Though the days of consciousness-raising are mostly passed, the days of consciousness seem to be upon us, or, at least, to be upon philosophers. Dennett's recent Consciousness Explained is the flagship for a flotilla of new major works on the subject, by Flanagan (1992), Jackendoff (1988), Searle (1992), Seager (1992) and others. It seems to be something of a convention in such work that one begins by complaining that consciousness is a sorely neglected topic among philosophers; this cliché has created the faintly comical situation in which everyone is saying that no one is talking about consciousness. For our part, therefore, we shall seek to escape the convention by inverting it: here are yet more papers about consciousness.

Thanks largely to Daniel Dennett, I am a recent convert to what many will regard as the shocking hypothesis that qualia do not exist. This admission is not quite a confident sighting of that rarest of philosophical birds, an unequivocally sound and valid argument. For one thing, I have, like many, been frustrated by and suspicious of philosophers' use of qualia for some time, and have often wished them dead (the qualia, not the philosophers); so I was an easy mark. More to the point, I was persuaded by Dennett without being persuaded by his arguments. This is not intended as a confession of a Kirkegaardian penchant for preferring to believe the conclusions of bad arguments. Dennett enabled me finally to kick qualia out of my private (now public) ontology by providing, in the later sections of his “Quining Qualia” (Dennett 1988), an alternative conceptual vocabulary for talking about the contents of perceptual and reflective experience that genuinely makes no appeal, surreptitious or otherwise, to qualia. Furthermore, Dennett's most general motivations for banishing qualia—the convictions that there is no compelling evidence for them, that they serve no reliable explanatory purpose and that the hypothesis of their non-existence dissolves some otherwise wrenching philosophical dilemmas—are the right ones, and his paper made this clear to me. However, I feel the need to quine qualia again for myself, because I want them to stay dead, and am afraid that, due to some infelicities in his argument, Dennett has only wounded them.

Depuis fort longtemps le matérialisme – ou, si l'on veut, la physique – se présente comme la théorie universelle, celle qui dévoile la vraie nature de toute chose et est done capable de tout expliquer. Cette prétention grandiose s'est toujours butée contre certains phénomènes psychiques qu'il paraissait invraisemblable de croire réductibles à la simple matière. Mais au cours de ce siècle un grand nombre de ces phénomènes psychiques ont été conquis par le matérialisme. Ainsi la biologie moléculaire a intégré la vie à la physique; linformatique nous a montré que la simple matière peut être capable de faire des ealculs rationnels et la cybernétique la dote de comportements finalisés. Ce sont là des progrès importants et qui s'accélèrent: la victoire du matérialisme semble assurée.

Qualia are phenomenal properties of sensations and perceptual states: they are whatever it is that gives such states their “felt,” qualitative character. (In speaking of sensations, I speak of course not of mental objects or mental contents, but of mental events—of sensings, not sensa.)

Deux ou trois articles (plus ou moins) récents, Nagel (1974), Block (1978), Jackson (1982), forment la toile de fond de discussions actuelles au sujet des qualia et du caractère subjectif de l'expérience, du moins en philosophie de l'esprit. Ces articles ont ceci en commun qu'ils visent tous à montrer qu'un certain aspect de l'expérience consciente – les qualia ou sa dimension subjective – remet en cause l'une ou l'autre, ou l'ensemble (Jackson 1982, 1986) de nos théories psychophysiques. Ce qui est visé, au-delà des théories psychophysiques, c'est le physicalisme, entendu comme une théorie métaphysique portant sur l'ameublement de l'univers, comme l'affirmation que tout ce qui existe ce sont des objets physiques et des propriétés physiques ou des propriétés survenantes sur des propriétées physiqus. C'est pourquoi le point où l'attaque porte est le réductionnisme des théories qui affirment l'identité des états mentaux (ou des événements mentaux) et des états physiques (ou des événements physiques) du cerveau. Peu importe la forme précise de ces théories, qu'elles affirment l'identité des éats mentaux individuels avec des états individuels du cerveau (token identity) ou l'identité des types d'états mentaux avec des types d'états cérébraux, ou encore l'identité des états fonctionnels du cerveau avec les éetats mentaux, toutes sont censées trouver ici, dans deux ou trois expériences de pensée, leurs limites ou le sceau de leur échec.

