Mind-Body Physicalism

by Luke Muehlhauser on July 22, 2009 in General Atheism

I’m blogging my way through Sense and Goodness Without God, Richard Carrier’s handy worldview-in-a-box for atheists. (See the post index for all sections.) In my previous post, I wrote about Carrier’s section on the nature of mind. Today, I cover section III.6.6 The Evidence for Mind-Body Physicalism.

According to physicalism, the mind and body are purely physical systems. What think this is true? Because, Carrier says,

…it explains everything about us, and explains it well, with the fewest ad hoc hypotheses [and] because we have a tremendous and ever-growing body of evidence supporting it…

What is this evidence?

  1. Scientists have observed human brains working in dozens of ways, millions of times. But they have never observed a mind at work without a physical brain.
  2. Scientists have shown that for dozens of specific mental events, there is always a corresponding brain event. When people report seeing something, there is always activity in what we know to be the visual centers of the brain. When people report remembering something, there is always activity in the brain where we know memories are stored. And so on.
  3. When scientists stimulate the brain with electrodes, this always triggers “the same mental event when the same stimulus is applied in the same place.” On occasion, scientists will even find patients for whom stimulating a certain part of the brain will always cause a particular song to play in their head, or a particular memory to replay on their mind’s stage.
  4. Brain injury – or impairment with drugs or magnetic fields – “results in the loss of specific mental functions as the specific areas related to those functions are lost or numbed.” There are thousands of examples.
  5. Scientists now understand many of the chemicals that make the brain work, and changing the chemical makeup of the brain changes mental states and even personality.
  6. Comparative anatomy also testifies to physicalism. There is a direct correlation between increased mental powers and increased brain complexity – even within specific parts of the brain. For example, an animal with a highly developed sense of smell has a disproportionately large part of their brain devoted to smell.

Is there any evidence against mind-body physicalism? Carrier writes:

The evidence that is offered “against” [mind-body physicalism] differs in a very significant way from the evidence for it. The evidence for mind-body physicalism has been corroborated in laboratories and scientific field studies thousands and thousands of times… the evidence has converged from numerous different directions on the same conclusion.

In contrast, the evidence against mind-body physicalism is purely anecdotal, almost always ambiguous, and has often been shown to be outright fraudulent.

Carrier lists 5 kinds of evidence that has been offered against mind-body physicalism: (1) Near Death Experiences, (2) Out of Body Experiences, (3) communication with the dead, (4) ghost sightings, and (5) recalling memories from past lives – all of which are anecdotal, ambiguous, weak, and often fraudulent.

And, if mind-body physicalism is true, then of course life after the death of the body is impossible.1

Next, I discuss section III.7 The Meaning of Life.

  1. Absent a technology that could freeze a record of our memories, abilities, qualities, knowledge, etc. and transplant it into another body. []

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{ 31 comments… read them below or add one }

Sabio July 23, 2009 at 2:54 am

And, if mind-body physicalism is true, then of course life after the death of the body is impossible.

I think there are Christian theologies where the mind-body (one unit) of individuals is resurrected at once — no spirit drifting off to heaven.  I think N.T.Wright wrote about this.  Thus, this could make your comment false, I do believe.

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Reginald Selkirk July 23, 2009 at 5:15 am

Scientists now understand many of the chemicals that make the brain work, and changing the chemical makeup of the brain changes mental states and even personality.

“I don’t know what consciousness is made of, but i know it’s soluble in ethanol.”
 
Artificial brain ’10 years away’
Feel free to be skeptical of this claim.
 

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Kip July 23, 2009 at 7:29 am

Reginald:  I love that quote:

“I don’t know what consciousness is made of, but i know it’s soluble in ethanol.”

Where did you get it from?  And do you mind if I use it?  Thanks!

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Reginald Selkirk July 23, 2009 at 8:29 am

I can’t remember who I heard it from, but I’m sure that it’s not original. The Phrase Finder has a similar quote attributed to Thomas Blackwell, but with conscience rather than consciousness.
 

