Higher-order theories of consciousness

Post-publication activity

Higher-order theories of consciousness seek to explain what it is for mental states to be conscious, as against occurring nonconsciously, by appeal to other, "higher-order" mental states that represent one as being in the states in question. The term 'conscious' refers to several distinct phenomena, all having to do with the mind. One of these phenomena is the condition people and other creatures are in when conscious of those things. But when one thinks of a thing as being present to one, that does suffice for one to be conscious of that thing, even when one doesn't sense or perceive that thing. We can call this phenomenon transitive consciousness, because 'conscious' here takes a grammatical object.

A third phenomenon is a property of mental states themselves, independently of the kind of state and how it represents things. The thoughts, perceptions, and feelings we have in everyday life often occur consciously, but not always. We sometimes sense things subliminally, and hence independently of our stream of consciousness; examples occur in masked priming experiments (Marcel 1983; Breitmeyer and Ögmen 2006) and in blindsight (Weiskrantz 1997). And at times our thoughts and desires also occur outside of our stream of consciousness. Most of the issues about consciousness arise in explaining the difference between mental states that are conscious and those that are not. We can call this phenomenon state consciousness. Higher-order theories address only such state consciousness, seeking primarily to explain the difference between conscious and nonconscious mental states (though see also §6).

2. The transitivity principle

A crucial first step to explaining state consciousness is to characterize properly the data a theory must explain. Higher-order theories all embrace the idea that a mental state is conscious when the subject is appropriately conscious of that state. This characterization has venerable philosophical roots in the work of Aristotle (1984, I, 677 [425b12-13], II, 1849 [1170a32]), Descartes (1984/1641, II, 171), Locke (1975/1711, 115 [II, I, 19]), and Kant (1998/1787, 174 [A22/B37]); these diverse thinkers all held that we are in some way conscious of our conscious states. Because this initial step appeals to transitive consciousness, we can refer to the view that a state's being conscious consists in one's being conscious of that state as the Transitivity Principle (Rosenthal, 1997; henceforth TP). And because being conscious of a state involves some higher-order awareness, theories that adopt TP are known as higher-order theories.

TP has strong commonsense appeal. If somebody has a thought, perception, or feeling but is wholly unaware of having it, we do not regard that state as conscious. And that is logically equivalent to TP: A state is conscious only if one is in some suitable way conscious of it. Further, TP has broad application in empirical studies of consciousness; if an experimental subject is not at all conscious of a mental state, that state is generally not counted as conscious (see, e.g. Dienes and Perner 2004, Merikle et al. 2001).

If TP is correct, a satisfactory theory must specify in what way we are conscious of our conscious states. But not all ways of being conscious of our mental states suffices for them to be conscious. That awareness must be subjectively immediate; that is, we must not be aware of any mediating process or inference as making us conscious of our conscious states. This is not to say that no such process or inference can occur. Rather, it must not seem to the subject that the process or inference occurs; what matters for properly characterizing state consciousness is how things appear subjectively.

It might appear that TP is circular: It characterizes mental state consciousness in terms of consciousness: as a state we are conscious of. But this is not the case. We can be conscious of something even if the states involved in this process are not conscious states, as in subliminal perception or nonconscious thought. Subliminal perceiving makes us aware of the things perceived, though not consciously aware, as we might say; how could subliminal perceiving affect our mental functioning and behavior in respect of the subliminally perceived stimuli if it did not make one conscious of those stimuli? So not all transitive consciousness is state conscious, and TP is not circular.

The temptation to think otherwise is arguably due just to the tendency in everyday life to focus only on the conscious cases of mental functioning.

Though higher-order theories of consciousness all endorse TP, TP does not by itself specify the way one must be aware of a state for that state to be conscious. The various higher-order theories differ mainly in advancing different views about how TP is implemented. There are also theories that reject TP, e.g., the first-order theory of Dretske (1993, 1995, ch. 4), on which a state is conscious if one is conscious, or aware, of something in virtue of being in that state. But subliminal perception results in one's being aware of things one subliminally perceives, albeit not consciously aware of them. Dretske (2006) has sought to meet that difficulty by arguing that a case of perceiving is conscious only if one can cite it as a justifying reason for doing something. But since citing something requires being conscious of it, this response in effect invokes TP. A first-order theory is unlikely to be able to explain how conscious states differ from mental states that aren't conscious without appealing to the higher-order resources of TP.