Le modèle causaliste en théorie de l'action a pour point de départ l'idée que les rationalisations sont des explications causales de l'action, c'est-à-dire que les énoncés à propos des croyances et des pro-attitudes qui ont motivé un agent à accomplir une certaine action expriment les antécédents causaux de cette action. Pour reprendre un des exemples classiques, le meurtre de César par Brutus a été causé par le désir que Brutus avait de prendre le pouvoir et par sa croyance que la seule façon d'y parvenir était d'éliminer César. Bien qu'intuitive, cette position soulève immédiatement un problème du fait que les états intentionnels, en raison de leur contenu propositionnel, ne s'imposent pas d'office comme appartenant au règne des choses physiques et de la causalité. Comment, en effet, des entités d'ordre mental peuvent-elles interagir avec les entités complètement différentes que sont les événements physiques? Et même, plus largement, comment un événement mental peut-il avoir une quelconque efficace causale sur un événement physique ou sur un autre événement mental? Une réponse bien connue à cette difficulté est le monisme anomal de Davidson, selon lequel il n'y a pas d'obstacle à ce que le mental soit en relation causale avec le physique puisque les occurrences d'événements mentaux sont identiques à des occurrences d'événements physiques. Toutefois cette approche, qui, comme bien d'autres, mise sur une stratégie matérialiste pour ne pas isoler le mental du physique, en a conduit plus d'un à douter de l'indispensabilité du mental.

L'intentionnalité pose aux philosophes qui se réclament du matérialisme ou du physicalisme deux problèmes complémentaires qui sont les deux faces d'une même médaille. Premièrement, peut-on naturaliser l'intentionnalité? Deuxièmement, les propriétés intentionnelles des représentations sont-elles causalement efficaces? Un moteur peut-il être sémantique?

Those familiar with Paul Churchland's earlier work will expect A Neuro-computational Perspective to be lively, provocative and interesting. They will not be disappointed. Churchland is best known for his sceptical view of belief-desire psychology. He suspects this theory is hopelessly false. This welcome collection of his essays includes this work but also his papers on the subjective aspects of the mind and his more recent adventures in philosophy of science. Three themes unify the collection: an anti-sententialist view of cognition, an emphasis on the plasticity of the human mind and a strong endorsement of connectionist models of human cognitive processes.

The book under review consists of a “Problems” section, with chapters entitled “Ontology,” “Thought” and “Language”; and a “Proposals” section, with like-titled chapters. The first section is a survey; as might be expected of one of 126 pages, compression is the watchword. The reviewer felt that it did not live up to dust jacket copy, heralding a book “easily accessible to undergraduates.”

To approach the philosophical anthropology (p. 4) of Donald Davidson is to get ready for an unusually high number of laps around the hermeneutic circle. Apparently a problem-oriented philosopher, Davidson presents his views in a continuing series of dense, tightly focussed papers on narrowly circumscribed topics. The lines of the big picture are mostly implicit. Yet it is the scope and the power of this picture that has made Davidson one of the most significant philosophers of this century. Naturally, this makes Davidson's work an extremely tempting—and extremely treacherous—target for the exegete with synthesizing tendencies. Until now, the sense of danger seems to have won out; secondary expositions have largely confined themselves to particular aspects of his thought. For those seeking to appreciate the cohesion and comprehensiveness of Davidson's vision, there has been no alternative but, as Ted Honderich says, to “struggle and learn,” working their way through Davidson's papers, continually calibrating and recalibrating interpretations of Davidson's detailed philosophical proposals with the emerging pattern of their interrelationships.

