastic evidential
justification is generally thought to require that the belief be based
on the justifying evidence, where basing is some kind of psychological
relation (which psychological relation is a matter of some
controversy--see the entry on
 the epistemic basing relation).
 This makes it a partly empirical question whether we typically or
ever actually do base perceptual beliefs on experiences. Although it
seems intuitively plausible that we do, Jack Lyons (2020) argues that
the empirical facts about the contents of perceptual experiences and
about the time course of conscious experience and perceptual
categorization render this claim unlikely.



A final worry for seemings internalism is one that we encountered
above in
 section 3.1.2
 in connection with a different view: the proposal seems to be an
*ad hoc* attempt to get the desired nonskeptical answer without
further justification for the principle. What is it about seemings,
after all, that makes them able to generate justification? The desire
that *p* has propositional content but doesn't justify
the belief that *p*; the unjustified belief that *q* has
assertoric force but doesn't justify the belief that *q*
(Lyons 2008, Ghijsen 2014); imaginings can have phenomenal force but
don't justify beliefs (Teng 2018), and so on. Chudnoff 2018,
2021 holds that some seemings have a particular phenomenal character
("presentational phenomenology"), namely that of seeming
to put us in direct contact with an extramental reality. But he holds
that only some seemings have this phenomenology, and it's only
these that confer direct justification, so this view won't give
most seemings internalists all they want. Pollock's (1986)
epistemological theory of concepts addresses this worry by claiming
that it is part of the concept of, e.g., *red* that a certain
perceptual experience (or seeming) is a *prima facie* reason
for the belief that *x* is red. Most recent proponents of
seemings internalism have not embraced this part of Pollock's
view.


#### 3.1.6 Seemings Externalism



Some of the problems facing internalist evidentialist theories are at
least ostensibly solved by going externalist. A view we might call
"seemings externalism" holds along with seemings
internalism that perceptual beliefs are justified when based on a
fitting experience but is externalist about the fittingness relation,
allowing that what makes for fittingness need not be accessible by
reflection nor need supervene on the nonfactive mental states of the
believer. This sort of view is premised on the rejection of the
phenomenal determination principle articulated above. Assuming that
experiences are necessarily conscious and that conscious states are
necessarily accessible, seemings externalism nevertheless imposes an
internalist constraint on perceptual justification: one component of
justification must be an accessible mental state of the agent. But the
rest of the justificatory story is thoroughgoingly externalist. To
date, this sort of view has been developed in two ways, one
reliabilist and one functionalist.



An example of the first approach is Alston's (1988) internalist
externalism. He requires that every justified belief have some ground,
or evidence, and that this ground be accessible; that is the
internalist element. He claims, however, that what makes a ground
(good) evidence for some belief is that the ground reliably indicates
the truth of that belief, and this fact is one that need not be
accessible to the agent; this is the externalist element. (See
Comesana 2010 for a similar view.) Although Alvin Goldman is
best known for the reliabilist (etiological) theory to be addressed in
section 3.2, he also (2011) has developed a reliabilist/evidentialist
"synthesis", where experiential evidence plays a central
role in perception. (He does not, however, require that all justified
perceptual beliefs be based on some experience.) He offers a
two-factor reliabilist proposal for understanding evidence, which
combines process and indicator reliabilism (see entry on
 reliabilist epistemology);
 for *e* to be evidence for *h* (i) *e* must be
among the inputs to a reliable process that outputs *h*, and
(ii) there must be an objective fittingness relation between
*e* and *h*, that is, *e* must reliably indicate
the truth of *h*, in the sense of making *h* objectively
likely to be true. Both components, (i) and (ii), are externalist in
both the mentalist and accessibilist senses.



The second approach says that an experience fits the belief that
*p* if it's the function--in a biological or
teleological sense--of the state to indicate *p*
(Plantinga 1993, Bergmann 2006, 2013). On this view, there need not be
any necessary or intrinsic connection between a certain kind of
experience and the belief it justifies, and the belief need not even
tend to be true whenever the experience is undergone; all that's
required is that this belief be the *proper* response to the
experience, in the sense that a properly functioning agent (or an
agent whose perceptual/doxastic system is functioning properly) will
form that belief in response to that experience.



