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哲學家丹勒過世--Jane O'Grady
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我不熟悉丹勒教授的思想和著作，但經常在書本和論文中看到他的大名以及引用他的觀點。他是大師級的人物。轉載英國《衛報》上他的《訃聞》以誌哀；該文對丹勒教授的思想和觀點有簡明扼要的介紹。
Daniel Dennett obituary
Controversial US philosopher who sought to understand and explain the science of the mind
Jane O'Grady, 04/21/24
Daniel Dennett, who has died aged 82, was a controversial philosopher whose writing on consciousness, artificial intelligence, cognitive science and evolutionary psychology helped shift Anglo-American philosophy from its focus on language and concepts towards a coalition with science.
His naturalistic account of consciousness, purged as far as possible of first-person agency and qualitative experience, has been popular outside academia and hotly opposed by many within it.
One of the so-called Four Horsemen of New Atheism, along with Richard Dawkins, Christopher Hitchens and Sam Harris, he also wrote on Darwinism, memes, free will and religion.
“Figuring out as a philosopher how brains could be, or support, or explain, or cause, minds” was how Dennett, aged 21, defined his project. Having gained a philosophy degree at Harvard University in 1963, he was then doing a BPhil at Oxford University under the behaviourist philosopher Gilbert Ryle, but spent most of his time in the Radcliffe science library learning about the brain.
Many philosophers were (as they still are) trying to accommodate the mind, and its subjectivity, in third-person science. Yet it seems impossible to identify “intentionality” (the “aboutness” of thoughts) or “qualia” (the “thusnesses” of experience) as nothing but brain states or behaviour.
In dealing with “intentionality”, Dennett, however, had a novel strategy – “first content, then consciousness” – that reversed the usual line of enquiry. He proposed “to understand how consciousness is possible by understanding how unconscious content is possible first”.
Nature, he argued, has its own unwitting reasons – “free-floating rationales” that are “independent of, and more fundamental than, consciousness”. The ability of organisms to respond appropriately, if unconsciously, to things in the environment is a “rudimentary intentionality”. And, over aeons, the “blind, foresightless, purposeless process of trial and error” has knitted “the mechanical responses of ‘stupid’ neurons” (in certain creatures’ brains) into a “reflective loop [that] creates the manifest illusion of consciousness,” he thought. “Mind is the effect, not the cause.” As spiders mindlessly spin webs, homo sapiens has spun “a narrative self”.
What Ryle had dismissed as “the ghost in the machine” could thus be exorcised, not by denying its existence but by seeing it for what it is – a conjuring trick rather than magic, an illusion fabricated by what (in his 1995 book Darwin’s Dangerous Idea) he called evolution’s “reverse engineering”.
Dennett’s first book, Content and Consciousness was published in 1969. Sixteen other books and numerous papers adapted and extended its thesis – that intentionality can be ascribed, along a spectrum with no clear dividing line, impartially to minds, human brains, bees, computers, thermostats: it is a functional relation between object and environment. As to exactly when, in evolutionary or personal history, conscious intentionality arose, “don’t ask,” he said.
We can take what he called a “physical stance” towards something (considering its constituents and their causal interlockings) or a “design stance” (seeing it as fabricated, by evolution or humans, to serve a particular function) or an “intentional stance” (explaining its behaviour in terms of goals that it would sensibly pursue if it were rational).
“The intentional stance is thus a theory-neutral way of capturing the cognitive competences of different organisms (or other agents) without committing the investigator to overspecific hypotheses about the internal structures that underlie the competences.” We treat chess-playing computers, some animals and humans, as if they had beliefs and desires. But, he was furiously asked, don’t we humans actually have them?
Yes and no, apparently. There is no one-to-one match between brain states and mental states. It is the creature as a whole that has intentionality. The discrete individually identifiable mental states that we seem to be having are (in reality) “an edited and metaphorialised version of what’s going on in our brains” – equivalent to “user illusions” on a computer screen: like the hourglass, folder and dustbin icons, they betoken the complex processes occurring behind the scenes.