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Sabio July 23, 2009 at 5:15 pm

I just noticed — I never get e-mails on follow-ups on these posts.  Is there a way to trigger e-mail feedbacks.  If not, Luke, could you make one?

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lukeprog July 23, 2009 at 5:45 pm

Sabio,

You can get RSS updates for comments on each post. See “RSS feed for comments on this post” at the bottom of each page.

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Matt M July 24, 2009 at 8:46 am

Does Carrier deal with the philosophical zombie problem? While it doesn’t really invalidate physicalism it does raise some interesting questions.

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Reginald Selkirk July 24, 2009 at 9:50 am

Matt M: Does Carrier deal with the philosophical zombie problem? While it doesn’t really invalidate physicalism it does raise some interesting questions.

From the link: “While [the zombie] behaves exactly as if it does feel pain (it may say “ouch” and recoil from the stimulus), it does not actually have the experience of pain as a putative ‘normal’ person does.
That seems to me a biologically unsophisticated argument. With modern day technology, we could track the nerve response all the way from the site of poking to doing magnetic imaging of the involved brain areas. Also, the very simple technology of checking reflexes should distinguish between a simple instinctive response and a consciously feigned one.
I reiterate that we should consider dropping medieval concepts, e.g. qualia, and try to build up from what we do know of neuroscience.
 

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Haukur July 25, 2009 at 5:24 am

Where’s Cartesian? This blog is going to be a lot less interesting without him.

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Kip July 25, 2009 at 9:20 am

Haukur: Where’s Cartesian? This blog is going to be a lot less interesting without him.

I don’t think so, but to each his/her own.  Anyway, I’d wager he’ll be back.

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Matt M July 26, 2009 at 12:27 am

Reginald Selkirk: That seems to me a biologically unsophisticated argument. With modern day technology, we could track the nerve response all the way from the site of poking to doing magnetic imaging of the involved brain areas.

Can you reduce consciousness entirely to the realm of neuroscience? Doesn’t that assume that brain activity and conscious experience are the same thing? Which is exactly what the zombie argument calls into question.
 
I’m not here to defend the argument – I don’t have the expertise to do so. I just think it raises interesting questions about the nature of consciousness and was curious as to whether Carrier has anything to say on the matter.

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cartesian July 27, 2009 at 6:39 am

I was on vacation for the last week or so.
 
Consider this argument:
 
1. Scientists have observed fires working in dozens of ways, millions of times. But they have never observed smoke at work without a fire (however small).
2. Scientists have shown that for dozens of specific smoke events, there is always a corresponding fire event. When people report gray smoke, there is always a certain kind of activity in the fire. When people report a black smoke, there is always a different sort of activity in the fire. And so on.
3. When scientists stimulate the fire, this always triggers “the same smoke event when the same stimulus is applied in the same place.”
4. Fire injury – or impairment with blankets or water – “results in the loss of specific smoke functions as the specific areas related to those functions are lost or numbed.” There are thousands of examples.
5. Scientists now understand many of the chemicals that make fire work, and changing the chemical makeup of the fire changes smoke states.
6. Comparative anatomy: There is a direct correlation between increased smoke powers and increased fire complexity – even within specific parts of the fire. For example, a very light and clean cloud of smoke has a disproportionately large part of its fire devoted to those artificial fire logs.

Therefore, smoke is fire.

This argument is clearly very bad. All the correlations between fire and smoke are perfectly compatible with the claim that fire causes smoke. Those correlations are not at all evidence for the claim that smoke is fire.
Similarly, all the correlations you point out between the mind and the brain are compatible with non-physicalism. So those correlations are not at all evidence for the claim that minds are brains.

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cartesian July 27, 2009 at 6:51 am

>>Carrier lists 5 kinds of evidence that has been offered against mind-body physicalism: (1) Near Death Experiences, (2) Out of Body Experiences, (3) communication with the dead, (4) ghost sightings, and (5) recalling memories from past lives – all of which are anecdotal, ambiguous, weak, and often fraudulent.>>
 
That’s weird. The contemporary dualist philosophers of mind I know of don’t appeal to any of these.
 