Higher-order theories are well-suited to explain how conscious states differ from mental states that are not conscious. But a second question arises for such theories. If a state is conscious in virtue of one's being conscious of being in that state, why does such higher-order consciousness ever occur? Why is it, given TP, that mental states are ever conscious? (See §6.)

3. Inner-sense theory

The dominant traditional way of implementing TP is the inner-sense theory, on which a mental state is conscious in virtue of one's having a higher-order perception of that state. The approach has been forcefully defended by D. M. Armstrong (1980) and William G. Lycan (1996). Sensing and perceiving are likely the first things to come to mind when one thinks of being conscious of things. So it is natural to understand TP in terms of sensing or perceiving one's conscious states. The idea that we perceive our conscious states, moreover, may seem tempting as a way to explain the conscious qualitative character of many states. In particular, the mental qualities we are conscious of differ in myriad fine-grained ways, seemingly outstripping the ability of concepts to capture those differences. So perhaps the differences in virtue of which we are conscious of our qualitative states can be captured only by higher-order perceptual awareness, which itself involves mental qualities. It is inviting, moreover, to hold that our awareness of our conscious states serve to monitor our mental states, much as ordinary perceiving monitors external and bodily conditions. This monitoring analogy between mental states' being conscious and perception is often held to constitute another advantage for the inner-sense theory.

But there is room for doubt about the inner-sense theory. Sensing and perceiving always involve mental qualities, but there is no reason to believe that any mental qualities figure in the higher-order states in virtue of which we are conscious of our conscious states. The mental qualities that are essential to ordinary perceiving enable us to perceive physical objects, not mental states, and we know of no other mental qualities that might be available for perceiving mental states. Even when our higher-order awareness is conscious, as when we are introspectively conscious of some state, we are not aware of any higher-order mental qualities. The mental qualities that occur in qualitative consciousness are qualities of the states we are conscious of, not the qualities by way of which we are conscious of them. To sustain the inner-sense theory, one would have to invent higher-order mental qualities to do the job.

Lycan acknowledges all this, but contends that the higher-order awareness involved in implementing TP is nonetheless best modeled on sensing. Lycan urges that the monitoring that results in some of our mental states' being conscious "is the functioning of internal attention mechanisms directed upon lower-order psychological states and events" (2004, 99). And he holds that these attentional mechanisms operate in a quasi-perceptual way. Just as we have voluntary control over what we perceive, for example, so we have considerable voluntary control over which of our mental states are conscious.

But it is unclear that we do have much voluntary control over which of our mental states are conscious. And even if we do, our higher-order awareness will not on that account resemble perceiving more than thinking, since we also have considerable voluntary control over our thoughts. And thinking about things allows us to focus attention on them no less than perceiving them. It is questionable whether any nonqualitative aspects of perceiving will sustain a compelling analogy with the higher-order awareness we have of our conscious states (Rosenthal, 2004).

It still might seem, however, that the analogy with monitoring provides support for the inner-sense model. But that too can be questioned. We monitor environmental and bodily conditions perceptually, but there are other ways that monitoring of one's own mental states might occur. Thoughts about those states would successfully monitor those states if the states led reasonably reliably to the thoughts. So monitoring alone does not support an inner-sense approach over an alternative theory that relies instead on higher-order thoughts. More important, consciousness often does not play any monitoring role whatsoever. As Nisbett and Wilson (1977) have shown, we are sometimes conscious of ourselves as being in various mental states that we are not actually in. Such confabulatory consciousness, which also occurs in various dissociative disorders (Hirstein 2005), though extensive work in social psychology has shown that it also occurs in everyday life. In everyday contexts it seems to make our mental lives seem more sensible or otherwise acceptable to ourselves or to others. In these cases, which may not be all that rare, our being conscious of ourselves as being in particular mental states does not serve to monitor our actual mental functioning. This may undermine the appeal to monitoring in theorizing about state consciousness. Edmund T. Rolls (2004) has pressed a different appeal to monitoring in this connection. He forcefully argued that locating the errors that can occur in multistep inferences requires higher-order mental monitoring that would result in the steps' being conscious. But it is also arguable that intentional states have causal ties among themselves that enable, without any higher-order monitoring, the locating of erroneous steps in multistep reasoning. These concerns about inner sense suggest that the higher-order states responsible for mental state conscious may be better modeled on thought than on sensation or perception. This leads us to the second major class of higher-order theories, the higher-order-thought theory. There are several competing versions of such theories; we consider them in turn in the next three sections.