“No part of the brain is the thinker that does the thinking, or the feeler that does the feeling,” said Dennett, nor is, or does, the brain as a whole. Instead there are “multiple channels in which specialist circuits try, in parallel pandemoniums, to do their various things, creating multiple drafts as they go” – until, from among “concurrent contentful events in the brain … a select subset of such events ‘wins’ … The way to explain the miraculous-seeming powers of an intelligent intentional system is to decompose it into hierarchically structured teams.” These consist of “relatively ignorant, narrow-minded, blind homunculi that produce the intelligent behaviour of the whole”.
“Yes we have a soul but it’s made of lots of tiny robots” was the headline of an article about him in the Italian newspaper Corriere della Sera, and Dennett endorsed it with amusement. He loved making furniture, building fences, mending roofs, tinkering with cars and boats; and, among the many things he constructed were sets of nested Russian dolls to illustrate his philosophy. The outside doll was “Descartes”; inside that was “the Middle Ghost” (a reference to Ryle’s) – but inside that was a “Robot”. “We are not authorities about our own consciousness,” he said. The robot is masked by the ghost.
Dennett pronounced qualia to be illusions. Ever since Descartes, we have tended to assume that we have “mental images”, as if, said Dennett, we could view little pictures, visible only to ourselves in an inner “Cartesian theatre”.
If so, we should be able to count the number of stripes on the tiger we are imagining, and say whether we have been seeing it face-on or sideways. No such definite information is available. Mental images are indeterminate in a way that pictures cannot be, and closer to generalised linguistic descriptions. So limited and poor is our access to our own conscious experiences, said Dennett, that it “does not differ much from the access another person can have to those experiences – your experiences – if you decide to go public with your account”. Indeed “our first-person point of view of our own minds is not so different from our second-person point of view of others’ minds”. We take an intentional stance on ourselves.
Dennett’s views remained pretty consistent throughout numerous books and papers, but in recent years he became more lenient towards mental imagery. He was impressed by neuroscientific research suggesting that there are specific observable brain activities that potentially may be decoded as imaging processes.
And, having been stern in denying what is disparagingly called “folk psychology” (a term he invented), he began to describe himself as “a mild realist” about mental states, prepared to concede that “the traditional psychological perspective” is not merely something described by third-person observers.
Avoiding accusations that he smuggled in the subjectivity he so adamantly denied, Dennett had recourse to “memes”, a concept (invented by Dawkins) modelled on that of genes. Memes are units of cultural practice, including anything from language to drama to wearing a baseball cap backwards to clapping as a form of praise. They are, in Dennett’s words, ‘“prescriptions” for ways of doing things that can be transmitted to, and from, human brains, and that “have their own reproductive fitness, just like viruses”. We are infected by memes, and it is “the memes invasion … that has turned our brains into minds”.
Dennett also applied a Darwinian approach to free will. “A billion years ago, there was no free will on this planet, but now there is. The physics has not changed; the improvements in ‘can do’ over the years had to evolve.” We are now able to predict probable futures, and to pursue or avert them. We are not deluded about having that capacity; as we are, he fulminated, about religion. Breaking the Spell (2006) was judiciously named. That was what he was urging religious people to do.
Born in Boston, Dennett spent the first five years of his life in Lebanon. His father, also Daniel, was a counter-intelligence officer posing as a cultural attache to the American embassy in Beirut. He died in a plane crash in 1947 (later, Dennett’s sister, the investigative journalist Charlotte Dennett, would claim Kim Philby’s connivance in it). Dennett’s mother, Ruth Leck, a teacher and editor, took the children back to Massachusetts.
Reprieved from matching up to his father’s expectations, Dennett said, he nonetheless grew up in his father’s shadow. But little could sap his exuberant self-confidence. Characteristically, the title of his 1991 book was Consciousness Explained.
In 1959, having just begun a maths degree at Weslyan University, Connecticut, Dennett read Willard van Orman Quine’s From a Logical Point of View. He was so excited that he decided “to be a philosopher, and go to Harvard and tell this man Quine why he is wrong”. The first two he managed, though for a time he worried that Quine (later a great friend) was more interested by Dennett’s sculpture than his philosophising.
Dennett did contemplate being a sculptor, and would, he said, certainly have studied engineering had his family not been so arts-oriented. Co-director of the Center for Cognitive Studies at Tufts University in Massachusetts, in 1993 he joined the Humanoid Robotics Group at the Massachusetts Institute of Technology to construct a robot (Cog) that would be not only intelligent but conscious. The project ended in 2003, and Cog was retired to a museum.
