Brain in a vat

Discussion in 'General Philosophy' started by James R, Nov 22, 2016.

  1. James R Just this guy, you know? Staff Member

    Jan Ardena:

    I think you're still missing the point of this philosophical discussion. Before I respond to your last post point-by-point, I'll try to set out the argument succinctly one last time for summary purposes.

    We all live our lives every day trusting that our sense impressions accurately reflect real things about the world. So, you believe you have a body, with a brain in your skull. You think that you see the world more or less as it is. You have human feelings such as love, and frustration and sadness and joy and all those other things. You consider yourself to be a more-or-less autonomous individual.

    The brain-in-a-vat picture exposes the fact that you can't actually know that any of these things that you take for granted is true in fact.

    Start with a simple example, more closely tied to what you call "the real world". When you look at something, you don't see the thing directly. Light comes into your eyes, and is turned into electrical signals, which are then processed by your brain. The last step in that process is you being consciously aware of a sense impression like "I can see an apple." So, the first thing to notice is that you have no direct perception of the apple. Your entire experience of the apple is filtered through your senses and through your brain.

    Now we ask the question: would your perception be any different if we were, for example, to remove the actual apple and instead stimulate the appropriate parts of your visual cortex to re-create that mental image you have of an apple in all its usual detail? It shouldn't be too much of a stretch to realise that your perception wouldn't be any different, especially seeing that something very similar happens when you watch a TV picture of an apple or a 3D projected image of an apple.

    Going a step further, what if we could replace all the sensory inputs to your brain using technology sophisticated enough to produce exactly the same sense perceptions as you have while you're walking around in the "real world". The "feed" to your brain could come from the real world, but it needn't. It could, for example, be simulated, like a virtual-reality projection.

    In this later case, would you know the difference between the "fake" sensory inputs and the "real" ones. Again, it shouldn't be a stretch to conclude that there's no way you could know the difference, given a good-enough simulation (or feed).

    Now realise that if we have managed to duplicate your sense impressions by wiring up your brain, then as far as you're concerned it doesn't matter where that brain is physically located any more. If we scooped your brain out of your skull and through a miracle of modern medicine managed to preserve it, wired-up, in a suitable vat of nutrients, you wouldn't notice any difference from having it your skull.

    If you want to go for one last step, why bother with the physical brain, or indeed the physical world, at all? A sophisticated-enough computer could, in principle, instead duplicate all of the functions carried out by your biological brain, and we could feed that computer the usual feed of sense impressions. But now, both you and the world as you know it exist entirely within a complicated and detailed simulation instead of in the "real world" that you perceive.

    You can call this a thought experiment or a game if you like. But here's the clincher: this scenario, or something like it, could be your reality, right here and now.

    In other words, there's no conceivable test you can carry out to distinguish "you" being a flesh-and-blood human being walking around in the world from "you" being a brain in a vat or a computer simulation of a person.

    You might object that a computer simulation of a human being is not a human being. That is an interesting discussion in itself, but somewhat beside the point here. The point is that, according to your lived experience, there would be no way to distinguish the two situations, even if there is a meaningful difference. Computer-simulated you would perceive all the same things as "real" you, think all the same thoughts, have the same loves and joys and sorrows that you have etc. It might even occasionally speculate about whether it could possibly be a brain in a vat.

    Just to emphasise: in the brain-in-a-vat scenario, it's very hard to argue that the brain in the vat wouldn't be "you". If your brain was in a vat, wired up for all the usual sense impressions that you normally have, that brain would be experiencing all the things you normally experience. It would think all the same thoughts you usually think. It would be you just as much as the flesh-and-blood brain you currently think you have is you.

    For religious people, of course, this whole idea that your brain is the essence of "you" seems unpalatable. There must be something more! So, as a religious person, you'd probably say that the "real" you is some kind of disembodied soul or spirit. Again, this is somewhat off-topic for the discussion, but we could ask what the nature of the connection of this soul or spirit to a physical body and brain is; this one is probably better left for a different thread.