For example, look around page 376 in this book:
http://books.google.com/books?id=OiYmHn9pe2EC
 
And around 123 in this book:
http://books.google.com/books?id=0fZZQHOfdAAC
 
A report of several contemporary arguments starting on page 111 of this book:
http://books.google.com/books?id=dCW023Hc1q4C
And Hasker’s own “Argument from Reason” starts on page 64 of that book.
 
Those are just a few examples. I think Carrier is pretty ignorant of the literature here.
 
 
 

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lukeprog July 27, 2009 at 7:34 am

cartesian,

It all depends what you mean by “brain” and “mind” and related words. I think the analogy is quite a good one. If we transpose your points with points about the brain and personality/emotions/etc., I would conclude inductively that the brain causes emotions, personality, etc. (which we call “mind”). Like I said, the mind is what the brain does. The mind is what the brain causes.

Also, thanks for the links to arguments against mind-body physicalism. That’s wonderful.

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cartesian July 27, 2009 at 9:38 am

Here’s the Unger chapter, by the way:
http://www.mediafire.com/?nwwby49u3oj
 
It’s written in a pretty bizarre (but funny, I think) style. He’s sort of a weird dude, but very very smart.
http://philosophy.fas.nyu.edu/object/peterunger

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cartesian July 27, 2009 at 9:55 am

>>It all depends what you mean by “brain” and “mind” and related words.>>
 
By “brain” I just mean that squishy wilted-cabbage-looking thing in your skull. By “mind” I just mean a thing that thinks. What depends on these definitions?
 
>>I think the analogy is quite a good one. If we transpose your points with points about the brain and personality/emotions/etc., I would conclude inductively that the brain causes emotions, personality, etc. (which we call “mind”).>>
 
OK, but just note that saying that the brain causes mental events is quite different from what you go on to say, namely that “the mind is what the brain does.” A dualist would be happy with the claim that brain events cause mental events. But a dualist wouldn’t accept the claim that brain events just are mental events (speaking of the types here, not the tokens).
 
I think the evidence you provide in your original post supports at most the claim that brain events cause mental events.
 
>>Also, thanks for the links to arguments against mind-body physicalism.>>
 
No problem. Hope you enjoy them as much as I have. You may also like Plantinga’s stuff on dualism:
http://www.mediafire.com/?1zbi1l39mcd
http://www.mediafire.com/?d00m4xot94u
 
In section III of “Against Materialism,” Plantinga has really good responses to typical arguments for materialism/against dualism.

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cartesian July 27, 2009 at 9:56 am

Last link:
http://philosophy.fas.nyu.edu/docs/IO/1179/mentalproblem.pdf
 
That’s a much shorter and straightforward presentation of Unger’s argument for substance dualism.

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lukeprog July 27, 2009 at 3:07 pm

cartesian,

Thanks. Also, here is van Inwagen’s reply to “Against Materialism.” I already started drafting a post series on these two articles.

Before I narrow down my response about dualism and fire/smoke, I’d like to clarify something. Do you think that ‘the squishy wilted-cabbage-looking thing in your skull’ is not identical with nor physically contains ‘the thing that thinks’? You believe these are separate substances?