Dennett was Austin B Fletcher professor of philosophy at Tufts, and visiting professor at a host of other universities, including Oxford and the London School of Economics. His memoir, I’ve Been Thinking, was published in 2023.
He and his wife, Susan (nee Bell), whom he married in 1962, lived in North Andover, Massachusetts, and he also hobby farmed in Maine for more than 40 summers, blissfully “tillosophising” on a tractor, sailing his boat Xanthippe, fixing buildings and digging drains. Dennett loved solving puzzles and disinterring the inner workings of machines – above all those of “the miraculous-seeming” mind. “No miracles allowed,” he said.
He is survived by Susan, a daughter, Andrea, and son, Peter, and six grandchildren, and his sisters, Cynthia and Charlotte.
Daniel Clement Dennett, philosopher, born 28 March 1942; died 19 April 2024
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意識與「丹勒弔詭」 -- John Horgan
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下文批評丹勒教授對「意識」的看法。我同意霍根先生的觀點。
Consciousness and the Dennett Paradox
John Horgan, 04/20/24
Daniel Dennett died yesterday, April 19, 2024. When he argues that we overrate consciousness, he demonstrates, paradoxically, how conscious he is, and he makes his audience more conscious. This “Dennett Paradox” is a rip-off, and corollary, of the Sapolsky Paradox. I found this photo of Dennett on Wikipedia. (請至原網頁參看照片)
Hoboken, April 20, 2024. Daniel Dennett’s death feels like the end of an era, the era of ultra-materialist, ultra-Darwinian, swaggering, know-it-all scientism. Who’s left? Dawkins? Dennett isn’t as smart as he thinks he is, I liked to say, because no one is. He lacked the self-doubt gene, but he forced me to doubt myself, he made me rethink what I think, and what more can you ask of a philosopher? I first encountered Dennett’s in-your-face brilliance in 1981 when I read The Mind’s I, and his name popped up at a consciousness shindig I attended just last week. To honor Dennett, I’m posting a free, revised version of my 2017 critique of his claim that consciousness is an “illusion.” I’m also coining a phrase, “the Dennett Paradox,” explained below.— John Horgan
Of all the odd notions to emerge from debates over consciousness, the oddest is that it doesn’t exist, at least not in the way we think it does. It is an illusion, like “Santa Claus” or “American democracy.”
Descartes said consciousness is the one undeniable fact of our existence, and I find it hard to disagree. I’m conscious right now, as I type this sentence, and you are presumably conscious as you read it (although I can’t be absolutely sure).
The idea that consciousness isn’t real has always struck me as crazy, but smart people espouse it. One of the smartest is philosopher Daniel Dennett, who has been questioning consciousness for decades, notably in his 1991 bestseller Consciousness Explained.
I’ve always thought I must be missing something in Dennett’s argument, so I hoped his book From Bacteria to Bach and Back: The Evolution of Minds would enlighten me. It does, but not in the way Dennett intended.
Dennett restates his claim that Darwinian theory can account for all aspects of our existence. We don’t need an intelligent designer, or “skyhook,” to explain how eyes, hands and minds came to be, because evolution provides “cranes” for constructing all biological phenomena.
Natural selection yields what Dennett calls “competence without comprehension.” (D.D. loves alliteration.) Even the simplest bacterium is a marvelous machine, extracting from its environment what it needs to survive and reproduce. Eventually, the mindless, aimless process of evolution produced Homo sapiens, a species capable of competence and comprehension.
But human cognition, Dennett emphasizes, still consists mainly of competence without comprehension. Our conscious thoughts represent a minute fraction of all the information processing carried out by our brains. Natural selection designed our brains to provide us with thoughts on a “need to know” basis, so we’re not overwhelmed with data.
Dennett compares consciousness to the user interface of a computer. The contents of our awareness, he asserts, bear the same relation to our brains that the little folders and other icons on the screen of a computer bear to its underlying circuitry and software. Our perceptions, memories and emotions are grossly simplified, cartoonish representations of hidden, hideously complex computations.
