Cover of the first edition
|Author||Daniel C. Dennett|
|Publisher||Little, Brown and Co.|
|Media type||Print (Hardcover and Paperback)|
|LC Class||B105.C477 D45 1991|
|Preceded by||The Intentional Stance|
|Followed by||Darwin's Dangerous Idea|
Consciousness Explained is a 1991 book by the American philosopher Daniel Dennett, in which the author offers an account of how consciousness arises from interaction of physical and cognitive processes in the brain.
Dennett puts forward a "multiple drafts" model of consciousness, suggesting that there is no single central place (a "Cartesian theater") where conscious experience occurs; instead there are "various events of content-fixation occurring in various places at various times in the brain". The brain consists of a "bundle of semi-independent agencies"; when "content-fixation" takes place in one of these, its effects may propagate so that it leads to the utterance of one of the sentences that make up the story in which the central character is one's "self". Dennett's view of consciousness is that it is the apparently serial account for the brain's underlying parallelism.
One of Dennett's more controversial claims is that qualia do not (and cannot) exist as qualia are described to be. Dennett's main argument is that the various properties attributed to qualia by philosophers—qualia are supposed to be incorrigible, ineffable, private, directly accessible and so on—are incompatible, so the notion of qualia is incoherent. The non-existence of qualia would mean that there is no hard problem of consciousness, and "philosophical zombies", which are supposed to act like a human in every way while somehow lacking qualia, cannot exist. So, as Dennett wryly notes, he is committed to the belief that we are all philosophical zombies (if you define the term "philosophical zombie" as functionally identical to a human being without any additional non-material aspects)—adding that his remark is very much open to misinterpretation.
Dennett claims that our brains hold only a few salient details about the world, and that this is the only reason we are able to function at all. Thus, we do not store elaborate pictures in short-term memory, as this is not necessary and would consume valuable computing power. Rather, we log what has changed and assume the rest has stayed the same, with the result that we miss some details, as demonstrated in various experiments and illusions, some of which Dennett outlines. Research subsequent to Dennett's book indicates that some of his postulations were more conservative than expected. A year after Consciousness Explained was published, Dennett noted "I wish in retrospect that I'd been more daring, since the effects are stronger than I claimed". Since then, examples continue to accumulate of the illusory nature of our visual world.
A key philosophical method is heterophenomenology, in which the verbal or written reports of subjects are treated as akin to a theorist's fiction—the subject's report is not questioned, but it is not assumed to be an incorrigible report about that subject's inner state. This approach allows the reports of the subject to be a datum in psychological research, thus circumventing the limits of classical behaviorism.
Dennett says that only a theory that explained conscious events in terms of unconscious events could explain consciousness at all: "To explain is to explain away".
Critics of Dennett's approach, such as David Chalmers and Thomas Nagel, argue that Dennett's argument misses the point of the inquiry by merely redefining consciousness as an external property and ignoring the subjective aspect completely. This has led detractors to nickname the book Consciousness Ignored and Consciousness Explained Away. Dennett and his eliminative materialist supporters, however, respond that the aforementioned "subjective aspect" of conscious minds is nonexistent, an unscientific remnant of commonsense "folk psychology", and that his alleged redefinition is the only coherent description of consciousness.
However, John Searle argues that Dennett, who insists that discussing subjectivity is nonsense because it is unscientific and science presupposes objectivity, is making a category error. Searle argues that the goal of science is to establish and validate statements which are epistemically objective (i.e., whose truth can be discovered and evaluated by any interested party), but are not necessarily ontologically objective. Searle calls any value judgment epistemically subjective. Thus, "McKinley is prettier than Everest" is epistemically subjective, whereas "McKinley is higher than Everest" is epistemically objective. In other words, the latter statement is evaluable (in fact, falsifiable) by an understood ("background") criterion for mountain height, like "the summit is so many meters above sea level". No such criteria exist for prettiness. Searle writes that, in Dennett's view, there is no consciousness in addition to the computational features, because that is all that consciousness amounts to for him: mere effects of a von Neumann(esque) virtual machine implemented in a parallel architecture and therefore implies that conscious states are illusory. In contrast, Searle asserts that, "where consciousness is concerned, the existence of the appearance is the reality."
Searle wrote further:
To put it as clearly as I can: in his book, Consciousness Explained, Dennett denies the existence of consciousness. He continues to use the word, but he means something different by it. For him, it refers only to third-person phenomena, not to the first-person conscious feelings and experiences we all have. For Dennett there is no difference between us humans and complex zombies who lack any inner feelings, because we are all just complex zombies. ...I regard his view as self-refuting because it denies the existence of the data which a theory of consciousness is supposed to explain...Here is the paradox of this exchange: I am a conscious reviewer consciously answering the objections of an author who gives every indication of being consciously and puzzlingly angry. I do this for a readership that I assume is conscious. How then can I take seriously his claim that consciousness does not really exist?
- Dennett 1991, p. 365
- Dennett 1991, p. 260
- Dennett 1991, p. 406. "Are zombies possible? They're not just possible, they're actual. We're all zombies. Nobody is conscious — not in the systematically mysterious way that supports such doctrines as epiphenomenalism." In a footnote Dennett states: "It would be an act of desperate intellectual dishonesty to quote this assertion out of context!"
- Spinney 2000
- Dennett 1991. See e.g. chapter 5 on "Orwellian and Stalinesque Revisions". Memory is central to much of Dennett's book, with reference found throughout.
- Spinney 2000, p.30
- Barash 2003
- Carruthers 2005, p. 32
- Searle, J R: The Mystery of Consciousness (1997) p. 95–131
- Barash, David P. (March 22, 2003), "Dennett and the Darwinizing of Free Will", Human Nature Review, 3, pp. 222–225
- Carruthers, Peter (2005), Consciousness: Essays from a Higher-order Perspective, Oxford University Press, p. 247, ISBN 978-0-19-927735-3
- Dennett, Daniel (1991), Allen Lane (ed.), Consciousness Explained, The Penguin Press, ISBN 978-0-7139-9037-9
- Spinney, Laura (November 18, 2000), "Blind to change", New Scientist (No.2265), pp. 29–32
- Dennett, Daniel (1988). Quining Qualia.
- Lormand, E. Qualia! (Now Showing at a Theater near You)
- de Leon, D. The Qualities of Qualia