Objections to these views are typically just specific applications of
objections to the relevant externalism: reliabilist and teleological
theories more generally. For instance, clairvoyance objections
(BonJour 1980) aim to show that reliability is not sufficient for
*prima facie* justification, and new evil demon arguments
(Lehrer & Cohen 1983, Cohen 1984) insist that reliability is not
necessary (see the entry on
 reliabilist epistemology).
 One way to run the new evil demon argument is to image an
experiential state that seamlessly transitions from reliably
indicating p to not reliably indicating p; intuitively the agent
remains justified throughout and should not change their mind or
suspend belief halfway through (Smithies 2019, Pautz 2020).
Functionalists might have resources here that reliabilists do not,
unless these arguments are sufficient to establish a general
internalism. However, they face the additional problem of the Swampman
(Davidson 1987, Sosa 1993), who is a randomly occurring (therefore,
lacking in any biological functions) molecular duplicate of a normal
person; intuitively he seems to have justified perceptual beliefs,
although this cannot be accounted for in terms of function, at least
on some views about functions. Perhaps, however, Swampman can fairly
quickly acquire some functions as the result of interactions with his
environment (Graham 2019) and thereby have justification fairly soon
after his appearance, even if not immediately.


### 3.2 Etiological Approaches



If experiences have justificatory power only when reliability or
proper function are added into the mix, one might wonder if it's
better to just omit any reference to experience and instead simply
analyze perceptual justification directly in terms of reliability or
proper function. Indeed, these make up two prominent etiological
approaches to perceptual justification and knowledge. A third
etiological approach is an inferentialist one. All three reject the
Metaevidential Principle and access internalism.



Goldman (1979, 1986) argues that justification results from the
operation or exercise of a cognitive process whose operation is
objectively likely to yield true beliefs; the process must really be
reliable in this sense, but the agent need not be aware of that
fact.[5]
 (To be ultima facie justified the agent must not have reasons to
think the process unreliable.)



A reliabilist theory of perceptual justification falls out from a
reliabilist theory of justification in general, the simplest version
of which is one that holds



(SR): a belief is *prima facie* justified iff it is the result
of a reliable cognitive process.



By claiming that reliability is sufficient for perceptual
justification, the theory allows for justification in the absence of
experiences or anything else that the agent might use as evidence for
the belief. It allows that blindsighters and zombies could have
perceptual justification. (Blindsight is a real phenomenon where
patients with damage to early visual cortex are capable of forming
reliable perceptual judgments in the absence of perceptual
experiences; philosophical depictions of blindsight tend to be
somewhat fictionalized. Zombies in philosophical parlance are
creatures otherwise just like us but lacking conscious experiences
altogether.) It is nonevidentialist in the further sense that even
where some link in the causal chain happens to count as an evidential
state for the cognizer (i.e., one on which they might base a belief),
that state's status as evidence is irrelevant to its epistemic
role, so long as it still makes the same contribution to the
reliability of the overall process.



A different kind of broadly reliabilist theory emphasizes skills or
competences, rather than cognitive processes (Sosa 1991, 2007, 2021).
Skills will likely be individuated in different ways than cognitive
processes, and reliability might be assessed differently for different
skills (as one does with performances more generally: a skillful
driver must almost never wreck the car, while a skillful batter might
strike out more than half the time). Nevertheless, the view is still
reliabilist in that skill is a matter of having a high enough
propensity to believe truly. Ernest Sosa's influential
development of this view distinguishes "animal
knowledge"--a belief is true because competently
formed--from "reflective knowledge"--where the
subject has true-because-competently-formed belief that a lower order
belief is true because competently formed. Concepts of animal and
reflective justification are easily derived from these. Although Sosa
denies the Metaevidential Principle for animal
knowledge/justification, he embraces it for reflective
knowledge/justification.



One reliabilist theory that aims at perceptual justification in
particular holds that it is not merely reliability that gives
perception its epistemic force but also the fact that perceptual
beliefs have a distinctive psychological provenance. In particular,
they are the outputs of (weakly) "modular" perceptual
processes (where what counts as a perceptual module is spelled out in
architectural terms, rather than in terms of phenomenology or the
agent's background beliefs; Lyons 2009). This
"inferentialist reliabilist" theory (so-called not because
of its treatment of perception but because of its treatment of some
nonperceptual belief) claims that reliability is only sufficient for
the (*prima facie*) justification of the outputs of modular
processes, but that the reliabilist can and should impose inferential
requirements (understood in reliabilist ways) on other beliefs. Though
the view is designed as a version of reliabilism, a mentalist
internalist could accept the modularity part and drop the reliability
part, claiming that the outputs of perceptual modules are thereby
*prima facie* justified whenever held, irrespective of either
experience or reliability.