None of this is novel or controversial. Dennett is just reiterating, in his oh-so-clever, neologorrheic fashion, what mind-scientists and most educated lay folk have long accepted, that the bulk of cognition happens beneath the surface of awareness. Dennett even thanks the much-vilified Freud for his “championing of unconscious motivations”!
Trouble arises when Dennett, extending the computer-interface analogy, calls consciousness a “user-illusion.” I italicize illusion, because so much confusion flows from Dennett’s use of that term. An illusion is a false perception. Our thoughts are imperfect representations of our brain/minds and of the world, but that doesn’t make them necessarily false.
Take this thought: “Donald Trump is a narcissistic jerk.” That is an extremely compressed statement about an extremely messy external reality. Moreover, my ability to think the thought, or type it on my laptop, depends on complex hardware and software, the workings of which I am happily ignorant. But that doesn’t mean “Donald Trump is a narcissistic jerk” is an illusion, any more than “2 + 2 = 4.”
What if I think "2 + 2 = 5,” “Global warming is a hoax” or “Donald Trump is the wisest man on earth”? What if I am psychotic, or living in a simulation created by evil robots, and all my thoughts are illusions? To say my consciousness is therefore an illusion would be to conflate consciousness with its contents. That’s like saying a book doesn’t exist if it depicts non-existent things. And yet that is what Dennett seems to suggest.
Consider how Dennett talks about qualia, philosophers’ term for subjective experiences. My qualia at this moment are the smell of coffee, the sound of a truck rumbling by on the street, my puzzlement over Dennett’s ideas. Dennett notes that we often overrate the objective accuracy and causal power of our qualia. True enough.
But he concludes, bizarrely, that therefore qualia are fictions, “an artifact of bad theorizing.” If we lack qualia, then we are “zombies,” creatures that look and even behave like humans but have no inner, subjective life. Imagining a reader who insists he is not a zombie, Dennett writes:
“The only support for that conviction [that you are not a zombie] is the vehemence of the conviction itself, and as soon as you allow the theoretical possibility that there could be zombies, you have to give up your papal authority about your own nonzombiehood.”
Think you’re conscious? Think again.
Dennett gets annoyed when critics accuse him of saying “consciousness doesn’t exist,” and to be fair, he never flatly makes that claim. His point seems to be, rather, that consciousness is so insignificant, especially compared to our exalted notions of it, that it might as well not exist.
When I encounter a baffling belief, at some point I stop trying to understand the belief and focus on the believer. What’s the motive? Why would Dennett expend so much energy advancing such a preposterous position?
Like many philosophers, Dennett clearly gets a kick out of defending positions that defy common sense. But his primary agenda is defending science against religion and other irrational belief systems. Dennett, an outspoken atheist, fears that creationism and other superstitious nonsense will persist as long as mysteries do. He thus insists that science can untangle even the knottiest conundrums, including the origin of life (which he asserts that recent “breakthroughs” are helping to solve) and consciousness.
Dennett accuses those who question science’s power of bad faith; these doubters don’t want their “beloved mysteries” explained. Dennett can’t accept that anyone might have legitimate, rational reasons for resisting his reductionist vision.
Some people surely have an unhealthy attachment to mysteries, but Dennett has an unhealthy aversion to them, which compels him to stake out unsound positions. His belief that consciousness is an illusion is nuttier than the belief that God is real. Science has real enemies—some in positions of great power--but Dennett doesn’t do science any favors by shilling for it so aggressively.
Let me nonetheless conclude by thanking Dennett. Agree with him or not, I always find him provocative and entertaining. And when he argues passionately, brilliantly, against consciousness, he not only demonstrates how hyper-conscious he is; he also rouses the rest of us from our zombie-like torpor and makes us more conscious. Call it the Dennett Paradox.
Further Reading:
My recent quantum experiment made me more sympathetic toward Dennett’s notion of “competence without comprehension.”
See also my profile of Douglas Hofstadter, who shares Dennett’s views of the mind, in my book Mind-Body Problems.
And here are a few columns haunted by Dennett’s ghost:
Free Will and the Sapolsky Paradox
Quantum Mechanics, the Chinese Room and the Limits of Understanding
The Dark Matter Inside Our Heads
The Solipsism Problem
The Delusion of Scientific Omniscience
Drawing a Pen with the Same Pen and Other Strange Loops
The Brouhaha Over Consciousness and “Pseudoscience”
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