    If you think the soul is important, then as far as the brain-in-a-vat scenario goes, the pertinent questions are: does the soul follow the brain, even if it is in a vat, or does it require an intact body to function correctly? Or would the soul depart if the brain was transferred to a vat? Can a soul only exist inside a flesh-and-blood human being? Could a computer-simulated person or a brain in a vat know that it didn't have a soul (if indeed it is the case that these things are "soulless")?
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  3. James R Just this guy, you know? Staff Member

    Here's my response to your last post, Jan.

    Let me be clear about my point of dispute with you.

    I am not asserting here that you are a brain in a vat, although it is possible that you are, as explained above.
    I am saying you can't know that you're not a brain in a vat.

    You, in opposition to this, are saying both that you can and do know (for sure) that you are not a brain in a vat.

    I am trying to get you to explain how it is that you can make this knowledge claim, and whether it is a justifiable claim to make. Obviously, I'm saying that you have no defensible basis on which to make this claim to knowledge.

    Your argument for your knowledge claim, as far as I can make out so far, is little more than a vague appeal to "common sense", or something similar, combined with numerous attempts to dismiss the conundrum as fundamentally absurd or implausible (though without giving any reasons for saying that).

    It's air tight unless you or somebody else can find some flaw in it.

    Again, to emphasise, I do not need to show that you are a brain in a vat in order to dispute your claim that you know that you are not. My argument with you is not about the fact of your being or not being a brain in a vat. My argument is that you can't know either way.

    The brain-in-the-vat scenario should be a comfortable one for you, then. That brain in the vat would experience this existence as an illusion of sorts, and any real or simulated body that the brain controlled would merely be a vehicle for the brain's consciousness.

    Why wouldn't you tell the brain that it was living in an illusion? Suppose you were standing in the lab looking at it in its vat. You'd be right about telling it what the real situation was, wouldn't you? I can conceive that you might want to lie to the brain to spare its feelings, perhaps. But that wouldn't change the reality.

    I agree with you that it is a fact that you are asserting that you are not a brain in a vat.
    I disagree with your claim that you can know this, absolutely, without a doubt (as opposed to merely believing it).
    And, as I explained, (3) is not a developed counter-argument, even though you appear to think it is important in some sense.

    A brain in a vat would have the same capacity to indulge in pure speculation as a brain that is in a skull.

    It's a philosophical question: to what extent can we or can't we trust our sense impressions as giving us a true picture of reality?

    As I said previously, it makes zero practical difference to your life whether you are a brain in a vat or a flesh-and-blood human being with a body. Such is the nature of many philosophical speculations.

    And again, I repeat that my dispute with you here is not about whether you are a brain in a vat or not. It is about what you can or can't know.

    It can be either way around. The question is: what can you know?

    As far as we know. (See, you said it again.)

    Of course you think that. But you'd think that even if you are, in fact, a brain in a vat.

    I haven't asked you to prove that you're not a brain in a vat, although if you can do that then you can certainly legitimately claim to know that you are not a brain in a vat.

    I have only asked you to explain how you know that you're not a brain in a vat. Because I don't think that's something you can know for sure.

    See my previous post.

    We can take it as given that you don't self-identify as a brain in vat. But that doesn't mean you aren't one.

    Sorry, I've lost track of which question I'm supposed to be answering yes or no. Am I a human being? Yes. Do I know that I'm not a brain in a vat? No.

    It wouldn't surprise me at all if this kind of philosophical question was touched on in vedic literature. It would be put in different terms, but the discussion would be similar.

    If you're a flesh-and-blood human being, then you have brain in a vat that you like to call your skull. Are you saying that "you" have nothing to do with your brain? (See my previous post on this point, too.)

    If you think that the brain-in-the-vat scenario is impossible for technological reasons - even taking into account future advances in technology, perhaps you should explain why you believe that it is impossible.

    If you can establish the technological impossibility of the brain-in-the-vat or simulation, then once again you might have a legitimate reason for claiming to know that you are not a brain in a vat.

    As much as the brain in your head is.


    That is not in dispute, as far as I can tell.

    Would a brain in a vat converse differently? If you can establish that it would, then again you might have the beginnings of an argument.
    Last edited: Nov 29, 2016
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  5. karenmansker HSIRI Banned

    I believe that JamesR and DaveC really ARE just two brains in the same vat . . . . . I also believe that Jan IS NOT a brain in a vat.
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  7. DaveC426913 Valued Senior Member

    So you recognize the validity of the thought experiment. That's a good thing.
  8. Seattle Valued Senior Member

    I believe that it's more likely than not that Jan is a brain in a vat. No one has ever seen Jan. There is some confusion as to sex due to the unisex name. A brain in a vat would be more likely to be evasive and to parse words.