4. Distinct higher-order thoughts

Since we are conscious of things by perceiving them or by having thoughts about them as being present, the shortcomings of inner sense strongly suggest pursuing a higher-order thought approach. The main version of this theory, defended by David M. Rosenthal (1980, §3, 1986, 1997, 2005), holds that the higher-order thoughts (HOTs) responsible for state consciousness are distinct states from the lower-order states they are about. The distinct HOTs will each be to the effect that one is in some state of a particular type. We are seldom conscious of ourselves as having such HOTs, but that is to be expected; since HOTs are themselves mental states, no HOT will be conscious unless one has a third-order thought about it. And we can safely assume that this would seldom happen.

HOTs have many of the advantages of inner sense. HOTs can subserve such monitoring as actually occurs if the monitored state has a reasonably reliable connection to the occurrence of a HOT. More important, HOTs can accommodate the apparent immediacy with which we are aware of our conscious states. Since the HOTs that make us aware of our conscious states will seldom themselves be conscious, it will not seem that any inference or other process makes us conscious of our states. And to reiterate, this is all that immediacy requires: that the consciousness we have of our conscious states seems to the subject to be direct and unmediated. Nonconscious HOTs explain how this subjectively immediate awareness occurs.

There are additional reasons to posit HOTs. The close tie between consciousness and speech points to the presence of HOTs. Verbally expressed thoughts are always conscious, and what's more they are pragmatically equivalent to reports of those thoughts; whenever one says, "It's raining," one might just have well said, "I think it's raining." And since one often won't even recall which of the two was said, that pragmatic equivalence is, for us, automatic and second nature. Reports express HOTs. So the best explanation of the ease with which we move between such verbally expressing and reporting is the prior presence of HOTs in both cases. And this, in turn, explains why verbally expressed thoughts are always conscious; we are conscious of them by way of the HOTs accounting for the ever present availability of reports.

In addition, when we consciously see something, we can be conscious of our visual experience in more or less fine-grained ways. One may be conscious of one's experience of red, for example, as a relatively generic experience of red or as an experience of a highly specific shade. Sometimes this variability is a function of perceptual conditions, but not always; attention to one's experience may make one conscious of that experience in more detailed and fine-grained ways. HOTs offer a credible explanation of this variability in how we are conscious of our qualitative experiences. The way we are conscious of a qualitative state, on the HOT hypothesis, is a matter of how the accompanying HOT conceptualizes that state's mental properties. The way we are conscious of our qualitative experiences varies with the fineness of grain with which our HOTs represent those experiences.

Questions do arise for the HOT theory, however. For one thing, any theory of consciousness must explain the lighted-up qualitative character of conscious mental qualities. It's unlikely that inner sense can do so, since the higher-order mental qualities it posits would themselves need to be explained. But the HOT theory has its own difficulty here. Since HOTs are purely intentional states and so have no qualitative character, it may seem intuitively implausible that they could result in there being something it's like for one to be in conscious qualitative states.

But there is reason to think that HOTs can actually give an informative explanation here. We sometimes become conscious of differences among mental qualities only when we have words to hang those differences on, as with the different mental qualities that result from tasting various wines. Such mental taste qualities may, early on, be indistinguishable to one, that is, indistinguishable so far as conscious perceiving is concerned. But on learning suitable wine-tasting terms we sometimes come to be conscious of the qualities as distinct. Learning new words reflects the learning of the concepts those words express, concepts that result in our being able to have more fine-grained thoughts about our mental qualities. Since purely intentional states about mental qualities can by themselves result in what it's like for one to be more fine-grained, HOTs can presumably result in there being something it's like for one in the first place

But this points to yet another worry for HOT theory. Clearly, we do not have words for all the subtle variations in qualitative character that occur consciously in us. So it is unlikely that we have concepts for them. This presents a challenge for the HOT hypothesis, and an apparent advantage of inner sense. If our concepts cannot capture all the conscious differences among our qualitative states, neither can our thoughts. Higher-order sensations, however, would face no such difficulty, since their qualitative differences could be as fine-grained as are needed to capture those of our first-order qualitative states.

