Poll about realism

[PixyMisa]

Unless the brain in the vat knows that it is a brain in a vat, yes.

Yep. Of course, that would contradict the premise of the argument.

The program run by the computer, in every respect of the term, is the brain's reality.

Yep. What JustGeoff calls the "real world" in the case of the brain in the vat doesn't even exist as far as the brain is concerned. The brain's real world is the simulation, and any arguments regarding the brain's perceptions must refer solely to the simulation.

 

[PixyMisa]

I'm not. Personally, I argue you can't artificially induce a veridical brain state. The point is that even though the brain can't tell the difference, we still know there is a difference.

That difference is external to the universe, and therefore causally disconnected (by definition). So it is a logical fallacy to apply that knowledge to any description of the processes inside the universe.

Sorry, PixyMisa, but I haven't defined "real" at all. You have, and you defined it as follows:

As I said, that definition comes from outside the universe, and therefore cannot be applied to anything inside the universe. And I said that before I realised that I wasn't varying the definition of "real" at all. Sorry, my mistake.

Oh, and as I said, it is impossible for you to know whether our universe is real, so the argument still fails.

 

[UndercoverElephant]

Unless the brain in the vat knows that it is a brain in a vat, yes. The program run by the computer, in every respect of the term, is the brain's reality.

So you are doing the same thing as PixyMisa. You are claiming that both the BIV and the veridical perciever are experiening a "real world", even though we all know that there is something fundamentally "unreal" about the world being experienced by the BIV. This is the whole point of the argument from hallucination. To defend direct realism you have to have a consistent definition of "real". You've got to be able to account for the fact that we know that what the BIV experiences isn't real in the same way that veridical experiences are. As soon as you resort to two different definitions of what "real" means then you are just using confused semantics to escape the logic. You have "Real-A" and "Real-B" instead of "Real" and "Not real". This doesn't work.

 

[UndercoverElephant]

Pixy Misa,

I have now completely lost track of what position you are trying to defend, because your replies are not consistent. It would help me if you would go back to the argument from hallucination, as presented, and explain

a) which premise you are challenging, or

b) whether you are challenging the soundness and logic of the argument itself.

When doing so you will need to have only one definition of "real". Define it however you like, but stick to one definition.

Geoff

 

[cpolk]

Still not sure what you mean, but things happening exclusively within the body are internal to the body. Whether they are also internal to experience is another matter.

In the context of this hypothetic, is a function that happens within the body but not the brain be considered to be internal to the brain, which would be indirect, or external to the brain, which would be direct?

Yes, but would anything percieve those images? Do you think a disembodied eye can have experiences of objects?

Do you think we can have visual experiences of objects without an embodied eye? (I've proven I can play the semantics game in previous threads. )

Regardless of what function our brain plays, we do not see with our brain; we see with our eyes. Remove the eyes, and you remove the vision.

Your eye is part of the causal chain that results in a perception of a tree.

But is the eye internal or external to the brain, since it - not the brain - is what creates the actual image of the tree?

Surely the computer would just need to know exactly how the optic nerve encodes visual images? Why would it need to know how this data becomes an experience? The brain does that bit.

Not sure what you mean......

You are right - the only way the computer can create an artificial world to the brain is if it is programmed to simulate our own world in the perspective of a human (ex., though our nerve encoding). If the program does not know how the brain functions, not only can it not simulate the real world, but it cannot uphold anything it does simulate, as it must be able to predict the brain's ability to learn and experience.

In other words, in order to encode those things into the brain, it has to know how the brain functions.

If a computer has the technology to create an artificial world and encode it for a real brain, then why not forgo the brain in a vat, and just use that same technology to make an artificial brain?

 

[cpolk]

So you are doing the same thing as PixyMisa. You are claiming that both the BIV and the veridical perciever are experiening a "real world", even though we all know that there is something fundamentally "unreal" about the world being experienced by the BIV.

The BIV doesn't know that, so we don't "all" know that.

This is the whole point of the argument from hallucination. To defend direct realism you have to have a consistent definition of "real". You've got to be able to account for the fact that we know that what the BIV experiences isn't real in the same way that veridical experiences are. As soon as you resort to two different definitions of what "real" means then you are just using confused semantics to escape the logic. You have "Real-A" and "Real-B" instead of "Real" and "Not real". This doesn't work.

I'm in the lab, standing next to this BIV. is that what you are imaging?

If you are mentally aware, then you have to have a single reality.

In my world, there is the real world that I experience, and the world that is artificially created for the BIV.

To the BIV, reality is that artificial program. The BIV knows absolutely nothing of what I call reality.