In addition to or instead of reliability, one could endorse a
functionalist view about the justification of perceptual beliefs.
Tyler Burge (2003, 2020) and Peter Graham (2012, 2019) are the most
prominent proponents of this sort of view in its non-evidentialist
mode. Both hold that the belief-forming process need not be reliable,
but it must have the (teleological) *function* of producing
reliably true beliefs. This requires that the process be (/have been)
reliable in normal conditions--i.e., the conditions where
producing a particular result led to the establishment of that result
as the function. For Burge, however, the functions derive from the
fact that percepts and beliefs are representational states, and
it's an a priori condition on any representational state that it
has the function of representing correctly; thus the view is that
perceptual justification (he calls it "entitlement")
requires that the perceptual process and its elements be reliable in
those conditions in which the contents of those elements was fixed.
For Graham, the functions result from the empirical fact that the
processes have done the organism (or its ancestors) some practical,
biological good.



These views are fully externalist, but there is a kind of etiological
view that is compatible with mentalism. An
"inferentialist" theory holds that perception involves an
inferential or quasi-inferential process and that perceptual beliefs
are justified or not, according as the inferential moves pass muster
vis-a-vis whatever the ordinary standards are for inference more
generally. The inference to be evaluated can be unconscious and of the
Helmholtzian sort that perceptual psychologists talk about (Siegel
2013, 2017), or it can be a move from conscious, person-level
contents, like low-level sensory contents, to high level perceptual
categorization beliefs (e.g., 'there's a cat')
(Markie 2006, 2013; McGrath 2013, 2018). The latter option ends up
being a version of the evidentialist theories discussed above (usually
a conservative kind of modest foundationalism) and won't get
repeated treatment here; but the former is a distinctive theory of
perceptual justification. Susanna Siegel takes her inferentialism so
far as to claim that nondoxastic perceptual experiences are themselves
epistemically evaluable and can be effectively unjustified, if their
etiology is an inferentially bad one. Although the inferentialist can
make explicit appeal to experiences, one can also develop an
inferentialism that assigns no significant role to experience as such
(Ghijsen 2021), and in any case, the experience is merely one link in
the inferential chain on the basis of which the perceptual belief is
evaluated. (As stated above, the evidential, etiological, and
world-involving approaches were not held to be mutually exclusive.)
One putative counterexample to Siegel's inferentialism involves
an agent who believes for no good reason that the woods around them
are full of snakes, and this irrational belief affects their
perceptual experiences in such a way that they are now better at
spotting snakes that are actually there (Lyons 2011). Intuitively, the
agent is justified in their perceptual beliefs, despite an irrational
inferential etiology.



As with the seeming externalist views, the standard clairvoyance, new
evil demon, and Swampman objections to reliabilist and functionalist
theories are leveled against these theories of perceptual
justification. Proponents of the phenomenal determination principle
(section
 3.1.5
 above) will reject all of these views as incompatible with that
principle (Smithies 2019, Pautz 2020). A closely related issue
concerns agents who don't have any experiences. Because these
theories allow perceptual justification in the absence of any
experience, they will allow zombies and blindsighters to have
perceptual justification, so long as their perceptual processes are
reliable, or functioning normally, or drawing rational unconscious
inferences, and so on. Intuitions on this matter seem to be divided;
some authors think this consequence is a virtue of such views
(Plantinga 1993, Lyons 2009, Tucker 2010), though others think it is
clearly a vice (e.g., Smithies 2019, Johnston 2011).


### 3.3 World-involving Approaches



The theories considered so far all consider the justification of a
particular belief to be independent of whether the agent is
veridically perceiving on that occasion, or is hallucinating or being
deceived by a Cartesian demon, etc. (although some of these views
would allow that widespread and persistent deception reduces
reliability, and certain *kinds* of hallucination might involve
a different relevant etiology from normal veridical perception). On a
world-involving view, the mere fact that the agent is veridically
perceiving means that the agent has a kind of justification that no
hallucinating subject could have. Such a view is sometimes also
referred to as "epistemological disjunctivism" (Pritchard
2012), though some proponents reject this label (Schellenberg 2018).
On this sort of view, the agent in the "good" case
(veridical perception) has the best sort of empirical evidence one
could hope for: the world itself is made manifest through perception;
the agent in the "bad" case (hallucination) has either no
justification at all (Byrne 2014, 2016) or a different and presumably
inferior kind of justification (Williamson 2000, Millar 2011, 2019,
Schellenberg 2013, 2018).