    Therefore can we all just accept that it's likely that Jan is a brain in a vat (not that there's anything wrong with being a brain in a vat).?
  9. DaveC426913 Valued Senior Member

    The BiaV thought experiment simply highlights the fact that our experience of reality is at ... well ... arm's length from the world.

    This cannot be rationally denied. (It can certainly be irrationally denied.)
  10. James R Just this guy, you know? Staff Member

    I'll take that as a compliment. Thanks.
  11. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

    JamesR, I think Jan is incapable of having a sensible discussion on the matter. He seems incapable of getting past the "but I know differently." Whether this is simple intellectual incapability or a dishonest stubbornness, I wouldn't care to speculate, the end result is the same in both cases: futility.

    I recall another thought experiment where one was asked to consider two cases: one where God did not exist and the universe came about naturally, and one where God did exist and brought the universe into existence etc.
    Jan couldn't accept the first case because, according to Jan, if God didn't exist then nothing would exist.
    While, as a believer, Jan is entitled to this view in general, it does nothing to engage with the thought experiment and the longer it went on the more it showed that Jan was incapable of engaging with such experiments.
    I fear that this is simply another such instance.
  12. James R Just this guy, you know? Staff Member


    Yes. You're most likely right about Jan. Nevertheless, I thought other people might enjoy reading about this thought experiment, if they aren't already familiar with it.
  13. Xelasnave.1947 Valued Senior Member

    I suppose when you dream you think everything is real which hints that if you were a brain in a vat you could be fooled.

    However dreams are presumably built upon a physical experience so briefly a brain in a vat may have to have had physical experience before it could except generated realities when in the vat.

    Sometimes in a dream you can determine it is a dream because it does not fit learned physical experience.

    So I wonder if the brain in the vat may be able to tell by runing tests somehow.

    I can test if I am in a dream so I wonder if I could test if I am a brain in a vat.

    I suppose it finally turns on the brain involved.

    Some brains are obviously fooled easier than others.

    I do think I could argue both pro and con either side a benefit of a past life.

  14. birch Valued Senior Member

    As for not knowing where you exist whether in a body or petri dish, the same analogy could be extended to the universe itself. It could be floating, speeding or hurtling somewhere-else right now. Just as a drop of water can be anywhere. And as for the big bang, there is no definitive reason it cant happen again at anytime to disrupt the whole universe, end it all or some other universe starts anew. We know of natural aging but thats a projection and has nothing to do with chance and unknown factors.

    Some think the universe is infinite but i doubt it. We really dont know where this universe is at or where or what we exist in as we yet know whats beyond.
    Last edited: Nov 30, 2016
  15. OceanBreeze Registered Member

    Once the simulation becomes indistinguishable from the “real thing” from our perspective, the simulation IS the real thing. Only The Sim Master knows! One nice thing about being in a simulation; death is also simulated! The Sim Master can recycle us into whatever else he wants, but as energy we cannot be destroyed.
  16. OceanBreeze Registered Member

    We should hope that there is no such experiment. What do you suppose would happen to us if we ever found out we are really a simulation with no free will? My guess is we would all go insane. In fact, it is probably not healthy to even think about such things. We have more than enough toys to play with in our universe without the need to look outside. Well, at least not at this stage in our development.
  17. Xelasnave.1947 Valued Senior Member

    Well I see the situation really only a little different to realising you are nothing more than a wage slave where at the end of the money there is too much month left.
    The free will may be there but the choices are very limited.
  18. birch Valued Senior Member

    It sure does and we dont even see everything or even as it is just as all the microbes everywhere. Can you imagine looking at someone's face and seeing it teeming with trillions of tiny creatures??? Just one drop of pond water is teeming with creatures with their own drama unaware of us.