But we need not have individual concepts for each mental quality to capture all their qualitative differences conceptually. We routinely use comparative terms to describe colors that differ only slightly from one another; we say, e.g., that one is brighter than the other or has more blue in it or is darker. So it may well be that we are conscious of subtle differences among the corresponding mental qualities partly in those terms. It does not seem, of course, as though we are conscious of mental qualities even partly in comparative terms. But, since the relevant HOTs would seldom be conscious, we have little reason to trust our pretheoretic intuitions about how HOTs would represent the subtle differences among conscious mental qualities. And when we describe the differences in comparative terms, our descriptive speech acts, which capture the way we are conscious of the relevant qualitative states, thereby express higher-order thoughts cast in those very same comparative terms.

5. Intrinsic higher-order thoughts

A theory positing distinct HOTs is not the only version of the higher-order thought approach. Brentano advanced a theory on which higher-order awareness is due to intentional content that is intrinsic to each conscious state (Brentano 1973/1874, II, ii). Each conscious state is a representational compound, which represents both some aspect of the world and that very state itself. This approach has been more recently defended by Rocco J. Gennaro (1996) and Uriah Kriegel (2006; cf. Kriegel and Williford, 2006).

Proponents of intrinsicalism about higher-order awareness argue that their view squares with the phenomenological sense that distinct higher-order awareness seldom occurs; we are immediately conscious of a conscious state because that awareness is part of the state itself. The advocates of intrinsicalism also urge that it can handle a problem some have raised for higher-order theories. A distinct higher-order perception or thought could misrepresent one's mental life, either by making one conscious of a state in a way that distorts its nature or by making one conscious of a state that one simply is not in. And Joseph Levine (2001) and Karen Neander (1998) have argued that there is no principled answer to what it would be like for one in such a case. Would a sensation of red along with a higher-order awareness of that sensation as green be subjectively like seeing red? Or would it be like seeing green? Intrinsicalism appears to help, since an intrinsic higher-order awareness might be unable to misrepresent the state of which it is a part. But intrinsicalism arguably fails to avoid this concern. There is no reason why a state's higher-order content could not misrepresent that state. If a conscious state is a compound of a content about the world, something green, for example, and content about that very state, the higher-order content might represent the state as being about something red, rather than something green. Thus, Levine's and Neander's worry remains. Further, even intrinsic higher-order content might radically misrepresent the state's first-order content, to the point of severing the representational connection between the two altogether. Intrinsicalism gains no advantage here (Weisberg 2008).

Intrinsicalism cannot sidestep that worry. But, that aside, higher-order theories arguably face no difficulty about such cases. What it's like for one is determined on these theories by the way the higher-order awareness represents the first-order state. Consciousness is a matter of mental appearance, that is, of how our mental states appear to us. And on higher-order theories, that mental appearance is due solely to the higher-order awareness. So those theories offer a determinate answer to Levine's and Neander's worry (see Rosenthal 2004).

Intrinsicalism holds that the higher-order intentional content in virtue of which one is conscious of a conscious state belongs to the state itself, rather than to a distinct state. Whether that is so depends on how we individuate intentional states. We do not do so by the content of the states, since a single state may have compound content that conjoins several simpler contents. Rather, we individuate intentional states by appeal to their mental attitude, such as believing, wondering, desiring, and the like; no single state has two distinct mental attitudes.

But an assertoric mental attitude is needed for one to be conscious of something; doubting or wondering about something does not make one conscious of that thing. The higher-order states that implement TP must have an assertoric mental attitude. So when a doubt, e.g., is conscious, there must be two mental attitudes, the doubting itself and the assertoric attitude in virtue of which one is conscious of the doubt. Since we individuate mental states by way of mental attitude, the higher-order content must accordingly belong to a distinct HOT.

There is an additional difficulty for intrinsicalism. On the Libet (1985) and Haggard (1999) results, we are conscious of states only slightly after those states themselves occur. And intrinsicalism does not fit comfortably with those findings. Perhaps higher-order content arises slightly after the rest of the state, but the intrinsicalist must explain why that higher-order content counts as intrinsic. It remains unclear whether there are substantial advantages to construing higher-order content as intrinsic.

