Weisberg et al. (2008) presented subjects with two explanations for psychological phenomena (e.g. attentional blink). Some subjects got the regular explanation, and other subjects got the 'with neuroscience' explanation that included purposely irrelevant verbiage saying that "brain scans indicate" some part of the brain already known to be involved in that psychological process caused the process to occur.
And yet, Yale cognitive science students rated the 'with neuroscience' explanations as more satisfying than the regular explanations.
Why? The purposely irrelevant neuroscience verbiage could only be important to the explanation if somebody thought that perhaps it's not the brain that was producing certain psychological phenomena. But these are Yale cognitive science students. Somehow I suspect people who chose to study cognition as information processing are less likely than average to believe the mind runs on magic. But then, why would they be additionally persuaded by information suggesting only that the brain causes psychological phenomena?
In another study, McCabe & Castel (2008) showed subjects fictional articles summarizing scientific results and including either no image, a brain scan image, or a bar graph. Subjects were asked to rate the soundness of scientific reasoning in the article, and they gave the highest ratings when the article included a brain scan image. But why should this be?
I remember talking to a friend about free will. She was a long-time physicalist who liked reading about physics and neuroscience for fun, but she didn't read Less Wrong and she thought she had contra-causal (libertarian) free will.
"Okay," I said. "So the brain is made of atoms, and atoms move according to deterministic physical law, right?"
"Right," she said.
"Okay. Now, think about the physical state of the entire universe one moment before you decided to say "Right" instead of something else, or instead of just nodding your head. If all those atoms, including the atoms in your brain, have to move to their next spot according to physical law, then could you have said anything else than what you did say in the next moment?" (Neither of us understood many-worlds yet, so you can assume we're talking about a single Everett branch.)
She paused. "Huh. I'll have to think about that."
"Also, have you heard about those studies where brain scans told researchers what the subjects were going to do before the subjects consciously decided what they were going to do?"
"No! Are you serious?"
"Yup. Sometimes they could predict the subject's choice 10 seconds before the subject consciously 'made' the choice."
"10 seconds? Wow. I didn't know that."
I think that maybe the 'with neuroscience' explanations and brain scan images are more satisfying partly because they remind us we're physicalists. They remind us that reductionism marches on, that psychology is produced by physical neurons we can take pictures of.
Just like most people, physicalists walk around all day with the subjective experience of a 'unity of consciousness' and contra-causal free will and so on. If a physicalist isn't a researcher who studies all the latest successful reductions in neuroscience or biology or physics all week long, and doesn't read Less Wrong every day, then it's possible to get lost in the feel of everyday experience and thus be surprised by a headline like 'Brain Scanners Can See Your Decisions Before You Make Them.'
Sometimes even physicalists need to be reminded — with concrete reductionistic details — that they are physicalists. Otherwise their normal human anti-reductionistic intuitions may creep back in of their own accord. That's one reason it helps to study many sciences, so you have many successful reductions in your head, and see (at some resolution) the entire picture, from psychology to atoms. As Eliezer wrote:
Study many sciences and absorb their power as your own. Each field that you consume makes you larger. If you swallow enough sciences the gaps between them will diminish and your knowledge will become a unified whole.
To her credit, my friend no longer believes in contra-causal free will.
The comments of yours I've read are always clear and insightful, and usually I agree with what you say. I have to disagree with you here, though, about your supposed second fallacy.
I disagree. Arguments against qualia typically challenge the very coherence of anything which could play the desired role. It's not like trying to prove fire doesn't exist, it's like trying to prove there is no such thing as elan vital or chakras.
I deny the existence of UFOs. It's pretty clear what UFOs are - spaceships built and flown to Earth by creatures who evolved on distant planets - and I can give fairly straight-forward probabilistic reasons of the kind amenable to rational disagreement, for my stance.
I (mostly) deny the existence of God. Apologies if you're a theist for the bluntness, but I don't think it's at all clear what God is or could be. Every explication I've ever encountered of God either involves properties which permit the deduction of contradictions (immovable rocks/unstoppable forces and what-not), or are so anodyne or diffuse as to be trivial ('God is love' -hence the 'mostly'). There is enough talk in our culture about God, however, to give meaning to denials of His existence - roughly, 'All (rather, most of) this talk which takes place in houses of worship and political chambers involving the word 'God' and its ilk, involves a mistaken ontological commitment'.
Do I deny the existence of consciousness, or subjective experience? If my wife and I go to a hockey game or a play, we in some sense experience the same thing -there is a common 'objective' experience. But equally we surely have in some sense different experiences - she may be interested or bored by different parts than I am, and will see slightly different parts of the action than I. So clearly there is such a thing as subjective experience, in some sense. This, however, is not what is at issue. Roughly, what we are concerned about is a supposed ineffable aspect of experience, a 'what it is like'. I deny the existence of this in the sense in which I deny the existence of God. That is, I have yet even to see a clear and coherent articulation of what's at issue. You imply the burden of argument is with the deniers; I (following Dennett and many others) suggest the burden is with defenders to say what it is they defend.
Are qualia causally efficacious, or not? If they are, then they are in principal objectively detectable/observable, and hence not worthy of the controversy they generate (if they have a causally efficacious 'aspect' and a non-efficacious, one, then just factor out the causally efficacious aspect as it plays no role in the controversy). On the flip side, of course, if qualia are not causally efficacious, then they aren't responsible for our talk of them - they aren't what we're presently talking about, paradoxically.
It seems to me the best case for exponents of consciousness is to force a dilemma - an argument pushing us on the one hand to accept the existence of something which on the other appears to be incoherent (as per just above). But I have yet to see this argument. Appeals to what's 'obvious' or to introspection just don't do it - the force of the sort of arg above and the several others adduced by Dennett et. al., clearly win out over thumping one's sternum and saying 'this!', simply because the latter isn't an argument. The typical candidates for serious arguments in this vein are inverted spectrum or Black and White Mary type-arguments, but it seems to me they always just amount to the chest thumping in fancy dress. Would be interested to hear of good candidate arguments for qualia, though, and to hear any objections if you think the foregoing is unfair.
I think there's some hindsight bias there, in the case of chakras. It is by no means obvious that these supposed centres of something-or-other distributed along the spine and in the head don't exist. One might be sceptical purely on account of the sources of the concept being mystical or religious, but the same is true of... (read more)