Common to the various forms of epistemological disjunctivism is the
idea that, normally, when you see a barn, you thereby know that
there's a barn in front of you. This can be understood in two
very different ways. On the "evidential" construal, the
relevant seeing is a non-doxastic, non-epistemic factive experiential
state, on which your belief that there's a barn is based. This
state can be understood along the lines of metaphysical disjunctivism
 (section 2.1.4,
 2.3.3 above), as a world-involving relation of a subject to a
perceptual object; or it can be understood as an internal (e.g.,
representational) state that has a different epistemic potency when
it's veridical. On the "constitutive" construal,
your seeing that there's a barn just is your knowing that
there's a barn, since seeing that p is a determinate of the
determinable, knowing that p. The first kind of seeing is consistent
with the agent being in fake barn country (see entry on
 epistemology),
 or having good reasons to believe they're being deceived, or
suspending belief about whether there's a barn; the second kind
of seeing--assuming that defeaters and environmental luck block
knowledge, and that knowledge requires belief--is not.



The pioneer of this general approach is John McDowell (1982), although
it is difficult to know just what view he endorses. There are hints of
metaphysical disjunctivism and an evidential construal of seeing,
especially in earlier writings, although he has long insisted that one
does not see that there's a barn in fake barn country. One
possibility is that McDowell's talk about seeing is simply a
particular kind of "conclusive reason" (in the sense of
Dretske 1971) (Graham and Pederson 2020).



One key motivation for a world-involving approach is the idea that if
the warrant (/evidence/justification) that we have in the good case is
no different from the warrant we have in the bad case, then it must be
in itself neutral between these possibilities and thus can't
justify, say, the belief that there's a real table there, rather
than a hallucinated table--at least, not without a hefty
contribution from background knowledge (McDowell 1982, 2011, 2018). A
second motivation is the claim that some or all evidence is factive.
Some epistemologists hold that all evidence is factive, in the sense
that only true things can serve as evidence (Williamson 2000,
Littlejohn 2012, Byrne 2014); this would preclude hallucinations from
conferring evidence on perceptual beliefs. Schellenberg (2013, 2018)
argues that successful exercises of perceptual capacities yield a
special, superior, kind of evidence--"factive
evidence"--which is absent in cases of hallucination,
though she thinks hallucinations do provide another kind of evidence
 (section 3.1.4
 above).



Direct world-involvement theories tend to be instances of modest
foundationalism
 (section 3.1.4
 above), holding that perceptual knowledge and justification are
direct, and therefore denying the Metaevidential Principle, at least
in a form that holds that the metaevidential knowledge/justification
is *prior* to the perceptual knowledge/justification. Some
proponents also reject the No-Good-Reason Claim, holding that in
veridical perception, not only is the world manifest to us, but so is
that fact (Pritchard 2012, McDowell 2011), even though the good case
and the bad case are in some sense indistinguishable. This would
support a form of access internalism, though an unusual one and one
that some other internalists will find unsatisfactory (Smithies 2013).
Although mentalist internalism is defined in terms of nonfactive
mental states, McDowell's defense of epistemological
disjunctivism has always been motivated by a kind of internalism, and
he thinks that states of seeing, though factive, satisfy whatever
needs our internalist intuitions demand. Other versions of the view
are staunchly externalist (Williamson 2000, Schellenberg 2013).



The biggest objection to this general approach is that it
doesn't allow or doesn't illuminate perceptual
justification in cases of error, at least not in cases of
hallucination. Those with more conventional internalist intuitions
will think that some or all hallucination victims will be just as
justified as veridical perceivers (even though the former won't
be in a position thereby to know). In fact, the New Evil Demon
objection to reliabilism
 (section 3.1.6
 above, entry on
 reliabilist epistemology)
 takes this as an obvious starting point, and many externalists have
crafted or modified their theories to accommodate this intuition
(Goldman 1986, 1988, Graham 2012). Some disjunctivists have tried to
blunt the impact of this objection by suggesting that there's
another kind of justification or another route to justification
available in the bad case. Schellenberg (2013, 2018) allows that
there's a degree or dimension of justification available even in
the bad case; and Williamson (2000) suggests that sufficiently
sophisticated hallucinators have introspective knowledge that things
look F, and this affords them inferential justification for thinking
that something is F.


## 4. Conclusion



The epistemological problems of perception have traditionally centered
on the threat of skepticism, in particular, on the "veil of
perception" implicated by a well-known metaphysics of
perception, which threatens to lead to skepticism. Although much of
the history of philosophy has involved attempts to find metaphysical
solutions to this problem, recent decades have seen a proliferation of
dedicatedly epistemological theories, offering more direct responses
to these concerns. Even if we have a metaphysics in place, we will
still need to make difficult decisions about the epistemology. Various
evidential, etiological, and direct world-involvement theories have
been proposed, including combinations of these. Each of these three
admits of internalist as well as externalist variants. The result is
an active and ongoing area of research in epistemology.