On Philosophy

July 20, 2006

The Problem of Other Minds

Filed under: Mind — Peter @ 2:08 am

I often use a theory’s inability to solve the problem of other minds as evidence that a theory is lacking something important. For example see here or here. Generally my argument goes as follows: we only have access to physical facts about other people, and since the theory in question argues that the mind depends on things other than the physical we can’t deduce from the physical facts that the other person has a mind. Thus the problem of other minds can’t be solved by the theory. One way such a theory might attempt to defend itself would be to argue that we have access to a non-physical awareness of other minds, but since it is obvious, by experiment, that we can’t detect the presence of other people in the absence of physical information I dismiss this possibility.

A much more interesting defense goes as follows: we have access to non-physical information telling us when another person has a mind, and that this information “piggybacks” on the physical information (which explains why we can’t sense the presence of other people in the absence of physical information). A bad way to respond to this is to say that it violates information theory, since information theory contains some implicit assumptions of materialism, which those who defend an immaterial theory of the mind may reject. We might then create the following defense: we can’t tell if a person has a mind from seeing a small square of their skin, and shouldn’t this be enough to give us access to the non-physical information? This response is also insufficient because the person we are debating with could always respond with the assertion that this small patch doesn’t give us enough of the non-physical information to make a judgment.

A valid response to this idea is to consider other situations where we feel that we can deduce the presence of other minds, for example by observing actors in a film we deduce that the actors have minds. However there is no direct connection between the actors and us to carry the non-physical information, and thus the idea of non-physical information riding on physical information cannot explain how we are able to know that other people have minds. Of course our mental immaterialist might argue that somehow the non-physical information has found its way onto the film as it was being shot, and then was somehow copied by the physical process of making copies of the film for distribution, and was then released from the copy onto the screen, but honestly this assumption is so convoluted and unwarranted (and slightly ridiculous), that we can reject it simply with Occam’s razor.

Anyways I just thought I should mention this reasoning, since I am sure that I will use the problem of other minds in future arguments as well, and I would rather simply link to this comment when someone eventually brings up the objection I have raised here. If you want to read some philosophy that makes actual headway I encourage you to read the other post I made today, it was much more interesting.



  1. Why not use language as evidence of other minds, like Wittgenstein did, and in a way, Kant too? You argued elsewhere about meaning, inter-subjectivity, context, and language. If language is context-dependent, as you claim, don’t you think that that the problem of other minds is solved? Or, does the question of context-dependency merely beg the question of other minds?

    The beauty of the language defence is that I do not to prove access to non-physical information – once I begin talking, I may assume it. And if I expect anyone to understand me, then I have also solved the other-minds problem, at least, in the form that you define it (the deduction of the existence of other minds).

    The problem of other minds, as far as I understand it, has more to do with the issue of ascertaining that others experience the world as I do, and is not so much a question of whether or not you (i.e. the other) have a mind. Either way, my proposed solution (naturally, taken from Wittgenstein and many others) solves both questions, because language assures intersubjectivity (other minds), and concepts assure sympathy (similar feelings).

    cheers, jh

    Comment by jay aich — July 22, 2006 @ 1:18 am

  2. Um, no I don’t think language provides evidence of anything non-physical, or at least there is no reason to believe that it does. Language is a subset of behavior, which is completely physically explained. And Wittgenstien and Kant (especially Kant) are known to be wrong about many things.

    Comment by Peter — July 22, 2006 @ 1:22 am

  3. I suppose you could accuse me of begging the question, so here is another reason to believe that language doesn’t give us a reason to believe that something has a mind, even if it did contain a non-physical connection with the world. Consider the following situation: you shake a box of blocks and spill them on the floor. To your surprise they spell: “stop shaking me”. If you believe that these words contain a non-physical connection to the world then clearly this connection isn’t a reason to believe that something has a mind, since the box doesn’t have a mind. On the other hand if these words don’t contain a non-physical connection then there is no reason to believe that any words you come accross have such a connection, since there is no difference between the words spelled out by the blocks and words created by people, at least as far as you can tell. (and a simple experiment could prove this if you doubt me)

    Comment by Peter — July 22, 2006 @ 3:56 am

  4. One sentence is not language. If the box could pass the Turing Test, then human-like brains or no human-like brains, I would accept that it must have a mind.

    Comment by Carl — July 22, 2006 @ 4:14 am

  5. Read my very first post.

    Comment by Peter — July 22, 2006 @ 4:37 am

  6. I like your argument and agree that our knowledge of other minds entails that other minds must be physical. I am intersted in developing a closely related argument, the gist of which is that our ability to even conceive of minds other than our own necessitates conceiving of them as being physically distinct from us. I’ve posted a bit on the topic here and plan to develop it more soon.

    Comment by Pete Mandik — July 22, 2006 @ 6:31 am

  7. I’m not sure I know what you mean when you say we only “have access” to physical facts about other people. Maybe we can only perceive facts about their physical bodies, but how would this show that we can’t come to know things about their non-physical minds by drawing inferences from what we perceive? Is the case of the actors on the movie screen supposed to block this possibility? If so, I really don’t get how it works — what difference would the fact that we’re perceiving a body indirectly (on screen) make to what conclusions we could draw from the facts we perceive concerning it?

    Comment by Geoff — July 25, 2006 @ 7:28 pm

  8. See earlier posts about causation and causal closure of the material world.

    Comment by Peter — July 25, 2006 @ 11:25 pm

  9. “See earlier posts about causation and causal closure of the material world.”

    Yes, I’m sure they’re very interesting, but irrelevant to the simple question: what do you mean by “have access to”? If you mean something like “perceive”, then the claim that we can only have access to physical facts about other people is very plausible, but nowhere near as strong as you’d need to show that if their minds are non-physical we can’t have knowledge of them, since there are many ways of gaining knowledge about X besides perceiving X. On the other hand if by “have access to” you mean something like “can know anything at all about”, well then you’ve got a claim that’s definitely strong enough to establish your conclusion, but it’s extremely far from obvious that it’s true, and even further from obvious why the causal closure of the material world (which I’m happy to accept!) would give us reason to think that it is.

    Comment by Geoff — July 26, 2006 @ 3:29 am

  10. To know something you must able to deduce facts about from evidence (justification). Since you only have information directly about the physical, and no non-physical causation = no evidence. If you think you can get evidence of p without percieving p or percieving a consequence of p I would be happy to know how.

    Comment by Peter — July 26, 2006 @ 8:51 am

  11. sorry, forgot about this discussion. the problem with your box example is contained within the adverb ‘surprised.’

    if that were to happen, of course i would be surprised, precisely because the chance of a non-animate entity hitting upon such a combination of letters and signifiers would be amazing.

    the same thing would happen if a baby said that, or a non-English speaker.

    but the fact that i would not be surprised if my students would protest ‘stop shaking me’ clearly points out that we have a sympathetic relationship – i.e., the ability to share feelings. this, to me, is more evidence of how language solves this trivial problem of other minds.

    Comment by jay aich — June 21, 2007 @ 3:16 pm

  12. I am not about to resume a discussion of a post that is over a year old.

    Comment by Peter — June 21, 2007 @ 3:19 pm

  13. ok then. so much for philosophia perennis.

    Comment by jay aich — June 22, 2007 @ 4:51 am

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