Can one sense one’s own mind, as one senses nonmental entities in one’s environment and body? According to many contemporary philosophers of mind, the fraudulent commonsense idea of a "mind’s eye" obstructs clearheaded attempts to explain introspection and consciousness. I concede that inner sense cannot directly explain consciousness and introspection in all their forms, but I do think a carefully specified kind of inner sense can account for one very special kind of introspective consciousness. It is special because it is the key to explaining the most puzzling kind of consciousness, phenomenal consciousness—there being "something it is like" to have certain mental states. My aim in this paper is to defend this view against accusations—twenty-two in all!—rather than to argue positively for the view. However, I begin by indicating some of the motivation for the account I defend.

Postcartesian philosophers in almost every major tradition have turned to inner sense for a description or explanation of consciousness. The interesting regularity, historically speaking, is that key progenitors of these traditions appeal to inner sense. It is as if inner sense is the persistent, instinctual, null hypothesis about consciousness. At the dawn of British empiricism, Locke writes that "[c]onsciousness is the perception of what passes in a Man’s own mind" (1689, 115; II, I, 19); he holds that this faculty of reflection, "though it be not Sense, as having nothing to do with external Objects; yet it is very like it, and might properly enough be call’d internal Sense" (1689, 105; II, I, 4). The rationalist who is in many ways Locke’s counterpart, Leibniz, recommends that "it is well to make a distinction between perception, which is the inner state of the monad representing external things, and apperception, which is consciousness or the reflective knowledge of this inner state itself" (1714, 637). German idealism arrives with Kant, who refers to "empirical apperception" of a "flux of inner appearances"—mentioning that "[s]uch consciousness is usually named inner sense" (1787, 136; A 107). Phenomenology and experimental psychology find common ancestry in Brentano, who maintains that mental states are known most fundamentally through "inner perception" (1874). Likewise David Armstrong—perhaps the first analytic philosopher to attempt a systematic theory of mind in the contemporary aftermath of behaviorism—identifies introspective consciousness with "inner sense" (1968).

How is inner sense supposed to be distinctively analogous to outer sense? Is there an illuminating analogy? Armstrong explains inner sense as being, like outer sense, "selective" (incomplete, about the mind or environment), "fallible," and "causal" (1980). This is not much of an analogy, since probably all cognitive processes display these features. Even one’s most theoretical scientific beliefs, for example those about quantum-mechanics or cosmology, are selective, fallible and causal, without being sensory in any interesting sense. Another initially tempting idea is that inner sense is a causal but noninferential source of evidence about mental states (or, more cautiously, that it is as low as outer sense on flexible, all-things-considered inference). But this wouldn’t distinguish inner "sense" from inner "reactions" of other sorts. Also, many sworn enemies of inner sense favor views according to which introspection produces beliefs noninferentially, and without the involvement of any sensory states. Lack of inference is insufficient to qualify a process as "sensory." In my view, the products of inner sense are sensory due to their use, even if not due to their origin. They are literally states of the various outer-sensory systems themselves, rather than being states of a distinctive inner faculty. This makes available a strong sense in which the products of inner sense count as visual, auditory or other sensory states, with minimal violence to the ordinary use of these terms. I will describe some consequences of this view at the end of this section, after detailing the inner-sense theory of phenomenal consciousness.

An inner-sense theory of phenomenality would be flatly circular if sensing, itself, presupposed phenomenality. This point is so important to the view and to criticisms of it that it deserves a name. With apologies to Merleau-Ponty:

The Nonphenomenology of Perception—One can have states that are sensory even though there is nothing it is like for one to have them.

"Perception" is nonphenomenal in the sense that neither the concept of a perceptual state nor the property of being a perceptual state presupposes that the state is phenomenal. Of course, the concept and property do not preclude phenomenality—individual states can be both perceptual and phenomenal. I reserve the word "experience" for phenomenal states, whether perceptual or otherwise. (I also use "sense" and "perception" synonymously—likewise for their respective cognates. And "having a mental state" broadly covers having or being in or undergoing mental states, events, processes, structures, objects, acts, etc.) Since I think the Nonphenomenology of Perception is best supported by actual cases, I will not delay over what senses of "can" should be involved in the principle—conceptual possibility, logical possibility, biological possibility, etc. In cases of subliminal visual perception (Dixon, 1987) and "blindsight" (Weiskrantz, 1988), subjects act on the basis of information about the visual features of objects, despite denying—sincerely and without hypochondria—that they have relevant visual experiences. It is plausible, though somewhat controversial, that in at least some cases there is nothing it is like to have subliminal and blindsight states. Also, the early layers of processing in vision and other sensory modalities seem not to constitute experience; further processing is necessary. Otherwise, it would be difficult to explain why phenomenal visual experiences are not continually like double images—since one has separate left-eye-caused and right-eye-caused early visual states. It would also be difficult to explain why one seems not to see arrays of incoming brightnesses, i.e., why phenomenal experiences do not represent distant objects as being "behind" two splotches of light near one’s eyes.

Many rival theories of phenomenal consciousness can accept the Nonphenomenology of Perception. Theories diverge over what needs to be added to nonphenomenal sensing to reach phenomenal experience. Inner-sense theories hold that experience arises only when states are innerly sensed, states that otherwise ("on their own") would be nonphenomenal. Call the states directly produced by inner sense "I-states," since they are typically inner-directed (or about one’s own mental states). Similarly, call the states directly produced by outer sense "O-states," since they are typically outer-directed (or about things other than one’s own mental states, such as environmental or bodily entities). Typically, I-states are sensitive to neural or functional features of O-states, while O-states are sensitive to environmental features of environmental entities (I illustrate some such features under Accusation 14, below). On an inner-sense view a perceptual or imaginative experience as of some entity E (an object, event, etc.) essentially involves both O-states and I-states of O-states, as illustrated here (where the dashed arrows signify causation that is typically present but not strictly required):

The important point is that on a properly formulated inner-sense theory experience is compositional. An experience as a whole need not be innerly sensed. Rather, a component of an experience (an I-state) represents another component of the experience (an O-state). In a derivative way, the experience itself may be said to be innerly sensed in virtue of having a part that is innerly sensed, just as a house may be sensed in virtue of having a part that is sensed. And since the inner sensing is itself part of the experience, the experience may be said to represent itself, "reflexively," in addition to representing features of E.

I will now sketch four styles of argument I use elsewhere for this overall view. The first is analysis of the concept of phenomenal consciousness (under review-a—hereafter, "Stopgap"). From wholly nonphenomenal premises about inner sense we can deduce, as a matter of conceptual necessity, that there is something it is like to have mental states. Roughly, if a mental state essentially appears to its bearer to have some feature F, then it is "F-like" for its bearer, so it is "like something" for its bearer. Strictly speaking, for a state innerly to appear to its bearer as a whole, rather than to some small part of its bearer’s brain, the I-state must be poised for wide and systematic influence on cognition and conation—it must be available to "central" systems of belief and desire (see Fodor, 1983). So the diagram of experience must be complicated as follows (where the solid arrow signifies causation that is required for full-blown experience):

In addition, O-states may (and normally, do) have their own outputs to central systems. Neither inner sensing of a state without central availability, nor central availability of the state without inner sensing, suffices clearly for phenomenality of the state. A state that is innerly sensed, but not in a centrally available way, is perhaps like something but not like something for its bearer. A state that has impact on central systems, but that is not innerly sensed, is perhaps for its bearer but not like something for its bearer. Only as a unit does centrally available inner sense insure that the state is like something for its bearer.

The second style of argument is inference to the best explanation of allegedly troublesome features of qualia (1994—hereafter, "Qualia!"; see also section 7 of "Stopgap"). If the presence of (centrally available) inner sensing explains there being something a state is like, the specific content of the inner sensing should explain what the state is like, its "phenomenal properties" (or "qualia"). Roughly, if a mental state essentially innerly appears to be Q, then the state has phenomenal property (or quale) Q. The adjective "phenomenal" in "phenomenal property" functions similarly to the adjective "apparent." This means that an experience can have a phenomenal property (or quale) Q without having (property) Q. The appearance of Q may be false; an I-state may misrepresent an O-state as having Q, just as an O-state may misrepresent the features of environmental objects. But even if the appearance is false, the experience has quale Q. The property of having quale Q is literally a property of experiences, namely, an experience’s property of representing itself in certain (e.g., inner-sensory) ways as Q. To be sure, a quale (e.g., Q) of an experience is itself a real property, with real (intentional) relations to the experience, even if it happens not to be a property of the experience. This captures what is true in qualia "realism"—the property Q can exist and bear the "is a quale of" relation to an experience, and can even be had by the experience. It is also the key to explaining features of qualia such as:

Subjectivity—For an experience to be is (at a minimum) for it to be sensed.

Infallible introspectibility—If an experience is represented as Q—in inner sense, if not in judgment—then it has quale (phenomenal property) Q.

Complete introspectibility—If an experience has quale (phenomenal property) Q, then it is innerly sensed as Q.

Intrinsicality—An experience represents itself as Q.

Invertibility—Two experiences can have the same extrinsic causes and effects, but represent themselves differently.

The theory explains all of this while preserving insights from philosophical frameworks that have often been thought incompatible with these claims, such as:

Eliminativism—An experience need not have Q.

Representationalism—An experience’s having quale Q is entirely a matter of what the experience represents (via its component I-states).

Functionalism—An experience’s particular qualia are matters of what parts of it (O-states) "do" to other parts (I-states).

One advantage of the inner-sense theory is that it makes sense of so many apparently plausible though apparently conflicting views of qualia.

Third, there is inference to the best explanation of phenomenal illusions (under review-b—hereafter, "Illusions"; see also 1996b—hereafter, "Nonphenomenal"). Inner sense provides an independently plausible unified explanation of two widespread illusions built into phenomenal experience. The "image illusion" is an appearance of phenomenal objects subjectively having normal environmental properties: one "sees mental images" as having shape, "feels pains" as throbbing, "hears inner speech" as having variable pitch, etc. The "transparency illusion" is an appearance of normal environmental objects objectively having phenomenal properties: from various perspectives one perceives constant-shaped objects as having varying modality-specific shape-looks and shape-feels, etc. The key to explaining the illusions is that there are "binding confusions" between O-states and I-states. O-states and I-states represent features that are not in fact had by the same things (at best, O-states represent features of environmental entities and I-states represent features of O-states). The confusion is that these states mistakenly attribute these features to the same objects, or, in other words, that the states operate as if they are about the same objects. O-states and corresponding I-states represent the bearer of these features in a unified way, as if by using the same variable, name, or dummy constant (say, ‘x’):

The transparency illusion results when the inner (neural or functional) features Q represented by I-states are "projected" onto the environmental or bodily objects represented by O-states. (This does not mean that perceptual experience is wholly illusory—the O-states may be perfectly accurate about the features of the objects.) Conversely, the image illusion results when the outer (environmental or bodily) features P represented by O-states are misattributed to the inner objects represented by I-states (namely, O-states). (Attention determines which illusion is present—when attention is directed outwardly, O-states have priority over I-states and x is identified as an outer object, but when attention is directed inwardly, I-states have priority over O-states and x is identified as an inner object.)

The final style of argument is inference to the best explanation of correlations. The illusions are present in all clear cases of phenomenal consciousness, despite the otherwise wild heterogeneity of these cases (see sections 1 and 3 of "Illusions"):

(i) clearly conscious perceptual experiences, such as tastings and visual experiences;

(ii) clearly conscious bodily-sensational experiences, such as pain, tickle, and itch experiences;

(iii) clearly conscious imaginative experiences, such as those of one’s own actions or perceptions; and

(iv) clearly conscious experiences in thinking, as in streams (or trains) of thought in words or in images.

Call these the "Qualitative Quartet." The transparency illusion—the appearance as of objective looks and feels—is rife in normal perception, misperception, dreams, and diffuse bodily sensation. The image illusion—the appearance as of subjective likenesses—is most at home in normal imagination, degraded perception, thought, and nondiffuse bodily sensation. By contrast, inner sense and the illusions are absent for attitudes and moods (see "Illusions"). On the inner-sense theory this explains why phenomenality is absent for attitudes and moods—even when they are conscious in some sense (I argue for this absence on independent grounds in "Nonphenomenal"). While there is often something it is like when we have a conscious mood or attitude, this is not due to the mood or attitude itself but due to coexisting Quartet experiences. Conscious moods and attitudes are not themselves phenomenal—they may be for a creature but they are not like something for the creature.