 

[PixyMisa]

Pixy Misa,

I have now completely lost track of what position you are trying to defend, because your replies are not consistent. It would help me if you would go back to the argument from hallucination, as presented, and explain

a) which premise you are challenging, or

b) whether you are challenging the soundness and logic of the argument itself.

When doing so you will need to have only one definition of "real". Define it however you like, but stick to one definition.

In fact, I had done this from the beginning, but didn't realise it. I apologise for that particular confusion.


Okay, from the top:

The argument from hallucination does not say anything about anything. The brain in a vat is in a causally-closed universe of its own. What is in that universe is real in all respects to the brain. What the precise definition of real is doesn't matter; it suffices to say that it is the same definition that we apply in our universe. We can only say something is real or not real by observation, and logic based on observation, exactly the same as the brain in the vat.

So the way the brain perceives things in its universe is the same as the way we perceive things in our universe.

There are reasons why I consider direct realism to be the better paradigm, but they are practical and entirely unrelated to philosophical positions. I am simply pointing out that the brain in the vat argument is not any sort of argument at all.

 

[PixyMisa]

I have now completely lost track of what position you are trying to defend, because your replies are not consistent.

Oh, and by the way, the only inconsistency was when I realised that I wasn't being inconsistent, and I already explained that.

 

[UndercoverElephant]

In fact, I had done this from the beginning, but didn't realise it. I apologise for that particular confusion.


Okay, from the top:

The argument from hallucination does not say anything about anything. The brain in a vat is in a causally-closed universe of its own. What is in that universe is real in all respects to the brain. What the precise definition of real is doesn't matter; it suffices to say that it is the same definition that we apply in our universe. We can only say something is real or not real by observation, and logic based on observation, exactly the same as the brain in the vat.

So the way the brain perceives things in its universe is the same as the way we perceive things in our universe.

There are reasons why I consider direct realism to be the better paradigm, but they are practical and entirely unrelated to philosophical positions. I am simply pointing out that the brain in the vat argument is not any sort of argument at all.

Pixy Misa,

It would help me if you would go back to the argument from hallucination, as presented, and explain

a) which premise you are challenging, or

b) whether you are challenging the soundness and logic of the argument itself.

I need you to address the argument itself. Arm-waving doesn't suffice.

If there is something wrong with this argument then it is either the logic of the argument, or the definition of the premises. If you can't explain which of these things is wrong, then you have not defeated the argument. You haven't even responded to it.

I need to take a break. Will be back in a few hours.

 

[.13.]

You can't have something which is both an experience of a real physical object and a hallucination at the same time. These things are defined is such a way as to make them mutually exclusive. If there is a real object then it is a perception. If it there is no real object then it is an hallucination. If there is a real object (say, a stick) which looks bent to you but is actually straight then it is an illusion, that is to say you are percieving a real object, you just made a mistake about exactly what you percieved. The hallucinator isn't percieving a real object at all, unless you want to claim it is incorrectly percieving the probe in its brain - a highly complex case of illusion. I think that argument fails because its an unshatterable illusion.

I don't know if you misunderstood me. I'll rephrase. Let's say I see a hallucination of a stick. Why the second stick that I see next to it can't be real? Or have I misunderstood you somehow?

 

[UndercoverElephant]

I don't know if you misunderstood me. I'll rephrase. Let's say I see a hallucination of a stick. Why the second stick that I see next to it can't be real? Or have I misunderstood you somehow?

The stick is an example of a different argument against direct realism, the argument from illusion. That argument says that if you see a stick in water it looks bent, but you know that the stick is really not bent, therefore you can't be directly aware of objects in the physical world. The problem with that argument is that instead of saying "I percieve a bent stick" you can just say "I percieve a stick which looks bent." You are still perceiving a stick. To take another example, if a trainee pilot is in a simulator position over London he sees a city from 30,000 ft but is actually looking a mirror. But it isn't a "hallucination" because he really is looking at mirror, regardless of the fact that he thinks he is looking at a city. In the case of the brain in the vat there is no illusion to be shattered because the BIV isn't perceiving any object in the physical world whatsoever. So there is no illusion being had and it is classed as a hallucination instead. That is the critical difference between the two arguments.

 

[Dogdoctor]

I think indirect realism makes the most sense. In the case of hallucination what you are not seeing but remembering or a process similar to remembering. If you can see an object in your memory what does that mean?
Any way what you see is not the object but light reflected off the outside of the object. You can feel the outside of an object. You can smell the outside of an object. What is inside you mind makes a judgment or interpretation. The object has properties much more complex than your senses detect or your mind can understand. Not that we need to understand them but we don't even come close to knowing exactly what and object is in terms of molecules and subatomic particles and that is what the object is.

 

[cpolk]

I think indirect realism makes the most sense. In the case of hallucination what you are not seeing but remembering or a process similar to remembering. If you can see an object in your memory what does that mean?