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cartesian July 28, 2009 at 6:49 am

Yeah, I’m familiar with that van Inwagen reply. I don’t know why it needed to be so long — the reply is pretty simple. Plantinga points out an inconsistent set of propositions:
(1) There’s a possible world in which my body undergoes this rapid replacement.
(2) There’s no possible world in which my body survives this process.
(3) There’s a possible world in which I survive this process.
(4) If x=y, then necessarily x=y
(5) I am my body
 
Every deductively valid argument can be construed as a set of inconsistent propositions. So it’s up to the person evaluating the argument to decide which proposition is least credible, and then give up that one. For Plantinga, (5) is least credible. For van Inwagen, (3) is least credible.
 
van Inwagen is a teensy bit dishonest when he relates this argument. He makes it sound like Plantinga is claiming something stronger than (3), namely: If my body were to undergo this process, I would survive. That’s a much stronger claim than Plantinga needs, and so it’s less credible. Plantinga is just relying on a bare claim of metaphysical possibility. To deny it is to assert a strong claim of metaphysical necessity. Of course it’s open to van Inwagen to respond in this way, but I don’t find it very plausible.
 
Also, note that van Inwagen is only responding to Plantinga’s replacement argument, which is just one of the arguments Plantinga gives against materialism in that article. There’s also the so-called “Argument from Impossibility.”

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cartesian July 28, 2009 at 6:54 am

lukeprog: Before I narrow down my response about dualism and fire/smoke, I’d like to clarify something. Do you think that ‘the squishy wilted-cabbage-looking thing in your skull’ is not identical with nor physically contains ‘the thing that thinks’? You believe these are separate substances?

No, I do not think that brains are identical with minds/persons. Yes, I think they are two separate substances.
 
I’m not sure what it means to ask whether brains “physically contain” minds/persons. I think minds/persons are located in space and time; maybe that’s what you’re asking. My mind is (i.e. I am) right here (*pointing between my eyes*), for instance.

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Haukur July 28, 2009 at 7:17 am

I’m only 30 pages into Unger but already this is the most interesting argument for dualism I’ve seen.

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lukeprog July 28, 2009 at 5:35 pm

cartesian,

Hmmmm. So minds are physically located near brains (except in the case of God), but they are made of a different substance? Minds are not made of gluons and electrons and such? I’d just like to clarify your position so I don’t *totally* misrepresent your position.

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cartesian July 28, 2009 at 6:10 pm

lukeprog: So minds are physically located near brains (except in the case of God), but they are made of a different substance?

Some minds and brains are colocated. I’m right here (*points between his eyes*), and so is at least part of my brain. So I and (at least part of) my brain seem to be colocated, as a contingent matter of fact. But that could easily change, say if my brain were removed from my skull, but the connections left intact using radio transceivers. I’d still be here, but my brain would be elsewhere.
 
“Substance” is ambiguous. Sometimes it means stuff, and sometimes it means thing. In the first sense, silly putty is a different type of substance from rocket fuel. Those two things are made of different stuff. In the second sense — which is far more common in philosophy than out of it — those two things are substances in the same sense. They’re both things that endure through time, have properties, etc.
 
I think minds/people are things, so they’re substances in that second sense. But I don’t think they’re made out of any stuff, so they’re not substances in that first sense. I think they’re simple, i.e. they don’t have any parts. Like electrons. Minds are things, but they’re not made out of other things.
 
Thanks for trying to get the view right before you object. I look forward to the objections.

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lukeprog July 28, 2009 at 7:24 pm

cartesian,

There is so much to object to I don’t know where to start, but let me just go back to your fire/smoke analogy instead. The reason we posit two different things (fire and smoke) in your analogy is that we have a great deal of evidence for each of them as separate entities. You can have one without the other, they each have distinct properties, etc.

But when it comes to mind/brain, I just don’t see any good evidence for the “second” posited thing. And since I don’t need to posit such an exotic creature as a spaceless, partless, non-physical seat of personality and consciousness in order to explain the witnessed phenomena, I don’t. To me, positing an immaterial ‘mind’ behind the activity of the brain is still akin to positing an immaterial god behind the activity of lightning. You are free to do so, but there’s just no reason to do so, and any properties you assign to it are arbitrary.

I’ll reserve my comments on the general problems associated with positing supernatural entities for an upcoming post series inspired by Dawes’ excellent Theism and Explanation.