I have said that I-states count as sensory due to their use, i.e., due to their functioning as outer-sensory states, as O-states. The binding confusions between O-states and I-states are one illustration of this. The unification of O-states and I-states into phenomenal experience is another. Once I-states are produced, in whatever way, they are processed like O-states, as further states in particular sense modalities. For example, I-states in vision help to produce visual beliefs, help to control visuomotor skills, and are not introspectively distinguished in kind from visual O-states. I-states should differ from inner judgments (or beliefs) in several ways that O-states differ from judgments, on plausible psychological assumptions (cf. Fodor, 1983). Compared with judgments, O-states (i) are largely under stimulus control, (ii) are in control of reflexes and motor skills, independently of countervailing desires, (iii) are resistant to rational inference and will, (iv) are restricted in content, and (v) are not easily matched in content by desires, memories, communication-intentions, etc. Similarly, we should expect I-states (i) to be largely under control of O-states, (ii) to guide reflexes and skills, (iii) to be difficult to form by will or reason, (iv) to involve a limited range of contents, and (v) to be difficult to remember and express in public language. The account I offer makes many commitments about the function of inner-sensory states, but makes no commitments about the internal structure of the process of inner sense.

It would be difficult to complete a list of the prominent philosophers who have brought charges against inner sense. Plaintiffs range from staunch eliminativists about qualia (Gilbert Harman, Daniel Dennett) to staunch realist/antireductionists about qualia (Colin McGinn, John Searle, David Chalmers). They are aided by defenders of rival reductionist theories of phenomenality (Robert Kirk, Michael Tye) and of introspection (Gilbert Ryle, Sydney Shoemaker, William Lyons), and also by some doing pro bono work, not obviously in the service of their own positive views (Dan Lloyd, Christopher Hill). The higher-order-thought theory of consciousness is perhaps the closest kin to inner-sense theories, but its staunchest proponent (David Rosenthal) and staunchest opponents (Fred Dretske, Güven Güzeldere) harmonize that inner sense is a nonstarter. Some complaints are even due to erstwhile defenders of inner sense (Brentano, Armstrong)! In addition, although I do not discuss them, there are accusations due to a long line of phenomenologists (including Edmund Husserl and Jean-Paul Sartre) and, at the other extreme, accusations due to a long line of opponents of the myth of the given (including Ludwig Wittgenstein and Wilfrid Sellars).

First, I discuss arguments against the very existence of inner sense, arguments based largely on introspection and phenomenology. Scientifically-based arguments against the existence of inner sense follow. Then I turn to an assortment of arguments to the effect that, even if inner sense does exist, it is unnecessary for phenomenal consciousness or insufficient for phenomenal consciousness. In a few cases I violate this classification in order to juxtapose accusations that may be answered similarly. Nevertheless, the discussions are for the most part independent, with some explicit cross-references, so readers are encouraged to follow their own priorities. For convenience, in the following table I list the accusations I address.

Shoemaker presses the accusation as follows:

[P]erceiving something involves there being a sense-experience, an appearance, of it. It seems widely agreed that introspection does not have this feature, and this is perhaps the most commonly given reason for denying that it should count as perception. No one thinks that in being aware of a sensation or sensory experience one has yet another sensation or experience that is "of" the first one, and constitutes its appearing to one in a particular way. (1994, 255)<1>

I agree that when we introspect experiences, we don't get new experiences of the experiences. On my inner-sense account an experience represents itself, in virtue of having component I-states that represent component O-states. The two states (O- and I-) combine to form a single experience.

The accusation would be correct if every sensing did "involve" a sense-experience, as Shoemaker alleges. Then each distinct sensing—the O-state and the I-state—would involve a distinct experience. But this cannot be assumed in objecting to inner-sense theories; it violates the Nonphenomenology of Perception. Without the I-state, the O-state yields no experience as of an object. Without the O-state, the I-state yields no experience as of an object (see Accusation 8). The position is that outer sense and inner sense together generate experience in the first place.

This accusation is similar to the preceding one except that it concerns duplicate qualities rather than duplicate states. Even if it is granted that inner sense involves only a single experience, a plaintiff might expect that this single experience would involve distinctive outer-sensory and inner-sensory qualities. As Lyons argues:

If to introspect were in any literal sense to employ an inner sense, then it would have its own phenomenology. Just as the phenomenal experience of tasting is different from the phenomenal experience of touching … so we should expect that if to introspect were to employ an inner sense, then introspecting would involve a sui generis experience with its own phenomenological qualities …. [But] [a]ny experiential qualities in introspecting a patch of blue seem to be borrowed from the first-level experience, which is perceiving a patch of blue. (1986, 96)<2>

According to this accusation there is a fundamental disanalogy between inner and outer sense: inner sense doesn’t have "its own" phenomenal properties. I accept the point that inner sense does not have its own phenomenology. However, I wish to deny the premise that it should, if it is to be fully analogous to outer sense. The premise is based on the view that outer perception has its own phenomenology. This is plausible so long as we focus only on full-blown conscious outer-sensory experience. But many outer-sensory states are much humbler, given the Nonphenomenology of Perception. According to a properly formulated inner-sense theory there is nothing it is like simply to have an O-state, nothing it is like simply to sense outerly. Ordinary outer sense is not sufficient for phenomenology; unadorned O-states are not phenomenally conscious and involve no phenomenal qualities. So it is not a disanalogy that I-states don’t have their own phenomenology, distinct from that of ordinary O-states.

The accusation alleges that "introspecting a patch of blue" borrows its phenomenal qualities from "perceiving a patch of blue." But the qualities of "introspecting a patch of blue"—at least for inner-sensory introspection, i.e., innerly sensing an O-state as of a patch of blue—aren’t "borrowed from" but bestowed upon "perceiving the patch of blue," a state that would otherwise be nonphenomenal. My position is that outer sense and inner sense together generate phenomenal properties (qualia) in the first place. A quale belongs to them jointly, i.e., to the experience they jointly compose. Güzeldere considers a response that is similar in effect:

One possible move for the [inner sense] theorist could be to claim that the sensory quality involved in second order perception is the same as the one involved in the first order state being introspected. But this is entirely ad hoc as an answer to the objection. (1995, 343)

But the response is not ad hoc. It is the essence of any inner-sense theory of phenomenality. It appeals to a principle that is fundamental to inner-sense theories from the outset, and plausible on independent grounds of subliminal perception, blindsight, early-visual states, etc.—the Nonphenomenology of Perception.

Several authors have remarked on what G. E. Moore (1905, 450) calls the "diaphanous" nature of visual experience, the apparent difficulty or impossibility of noticing qualitative features of experience rather than features of the external world. When one tries to attend to features of normal experiences, one normally "sees through" the experiences to nonmental—environmental or bodily—objects. Given diaphanousness, there seems to be no role in normal visual experience for inner sensing of mental phenomena, distinct from outer sensing. Gilbert Harman presses this accusation as follows:

When [someone] sees a tree before her, the colors she experiences are all experienced as features of the tree and its surroundings. … Nor does she experience any features of anything as intrinsic features of her experience. … Look at a tree and try to turn your attention to intrinsic features of your visual experience. I predict you will find that the only features there to turn your attention to will be features of the presented tree, including relational features of the tree "from here." (1990, 39; cf. 41)<3>

Defenders of introspectible intrinsic qualia may claim not to satisfy Harman’s prediction (see Block, 1990, 72-74); this response gains some plausibility in cases of degraded vision (e.g., blurred or doubled vision), discussed in Accusation 18 below. It is also not clear how, if at all, Harman’s claims are supposed to generalize from visual perception to visual imagination, where features are often introspected as if they belong to alleged mental objects within experience. Also, Harman runs together "attending" to something and "experiencing" it, thereby forgetting about inattentive experience—a common mistake I highlight in Accusations 15-18, below. Nevertheless, Harman’s prediction is plausible in the main.

In whatever cases Harman’s prediction stands, it shows that seeings do not seem introspectively to have intrinsic properties. Harman moves directly to the "eliminativist" conclusion that seeings have no introspectible intrinsic properties. This is a leap. For all Harman has shown, it may be that one (innerly) senses an O-state’s having some intrinsic property Q, but senses it as an environmental object’s having Q. Just as one can perceive an object as a different object, so one can perceive an object’s having a property as a different object’s having the property. I hear the ventriloquist’s speaking, but I hear it as the dummy’s speaking. Likewise, in watching a big-screen, fast-paced, high-visual-fidelity film consisting of life-size images, it is surprisingly hard to see colors and shapes as being on the screen rather than in the scene. If one blocks out the surrounding room (perhaps by looking through a tube), it does not seem that one is looking at a screen at all. Nevertheless, what one is seeing is a screen, and the colors and shapes one sees are on it. By contrast, when the film becomes degraded or blurred, it is easy to see the colors and shapes as being on the screen. One does not see subtitles or credits as being in the scene rather than on the screen; perhaps these are similar to apparent afterimages that can seem "superimposed" over normal perceptual experience.

In a slightly different context, Harman himself concedes the basic point: "one might be aware of intrinsic features of experience without being aware of them as intrinsic features of experience" (1990, 42). He argues that such a mistakenly-perceived property would not be "psychologically significant" in any sense that would amount to an "objection to functionalism" (1990, 42-43). I am not concerned to dispute this; the primary aim of Harman’s discussion is defending functionalism, and in that I wish him well. But his concession undermines his secondary aim, of attacking inner sense. The latter aim is unnecessary to the former, since a properly-formulated inner-sense theory need not be in any way hostile to functionalism.

In order to resist Harman’s eliminativism about introspectible intrinsic properties of experience, one does incur a serious burden of explaining what these properties are, and why they seem to belong objectively to trees and other environmental objects rather than to experiences. The inner-sense theory delivers, in its explanation of the transparency illusion: as I argue in section 2 of "Illusions," I-states and O-states use the same "terms," and so when attention is directed outwardly and objects are identified as outer, the properties represented in inner sense are mistakenly attributed to the outer objects. Harman might object that we should only as a last resort suppose that normal perceptual experience is subject to an illusion. However, he has no leverage to make such an objection. In "Illusions" (section 1) I argue that we would be subject to a widespread illusion even on Harman’s own view, according to which we see "relational features of the tree ‘from here.’"

[A] visual experience does not just present a tree. It presents a tree as viewed from a certain place. Various features that the tree is presented as having are presented as relations between the viewer and the tree, for example, features the tree has from here. The tree is presented as "in front of" and "hiding" certain other trees. It is presented as fuller on "the right." It is presented as the same size "from here" as a closer smaller tree, which is not to say that it really looks the same size, only that it is presented as subtending roughly the same angle from here as the smaller tree. To be presented as the same in size from here is not to be presented as the same in size, period. (1990, 38)

The illusion here consists in the fact that we experience many of these allegedly "relational" features of trees as being stuck on the trees, without relation to us. As we move around a tree, we in fact bring about and participate in varying spatial relations to the tree—and thereby bring about and participate in what Harman wishes to call the tree’s "size-from-here" and "shape-from-here." But we do not seem to create or participate in any size-ish or shape-ish properties of the tree—all such features seem intrinsic to the tree. It does not seem to one as if by moving one brings about new shape-ish features in the way one brings about new spatial relations to the object. Rather, it seems that, from here, one can discover that the tree has this objective look—stuck on one side of it, say—while from there, one can discover that the tree has that objective look—stuck on another side of it. Harman is incorrect in suggesting that shape-looks and size-looks are "presented as relations between the viewer and the tree." So if Harman’s faith in diaphanousness were apt—if appearances of diaphanousness were not deceiving—this would license the elimination not only of introspectible intrinsic properties of experience, but also of introspectible nonintrinsic relations, including relations that are suited to explaining the difference in sensitivities to the varying looks of objects—looks of their shape, location, reflectance, etc. The argument would prove too much.