6. Other approaches: dispositional HOT and mixed theories

There are several additional varieties of higher-order theory. Closely related to intrinsicalism is the dispositionalist version of the HOT theory advanced by Peter Carruthers (2000), on which a state is conscious if one is disposed to have a HOT about it. Like intrinsicalism, this dispositionalist theory avoids commitment to distinct, occurrent higher-order states. Carruthers argues that actual HOTs would in effect replicate the first-order states, and would strain our cognitive capacities. All that is required for consciousness, he urges, is that mental states are disposed to cause HOTs, easing the cognitive burden of full replication.

But since we do not now know what cortical resources subserve specific thoughts, we have no reason to think we lack the resources needed for occurrent HOTs. And we may need fewer resources than it seems pretheoretically. Conscious visual perception seems equally acute throughout our visual field. But as Dennett (1991) has stressed, that subjective sense is confabulatory; so we doubtless need far fewer HOTs for conscious parafoveal vision than for conscious central vision (see Weisberg 1999).

There is also an issue about whether a dispositionalist theory can implement TP at all, since simply being disposed to have a thought about something does not result in one's being conscious of that thing. Carruthers seeks to meet this difficulty by appeal to a theory on which a state's intentional content depends in part on what other mental states it is disposed to cause. If a state is disposed to cause a HOT, it thereby has higher-order content itself; it is both about the world and about itself. In this way as well, Carruthers's view resembles intrinsicalism. But on this theory, no state that is even disposed to cause an actual HOT could fail to be conscious. Thus all potentially conscious states will be conscious on this position. Unlike Carruthers's dispositionalist theory, however, intrinsicalism offers no mechanism by which states might come to have the posited intrinsic higher-order content.

Another variation on higher-order theory appeals to the ties to other states and to behavior that mental states seem to have when they are conscious. Global-workspace theories hold that a state is conscious if it has the potential to affect a broad range of mental functioning and behavior. This approach generally makes no appeal to TP or to higher-order content. Robert Van Gulick (2004), however, has sought to combine global-workspace theory with aspects of higher-order theory, arguing that a state's having global connections results in one's being conscious of oneself. But it is questionable whether this view is a type of higher-order theory at all. Van Gulick's appeal to awareness of oneself has an air of being higher-order, but one can be aware of oneself without thereby being aware of any of one's mental states. It is unclear, therefore, how this approach implements TP.

TP aside, it is in any case arguable that global-workspace theories fail. Many states that we do not count as conscious have global connections to many other mental states and to behavior, e.g., many desires and beliefs that aren't conscious. And many indisputably conscious states, such as conscious peripheral perceptions, have at most minimal connections with other mental states and with behavior. Global connectedness may be typical of many conscious states, but it does not distinguish mental states that are conscious from those that are not. And it is unclear that there is any utility to a mental state's being conscious over and above that state's occurring without being conscious (Rosenthal 2008). Thomas Metzinger's (2003) "phenomenal self model" theory also blends elements of higher-order theory and the global-workspace approach. Metzinger contends that a mental state is conscious when (in addition to satisfying other constraints) the subject is aware of that state by way of a model representing self, representational state, and the intentional connections between self, state, and world. This model must be also be appropriately "transparent" to the subject; it must not seem to the subject that the model is present. Thus, Metzinger's view arguably implements TP: The self-model makes one conscious of one's conscious states in a seemingly direct way. In addition, however, Metzinger holds that global-workspace connections as necessary for mental state consciousness. But if workspace connections are neither necessary nor sufficient for state consciousness, Metzinger's theory coincides with the higher-order theory and can be evaluated accordingly, as falling under one or another of the varieties of higher-order theory detailed above (see Weisberg 2003, 2005).

As noted earlier, higher-order theories have an advantage over first-order theories in explaining what it is for a state to be conscious, i.e., how mental states that are conscious differ from those that are not. But there is another question that any theory of consciousness, and higher-order theories in particular, must also address: Given that not all mental states are conscious, why is it that any are conscious at all? As already noted, intrinsicalism by itself offers no suggestion about how some speech acts, but not all, might come to have intrinsic higher-order content. By contrast, theories that appeal to functional role, such as Van Gulick's (2004), can seek to answer this second question by appeal to evolutionary adaptive value. But that explanation requires that the consciousness of mental states have some utility that would subserve the relevant selection pressures. In particular, they would have to have some beneficial role that that the mental states in their nonconscious form do not have. And it is arguable that the added benefit conferred by mental states' being conscious is minimal (Rosenthal 2008). Carruthers's (2000) dispositionalist theory appeals to the social utility of a dedicated capacity to discern what states others are in; but it's unclear why discerning that consciously would have greater utility than doing so nonconsciously. Also, it's not obvious why creatures that were good at discerning what mental states others are in would thereby have similar access to their own, given the reliance on observable behavior in one case, but not in the other.