    But this goes even further to interdimensional and i suspect there is more or of a different nature that we cant detect at all or barely because it is just not within our senses to.
  19. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

    We can be recycled as many times as he sees fit, but without memories from one incarnation to the next we are distinct entities and each death remains as meaningful as if we only had one incarnation.
  20. wellwisher Banned Banned

    Say we had one person, from each language of the world, assembled in a room. In the middle of the room, I place a nice red apple on the table. We will all see the same apple, due to the way light enters the eyes and brain. This can be proven by having each person rough sketch what they see, and then color it in. You will not see lot of sketches of cats, trees and cars.

    In terms of language, on the other hand, few if any of these people will agree, on the noise we need to use, to express what we see, using spoken language. The German and Chinese person will make different sounds. The unknown sound, from another language, will appear to say nothing to the untrained ears. What is common to the eyes, will appear to be more diverse and exotic due to the wide range of fancy noises. The collective ears can tell the tone and the pitch, of each sound made. We can demonstrate this by having each person repeat the noise. However, the meaning of the noise will appear subjective and arbitrary, since we can't all agree.

    Although we can all see the same thing; apple, language creates a barrier between what we see inside the brain, and how each of us interpret and explain what we see.

    Slang often recycles old words to create new meaning. For example, the singer, Micheal Jackson, used the word "bad" to imply Cool and Tough. Not everyone will conform to the new noise association, in the same way. Some people will continue to use the traditional definition of bad, as meaning the opposite of good. The new definition defines bad, containing elements of good and prestige. The traditionalists, being pointed out the "bad" boy, by their hip son, will see the same person, but the filters of language may extrapolate a criminal and not a youth group leader. They both see the same thing, but words get in the way in terms of filters of the mind used for interpretation.

    PC adds even more confusion, because it defines its own voter base, in terms of new and improved fluffy terms, creating confusion with filters that use traditional language. Many people may not see, what PC tries to define, because they can't see the warm smoke up the skirt. It does not exist in the visual world. Since we can't transfer what we see, without language, confusion appears in output and input.

    When you start to discuss science, especially of things we can see for ourselves; black holes, hydration along the DNA, you need to depend on language, which is nebulous and not as universal as visual. People start to parrot the words. If your words don't align to traditions, it has to be wrong, since there is no universal visual to compare and reverse engineer the words.

    Men are visual animals, while females are more verbal. The impact of a feminist culture is to add confusion; diversity, followed by conformity to words, since there is no universal standard, of visual, to set the record straight, so we conform the words to the universal visuals.
  21. DaveC426913 Valued Senior Member

    - Being in a sim or not, and
    - having free will or not
    are entirely independent issues.

    You can
    • not be in a sim and have free will
    • not be in a sim and not have free will
    • be in a sim and have free will
    • be in a sim and not have free will
    You're going to ask the obvious question:
    How is it possible to have free will in a sim?

    To which I ask
    Indeed. How is it possible to have free will when not in a sim?
    What - exactly - is the diff?
  22. Jan Ardena Valued Senior Member


    can I assume that I have knowledge of the possibility of actually being a brain in a vat?

  23. Michael 345 New year. PRESENT is 69 years old Valued Senior Member


    "You believe the world operates purely naturally, I find it interesting that you haven't proved it. Can you?"

    The main reason I consider the world HAS to operate 'naturally' <<< (here I would say "by fixed unbreakable laws of physics") is that universe would be impossible if Magic / God / Miracles (MGMs) operated.

    Problem is ALL versions of MGMs are on a equal footing.

    One MGM has just as much validity as another. Where as there is only 1 system of unbreakable Laws of Physics.

    Do we know them all? No.

    Do we understand all of the ones we do know. Most of them.

    Some of those we don't understand can be seen as works in progress.

    To illustrate a world where MGMs operated. Remember here there are NO rules.

    God 1 *Today I will make earth gravity twice as strong*.

    We are dragging ourselves around when

    God 2 looks down *Heaven's above. Today I will make earth gravity a quarter of what it is now*.

    Fill out the rest for yourselves. I will continue the theme if 2,000 of you ask nicely.

    Please Register or Log in to view the hidden image!

    "There are two options. My brain is in a vat, or it isn't."

    There are 4 options. My brain is in a vat, a jam jar, a coffee pot, or none of the above.

    Option 2 is correct. I know this is a fact. Every morning when I wake up there is jam on the pillow.

    Please Register or Log in to view the hidden image!

    . Raspberry.

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