Lyons considers a view very much like my position on inner sense, namely, the view that we introspect "the products of an act of perception" (1986, 105). He presents the following argument against this position:

The theoretical source of this conviction is the view that there are phenomenal sense data that are the immediate products of the exercise of sense perception of any kind. At least from the time of Descartes, some philosophers have suggested that when we employ our senses, the information or data are in the form of an idea, impression, representation, presentation, percept, or sense datum in the mind (or at least our head) to which we have immediate, reportable, privileged access. Indeed we could not know what we are seeing, hearing, or tasting unless we could report on the qualities of these mental artifacts called sense data, for an object thus "interposes its appearance, like a sheet of glass, between itself and the observer." (1986, 105-106; the quote is from Ayer, 1956, ch. 3)<4>

Thus, Lyons suggests that to embrace inner sense of sensory states, one must be a "veil-of-perception" theorist. And since we have reason to reject the latter view (see the next accusation), we have reason to reject the former.

I agree that there are no "phenomenal sense data," "interposed" between environmental objects and one’s sensings of environmental objects. But a properly formulated inner-sense model of experience is not committed to sense data. Inner sense as I have described it requires two things: O-states of environmental objects, and I-states of the O-states. O-states aren’t "interposed" between environmental objects and our perceptions of them—they are our perceptions of environmental objects. And I-states certainly aren’t "interposed" between objects and our perceptions (O-states) of them; they come "after" O-states in the cognitive flowchart. Inner sensings are directed not at entities interposed between objects and one’s perceptions of them, but at one’s perceptions themselves. The causal chain in perceiving an apple needn’t proceed from the apple to an inner sensing and then to a sensing of the apple. Rather, on a more natural view, the causal chain goes directly from the apple to a sensing of the apple (an O-state), and then (in cases in which the apple-sensing forms part of a phenomenal experience) to an inner sensing (an I-state) of the sensing of the apple. Both outer sense and inner sense are "direct" in that neither requires mediation by further sensings. Nor are inner sensings required for outer sensings to be centrally available to beliefs and desires. Each kind of sensing can and does have its own independent impact on central systems.

There are two traditional ways to press this accusation. One arises as an objection to the view that there are sense data interposed between environmental objects and sensings of them. As Ryle argues:

The theory says that when a person has … a glimpse of a horse-race … [this] is explained in terms of his having a glimpse of something else, the patchwork of colours. But … then having a glimpse of colour patches … in its turn must be analysed into the sensing of yet an earlier sensum, and so on for ever. (1949, 213)

Whatever the merits of this as an argument against meddling sense data, it does not affect the present view, which is not committed to sense data (see the previous accusation).

The second traditional argument arises from the claim that all mental states are conscious, in the sense that one must be conscious of all one’s mental states. Brentano considers the following argument:

Hearing as the presentation of a sound is a mental phenomenon and certainly one of the simplest examples of one. Nevertheless, if all mental phenomena are conscious, a simple act of hearing seems not to be possible without an infinite complication of mental states. First of all, … along with the presentation of a sound we have a presentation of the presentation of this sound at the same time. … If every mental phenomenon must be accompanied by consciousness, the presentation of hearing must also be accompanied by consciousness, … [by] a presentation of the presentation of this act [of hearing, i.e., of the presentation of sound]. … It follows that those who deny the existence of unconscious mental phenomena must admit an infinite number of mental activities in the simplest act of hearing. (1874, 121-122)

Again, there is no commitment on the present view to the idea that all mental states are conscious, in any sense or disjunction of senses of "conscious." (For example, the states that provide arguments for the Nonphenomenology of Perception are good candidates for wholly unconscious mental states.) So inner sense cannot be shown to involve a regress in either of these traditional ways.<5>

Brentano defends both inner perception and the claim that all mental states are conscious. He avoids infinite regress by maintaining that inner perception is reflexive, that an inner perceiving represents itself (in addition to other things):

The presentation of the sound and the presentation of the presentation of the sound form a single mental phenomenon; it is only by considering it in its relation to two different objects, one of which is a physical phenomenon [the sound] and the other a mental phenomenon [the hearing], that we divide it conceptually into two presentations. In the same mental phenomenon in which the sound is present to our minds we simultaneously apprehend the mental phenomenon itself. (1874, 127)

This view is partially preserved on the present account, according to which experiences represent themselves. But experiences represent themselves only in a derivative sense, by containing parts (I-states) that represent other parts (O-states). I think nonderivatively reflexive representation would be difficult to explain (see section 6 of "Stopgap"). In any event, it would severely weaken the analogy between inner sense and outer sense—O-states are certainly distinct from their objects, so I-states should be distinct from their objects, O-states. Phenomenologists after Brentano have accordingly tended to see (nonderivative) reflexivity as a rival to inner sense.

Puzzlingly, Lloyd has pressed a distinct regress argument against reflexivity views; if it is successful it would also work against the present view that phenomenally conscious experiences are derivatively reflexive:

[L]et us suppose that every state of consciousness is (somehow) at the same time an introspective awareness of itself, and again, suppose this is a necessary feature of all states of consciousness. On this supposition, every state C = C¢ , where C is the primary state of consciousness (for example, a state of perceptual awareness), and C¢ is the secondary state of awareness of C. This entails an absurdity … according to which every state of consciousness is in fact an infinitude of distinct states, C = C¢ = C¢ ¢ = …. It also seems flatly contradictory. State C might be a perceptual awareness, perhaps of the emptiness of a glass, while C¢ is an awareness of C. Those are two distinct contents and seem to preclude identification as a single state. (1989, 184)

I do not see how to make sense of this accusation. Talk of "distinct states, C = C¢ = C¢ ¢ = …" would be an "absurdity"—how could states be "distinct" yet "="? But this is Lloyd’s talk, not Brentano’s or mine. At most, given Lloyd’s terminological use of primes, double-primes, etc., reflexivity views are committed to the following innocent claim: every state of (phenomenal) consciousness has (not "is") an infinitude of distinct names (not "states"): "C," "C¢ ," "C¢ ¢ ," …. There is also no reason to think that "distinct contents" entail "distinct states." A state can have a single conjunctive content combining two distinct contents—(for Brentano) that the glass is empty AND I am (hereby) aware that the glass is empty, or (for me) that x is empty AND x is Q. Or a state can be ambiguous or multiple in meaning—meaning both "the glass is empty" and "I am (hereby) aware that the glass is empty," or both "x is empty" and "x is Q." Such maneuvers are not applied ad hoc to conscious experience; I argue elsewhere (1996a), on independent grounds, that individual, token, mental states are normally multiple in meaning.

This is another very puzzling accusation against reflexive representation, which would hardly seem worth discussing were it not put forward by two philosophers who have thought most deeply about inner-directed representation. Rosenthal argues:

Being conscious is often thought of as a reflexive property of conscious states, as though such states were somehow conscious of themselves. … Being transitively conscious of something is a relation that a person or other creature bears to that thing. So only creatures can be transitively conscious of things. A mental state may well be that state in virtue of which somebody is conscious of a thing, but the state cannot itself literally be conscious of anything. (1990, 29-30)<6>

A mental state can represent itself without its being conscious (or aware) of itself, just as a state can represent a banana without its being conscious (or aware) of the banana. Just as the sentence "This sentence contains five words" has itself as a referent, so a mental state can have itself as a referent. The reflexivity of experience—whether Brentano’s nonderivative kind or my derivative kind (see the previous accusation)—certainly does not require experiences to be experiencers. I have no good guess about why it would be thought otherwise.

Shoemaker argues that "[n]o one thinks that one is aware of beliefs and thoughts by having sensations or quasi-sense-experiences of them" (1994, 255).<7> I agree, wholeheartedly. If attitudes were phenomenal experiences, this would undermine an inner-sense theory of phenomenal consciousness. But on independent grounds it is plausible that attitudes are not phenomenal (see "Nonphenomenal"). There is nothing conscious attitudes themselves are like, although there is often something accompanying states are like, states from the Qualitative Quartet—perceptual experiences, bodily-sensational experiences, imaginative experiences, and experiences in the stream of thought (I give some examples in the next paragraph). The absence of inner sense for attitudes is not a weakness of inner-sense as a theory of phenomenal consciousness, but one of its greatest strengths. A serious difficulty for theories of phenomenal consciousness is to explain why attitudes are not phenomenal, even when they are conscious in some other sense. Of course, attitudes can be excluded by fiat—for example, I think that Tye does this by a sheer stipulation that phenomenality requires "nonconceptual" content (1995, 137-139). But to my knowledge only inner-sense theories provide an explanation of the nonphenomenality of (conscious or unconscious) attitudes.

If we do not innerly perceive our attitudes, how do we know about them? Is inner sense completely irrelevant to attitude self-knowledge? Shoemaker turns the screws:

Further, it does not seem promising to suppose that for each belief or desire we can isolate something that is "inside the head," such that it is by being introspectively aware of that thing’s intrinsic, non-intentional properties that one is aware of the belief or the desire. For example, it does not seem plausible to model one’s introspective awareness of such intentional states on one’s perceptual awareness of drawings, maps, and sentences, where one perceives something having representational content by perceiving its non-intentional features—colors, shapes, etc. There simply are no promising candidates for the non-intentional features of beliefs, etc., that this would require. (1994, 260)

On the contrary, I think it is utterly normal, in becoming conscious of one’s attitudes, to have accompanying phenomenally conscious "symptoms" of the attitudes (see "Nonphenomenal"). For example, one’s standing, unconscious belief that snow is white may cause one to form an auditory image of quickly saying the words "snow is white" (or "I believe snow is white" or "Mon Dieu! La neige! Blanche!" or …). There are normally more aspects to this verbal imagery, which help one to determine which kind and strength of attitude (belief, desire, suspicion, etc.) is revealed via the thought. In cases of belief, for instance, one may imagine saying the words in an assertive tone of voice, and without any concomitant proprioceptive sensations of suppressed giggling, or auditory images as of appending "NOT!," etc. In addition to such verbal imaginings, there are often nonverbal imaginings, e.g., of a white expanse of snow, and perhaps visual imaginings of words. And consider William James’ interesting introspective report:

My glottis is like a sensitive valve, intercepting my breath instantaneously at every mental hesitation or felt aversion to the objects of my thought, and as quickly opening, to let air pass through my throat and nose, the moment the repugnance is overcome. The feeling of the movement of this air is, in me, one strong ingredient of the feeling of assent. The movements of the muscles of the brow and eyelids also respond very sensitively to every fluctuation in the agreeableness or disagreeableness of what comes before my mind. (1890, 288)

It is no part of my proposal that each belief or desire has a canonical phenomenal symptom, and I do not here assert (or deny) that every bit of attitude self-knowledge proceeds via phenomenal symptoms. But to say the least, we should be very suspicious of any view of introspection that marginalizes such an important and nearly ubiquitous entryway into knowledge of attitudes (see note <9>, below).

Searle argues as follows against the analogy between introspection and perception:

Let us try to take the analogy seriously. Suppose I see a bicycle. In such a perceptual situation there is a distinction between the object perceived and the act of perception. If I take away the perception, I am left with a bike; if I take away the bike, I am left with a perception that has no object, for example, a hallucination. But it is precisely these distinctions that we cannot make for the conscious thought. If I try to take away the conscious thinking of this token thought, say, that Bush is president, I have nothing left. If I try to take away the token occurrence of the thought from the conscious thinking of it, I don’t succeed in taking anything away. The distinction between the act of perceiving and the object perceived does not apply to conscious thoughts. (1992, 171)<8>

To answer this accusation, it is necessary to describe how the inner sense theory is supposed to apply to "conscious thought." We must be careful about what counts as a "thought." In one sense, "thought" refers to propositional attitudes generally, and in a related sense it refers to indicative propositional attitudes specifically—beliefs, hypotheses, etc. These senses are irrelevant to the present theory, which is not intended to apply directly to attitudes (see the previous accusation). In the phenomenally relevant sense of "thought," a thought is an element of the "stream of thought." First and foremost, this includes the fairly slow, roughly serial, and typically deliberate phenomena we try to describe as "talking to oneself" or "thinking in words." (There is also what we are tempted to describe as "thinking in images"—say, visual images of objects or words.) Such "inner speech" is simply conscious auditory imagining (or hallucinating) of speech. On the present view, it involves O-states of linguistic items, and I-states of such O-states.

