David M. Rosenthal
City University of New York, USA

The terms ‘conscious’ and ‘consciousness’ are used to refer to three different things.

(1) Most commonly these terms are used to describe people. People and other creatures are conscious if they are awake and responsive to sensory stimulation. Because this is a property of creatures, we can call it creature consciousness. An individual lacks such consciousness if it is asleep, in a coma, anesthetized, and so forth. Creature consciousness demands a mainly biological explanation, as against an explanation in mainly psychological terms.

(2) We also use ‘conscious’ to refer to an individual’s being conscious of something, either by sensing or perceiving that thing or by having thoughts about it as being present to the individual. Being conscious of something is the same as being aware of that thing. Because this use of ‘conscious’ demands a grammatical complement (being conscious of something), it is useful to call this phenomenon transitive consciousness.

(3) It is also common to distinguish thoughts, feelings, desires, perceptions, and other mental states that are conscious from those that are not. Because this kind of consciousness is a property of mental states, we can call it state consciousness. Both transitive and state consciousness require significant explanation in terms that are at least partly psychological, as against the predominantly biological explanation that suffices for creature consciousness.

Understanding transitive consciousness is mainly a matter of knowing what it is for a thought to be about something and what it is for a perception or sensation to be of something. These questions, though important, are not specifically about consciousness, but are more generally about the nature of thinking, sensing, and perceiving. So the pressing, unresolved questions that are specific to consciousness primarily concern state consciousness, that is, what it is for a thought, desire, perception, or other mental state to be conscious state.

Even when we are awake, not all the mental states we are in are conscious; so state consciousness is a distinct phenomenon from creature consciousness. State consciousness is also distinct from transitive consciousness. Perceiving is sometimes subliminal; an individual perceives something but is wholly unaware of doing so. Also, people’s behavior sometimes indicates that they have occurrent thoughts that they do not realize they have. These subliminal perceptions and unconscious thoughts often make the person who has them conscious of things, even though those states are not themselves conscious. We describe these cases colloquially as an individual’s being aware of something, but not consciously aware of that thing.

When there is convincing reason to think that an individual has a thought, desire, or perception but that individual is not at all conscious of those states, those states are not conscious. That implies that an individual’s mental states are conscious only if that individual is conscious of those states. Because this connection points to an explanation of state consciousness in terms of transitive consciousness, we can call it the transitivity principle.

The transitivity principle is widely acknowledged as providing a framework within which to study state consciousness. Indeed, prior to the late nineteenth century, mental states were seldom described as conscious. Instead, people spoke only of individual’s being conscious, in some immediate way, of that individual’s mental states. But it is clear that people were thereby saying of those states what we now say by describing them as conscious. This is evidence in support of the transitivity principle.

Though most current theories of state consciousness adopt the transitivity principle, that principle provides only a necessary condition for a mental state’s being conscious, and not a sufficient condition as well. Thus one might be aware that one has a thought, perception, or desire even when that state is not a conscious state. For example, one might be aware of thinking or desiring something only by noticing one’s own behavior or taking the word of somebody else who observes one’s behavior. But if one is not also aware of the state in a subjectively unmediated way, that state is not conscious.

Theories of state consciousness that adopt the transitivity principle and so agree that a state’s being conscious involves one’s being conscious of that state still sometimes differ about how we are aware of our conscious states (Rosenthal 2004). The most widely adopted traditional answer has been that we are aware of our conscious states by way of some inner sense (Locke 1975/1700, Kant 1998/1787). This is inviting because sensing seems subjectively unmediated, as does our awareness of our conscious states.

But one is also conscious of something when one has a thought about that thing as being present to one. And such thoughts can seem subjectively to be no less unmediated than our perceptions of things. So many contemporary theories hold that we are aware of our conscious states by having a thought that one is in those states. Because those thoughts are about other mental states, they are typically called higher-order thoughts (Rosenthal 2005).

Some theorists hold that these higher-order thoughts are dispositional states. But this is doubtful. Since merely being disposed to have a thought about something does not make one conscious of that thing, dispositional higher-order thoughts about one’s mental states would not make one conscious of those states.

Others hold that we are aware of a conscious state not by having a higher-order thought about the state, but because the state itself has, in addition to its ordinary mental properties, some higher-order content to the effect that one is in that state (Brentano 1973/1874). But it is difficult to come up with a suitable way of individuating mental states that permits that result. We individuate thoughts and other intentional states by reference to their mental attitude, for example, of believing, desiring, doubting, and the like. No single intentional state is case of both believing and wondering or of doubting and anticipating. Since many mental attitudes, such as doubting and wondering, do not make one conscious of anything, any higher-order content in virtue of which such a state is conscious must belong to a distinct state. So it is likely that the higher-order content belongs in all cases to a distinct state.

It is therefore likely that we are aware of our conscious states by having distinct, occurrent higher-order thoughts about them. An important consideration that independently points toward that conclusion involves the reporting of one’s own mental states. It is standard to determine whether somebody’s thought, desire, or perception is conscious by whether that individual can report being in the state. This test for state consciousness is not only common in everyday contexts, but is standard in experimental psychology as well.

Reports are assertions, and so express thoughts with the same content. So if one reports being in a particular mental state and that report subjectively involves no mediation by inference or observation, one expresses a subjectively unmediated higher-order thought that one is in that state. The ability to report a mental state is therefore a good indication that one has the very higher-order thought that one can report. Similarly, the inability to report a state indicates the absence of any such higher-order thought. The reportability test points to distinct, occurrent higher-order thought as the vehicle by means of which we are aware of our conscious mental states.

Some theorists contend that sensations and other qualitative states are essentially conscious and that their qualitative character and consciousness are therefore inseparable. But the occurrence of subliminal perceiving indicates otherwise; subliminal perceptions have qualitative character but are not conscious. It is also sometimes doubted that the consciousness of qualitative character could be due to higher-order thoughts about the relevant states. But thoughts can influence the way we experience things qualitatively, as when we drink apple juice when we expected iced tea. This influence of thoughts suggests that higher-order thoughts may well be responsible for what it is like for one to be in a qualitative state.

REFERENCES

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.
Kant, Immanuel (1998/1787). Critique of Pure Reason. tr. Paul Guyer and Allen W. Wood. Cambridge: Cambridge University Press.
Locke, John (1975/1700). An Essay Concerning Human Understanding. Ed. Peter H. Nidditch. Oxford: Oxford University Press.
Rosenthal, David M. (2004). Varieties of Higher-Order Theory. in Higher-Order Theories of Consciousness. Ed. Rocco J. Gennaro. Amsterdam and Philadelphia: John Benjamins Publishers, pp. 17-44.
Rosenthal, David M. (2005). Consciousness and Mind. Oxford: Clarendon Press.