An explanation is possible, however, that does not appeal to any such utility (Rosenthal, 2005, 2008). The consciousness of qualitative states, such as sensations and perceptions, may be a by-product of a creature's coming to have facility in registering its own perceptual errors (Rosenthal, 2005, pp. 218-9). And the consciousness of purely intentional states, such as thoughts, may be a by-product of the automatic pragmatic equivalence, noted above, between saying something and saying that one thinks that thing (Rosenthal, 2008, §4; 2005, pp. 303-305). In creatures habituated to say, roughly equivalently, that it's raining and that they think it's raining, HOTs will often accompany their first-order intentional states. Nonlinguistic creatures would then have no purely intentional states that are conscious, but pretheoretic intuition arguably insists only that their qualitative states are sometimes conscious.

References

Aristotle (1984), The Complete Works of Aristotle, ed. Jonathan Barnes, Princeton: Princeton University Press.
Armstrong, D. M. (1980), "What is Consciousness?", in Armstrong's The Nature of Mind, St. Lucia, Queensland: University of Queensland Press, 1980, pp. 55-67.
Breitmeyer, Bruno G., and Haluk Ögmen (2006), Visual Masking: Time Slices through Conscious and Unconscious Vision, 2nd edn., New York: Oxford University Press.
Brentano, Franz (1973/1874), Psychology from an Empirical Standpoint, ed. Oskar Kraus, English edition ed. Linda L. McAlister, tr. Antos C. Rancurello, D. B. Terrell, and Linda L. McAlister, London: Routledge & Kegan Paul.
Carruthers, Peter (2000), Phenomenal Consciousness: A Naturalistic Theory, Cambridge: Cambridge University Press.
Dennett, Daniel C. (1991), Consciousness Explained, Boston: Little, Brown and Company.
Dienes, Zoltán, and Josef Perner (2004), "Assumptions of a Subjective Measure of Consciousness: Three Mappings," in Gennaro (2004), pp. 173-199.
Dretske, Fred (1993), "Conscious Experience," Mind, 102, 406: 263-283.
Dretske, Fred (1995), Naturalizing the Mind, MIT Press/Bradford Books.
Dretske, Fred (2006), "Perception without Awareness," in 'Perceptual Experience, ed. Tamar Szabó Gendler and John Hawthorne, Oxford: Clarendon Press, 147-180.
Descartes, René (1984-91), The Philosophical Writings of Descartes, by René Descartes, translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch (vol. III with Anthony Kenny), 3 vols., Cambridge: Cambridge University Press.
Gennaro, Rocco J. (1996), Consciousness and Self-Consciousness, Amsterdam and Philadelphia: John Benjamins Publishing Company.
Gennaro, Rocco J. (2004), ed., Higher-Order Theories of Consciousness, Amsterdam and Philadelphia: John Benjamins Publishers.
Haggard, Patrick (1999), "Perceived Timing of Self-Initiated Actions," in Cognitive Contributions to the Perception of Spatial and Temporal Events, ed. Gisa Aschersleben, Talis Bachmann, and Jochen Müsseler, Amsterdam: Elsevier, pp. 215-231.
Hirstein, William (2005), Brain Fiction: Self-Deception and the Riddle of Confabulation, Cambridge, Massachusetts: MIT Press/Bradford Books.
Kant, Immanuel (1998/1787), 'Critique of Pure Reason, ed. and tr. Paul Guyer and Allen W. Wood, Cambridge: Cambridge University Press.
Kriegel, Uriah (2006), "The Same-Order Monitoring Theory of Consciousness," in Uriah Kriegel and Kenneth Williford (2006), pp. 143-170.
Kriegel, Uriah, and Kenneth Williford (2006), eds., Self-Representational Approaches to Consciousness, Cambridge, Massachusetts: MIT Press/Bradford Books.
Levine, Joseph (2001), Purple Haze: The Puzzle of Consciousness, New York: Oxford University Press.