We must also be careful about adopting Searle’s suggested procedure of "taking away" elements of a sensory encounter. The task should not be one of voluntarily controlling the existence of objects and states. This cannot always be done in the case of outer sense—I can close my eyes to prevent myself from seeing a bicycle, but when I am awake and a loud noise erupts, I can’t voluntarily prevent myself from hearing it. The (alleged) causal connections between O-states and I-states, in normal subjects, are much more difficult to control voluntarily. Instead, the task is to conceive of the absence of elements of a sensory encounter, and determine what remains. But how is this determination to be accomplished? Certainly introspective reports in Searle’s style have a role, but they are not the only legitimate source of evidence.

The inner-sense theory applied to conscious inner speech has the following consequence: if either O-states of words or I-states of these O-states are absent, then there is no conscious experience as of words remaining. But is Searle correct that there is nothing left at all? It is plausible that there can be O-states of words without accompanying I-states—perhaps these underwrite unconscious or subliminal linguistic processing. This would mirror the perceptual case—visual O-states without visual I-states underwrite unconscious or subliminal visual processing. Searle’s introspective method is wholly silent on whether such nonintrospectible states are possible.

Could there be I-states as of O-states, in the absence of accompanying O-states? Perhaps not for normal subjects, in the absence of breakdown. (Outer hallucinations do not require mechanical breakdown within the subject—an abnormal environment suffices—but inner hallucinations would.) Still, what might occur in such a case? There is some leeway on my account, which is appropriate for such an unclear case of breakdown. I think it most likely that a state consisting only of I-states would result in no experience at all. But given that qualia are primarily determined by the contents of I-states, perhaps I-states alone would be sufficient for an unusual kind of experience. The closest familiar comparison would be to experiences as of mental imagery with environmental properties (as contrasted with experiences in normal perception and nonlucid dreaming). These experiences occur when there are both I-states and O-states, but when the I-states have more salience and strength than the O-states. So perhaps if the O-states are wholly absent, the experience would be as of something inner, but without environmental properties—in the case of visual imagery, an apparent seeing of something mental without apparent shape, size, color-reflectance, etc.; in the case of auditory verbal imagery, an apparent hearing of something mental without apparent pitch and volume. These might be comparable to cases of perceptual agnosia, in which patients can perceive environmental objects without being able to recognize them: one might be able innerly to "see an image" or "hear voices in one’s head" by qualia without being able to "recognize" any normally correlative apparent shape, size, color-reflectance, pitch, volume, etc. To the extent that we have words and concepts ready for environmental properties but not for qualia, such mental imagery might be singularly ineffable—perhaps even a step toward the "pure experiences" countenanced in Buddhist texts: alleged experiences as of no ordinary perceptible properties, whether instantiated outerly or innerly. Again, Searle’s examination of his own experience leaves entirely open whether such psychologically unusual experiences—experiences that are not clearly as of experienced outer or inner objects—are possible.

Shoemaker is willing to accept that introspections and their objects are distinct (see the previous accusation), but he argues against inner sense by appeal to a related feature of normal perception:

[T]he objects and states of affairs which the perception is of, and which it provides knowledge about, exist independently of the perceiving of them …. Thus trees, mountains, etc. can exist without there being creatures with the capacity to perceive them, and it is in principle possible for houses, automobiles and human bodies to exist in this way. (1994, 254)

According to Shoemaker, if introspection is inner sense, then innerly sensed mental states should similarly be independent of inner sense. However:

… I think that the fundamental difference between perception and introspection is the failure of the latter to satisfy the "independence condition." Perception and introspection are of course alike in being modes of non-inferential knowledge acquisition. But … [i]n the case of introspection … the reality known and the faculty of knowing it are, as it were, made for each other—neither could be what it is without the other. (1994, 289)

His strategy is to show that "there is a conceptual, constitutive, connection between the existence of certain sorts of mental entities and their introspective accessibility," at least for creatures that have "the ability to conceive" of those entities (1994, 272-273). The disanalogy with outer sense is that one cannot be entirely introspectively blind to these mental entities, while one can certainly be perceptually blind to trees, mountains, etc.

His argument for this conclusion is long, complex, and worth pursuing, but not here. Even in advance of the details I think it can be shown that the overall argument is fallacious. It would prove too much. Just as there is an "independence condition" for normal perception, so there is an one for normal belief. Trees, mountains, houses, automobiles, and human bodies, etc. can all in principle exist without being believed in, and even without there being creatures capable of believing in them. If the argument yields any evidence that we do not have inner-directed sensings, it yields equally good evidence that we do not have inner-directed beliefs—inner sense would be "disanalogous" to outer sense only in the same sense that inner belief would be disanalogous to outer belief. If Shoemaker is right about the conceptual relation between introspection and introspected, then this would be a "fundamental difference" between belief and introspection! But of course that should not incline us to doubt the existence of innerly-directed beliefs.<9> Nor should Shoemaker’s argument, whatever the details, incline us to doubt the existence of innerly-directed sensings.

Shoemaker’s proceeds to argue, case by case, that introspectibility is necessary for the existence of pain feelings, perceptual experience, agency, and propositional attitudes. This provides another simple way to see that the argument presents no threat to the inner-sense theory I propose: the (fundamental) objects of inner sense are nonphenomenal O-states, rather than phenomenal pain feelings or perceptual experiences (see Accusations 1 and 2). I agree that pain feelings and perceptual experiences are dependent on introspection, and in addition my view explains this: the inner sensings of parts of these experiences are themselves parts of the experiences.

Rosenthal offers inner-sense theorists a gift:

There are analogies between sense perception and the way mental states are conscious that may encourage the adoption of a perceptual model. For one thing, the various sense modalities each enable us to respond differentially to a distinctive range of stimuli. Because being conscious of our mental states is an ability to respond differentially to the mental states we are in, it may somewhat seem like a sense modality dedicated to mental states. (1990, 32)

As it turns out, the gift is a Trojan horse:

However, the perceptual model does not withstand scrutiny. Whereas a range of stimuli is characteristic of each sensory modality, mental states do not exemplify a single range of properties. Rather, … mental states exhibit intentional or sensory character, and these two have little in common; nor do the sensory qualities special to the various modalities resemble each other. (1990, 33)

If Rosenthal’s idea is simply to disarm the "differential-response" point as a source of support for inner sense, then I wouldn’t mind. Nor would the citizens of Troy have minded if the Greek soldiers had simply jumped out of the horse, dismantled it, and taken it away peacefully. But Rosenthal seems to think his argument works as an objection to inner sense—indeed, as a bit of scrutiny that inner sense cannot withstand.

I agree that mental states are a heterogeneous class.<10> This heterogeneity is not a threat to my inner-sense theory of phenomenal consciousness, for two main reasons. First, inner sense is restricted to sensory O-states, rather than attitudes and other mental states. Second, my view is not committed to there being a single faculty of inner-sense. I-states are not states of a special inner-sense modality, but states of the separate outer-sense modalities themselves. There are inner-visual I-states of outer-visual O-states, inner-auditory I-states of outer-auditory O-states, etc. This is necessary (at least given our cognitive architecture) for the I-states to be bound with the O-states, generating image illusions and transparency illusions. Rosenthal is correct that qualia in various modalities are heterogeneous, but the various inner sense faculties are equally heterogeneous.

Although this accusation is often mentioned in passing, it is rarely taken to be seriously damaging to inner sense theories. In part this is because it is unclear just what is plausible or implausible, neurophysiologically. To my knowledge, the boldest statement of the accusation is due to Rosenthal:

Since perceiving depends on a dedicated organ or mechanism, the [inner] perceptual model raises the question of what special organ or mechanism subserves being conscious of one’s mental states. The absence of any such organ or mechanism may tempt one to conclude that being conscious must be something internal to conscious states [rather than something due to inner perception of the state]. (1990, 35)

Leave aside the contrast between "internal to conscious states" and "due to inner perception"—if inner sense is part of a conscious experience, the two are compatible. Rosenthal provides no positive reason to believe in "the absence of any such organ or mechanism," so the matter stands where inner-sense theorists have left it: with some support for a philosophical bet on inner sense, together with a wait-and-see attitude towards brain science.<11>

Of course, inner perceptions are not generated by literal inner eyes and ears, that are affected by light-waves or air-waves inside the head, transducing them into neural signals. The relevant innerly sensible features of O-states are already neural (or functional, but realized neurally), so there is no need for inner transduction. Although there are outer sense organs that produce O-states, there need not be inner sense organs that produce I-states. The mechanisms (if any) by which O-states cause I-states are not what make the latter sensory, in my view. Whether these mechanisms involve literal inner sense organs, or (hardwired or flexible) neural connections, or some kind of inference, or the cooperation of Martians or angels—all this is irrelevant to what it is like to have O-states and I-states, so long as the process (if any) is itself hidden from introspection.

Against inner sense and other "Theater" theories of consciousness, Dennett objects:

The brain is Headquarters, the place where the ultimate observer is, but there is no reason to believe that the brain itself has any deeper headquarters, any inner sanctum, arrival at which is the necessary or sufficient condition for conscious experience. In short, there is no observer in the brain. (1991, 106)

My inner sense theory requires no phenomenal gland. As I described in response to the previous accusation, I-states live among O-states, in the various sensory modalities themselves. (These are the same neighborhoods where Dennett’s "multiple drafts" live.) Counting by gross modalities, I would say, there are several observers distributed around the brain. Counting by processes that determine the specific contents of individual I-states, there are perhaps thousands upon thousands of microobservers. I mean for these claims to be empirically testable eventually, of course, given neuropsychological advances aided by introspection and by an appreciation of the various philosophical theories of consciousness. Since on my view I-states accompany O-states, it should not be surprising that current, unaided neuroscientific techniques are unable to detect them as I-states rather than as further O-states.

In the absence of direct neuroscientific evidence for or against inner sense, Dennett turns to indirect "engineering" considerations. He argues that inner sense would waste precious cognitive resources, if it involves anything distinct from mere judgments about experienced events. For example, he considers the "phi phenomenon" of vision, in which a flash of light is followed very rapidly by a second, nearby, flash, and one seems to see, not two separate points of light, but a single light moving from the first spot to the second. On any view, one’s visual or cognitive system must somehow (consciously or unconsciously) register the second point of light, and only then jump to the mistaken conclusion that there was light at the intervening points (without the registration of the second flash, we would have no good explanation of the direction of the concluded motion). A natural idea for defenders of inner sense is that one doesn’t merely conclude that there was motion, because in addition representations of the intervening spots are "filled in" so that the entire path appears lit. Dennett objects as follows:

[T]he brain doesn’t actually have to go to the trouble of "filling in" anything with "construction"—for no one is looking. … [O]nce a discrimination has been made once, it does not have to be made again …. [R]etrospectively the brain creates the content (the judgement) that there was intervening motion, and this content is then available to govern activity and leave its mark on memory. But … the brain does not bother "constructing" any representations that go to the trouble of "filling in" the blanks. That would be a waste of time and (shall we say?) paint. The judgement is already in, so the brain can get on with other tasks! (1991, 127-128)

There are three resources that Dennett says would be wasted by inner sense: discriminatory effort, time, and representational media (a defender of inner sense need not posit mental "paint"—neurons will do nicely, so long as they realize states that are innerly sensed). I respond to these charges more fully in "Qualia!," but I will summarize here:

Discriminatory effort—Given an O-state that p, inner sense needn’t rediscriminate or recheck or even re-represent that p; instead, it newly discriminates features of the O-state.

Representational media—Information about spatial position and motion may be most efficiently encoded and processed in an "array" representing spatial points. It might indeed be a waste first to reach a detailed judgment of motion and then to activate this array, "just for show." But the judgment of motion can be realized in this array or can be caused by it.

Time—If the array realizes or causes the judgment, activity in the array it is not a waste of time. Nor would it be a waste of time for this array to be innerly sensed, assuming (as I do) that O-states in the array can influence some judgments and behaviors without detouring through I-states. Inner sense is not some delaying mechanism postponing all cognitive upshot of outer sense.