The Laboratory of the Mind was written with two purposes in mind. The first was to contribute to the growing literature on thought experiments (TE) with a selection of the most interesting examples of the genre. The second and much more ambitious purpose was to serve as a “first attempt at a (modern) rationalist interpretation of science” (p. x).

Can we succeed in giving consciousness a naturalistic explanation, that is, an explanation in “broadly physical terms” (p. 23)? This is the “problem of consciousness” which, along with other aspects of the mind-body problem, is explored by McGinn in a collection of eight independently written but related, sometimes overlapping papers, all but two previously published. The papers span a decade and divergent approaches. The resulting juxtaposition of two contrasting “resolutions” of the problem by the same author invites their comparison.

Stephen Braude, a philosopher, believes that scientists, scholars and intellectuals ignore the wide range of evidence for psychic phenomena. They dismiss what is known and refuse to inquire further. He uses strong words such as “intellectual dishonesty and cowardice.” He means me and probably you. He made these allegations in his second book on parapsychology, The Limits of Influence, which is subtitled Psychokinesis and the Philosophy of Science. It was published in 1986. The editor of Dialogue thought that the charges had not been adequately discussed, and that the appearance of a paperbound edition would be a good occasion to treat them seriously.

Pollock's How to Build a Person is a highly sophisticated defence of the “strong” Artificial Intelligence (AI) program within the framework of a physicalist/functionalist ontology. Its central thesis is as robust as any defender of strong AI could possibly want it to be: to build a person—“a thing that literally thinks, feels, and is conscious” (p. ix)—is to build a physical system that adequately models human rationality; and building such a system is, essentially, a computational task. The epistemological groundwork for the computational task (a task already underway at the University of Arizona under the name “the OSCAR project”) is sketched in the sixth and last chapter of the book—a 64-page-long chapter (“Cognitive Carpentry”) where Pollock presents the main lines of a general theory of rationality which he has been developing over the course of many years. The bulk of the book (chaps. 1 to 4) is devoted to an articulation and defence of what Pollock takes to be the metaphysical underpinnings of his conception of a person as an intelligent machine: token-physicalism, agent materialism, psychophysical supervenience and (a form of) analytical functionalism. This part of the book, which will be the focus of this review, provides an account of “the physical basis for mentality”—an account of what it is that makes a physical structure capable of having mental states relevantly like our own. And since on the proposed account mental capacity “involves a way of codifying information—a system of mental representations” (p. 93), Pollock devotes a chapter (chap. 5) to the semantics of “the language of thought”; though basically a digression, since “semantics plays no role” in the computations involved in rational thought, the chapter is intrinsically very interesting, bearing as it does on current debates on thought ascription and content individuation.

This book on the Tractatus is lauded, on the dust jacket, as “the first to make sense of the work as a whole.” Both new and veteran readers of Wittgenstein, we are told, “will benefit from Donald Peterson's exceptionally clear explication and commentary on this crucial work of the twentieth century.” Grand claims, these; and both of them arguably false. To be sure, Peterson writes well; and there are parts of the book—especially those dealing with Wittgenstein's Grundgedanke (chap. 4) and Notation (chap. 7)—from which all will benefit. But the clarity of his writing can beguile neophyte and incautious veteran alike into supposing that the ideas he explicates are Wittgenstein's rather than the author's own.

In his Autobiography Russell describes how, in 1895, having recently completed his undergraduate studies in mathematics and philosophy at Cambridge, he formed the intellectual project that was to inform the rest of his life:

I remember a cold, bright day in early spring when I walked by myself in the Tiergarten, and made projects of future work. I thought I would write one series of books on the philosophy of the sciences from pure mathematics to physiology, and another series of books on social questions. I hoped that the two series might ultimately meet in a synthesis at once scientific and practical. My scheme was largely inspired by Hegelian ideas. Nevertheless I have to some extent followed it in later years, as much at any rate as could have been expected. (Autobiography 1.125)