Libet, Benjamin (1985), "Unconscious Cerebral Initiative and the Role of Conscious Will in Voluntary Action," The Behavioral and Brain Sciences, 8, 4 (December): 529-539.
Locke, John (1975/1700), An Essay Concerning Human Understanding, ed. Peter H. Nidditch, Oxford: Clarendon Press.
Lycan, William G. (1996), Consciousness and Experience, Cambridge, Massachusetts: MIT Press/Bradford Books.
Lycan, William G. (2004), "The Superiority of HOP to HOT," in Gennaro (2004), pp. 93-113.
Marcel, Anthony J. (1983), "Conscious and Unconscious Perception: An Approach to the Relations between Phenomenal Experience and Perceptual Processes," Cognitive Psychology 15: 238-300.
Merikle, P.M., Smilek, D., & Eastwood, J. D. (2001), "Perception without awareness: Perspectives from cognitive psychology," Cognition, 79 (April): 115-134.
Metzinger, Thomas (2003), Being No One: The Self-Model Theory of Subjectivity, Cambridge, Massachusetts: MIT Press/Bradford Books.
Neander, Karen (1998), "The Division of Phenomenal Labor: A Problem for Representational Theories of Consciousness," Philosophical Perspectives, 12: 411-434.
Nisbett, Richard E. and Timothy DeCamp Wilson (1977), "Telling More Than We Can Know: Verbal Reports on Mental Processes," Psychological Review, LXXXIV, 3: 231-259.
Rolls, Edmund T., (2004). "A Higher Order Syntactic Thought (HOST) Theory of Consciousness," in Gennaro (2004), pp. 137-172.
Rosenthal, David M. (1980), "Keeping Matter in Mind," Midwest Studies in Philosophy, V: 295-322.
Rosenthal, David M. (1986), "Two Concepts of Consciousness," Philosophical Studies, 49, 3 (May): 329-359.
Rosenthal, David M. (1997). "A Theory of Consciousness," In Ned Block, Owen Flanagan, & Güven Güzeldere (Eds.), "The Nature of Consciousness: Philosophical Debates, Cambridge, Massachusetts: MIT Press/Bradford Books, pp. 729-753.
Rosenthal, David M. (2004), "Varieties of Higher-Order Theory," in Gennaro (2004), pp. 17-44.
Rosenthal, David M. (2005), Consciousness and Mind, Oxford: Clarendon Press.
Rosenthal, David M. (2008), "Consciousness and Its Function," Neuropsychologia, 46.
Van Gulick, Robert (2004), "Higher-Order Global States (HOGS): An Alternative Higher-Order Model of Consciousness," in Gennaro (2004), pp. 67-92.
Weisberg, Josh (1999), "Active, Thin, and HOT! An Actualist Response to Carruthers' Dispositionalist HOT View," PSYCHE, 5, 6, http://psyche.cs.monash.edu.au/v5/psyche-5-06-weisberg.html
Weisberg, Josh (2003), "Being All That We Can Be: A Critical Review of Thomas Metzinger's Being No One: The Self-Model Theory of Subjectivity," Journal of Consciousness Studies, 10, 11: 89-96.
Weisberg, Josh (2005), "Conscious Constrained: A Commentary on Thomas Metzinger's Being No One," PSYCHE, 8, 17, http://psyche.cs.monash.edu.au/symposia/metzinger/Weisberg.pdf
Weisberg, Josh (2008), "Same Old, Same Old: The Same-Order Representational Theory of Consciousness and the Division of Phenomenal Labor," Synthese, 160, 2 (January): 161-181.
Weiskrantz, Lawrence (1997), Consciousness Lost and Found: A Neuropsychological Exploration, Oxford: Oxford University Press.

Internal references

Larry Weiskrantz (2007) Blindsight. Scholarpedia, 2(4):3047.

Thomas Metzinger (2007) Self models. Scholarpedia, 2(10):4174.

Higher-order theories of consciousness

Contents

2. The transitivity principle

3. Inner-sense theory

4. Distinct higher-order thoughts

5. Intrinsic higher-order thoughts

6. Other approaches: dispositional HOT and mixed theories

References

Recommended reading

External links

See also

Personal tools

Namespaces

Variants

Views

Actions

Search

Navigation

Focal areas

Activity

Tools