Though I take comfort in the absence of negative engineering arguments against inner sense, I concede that inner-sense theories would profit from a richer positive account of the engineering value of inner sense.<12>

Scientific investigations of introspection have revealed widespread "confabulation" in self-access. In trying to identify one’s beliefs and motivations, one systematically but sincerely reports attitudes one thinks rational or statistically normal in the circumstances, even if one doesn’t have them (see Nisbett and Wilson, 1977). Lyons argues on this basis that introspection is more a matter of theoretical inferences than a matter of inner sense:

When we claim to introspect the deliberations that precede our choices and actions, and in general make claims to be privy to our own cognitive processes, what we seem to be doing is more like adopting a likely rationale for a person exercising a choice in such circumstances rather than engaging in any process of observation of internal cognitive events or retrieval of information. (1986, 102)<13>

There is little room to doubt that introspection is often theory-laden in this sense. But the only question for the present inner-sense theory is whether introspection of phenomenal properties is theory-laden. The model of rationalizing or statistical guesswork does not extend easily to accessing one’s own current qualia. For example, untutored subjects offer consistent and apparently reliable reports of stinging (rather than throbbing) pain "feelings" when a limb has restricted blood flow. It is implausible to suppose that they are inferring these feelings in anything like the way one might form beliefs about another’s pain feelings, since there are no commonsense principles of rationality according to which one should feel stinging rather than throbbing, nor need the subject know any relevant statistical information about how people do feel in these circumstances.

Rosenthal describes a candidate case of phenomenal confabulation:

Our visual field seems to be replete with visual detail throughout. This is because eye movements provide foveal vision over a wide area, and we retain the visual information thus gained. Nonetheless, ... we are at any given moment aware of little visual detail outside the center of our visual field. It is natural to speculate that our seeming to see much of this detail may in effect be due to our confabulating detailed visual sensations. (1990, 47)

On the contrary, confabulation is a very extreme diagnosis. There is a much simpler explanation. As Rosenthal says, over time "we retain the visual information" from a large number of fixations between eye movements. This means that at each moment, while we newly represent details only from a small region, this new information is fit into a structure of old (well, moments-old) details about surrounding regions. At each moment we do have detailed visual representations of (nearly) the entire visual field—more detailed, anyway, than could be explained by the new information alone. The surrounding detail is not confabulated, but, in a sense, visually remembered. The only rub, apparently, is that visual memory does not flag the information as old, so we see surrounding features as present. In a normal environment—as opposed to a psychologist’s lab—this leads to little error, and to virtually no error that matters practically. Rosenthal misleads when he says that we are aware of little visual detail. We are aware of little new visual detail, but we represent (as current) much more detail.

Dennett argues that one can easily be wrong about the "changes and constancies" in one’s experience over even brief intervals of time (1988, 59). This is evidence against especially reliable memory access to what it was like to have past experiences, though it leaves open the possibility of especially reliable (or even infallible) access to ongoing experiences (for a fuller response to Dennett’s argument, see "Qualia!").

An inner-sense theory needs an account determining which properties of mental states are innerly sensed. Plaintiffs against inner sense have emphasized the implausibility of innerly sensing the contents of mental states. As Shoemaker remarks:

[I]ntentional states are standardly individuated by their contents, and when one knows about one’s intentional states introspectively what one knows is, standardly, just that one has a state of a certain kind with a certain intentional content, i.e., that one has a belief that so and so, a desire for such and such, or the like. And recent discussion of mental content seems to have established that a person’s having a state with a certain content consists in part in "external" facts about the person’s environment …. (1994, 259)

This presents a difficulty for inner-sense accounts of introspection. Shoemaker quotes Paul Boghossian’s (1989) query about how anyone could be "in a position to know his thoughts merely by observing them, if facts about their content are determined by their relational properties."<14> Shoemaker emphasizes that this point is not restricted to propositional attitudes:

If … what we are aware of in being aware of sensory states are their intentional objects, or intentional contents, then … [this] is also a reason for rejecting [the perceptual model’s] application to the case of awareness of sensory states. It would seem that the intentional content of sensory states, like that of beliefs and other intentional states, is determined in part by factors "outside the head" of the subject of such states. So what we are aware of in being aware of such states will not be "intrinsic" features of them … (1994, 264)

I agree that inner-sense cannot (simply and directly) account for introspective knowledge of content properties. I advance inner sense not as a general theory of introspection but as a theory of one specific kind of introspection, the kind (I claim) that explains phenomenal consciousness. I-states represent features of O-states, but they do not represent the representational relations of O-states. These are not plausible candidates for being innerly sensed, since they are relations between O-states and other things that are not innerly sensed—e.g., environmental objects.

What other features of O-states might I-states represent? Well, what other features do O-states have? Instead of O-state content, I-states might represent formal—intrinsic, physical—properties of O-states. These could include abstract "syntactic" features of O-states, and even features of O-states specific to their "hardware" realization, such as the rough number of neurons that realize an O-state, or their rough average rates of firing. (I do not assume that I-states involve complex descriptive concepts of neural structure or of psychological function; another possibility is that they respond to specific neural or psychological features in more primitive ways, just as in outer sense one may be sensitive to wavelengths or molecular motion without having concepts of waves or molecules.) As an illustration, consider Christopher Peacocke’s example of seeing two same-sized trees, at varying distances from one:

Your experience represents these objects as being of the same physical height and other dimensions …. Yet there is also some sense in which the nearer tree occupies more of your visual field than the more distant tree. This is as much a feature of your experience itself as is its representing the trees as being the same height. The experience can possess this feature without your having any concept of the feature or of the visual field: you simply enjoy an experience which has the feature …. (1983, 12)

As I described in Accusation 3, Harman and Tye say that we represent the trees as having different "sizes from here." I am skeptical of this kind of view (see section 1 of "Illusions"), and I think the inner-sense account presents a viable alternative (one compatible with functionalism, representationalism, and other views dear to Harman and Tye). Peacocke argues that "you simply enjoy an experience which has the feature" of different sizes-in-the-visual-field. However, it is not simply that the experience "has" this visual-field feature, in the way it might "have" the feature of being realized in, say, molecules. In addition, one is normally sensitive to an experience’s visual-field features (in a way one is not normally sensitive to its being realized in molecules). An inner-perception account can explain the visual-field differences in Peacocke’s two experiences, as well as one’s sensitivity to these features, as follows. Compared with O-states about the distant tree, O-states about the nearer tree are realized by (or causally connected to) many more O-states in retinotopic maps in the early visual system. This is just the sort of property to which inner sense may make one sensitive.

I-states may also represent interrelations among O-states, relations that cannot be reduced to their intrinsic (formal) monadic properties. These interrelations are better candidates for inner sense than O-state content, because their relata are all innerly sensed. As illustrations, consider cases of double vision and blurred vision. Typically we are sensitive to the doubleness or blurriness of such experiences. In double vision, we may innerly sense of two O-states (say, two matching perceptions of an edge) that they are two in number. In blurred vision, we may innerly sense of a certain O-state (say, a perception of an edge) that it is in a causal interrelation with an unusual set of other O-states (say, states that involve neurons unusually and poorly "lined up" in the retinotopic maps in primary visual cortex). In normal focal vision, by contrast, we are typically sensitive to the nondoubleness and nonblurriness of our experience. This could be explained by our innerly sensing related structural features of O-states. We detect of an O-state of an edge that it has no distinct matching O-state, and that it is in a causal interrelation to a standardly "lined-up" set of other O-states.

In addition to content features, there is another kind of feature that makes something an O-state: the functional relations that characterize modalities such as vision and hearing. But for the same reason that I-states do not represent the contents of O-states, it may not be plausible that an I-state represents the modality of an O-state—whether it is visual, auditory, etc. At least in one "wide" sense, modality features are also in part relations to entities that are not innerly sensed—e.g., sense organs. Instead of the wide modality of O-states, I-states might represent the force of O-states, which I think is or includes their degree of attentiveness. Perhaps this is reflected in O-state form, somehow. Attentive states may be realized in more rapidly firing neurons, for example. (Also, commitment to wide modality properties need not preclude commitment to "narrow" modality properties—perhaps in another sense an O-state’s being visual or being auditory can be explained in terms of its form, force, or relations to other O-states. If so, inner sense might be sensitive to narrow modality.)

Lyons cites the following result as a consensus among developmental psychologists:

[A] child acquires the ability, and some recognition of the ability, to do what goes under the label "introspect"—generally construed in this context as the "awareness and verbalization of one’s own thought processes"—somewhere around the age of eight years old. (1986, 97)

The worry is this: if children don't introspect, and if a kind of introspection helps constitute phenomenal experience, doesn't this mean that children lack phenomenal experiences?<15> For this and many other reasons it is crucial to distinguish between attentive inner sense and inattentive inner sense. Inner sense is required for phenomenal consciousness, but this inner sense need not be attentive. Inner sense of any sort produces I-states about specific O-states. But attentive inner sense—and much else besides—may normally be required for the development of general introspectively-based concepts of mental states. The age of inner sense predates the age of introspection—construed as involving inner-directed judgment and/or reports.

McGinn raises a similar objection with respect to many animals:

Consider unreflective animals, their awareness perpetually glued on to the external world for fear of what will befall them: they are certainly aware of objects in their environment, but have not the luxury of thoughts about their own mental states and selves …. (1982, 52)

It is perhaps true that animals have their attention glued to the external world, but this does not show that their awareness is glued there—perhaps they have inattentive awareness of the internal world. Furthermore, on the inner sense view this awareness need not be a matter of having (luxurious) "thoughts" about mental states, but instead can be a matter of having more primitive sensings of mental states.

Sometimes arguments for this conclusion rest on the same conflations that undermine the previous accusation—equating awareness in general with attentive awareness (thereby forgetting about inattentive awareness), and with judgment (thereby forgetting about sensing). Chalmers, for example, argues:

The tie between experiences and second-order judgments is much more indirect: although we have the ability to notice our experiences, most of the time we notice only the contents of the experience, not the experience itself. Only occasionally do we sit back and take notice of our experience of the red book; usually we just think about the book. (1996, 221)<16>

An inner-sense account of experience is not committed to continual noticing of (or attention to) one’s experiences, and is not committed to continual judgments about one’s experiences. Strictly speaking, it is not even committed to continual inner sensing of one’s experiences. The view is that one has continual inner sensings, inattentive or attentive, in one’s experiences (see Accusations 1 and 2).

Hill’s argument in support of the present accusation runs as follows:

It is quite clear, I think, that there is such a thing as a sensation of which one is not aware (an unconscious sensation, if you like), and, by the same token, that there is such a thing as coming to be aware of a sensation that was in existence prior to one’s state of awareness. Here is an example: As I pace back and forth in my room I find that I frequently pause in front of the window. Asking myself why, it suddenly dawns on me that I am quite cold, and that my pauses have been due to the succoring warmth of the sun’s rays. A second example: I find myself scratching one of my legs and come to realize that I am doing so for a reason—the leg is itching.

The "clarity" of these examples depends, I think, on an unclarity about the term "sensation." The crucial question is whether sensations are necessarily phenomenal—on whether there is necessarily something it is like to have a sensation. Hill begins his book by characterizing sensations as "concrete sensory events" (1991, 3); by the Nonphenomenology of Perception, this indicates that sensations need not be phenomenal. But he also sometimes uses the term "sensations" in such a way as to suggest that sensations are phenomenal by definition. Let us call nonphenomenal sensations "N-sensations" and phenomenal sensations "P-sensations." It is clear that there can be N-sensations of which one is not aware in any way—I have been calling these "O-states" all along. But this does not mean that there can be P-sensations—phenomenally conscious sensory states—of which one is not aware in any way. Again, I grant that one need not form beliefs about one’s P-sensations, and that one need not attend to them. But Hill’s examples do not provide evidence that inattentive inner sense is unnecessary for phenomenality.

Dretske has produced a novel argument to the effect that there are (phenomenally) conscious features of experience of which the creature is unaware in any way. The argument begins with a distinction and two definitions:

(1) All awareness comes in two kinds: being "thing-aware" and being "fact-aware."

(2) Perceiving an object or event (or state) x = being thing-aware of x.

(3) Perceiving or judging that p = being fact-aware that p.

(Dretske does not discuss whether the perceiving must be experiential, or whether wholly subliminal, nonphenomenal perceiving is sufficient for thing-awareness or fact-awareness.) He then diagrams two side-by-side "constellations" of black, irregularly shaped spots, labeled "Alpha" and "Beta." His instructions are for the reader to "[g]lance … long enough to assure yourself that you have seen all the elements" of the two constellations, encouraging the reader to "change fixation points in order to foveate (focus on the sensitive part of the retina) all parts" (1993, 272-273). The two constellations differ in that Alpha contains a single spot that Beta lacks, an easily visible spot of roughly the same size and shape as the rest. Dretske names this "Spot":

(4) Spot = the difference between Alpha and Beta.

