David Rosenthal

Consciousness and Mind presents David Rosenthal's influential work on the nature of consciousness. Central to that work is Rosenthal's higher-order-thought theory of consciousness, according to which a sensation, thought, or other mental state is conscious if one has a higher-order thought (HOT) that one is in that state. The first four essays develop various aspects of that theory. The next three essays present Rosenthal's homomorphism theory of mental qualities and qualitative consciousness, and show how that theory fits with and helps sustain the HOT theory. A crucial feature of homomorphism theory is that it individuates and taxonomizes mental qualities independently of the way we're conscious of them, and indeed independently of our being conscious of them at all. So the theory accommodates the qualitative character not only of conscious sensations and perceptions, but also of those which fall outside our stream of consciousness. Rosenthal argues that, because this account of mental qualities makes no appeal to consciousness, it enables us to dispel such traditional quandaries as the alleged conceivability of undetectable quality inversion, and to disarm various apparent obstacles to explaining qualitative consciousness and understanding its nature. Six further essays build on the HOT theory to explain various important features of consciousness, among them the complex connections that hold in humans between consciousness and speech, the self-interpretative aspect of consciousness, and the compelling sense we have that consciousness is unified. Two of the essays, one an extended treatment of homomorphism theory, appear here for the first time. There is also a substantive introduction, which draws out the connections between the essays and highlights their implications.

red and round. According to common sense, the red, round thing we see is the tomato itself. When we have a hallucinatory vision of a tomato, however, there may be present to us no red and round phys- ical object. Still, we use the words 'red' and 'round' to describe that situation as well, this time applying them to the visual experience itself. We say that we have a red, round visual image, or a visual experience of a red disk, or some such. Because we see physical objects far more often than we hallucinate, we apply terms for color and shape to physical objects far more often than to visual experiences. Moreover, different theories of perception explain in different ways the applications such terms have to physical objects and to visual experiences. But whatever their frequency and explanation, it seems clear that both sorts of application occur

Theories of what it is for a mental state to be conscious must answer two questions. We must say how we're conscious of our conscious mental states. And we must explain why we seem to be conscious of them in a way that's immediate. Thomas Natsoulas distinguishes three strategies for explaining what it is for mental states to be conscious. I show that the differences among those strategies are due to the divergent answers they give to the foregoing questions. Natsoulas finds most promising the strategy that amounts to the higher-order-thought hypothesis that I've defended elsewhere. But he raises a difficulty for it, which he thinks probably can be met only by modifying that strategy. I argue that this is unnecessary. The difficulty is a special case of a general question, the answer to which is independent of any issues about consciousness. So it's no part of a theory of consciousness to address the problem, much less solve it. Moreover, the difficulty seems to have intuitive force only given the picture that underlies the other two explanatory strategies, which both Natsoulas and I reject

Much of the perplexity that motivates modern discussion of the nature of mind derives indirectly from the striking success of physical explanation. Not only has physics itself advanced at a remarkable pace in the last four centuries; every hope has been held out that, in principle, all science can be understood and ultimately studied in terms of mechanisms proper to physics. Seeing all natural phenomena as explicable in terms appropriate to physics, however, makes the mental seem to be a singularity in nature. Chemistry and biology may well be reducible to physics, but the same seems hardly possible for the mental. The gulf between mind and physics seems too great to bridge, and the success of physics guarantees its standing. The place of mind in nature is thereby rendered problematic. This line of reasoning has tempted thinkers since Descartes to see the mind as not only independent of other natural phenomena, but as even somehow lying outside the natural order itself

Striking experimental results by Benjamin Libet and colleagues have had an impor- tant impact on much recent discussion of consciousness. Some investigators have sought to replicate or extend Libet’s results (Haggard, 1999; Haggard & Eimer, 1999; Haggard, Newman, & Magno, 1999; Trevena & Miller, 2002), while others have focused on how to interpret those findings (e.g., Gomes, 1998, 1999, 2002; Pockett, 2002), which many have seen as conflicting with our commonsense picture of mental functioning

Edited in hypertext by Andrew Chrucky. Reprinted with the permission of Professor David Rosenthal. Editor's Note: Due to the limitation of current hypertext, the following conventions have been used. In general, if an expression has some mark over it, that mark is placed as a prefix to the expression. All Greek characters are rendered by their names. Subscripts are placed in parentheses as concatenated suffixes: thus, e.g., HO is the chemical formula for water. Sellars' dot quotes are expressed by bold periods

As G. E. Moore famously observed, sentences such as 'It's raining but I don't think it is', though they aren't contradictory, cannot be used to make coherent assertions.' The trouble with such sentences is not a matter of their truth conditions; such sentences can readily be true. Indeed, it happens often enough with each of us that we think, for example, that it isn't raining even though it is. This shows that such sentences are not literally contradictory. But even though such sentences have unproblematic truth conditions, we cannot say the same about their conditions of assertibility. There are no circumstances in which one can use such sentences to perform coherent assertoric speech acts. Situations exist in which these sentences would be true, but none in which anybody could use them to say so

No mental phenomenon is more central than consciousness to an adequate understanding of the mind. Nor does any mental phenomenon seem more stubbornly to resist theoretical treatment. Consciousness is so basic to the way we think about the mind that it can be tempting to suppose that no mental states exist that are not conscious states. Indeed, it may even seem mysterious what sort of thing a mental state might be if it is not a conscious state. On this way of looking at things, if any mental states do lack consciousness, they are exceptional cases that call for special explanation or qualification. Perhaps dispositional or cognitive states exist that are not conscious, but nonetheless count as mental states