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cartesian July 29, 2009 at 7:13 am

Hi Luke,
>>The reason we posit two different things (fire and smoke) in your analogy is that we have a great deal of evidence for each of them as separate entities.>>
 
Just to be clear, the reason I brought up fire and smoke was to show that the argument Carrier gives for physicalism doesn’t succeed. His premises don’t decide between physicalism and dualism. A dualist could happily accept his premises. So it’s not a good argument for physicalism.
 
But I agree with you: we have reason to accept that fire and smoke are distinct. You rightly characterize these reasons:
 
>>You can have one without the other, they each have distinct properties, etc. But when it comes to mind/brain, I just don’t see any good evidence for the “second” posited thing.>>
 
Well, that’s why I linked you to arguments for the conclusion that dualism is true. I tried to point you in the direction of good evidence for the “‘second’ posited thing.” Zombie arguments, for example, try to show that it’s possible to have a brain without a mind. That’s sufficient to prove dualism. Unger’s argument can be construed as pointing out a property that minds have which brains lack. So can Swinburne’s, though I couldn’t find a link to his “Evolution of the Soul.” But you’re familiar with Swinburne’s argument from our debate.
 
And don’t mental properties just seem different from neural properties? Think of a burning, fierce pain. Now think of a bunch of neurons clicking away. Don’t those seem like different things? Even Dan Dennett says ‘yes’. On page 27 of ‘Consciousness Explained’ he says:

“It does seem as if the happenings that are my conscious thoughts and experiences cannot be brain happenings, but must be something else, something caused or produced by brain happenings, no doubt, but something in addition…”
If they seem different, well then the ball’s already rolling for dualism. You’d better have good reason to think they’re actually the same, if you want to maintain physicalism. You can’t just say “Well, I see no need to posit two things here.” You have to say “I have better reason not to posit two things here.”

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cartesian July 29, 2009 at 7:17 am

lukeprog: And since I don’t need to posit such an exotic creature as a spaceless, partless, non-physical seat of personality and consciousness…

Recall that I think minds/people are in space.

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lukeprog July 29, 2009 at 8:15 am

cartesian,

Carrier’s argument, along with Occam’s razor, would (perhaps) suffice to demonstrate physicalism. But it is disturbing that he does not address the philosopher’s arguments for dualism, which is something I’ll have to read up on when I find the time. But I don’t think there’s much more for us to say until I take the time to respond to the arguments you linked to, or until I can take the time to present arguments in favor of physicalism.

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cartesian July 29, 2009 at 9:15 am

lukeprog: Carrier’s argument, along with Occam’s razor, would (perhaps) suffice to demonstrate physicalism.

The premises Carrier presents are perfectly compatible with dualism. So what would be doing the work in this new argument you suggest would be Ockham’s Razor. According to that principle, between two equally explanatory theories, we ought to choose the one that posits fewer entities.
 
But if you agree with Dan Dennett (along with many others) that mental properties just seem different from physical properties, then physicalism won’t be as explanatorily powerful as dualism, since physicalism denies any difference. So then Ockham’s Razor won’t kick in. So even this new argument you suggest won’t get you physicalism.

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Reginald Selkirk August 1, 2009 at 11:35 am

Matt M: Can you reduce consciousness entirely to the realm of neuroscience? Doesn’t that assume that brain activity and conscious experience are the same thing?

I’m going to invoke Ockham’s Razor here. If neuroscience can some day explain pretty much everything about mental activity and consciousness, there will be no role left for supernatural explanations; analogous to how biochemistry has banished belief in a “life force.” (amongst educated people who accept the findings of science)
 

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Reginald Selkirk August 1, 2009 at 11:44 am

cartesian: But if you agree with Dan Dennett (along with many others) that mental properties just seem different from physical properties,

I’ll take rigorous scientific support over “just seeming” any day of the week.

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cartesian August 12, 2009 at 7:14 am

Reginald Selkirk: I’ll take rigorous scientific support over “just seeming” any day of the week.

So will I. Let me know when you get anywhere near rigorous scientific support for physicalism.

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