Now consider a reader, Reed, who follows Dretske’s instructions—taking care to perceive, focally, every part of Alpha, including Spot—but fails to become aware that Alpha and Beta differ. (This seems to be the normal case.) So, by stipulation:

(5) Reed perceives Spot.

From this Dretske concludes:

(6) Reed is thing-aware of the difference between Alpha and Beta.

And also by stipulation:

(7) Reed is not aware that Alpha and Beta differ.

From this Dretske’s concludes:

(8) Reed is not fact-aware of the difference between Alpha and Beta.

According to the next step in Dretske’s argument, Reed’s experiences of Alpha and Beta—E(Alpha) and E(Beta), respectively—are themselves "qualitatively different," in much the way that Alpha and Beta are different. The basic idea is that Spot is itself experienced, and does not merely lie in the direction of the gaze. If so, E(Alpha) must contain an experiential component, caused by Spot, that E(Beta) lacks. Dretske calls this component "E(Spot)":

(9) E(Spot) = the difference between E(Alpha) and E(Beta).

Given (7), it is also plausible that:

(10) Reed is not aware that E(Alpha) and E(Beta) differ.

From this Dretske concludes:

(11) Reed is not fact-aware of the difference between E(Alpha) and E(Beta).

Dretske marshals further arguments (see below) for the claim that:

(12) Reed is not thing-aware of the difference between E(Alpha) and E(Beta).

Given (1) and (9), Dretske concludes from (11) and (12) that:

(13) Reed is not aware of E(Spot), in any way.

This means one can have a conscious experience (or conscious element of experience) of which one is wholly unaware.

I think Dretske’s argument rests on a fallacy of ambiguity, ambiguity in the locution "fact-aware of the difference between …." I will try to explain the problem informally, by giving examples of fact-awareness that Dretske does not block. Then I will try to root out the ambiguity more formally.

I agree with Dretske that Reed is at no time fact-aware, about Spot, that it is a difference between Alpha and Beta. But this is only one particular fact about Spot. There are many other facts one could represent. Consider the moment when, during his scan of Alpha, Reed (by hypothesis) foveates Spot. He plausibly has several bits of fact-awareness about Spot—that it is there, that it is black, that it is a spot, etc. Otherwise Reed would not be so confident that Alpha is entirely composed of black spots. It need not be that Reed judges (or believes), about Spot, that it is there (is black, is a spot, …). Dretske sometimes writes as if fact-awareness requires belief-like representation, and as if sense-like representation is restricted to thing-awareness. But this identification is incorrect. For example, just as one can believe that something is F—using a "concept" of being F—one can sense that something is F—perhaps using a "percept" or "sensory mode of presentation" of being F. And, again, this sensing need not be attentive. Nothing Dretske says counts against this kind of inattentive outer-sensory fact-awareness about Spot. Further, if Reed has fact awareness about Spot, then by (4)—since Spot is the difference between Alpha and Beta—Reed has fact awareness about the difference between Alpha and Beta. He is fact-aware that a certain object is there (is black, is a spot); and this object is the difference between Alpha and Beta. Strictly speaking, (4) it is not quite correct—Spot is not "the" difference but "a" difference. Spot’s color (black) is also a difference. Even if all Reed sees is that blackness is there—somehow without representing Spot as any kind of object—this is enough to have fact-awareness about a difference between Alpha and Beta—about Spot’s color. On almost any theory of visual representation (at least, any theory compatible with wholly unconscious sensings), such a fact is sensed when Reed foveates Spot—sensing of such facts is present (or at least begun) in the retina, long before the visual individuation of objects.

The same points apply to fact-awareness about E(Spot). Reed of course lacks the particular bit of fact-awareness, about E(Spot), that it is a difference between E(Alpha) and E(Beta). But he may have much other fact-awareness about E(Spot)—for example, that it is there, that it is like this, that it is an experience, etc. As with outer fact-awareness about Spot, this inner fact-awareness about E(Spot) does not require belief-like representation. It is compatible with inattentive inner sense about E(Spot). The facts about E(Spot) that are innerly sensed may include facts about E(Spot)’s form, relations, or force (see Accusation 14)—that Q-ness is present, for some such feature. Dretske’s argument fails to show that an experience can have phenomenal features of which there is no awareness at all. Inattentive inner-sensory fact-awareness is perfectly safe from Dretske’s criticisms.

More formally, the central fallacy affects three transitions in Dretske’s argument: from (7) to (8), from (10) to (11), and from (11) and (12) to (13):

(7) Reed is not aware that Alpha and Beta differ.

(8) Reed is not fact-aware of the difference between Alpha and Beta.

(10) Reed is not aware that E(Alpha) and E(Beta) differ.

(11) Reed is not fact-aware of the difference between E(Alpha) and E(Beta).

(11) Reed is not fact-aware of the difference between E(Alpha) and E(Beta).

(12) Reed is not thing-aware of the difference between E(Alpha) and E(Beta).

(13) Reed is not aware of E(Spot), in any way.

These inferences trade on an ambiguity in the following schema used in (8) and (11)—where r, a, and b are schematic terms:

(F) r is not fact-aware of the difference between a and b.

This sort of locution is not formally introduced by (3), in terms of "r is fact-aware that p." For (8) to be supported by (7), and for (11) to be supported by (10), (F) must mean the same as:

(F¢ ) r is not aware that there is a difference between a and b.

(7) and (10) do, respectively, trivially support the following:

(8¢ ) Reed is not aware that there is a difference between Alpha and Beta.

(11¢ ) Reed is not aware that there is a difference between E(Alpha) and E(Beta).

The trouble is, (11¢ ) and (12) do not support (13). (11¢ ) does not rule out all kinds of fact-awareness about E(Spot); it merely rules out awareness of the specific fact, about E(Spot), that it is a difference between E(Alpha) and E(Beta). For (11) and (12) to cover all relevant ways of being aware of E(Spot)—so that together with (1) they support (13), (F) must mean something broader than (F¢ ). To derive (13), (F) must mean the same as:

(F¢ ¢ ) r is not aware that p, for any p that is about any x that is a difference between a and b.

(13) is supported by (12) and the following:

(11¢ ¢ ) Reed is not aware that p, for any p that is about any x that is a difference between E(Alpha) and E(Beta).

The trouble is that (11¢ ¢ ) is not supported by (10). The upshot: if (F) is used as (F¢ ) then, we may grant, the argument proceeds fine through (11). But even if (12) is also granted, (13) would not follow. On the other hand, if (F) is used as (F¢ ¢ ), then (8) doesn’t follow from (7), and (11) doesn’t follow from (10).

I could end here, but for completeness it is worth considering Dretske’s argument for (12), his argument against inner-sensory thing-awareness of E(Spot). He begins by crediting Rosenthal with "a convincing case against … ‘inner sense,’" describing the argument I discussed above as Accusation 2, and citing pages in which Rosenthal advances many arguments I address elsewhere in this paper (see Accusations 6, 8, 10, 11, and 13). Dretske adds only the following considerations:

… I think the "inner sense" approach loses all its attraction once the distinction between thing-awareness and fact-awareness is firmly in place. … For a person might well be thing-aware of E(Spot) … just as he is thing-aware of Spot, without ever being fact-aware of it. … This being so, the "inner sense" theory of what makes a mental state conscious does nothing to improve one’s epistemic access to one’s own conscious states. As far as one can tell, E(Spot) (just like Spot) may as well not exist. What good is an inner spotlight, an introspective awareness of mental events, if it doesn’t give one epistemic access to the events on which it shines? The "inner sense" theory does nothing to solve the problem of what makes E(Spot) conscious. On the contrary, it multiplies the problem by multiplying the facts of which we are not aware. We started with E(Spot) and gave arguments in support of the view that E(Spot) was conscious even though the person in whom it occurred was not fact-aware of it. We are now being asked to explain this fact by another fact of which [the person is] not fact-aware: namely, the fact that [the person] is thing-aware of E(Spot). Neither E(Spot) nor the thing-awareness of E(Spot) makes any discernible difference to the person in whom they occur. This, surely, is a job for Occam’s Razor. (1993, 279)

This argument rests squarely on the prior argument against fact-awareness of Spot and E(Spot)—the arguments for (8), (11), and (13)—and collapses if, as I have argued, the prior argument does. Dretske has no good argument that the viewer lacks all fact-awareness of Spot and E(Spot)—about which intrinsic properties they have, for example; all he has is an argument that the viewer lacks the fact-awareness that Spot and E(Spot) have certain complex comparative relations: that they differentiate Alpha and E(Alpha) from Beta and E(Beta).

Hill considers the following natural formulation of an inner-sense model:

[E]xtramental entities can exist without standing in any informational relations to the physical eye, and their internal qualities are never affected by their coming to stand in such relations. The inner eye hypothesis claims that the same things are true, mutatis mutandis, of sensations and one’s internal scanning device. It asserts that sensations can exist without being scanned, and also that the internal qualities of sensations do not change when one scans them. (1991, 119)

Hill argues against this view by providing examples of ways that attending to one’s sensations can change them. He calls the first "volume adjustment," in which, by increasing one’s attention to a sensation, one increases either its "intensity" or its "internal articulation." He illustrates these as follows:

But what is intensity? It seems to mean different things in different cases. Attention can increase the phenomenal volume of an auditory sensation, the vividness of a gustatory sensation, the severity of a pain, the importunity of an itch, and the strength of a feeling of pressure. … What happens when a sensation undergoes a change in internal articulation? Among other things, a change of this sort may involve the emergence of more minute details, a reduction in the fuzziness of details that are already at hand, a strengthening of the ties between constituents that are organized into gestalten (with an accompanying heightening of the salience of these gestalten), and the appearance of new gestalt phenomena as a result of the aforementioned changes. (1991, 120-121)

The second effect of attention is what Hill calls "activation," in which one seems to bring a sensation into existence, rather than merely modifying one:

It often happens that one has a description of a type of sensation in mind and one undertakes to determine whether it is currently possible to bring a sensation answering to that description to the surface of consciousness. Activation occurs if one succeeds in actualizing … a sensation of the right sort. Thus, for example, having lost touch with the aftertaste of one’s most recent cup of coffee …, one might suddenly recall the aftertaste and undertake to determine whether it is possible to experience it anew. After turning one’s attention to the area of phenomenal space in which taste sensations are encountered, one might experience the gradual rebirth of the aftertaste. (1991, 121)<17>

A theory of phenomenal consciousness should explain how it is possible for attention to have these effects on its object. Hill’s challenge is this: how can inner sense explain this, if it is to be analogous to noninterfering outer sense?

Some outer sensing does change (or interfering with) its object. Feeling an object with one’s fingertip changes the object as well as the finger. The sense in which feeling is more intimate than seeing may help explain why we more naturally speak of "feels" than of "looks" in discussing phenomenal consciousness—we speak of "raw feels" rather than "raw looks" (even in the visual case!), and we substitute "what it feels like" for "what it is like" more naturally than we substitute "what it looks like." But it would be a missed opportunity for the inner-sense theorist to resort to outer feeling to preserve the analogy with outer sense. I think Hill’s cases show no disanalogy with outer vision, and, more importantly, add crucial support to an inner-sense theory.

As I described in response to the previous accusation, Hill’s term "sensation" can be taken in either a nonphenomenal or a phenomenal sense. N-sensations are "concrete sensory states"—O-states—such that, by the Nonphenomenology of Perception, there is nothing it is like to have them. P-sensations are full-blown sensory experiences, phenomenal by definition. Care with respect to this ambiguity enables inner sense to address the current accusation. Inner sense may be noninterfering, like outer sense, in that it does not change (the internal properties of) N-sensations. At the same time, inner sense may explain volume adjustment and activation, because it does change P-sensations. Even if I-states do not change their objects, O-states, they may change states of which they are a part, experiences.

