Arguing over feely stuff

In Anglo-American or "analytic" philosophy, consciousness is one of the topics of the moment. For various different reasons, the first three-quarters of this century saw little attention paid to the investigation of consciousness in analytic philosophy. Gottlob Frege's massively influential work in the philosophy of language, mathematics and logic was premised on the rejection of psychologism: the doctrine that logic and meaning should be explained in psychological terms. With this rejection of psychologism came a lack of concern with traditional philosophical questions about perception, thought and consciousness.

The logical positivists rejected questions about consciousness for very different reasons. They were committed to verificationism, the doctrine that the only meaningful claims are those which can be scientifically tested. Questions about consciousness were considered beyond the reach of scientific investigation, and therefore meaningless. Insofar as psychology could be a genuine science, it must be behaviouristic, since only public, observable behaviour could be the subject of precise testing. This behaviourism remained at the heart of W. V. Quine's influential work, along with an independent suspicion of the coherence of philosophers' talk of the mind as a kind of theatre, with its objects laid out in an inner realm for inspection by the inner eye of consciousness.

We find a similar suspicion about "the inner" in the work of the postwar British philosopher of mind, Gilbert Ryle (The Concept of Mind) and Ludwig Wittgenstein, in his later work. Ryle explicitly attacked something he called "Descartes' myth" and Wittgenstein is sometimes taken as opposing the Cartesian picture of the mind. These targets have little in common with Descartes' actual views, and the Cartesian view is often formulated either in a way that makes the view so massively implausible that it is hard to see why anyone would bother attacking it, or in a way that is insufficiently precise as to make it unworthy of further discussion. What opponents of Cartesianism want to attack is a collection of the following ideas: the mind is a thing; the mind is not necessarily linked to the body or to the environment outside the mind; the mind is an inner theatre; the mind knows its own contents with a special authority, by means of a mechanism of inner sense or introspection. Many anti-Cartesians want to say instead that the mind is not a thing, but a kind of activity, it is essentially embodied and linked to its environment and the contents of the mind are not known in a special or authoritative way.

It is perhaps not surprising, then, that with all these different conceptual forces at work it was hard to make a place for the study of consciousness within analytic philosophy. Things were different in the so-called phenomenological tradition in philosophy, the tradition which (like the analytic tradition) has its roots in 19th-century Central Europe, but with the work of Edmund Husserl, Maurice Merleau-Ponty, Jean-Paul Sartre and Martin Heidegger, it somehow ended up with a very different set of preoccupations from those of the analytic tradition. "Phenomenology" literally means the theory of phenomena or appearances, but in Husserl's hands it became the name for a specific approach to mental appearances, or how our minds strike us. To exaggerate somewhat, Husserl's view was that at the foundation of philosophy, consciousness was the only thing that could be studied. The world must be "bracketed" (ie no substantial assumptions must be made about the underlying nature of things) and the starting point for philosophy was the precise characterisation of things as they appear before the mind - an approach that contrasts strikingly with the logical positivists' view that descriptions of consciousness should play no part in scientific philosophy at all.

However, it was hard for analytic philosophy to resist the intuitive intellectual pull of the problems of consciousness, and whatever the merits of Ryle's and Wittgenstein's attacks on the Cartesian picture, it is plain that to believe in consciousness, and to believe it raises philosophical problems, is not the same as being a Cartesian in this sense. An influential essay which invigorated analytic discussions of consciousness was Thomas Nagel's "What is it like to be a bat?", in which Nagel argued that "consciousness is what makes the mind-body problem really intractable ... without consciousness the mind-body problem would be much less interesting. With consciousness it seems hopeless." Since Nagel's article was published in 1974, analytic philosophers of mind have largely moved away from the behaviouristic positions of Ryle and Quine, and the problem of consciousness has become one of their main preoccupations.

The Nature of Consciousness brings together 50 essays, mostly reprinted from other sources, and mostly by philosophers, on the problems of consciousness. The book contains a long, highly readable introduction by Guven Guzeldere and divides into ten sections on such subjects as the metaphysics of consciousness, consciousness and content (ie mental representation) and consciousness and science. One hundred pages are devoted to some useful survey articles from the psychological and neuropsychological literature. Many of the articles will be familiar to those working in the field, but they are helpfully arranged here, with responses and counter-responses following on from key articles. Without doubt, this is the biggest, and best, anthology of writings on the philosophy of consciousness available. It will be an invaluable resource for scholars and research students.

With any anthology, one will have reservations about what gets left out, and what is put in. The writings of the phenomenologists - Franz Brentano, Husserl, Merleau-Ponty and Sartre - are completely ignored, which is perhaps understandable given the volume's aim to be as up-to-date as possible. But it does leave the unfortunate impression that these philosophers were working in such a different "tradition" that we analytic philosophers do not need to consider them. In fact, such talk of traditions is normally rather vague, and has the effect of cutting off potentially fruitful lines of investigation. The truth of the matter is that contemporary philosophy of mind will find more to discuss in the work of Merleau-Ponty (for example) than it will in Wittgenstein's Tractatus.

But one cannot expect everything from an anthology that attempts to cover issues in depth. A more just criticism of the volume concerns its conception of the problem area, even within analytic philosophy. For one odd thing about this book is that its size is not an indication of a wide range in its contents. As the above quote from Nagel indicates, one major question about consciousness is part of the mind-body problem: how are mental and physical phenomena related? The difficulty consciousness poses is that it is hard to understand how a mere physical thing, the brain, can produce something which seems so unphysical as consciousness. How can the manifest existence of consciousness be reconciled with the physicalist view that everything is fundamentally constituted by purely physical matter? It is fair to say, I think, that about half of the essays in this book are concerned directly with this question, and many more are concerned with it indirectly.

But there are other questions too. There are questions which do not directly address the issue of physicalism, but are concerned with how to properly characterise the phenomena of consciousness. For instance, there is little in this anthology about how perceptual experience should be understood (four papers), or bodily awareness (one paper) or conscious thought (two papers). Or if these subjects are discussed, the main interest is often solely in their bearing on the question of physicalism. Yet unless the phenomena of consciousness themselves are investigated in more depth, it is hard to understand a pervasive feature of the debate about consciousness: how there seems to be deep and irreconcilable disagreement about the obvious.

To take one example: many philosophers think that the consciousness of a mental state should be understood in terms of the state's having certain qualitative properties, or "qualia". Qualia are defined as those properties which give a mental state its characteristic "feel". Given this, it is hard to see how there can be disagreement about the existence of qualia. As Ned Block once said, echoing a remark of Louis Armstrong's (about jazz): if you have to ask what qualia are, you ain't never going to get to know. But there is such disagreement: a whole section of this anthology is devoted to the nature and existence of qualia. Some (like Daniel Dennett) deny the existence of qualia; others (like Gilbert Harman) think that what people call qualitative features are really representational features. How can we make sense of this disagreement? Given the innocuous way qualia were introduced into the debate, how can anyone deny that there are qualia? And how, in general, can there be disagreement about how conscious experience seems to us? It is curious how little illumination is shed on this question by the essays in this otherwise excellent anthology.

Tim Crane is reader in philosophy, University College London.