Consider first how inner sense explains activation—the "dawning of a new sensation" "when one turns one’s attention to a new region of phenomenal space" (1991, 126). Hill claims that activation is "flatly incompatible" with the inner eye hypothesis (1991, 126). However, I-states are tailor-made to bring new P-sensations into existence—without I-states, there are no experiences, but instead only O-states. Just as shifting outer-sensory attention to some location can generate O-states of formerly unperceived objects at that location, so shifting inner-sensory attention can generate I-states of formerly unperceived O-states. This "activates" a phenomenally conscious experience (a P-sensation) where there was none before: in keeping with the Nonphenomenology of Perception, O-states alone are not phenomenally conscious.

Can Hill argue that there is activation of N-sensations as well as of P-sensations? He does not do so, and in fact what he does say weighs against the claim that N-sensations are brought into existence by introspection:

What happens when one attempts to summon a sensation answering to some description into one’s phenomenal field? … It is natural to suppose that each sensation derives ultimately from a packet of information in an unconscious portion of one’s mind—a packet that has the potential to become a sensation with a particular set of phenomenal characteristics, but that must be subjected to further processing before it can achieve its potential. If this is right, the task of summoning a sensation of a certain kind into existence must have the following two steps. First, one attempts to determine whether there is an unconscious packet of information that is of the right kind to produce a sensation answering to the description one has in mind. Second, in the event that a packet of the right kind is available, one adjusts the controls that activate the appropriate information-processing mechanisms, and the packet is converted into a sensation. … (The activities involved in this process are of course largely unconscious.) (1991, 122)

With a few amendments to make this unconscious processing seem less intellectual, I would map this theory-sketch onto my framework as follows. Hill’s "packets of information" are my "O-states" (or "N-sensations"). Hill’s "sensations" (in this passage) are my "experiences" (or "P-sensations"). Hill’s "appropriate information-processing mechanisms" are the processes that form my "I-states." Given Hill’s points, then, I-states operate on preexisting O-states to form experiences. There is no attentional "activation" of N-sensations (O-states); and although there is attentional activation of P-sensations (experiences), this is explained on the inner-sense theory. All this is compatible with the claim that I-states do not interfere with their objects, O-states. Activation does not display a disanalogy between inner and outer sense. On the contrary, it provides data that support my inner sense account.

Next, consider how inner sense can explain volume adjustment—increases in the "intensity" and "internal articulation" of a sensation. Unlike activation, volume adjustment concerns changes to a preexisting experience—to a preexisting O-state/I-state pair. By attending to the O-state, one changes the content of the corresponding I-state (i.e., one "notices" something different about the O-state). Just as increasing outer-sensory attention to an environmental object can increase the detail or strength of one’s O-states of the object, so increasing inner-sensory attention to an O-state can increase the detail or strength of one’s I-states of the O-state. This "adjusts the volume" of the qualia, changing the "internal articulation" or "intensity" of the experience. On the view I have proposed, changes in the content of I-states change the "qualia" of experiences—what it is like to have an experience is determined by the contents of its component I-states. (There need be no change to the "internal" properties of O-states, so this does not compromise the idea that inner sense is noninterfering.) Furthermore, on independently plausible assumptions about the contents of I-states (see Accusation 11), the inner sense account explains the detailed changes in intensity and internal articulation of experience. Changed I-states representing the form and interrelations of O-states may explain changes in Hill’s "internal articulation"—level and clarity of detail, level and salience of gestalt organization, and so on. Changed I-states representing O-state force may explain changes in Hill’s "intensity"—sound-volume, taste-vividness, pain-severity, itch-importunity, pressure-strength, and so on. Again, evidence that initially seems to threaten the inner sense view in fact confirms it.

Hill’s volume-adjustment cases are similar to the often-remarked changes in experience that come from concentrated exposure in a perceptual domain such as wine-tasting or music-listening. Inner sense provides a plausible explanation of these changes as well. Such changes can occur quickly, as Dennett illustrates:

Pluck the bass … string [of a guitar] open …. Does it have describable parts or is it one and whole and ineffably guitarish? Many will opt for the latter way of talking. Now pluck the open string again and … lightly [touch] the octave fret to create a high ‘harmonic’. Some people … will describe the experience by saying ‘the bottom fell out of the note’—leaving just the top. But then on a third open plucking one can hear, with surprising distinctness, the harmonic overtone that was isolated in the second plucking. … The difference in experience is striking, but the complexity apprehended in the third plucking was there all along (being responded to or discriminated). After all, it was by the complex pattern of overtones that you were able to recognize the sound as that of a guitar rather than of a lute or harpsichord. (1988, 73-74)

We would like an account of what constitutes such changes in experience: in what way does the experience (or the qualia) get more complex? And how do these changes result from long-term or short-term "training"? Although training may build more complex concepts (of the sort that figure in judgments), these do not seem sufficient for changing experience. One can acquire new complex concepts about wine and music simply by reading books, for example. On the other hand, if it is suggested that some concepts can be acquired only by tasting wine (or wine-like stimuli) or listening to music (or music-like stimuli), why shouldn’t we think the tasting or listening changes experiences directly, rather than by detouring through concepts? It seems implausible to suppose that the listener in Dennett’s example needs to acquire a new concept, rather than some kind of temporary auditory modification. But although training may build more complex outer-sensory discriminatory abilities—bigger and better O-states—this does not seem to account for all such changes (e.g., in Dennett’s example, the sound’s "complexity" is discriminated "all along"—the O-states do not become more complex in content). If the perceptual modifications are not (always, only) due to changed concepts and O-states, what other kind of modification could there be?

The inner-sense account provides a modifiable level of representation besides concepts and O-states: namely, I-states. Training in wine-tasting or music-listening may change experiences, not merely by developing one’s theoretical concepts, and not necessarily by changing one’s outer-sensory discriminatory abilities, but by changing one’s inner-sensory sensitivities to one’s outer-sensory states. I agree with Dennett that "the complexity apprehended in the third plucking was there all along (being responded to or discriminated)," but this is only to say that the O-states—not the I-states—on the first and third plucking are constant and complex. On my account, the change in qualia is due to a change in I-states. The I-states on the first plucking may represent the complex O-states as simple, while the I-states on the third plucking represent these same complex O-states as complex.

In my responses to Accusations 15 and 16, I described ways in which philosophers have failed to apply the distinction between inner-directed sense (whether attentive or inattentive) and inner-directed attention. Drawing this distinction is compatible, however, with maintaining that inner-directed attention is a kind of inner-directed sensing, as illustrated in the discussion of the previous accusation. Perhaps one way of attending to perceptual states is by having attentive inner sensings of these states. Lyons rejects a related view:

It might be objected that one clear case of introspection … is that of attending to one's perceptual processes. To perceive and then attend to one's perceiving are clearly two processes, it might be argued …. My response is to deny that to attend to a process-as-experienced is a meta-process parasitic on a first-level process or activity. Attention is an adverbial modification of some first-level experience or activity. … One can perceive [something], and then one can do it attentively—that is, with care, banishing distractions, with alertness, concentration, and so on. (1986, 107)

This argument is a bit too sweeping. The best way to view something attentively is to focus one’s gaze on it. But this cannot handle all cases of attending to vision. Normally one is unaware of the fuzziness of one’s visual periphery (see Accusation 13), but one can willfully "attend to" the periphery and thereby notice the fuzziness with which one sees things there. This must be different from shifting one’s gaze to the periphery and so removing the fuzziness. Similarly, in degraded cases of vision, such as crossed-eye vision, it does not seem difficult to attend to the degradation—but it is the experience, not the environment, that seems degraded. Nevertheless, in general Lyons is right that it is at least very difficult to redirect attention from environmental objects to experiences of them.

A more general defense of my inner-sense view emphasizes that I-states are directed at O-states, not (except derivatively) at full-blown experiences. Accordingly, it is not a commitment of the present view that one can attend to full-blown experiences, much less that one can do so regularly, easily, or on command. I think a process can be "sensory" even if it is incapable of supporting attention, but others may disagree. If they are right, then my view does have a commitment to the claim that one can attend to O-states as well as to environmental objects. Whether there is such attention is not a matter to be settled purely introspectively, but by a combination of introspection and psychological theory. The cases described in the previous accusation—Hill’s activation and volume-adjustment, wine-training and music-training, Dennett’s guitar case—provide some evidence that there can be attentive inner sense of O-states, distinct from attentive outer sense of environmental objects.<18>

A similar response applies to the following informal experiment proposed by Shoemaker:

Raise both of your hands before you, about a foot apart and a foot in front of your face. Now perform the following two attention shifts [holding the focus of your eyes midway between the two hands]. First, shift your attention from one hand to the other. Second shift your attention from your visual experience of the one hand to your visual experience of the other. Do you do anything different in the second case than in the first? (1994, 266)

The present view is not committed to attentive inner sense of full-blown experience. Even if it were, it would not be committed to the idea that attention can be redirected at will. Outer attention is not always at our command. Raise both of your hands before you, and have a friend set your left one on fire. Now shift your attention to your right hand. Can you do so? Probably not, because your representation of your left hand captures your attention at the expense of your right hand, for excellent natural-selective reasons. Similarly, for excellent natural-selective reasons, environmental objects capture attention, at the expense of mental states. This does not show that mental states are (inattentively) unsensed, any more than the burning-hand case shows that one’s right hand is (inattentively) unsensed.

Lyons considers and rejects a distantly-related response to his initial argument:

It might be claimed, however, that … even if I perceive a beaker on the table …, and do so attentively, I can still stand above that activity, so to speak, and be a "spectator" of it. That is, when one has modified the first-level activity, such that one can now say it is done with attention to what one is doing, one can still stand off and attend to this attentive performance. … [This objection] begins to look as if it will fall into the old introspectionist pitfall in respect of the division of attention. If one is perceiving something attentively and if what can be attended to is severely limited, then it is doubtful that one could engage in any second-order process of attending to it. (1986, 108)

Although I think there is attentive inner sense that is distinct from attentive outer sense, it is no part of my view that in a single case one can have attentive inner sense while also having attentive outer sense. (On the contrary, it is crucial to my overall view that inner sense and outer sense are rivals for attention—see Accusation 21, below.) Being a "spectator" does not require being an attentive spectator. Nothing Lyons says even begins to militate against the inner-sense view.

Shoemaker presses another alleged disanalogy between introspection and outer sense:

[T]here are not different introspective perspectives on the same mental entities, in the way there are different perceptual perspectives on the same physical ones. … [I]t seems plausible that a nonfactual object of a perception-like epistemic access should be something on which different perspectives are possible. (1994, 255)

It may be that the force of this accusation turns on an ambiguity of the term "perspective." In a broad sense, a "perspective" is a way of representing something, and in a narrow sense, a "perspective" is a "spatial perspective," a perceptually relevant spatial relation between perceiver and perceived. I think one can introspect and innerly sense one and the same mental state in different ways, with different broad perspectives. For example, Dennett’s guitar-plucking case, discussed in response to Accusation 17, is arguably a case in which one-and-the-same O-state can give rise to different I-states, and consequently to different experiences. It is more plausible that inner sense lacks varying spatial perspectives. This is unsurprising, because inner sense does not represent spatial properties at all.<19>

Strictly speaking, spatial perspectives are not required for outer sensing, especially in outer-sense modalities that do not represent spatial properties. Taste—as distinguished from tactile sensation via the tongue—is a good example. We cannot taste where something is, and equally we cannot adopt different spatial perspectives in taste. (I leave aside the fact that different spatial regions of the tongue respond selectively to different flavors. For simplicity, imagine a tongue with varying taste buds intermingled uniformly, or imagine a tongue containing only sweetness receptors.) The difference Shoemaker identifies between inner sense and (some kinds of) outer sense is, at root, a difference in subject matter. But of course, inner-sense theorists are interested in pursuing an analogy with outer sense only modulo differences in subject matter. We would turn a deaf ear to a plaintiff who argued that inner sense has an inner subject matter and so—surprise, surprise—lacks a crucial feature of outer sense.

Blindsight subjects have portions of their visual field—"blindsight regions"—in which they (plausibly) deny that they have conscious experiences of specific stimuli. However, in some sense they have sensory states sensitive to these stimuli—"blindsight states." The key diagnostic feature of their condition is that these blindsight states lack substantial influence on central processes of belief and desire—the subjects don’t believe they are having experiences or sensory states of any sort, they are unable to report on what they perceive, they must be coaxed into responding, and when they do respond, they say they are only "guessing." It is difficult to see how these features alone could utterly "turn off" qualia. Perhaps they explain why blindsight states are like nothing for the person as a whole, but they do not seem to explain why blindsight states are like nothing, period. Something else seems to be missing; on the present view, the absence of inner sense, whether centrally available or not, explains the lack of qualia.

In short, there can be inner blindsight, in the sense that there can be centrally unavailable inner sensing. But this does not present a difficulty for the inner-sense theory of phenomenal consciousness. Innerly blindseen states are (or would be) phenomenal (i.e., like something), but not phenomenal for the person as a whole. This proposes to elevate, above the realm of clashing intuition, the controversy about whether or not "normal" (outer) blindsight is phenomenal. Blindsight states are not innerly sensed in a centrally available way. If they are not innerly sensed at all, they are nonphenomenal. If they are innerly sensed in a centrally unavailable way—if they are innerly blindseen—they are phenomenal but not phenomenal for the person as a whole. In principle we can discover the relevant ins and outs of blindsight.

Dennett provides a complicated argument that the distinction between conscious and unconscious states is vague—that some psychological states are neither determinately conscious nor determinately unconscious. He takes this result to weigh against what he calls the "Cartesian Theater," including any view according to which inner sense helps explain the conscious/unconscious distinction. As I argue more fully in "Qualia!," vagueness is not an objection to an inner-sense theory of consciousness, because it is independently plausible that inner sense is vague. After all, outer sense is vague—there is vagueness in the distinction between mere reflexive reactions to stimuli and (even unconscious) sensory representings of stimuli. In "Stopgap" I also discuss briefly the vagueness in the notion of "central availability"—how central is central, and how available is available?

Perhaps this is to jump out of the frying pan and into the fire, however, if the following argument of Chalmers’ is correct:

Either there is something it is like to be a mouse or there is not, and it is not up to us to define the mouse’s experience into or out of existence. To be sure, there is probably a continuum of conscious experience from the very faint to the very rich; but if something has conscious experience, however faint, we cannot stipulate it away. This determinacy could not be derived from any functional analysis of the concepts in the vicinity of consciousness, as the functional concepts in the vicinity are all somewhat vague. If so, it follows that the notion of consciousness cannot be functionally analyzed. (1996, 105)

We need to distinguish two respects in which conscious experience can be "faint": what is had can be faint, or the having of it can be faint. Chalmers’ claim is plausible on the first reading—even if there is something-faint it is like to be a mouse, there is something it is like to be a mouse. But perhaps instead there faintly-is (i.e., indeterminately is) something it is like to be a mouse, in which case it would neither be true nor false that there is something it is like to be a mouse. The possibility of indeterminately-having qualia is opened up by the vagueness of "central availability," and by the possibility that a state may neither be determinately an inner-sensory state nor determinately a mere inner reflex reaction, but somewhere in the vague between.<21>

This accusation arises in many disguises.<22> Kirk issues the following explanatory challenge:

Why should the perception of internal events necessarily involve conscious experience when … the perception of external events doesn’t? (1994, 154)

Dretske objects similarly to the idea that sensing a state—being "conscious of" the state, in one sense—is sufficient for a state itself to be conscious (phenomenally or otherwise). Unlike Kirk, he focuses on states closer to home:

We are conscious of a great many internal states and activities that are not themselves conscious (heart beats, a loose tooth, hiccoughs of a fetus, a cinder in the eye). (1995, 18)

To further tighten the screws Dretske appeals to unusual perceptions of brain states:

[W]hy suppose, as [inner-sense] theories do, that higher-order experiences of lower-order experiences make lower-order experiences conscious? Why should [someone’s] awareness of a process in his brain make that process a conscious thought? My awareness of it [via PET (positron emission tomography) and MRI (magnetic resonance imaging)] would not have this effect. Why should his? (1995, 109)

Dretske’s talk of "higher-order experiences" and "lower-order experiences" seems to embody his commitment to Accusation 1—about experiences of experiences. Given the response to that accusation we may reconstrue his terms as "I-states" and "O-states," respectively.

There is a single key to answering each of these complaints: a state (or event) is "like something" in the strongest, phenomenal sense only if it is necessarily like something, in order to exist at all. There is something it is like for one to have a certain state only if there is something it is like simply for one to have that state. (Compare: there is normally something it is like to fall off a cliff, but there is not something it is like simply to fall off a cliff—while in a coma, say. For this reason, falling off a cliff is not itself a phenomenal state.) Given a sensory construal of "being like something" as "appearing some way"—a construal I motivate at length in "Stopgap"—this means that a state is like something only if it necessarily appears some way, in order to exist at all. In short, phenomenal states are subjective states in the sense that for them to be is for (components of) them to be sensed. This obtains for experiences, on the inner-sense view, because they essentially involve one’s sensings of (components of) them. The inner sensings are necessary in order for the experiences to exist. By contrast, in Kirk’s case, outer sensings are not necessary for "external events" or "external objects" to exist. (All bets are off if idealism is true—maybe then "external" objects such as bananas do have phenomenal properties and "external" events do involve conscious experience.) Similarly, in Dretske’s "internal state" cases, heartbeats and the rest exist independently of being sensed. In Dretske’s final cases, the subject’s brain states also exist independently of someone else’s sensing them via brain scans. The kind of inner sense required for phenomenal consciousness is built into the experience innerly sensed. (So Kirk’s wonderment—that "the" perception of internal events necessarily involves experience—is misdirected from the start. Only a very specific kind of perception of internal events is necessary for experience.)

A fuller answer to the accusation stems from the conditions necessary for generating the phenomenal illusions—"image illusions" of phenomenal objects in one’s mind, and "transparency illusions" of phenomenal properties in one’s environment. The illusions are generated when O-states and I-states undergo binding confusions—when they are mistakenly applied to the same object. I-states and O-states interact to form the illusions (with or without external entities). But no such illusions are generated when O-states (without I-states) "interact" with external entities—bananas, heartbeats, others’ brain states, etc. Bananas and heartbeats are not representational entities at all, and so are not co-applied with O-states about them. Submitting to cross-examination:

"What about external representational entities, such as those in books?"

Books, bananas, and heartbeats are not sensory states at all, and so do not function in a unified way with O-states about them—for instance, they are easily distinguished introspectively. The same is true of sensory states in others’ brains, states of subjects different than the one who has O-states about them.

"What about a subject who senses his own brain states via brain scans or mirrors pointed at his open skull (cf. Güzeldere, 1995, 349), or by fingering his brain?"

Again, these brain states would exist independently of his sensing them, and would not be bound with his sensings of them or function in a unified way with his sensings of them.

"What about a subject who outerly senses the very brain state that is his outer sensing of it?"

Such a case is difficult to describe coherently, but even if it is possible, it would not generate a binding confusion. For states to be confused, they must be distinct—as O-states and I-states are.

"What about a subject who outerly senses his immediately preceding outer sensing—so these states are distinct? Throw in that the states are co-applied and function alike."

For two states to produce the illusions, they must exist at the same time (although they can have different onsets or lifespans)—as O-states and I-states do.

"What if the immediately preceding outer sensing persists, so that the two states do overlap in time?"

Okay, that’s a harder case, requiring discussion of further conditions that crucially shape the illusions. So far I have described only constraints on the confusedly bound states themselves; there are also constraints on the features represented by the confusedly bound states (I discuss all of these constraints in more detail in "Illusions," section 2).

First, the image and transparency illusions are normally complementary, varying according to whether attention is focused inwardly (by giving priority to I-states) or outwardly (by giving priority to O-states). For attention to be the determining factor, there must be a deep attentive rivalry among features represented by I-states and O-states—it must be difficult simultaneously to attend inwardly and outwardly. It is difficult to attend to an imagined banana while also attending to one’s (alleged) mental image of the banana. It is difficult to attend to the shape of an object while also attending to the (alleged) look of the shape. By contrast, the features represented by O-states are rarely rivals for attention—it is normally easy simultaneously to attend to the shape and reflectance, or shape and sound, or flavor and texture, etc., of an object.

Second, there are normal epistemological differences between "outer" and "inner" properties that are crucial to explaining what seems strangely ghostly or private about mental images and the varying looks and feels of a constant shape. A subject need not (and normally does not) perceive or think of them as mental, and he need not (and normally does not) perceive or think of them as being in some strange space. Rather, what is ghostly or private about looks, feels, and mental images is that they are normally only accessible monomodally, by one sense modality in one subject. The objects and properties represented by O-states are, by contrast, normally accessible polymodally. We are disposed to test our visual O-states of shape against tactile states, and to test our visual O-states about color-reflectance against (reports of) the visual states of others. But we have no natural dispositions to test I-states against the verdicts of other senses or other perceivers—understandably so, since in the circumstances that have shaped our natural dispositions, the neural or functional features represented by I-states are only accessible monomodally. In the image illusion, then, we have no independent dispositions to test the identifying properties of alleged images, the properties innerly sensed. In normal perception, objects do not seem monomodal like images, because we do have independent dispositions to test their identifying properties, the properties outerly sensed. Instead, some of their alleged properties seem monomodal, the properties innerly sensed but projected outward.

Now consider how these points apply to the residual putative counterexample, involving outerly perceiving one’s own immediately preceding, but persisting, outer perception. In this case, there are two distinct O-states, one that begins first and persists, and another that results from outer perception of it. Call these "O₁" and "O₂," respectively, and suppose they represent properties P₁ and P₂, respectively. Further, suppose they each use the same variable or term, "x." Then O₁ represents that x is P₁, and O₂ represents that x is P₂. Since these are temporally overlapping states, unless the case requires total breakdown in processing—rendering it too unclear to carry much weight as a counterexample—the system should treat these features P₁ and P₂ as compatible with one another, as color and shape are mutually compatible. (Otherwise, if P₁ and P₂ were mutually incompatible, as squareness and roundness are, O₁ and O₂ would have to compete with one another for credence.) Either P₁ and P₂ are the same feature, or they are not, depending on how the case is elaborated. But if they are one-and-the-same, then "they" cannot be rivals for attention and "they" cannot differ in monomodality and polymodality. Even if they are distinct features, they are all (apparently) compatible, outer-perceptual features, and so they should not be rivals for attention any more than shape and size are, and should not be treated as monomodal any more than shape and size are.

It matters to the phenomenal illusions that inner sense is inner rather than outer, in the sense that its subject matter is represented in a manner quirkily unlike normal, outerly sensed, subject matter—in a monomodal manner (so that the innerly-sensed subject matter seems private or ghostly), and in an attentively rival manner (making it difficult to attend to the private or ghostly subject matter in addition to the normal subject matter). On my account this is why inner sense can be sufficient for phenomenality even though outer sense—whether of bananas, heart beats, books, or brain states—is not.

Perhaps the most important feature of my inner-sense account, for addressing a wide variety of the accusations, is:

(a) Inner sense is (fundamentally) directed at nonphenomenal sensory states rather than phenomenal experiences, propositional attitudes, moods, skills, dispositions, the self, etc.

The keys to answering most phenomenologically-based accusations against the existence of inner sense are (a) and the following:

(b) Innerly sensed features need not be sensed as inner.

(c) Inner sensings do not mediate outer sensings.

(d) Inner sensings are part of phenomenal experience.

Two further features, together with (a), block most scientifically-based accusations against the existence of inner sense:

(e) Inner sense may be heterogeneously distributed in the brain, rather than a single faculty.

(f) Inner sense is directed at in-the-brain properties rather than wide content or modality properties.

Accusations to the effect that there is too little inner sense to explain all phenomenal experience are answerable by (a) and the following features:

(g) Inner sense need not involve judgments or complex, descriptive concepts.

(h) Inner sense need not involve attention.

Finally, these two features help to deflect arguments to the effect that inner sense is insufficient to explain phenomenal experience:

(i) Inner sense works together with central availability to explain normal experience.

(j) A specific kind of inner sense, tailored to explain the image and transparency illusions, is required.

Of course, other considerations are needed to make a positive case that inner sense exists, and that it is necessary and sufficient for phenomenal consciousness. But the prosecution has not shown this to be impossible, or even unlikely.

Ladies and gentlemen of the jury, the facts are clear, and the decision rests on your ability to do what is right. Search your conscience. Is it to be filled with guilt, or with inner sense?

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