It's not a memory. What he is saying is that the super-computer is giving the brain a fake universe, complete with a fake body and all five senses (also fake), and to the brain, that stick is completely real.

 

[Dogdoctor]

It's not a memory. What he is saying is that the super-computer is giving the brain a fake universe, complete with a fake body and all five senses (also fake), and to the brain, that stick is completely real.

It is a memory or something similar and in order for you to think it is real you have to make a judgment and say this is real or not. You might say only part is real or part not real. At any rate everything you see you make a judgment about it's reality or accuracy (did I just see that?). Perhaps people are unaware or some may assume everything they see is real. You look on the kitchen table and see an apple , is it real or is it plastic?

 

[cpolk]

It is a memory or something similar and in order for you to think it is real you have to make a judgment and say this is real or not. You might say only part is real or part not real. At any rate everything you see you make a judgment about it's reality or accuracy (did I just see that?). Perhaps people are unaware or some may assume everything they see is real. You look on the kitchen table and see an apple , is it real or is it plastic?

No no, really, the hypothetical here is that the super-computer is able to implant the image into the brain, using neural paths, to completely simulate an existence as you know it now. In other words, you, as you are right now, may be a brain in a jar, being fed your reality by a super computer.

Think back to the movies. Except, there is no pill. You cannot assume your reality is not real, because you are not in control of it - the super computer is in control.

 

[Dogdoctor]

No no, really, the hypothetical here is that the super-computer is able to implant the image into the brain, using neural paths, to completely simulate an existence as you know it now. In other words, you, as you are right now, may be a brain in a jar, being fed your reality by a super computer.

Think back to the movies.

Ok so he is setting up an unreal hypothetical situation to discuss reality. How bizarre, and I have no useful comments other than how does that relate to reality or understanding it? At any rate the rest of my thoughts about it stand. You see an apple is it an apple? a fake apple? a picture of an apple, a hologram of an apple? Does it have a worm inside? Does it taste good? You can't tell easily from looking at a distance.

 

[Iacchus]

No no, really, the hypothetical here is that the super-computer is able to implant the image into the brain, using neural paths, to completely simulate an existence as you know it now. In other words, you, as you are right now, may be a brain in a jar, being fed your reality by a super computer.

Think back to the movies. Except, there is no pill. You cannot assume your reality is not real, because you are not in control of it - the super computer is in control.

Sort of like the original episode of Star Trek called The Menagerie?

 

[cpolk]

Ok so he is setting up an unreal hypothetical situation to discuss reality. How bizarre, and I have no useful comments other than how does that relate to reality or understanding it? At any rate the rest of my thoughts about it stand. You see an apple is it an apple? a fake apple? a picture of an apple, a hologram of an apple? Does it have a worm inside? Does it taste good? You can't tell easily from looking at a distance.

Yes, but in this completely simulated world, you can touch it. Taste it. You will smell flowers. You will hear people having completely normal conversations with you. As the brain in the vat, there is absolutely no indication whatsoever that this isn't reality.

That's been my answer, too. It doesn't matter. If I've got no way of telling that it isn't reality, then it is.

 

[.13.]

The stick is an example of a different argument against direct realism, the argument from illusion. That argument says that if you see a stick in water it looks bent, but you know that the stick is really not bent, therefore you can't be directly aware of objects in the physical world. The problem with that argument is that instead of saying "I percieve a bent stick" you can just say "I percieve a stick which looks bent." You are still perceiving a stick. To take another example, if a trainee pilot is in a simulator position over London he sees a city from 30,000 ft but is actually looking a mirror. But it isn't a "hallucination" because he really is looking at mirror, regardless of the fact he is looking at a city. In the case of the brain in the vat there is no illusion to be shattered because the BIV isn't perceiving any object in the physical world whatsoever. So there is no illusion being had and it is classed as a hallucination instead. That is the critical difference between the two arguments.

You've lost me. I'm trying to figure out why can't I have hallucinations and real experiences. I'm not talking about a stick in a water that just seems bent but a real stick and a hallucinated stick side by side. Why can't the second stick be physical if the first one is a hallucination?

P5: Given this indistinguishability, we should conclude that since the objects of immediate awareness in hallucination are not external physical objects, the objects of immediate awareness in veridical perception aren’t physical objects either.

To me that reads:
If we can hallucinate some things then nothing is physical.

 

[UndercoverElephant]

I think indirect realism makes the most sense. In the case of hallucination what you are not seeing but remembering or a process similar to remembering. If you can see an object in your memory what does that mean?

That is slightly different. This is why the argument isn't the argument from dreaming: dreaming is phenomenologically different to being awake. So is remembering visual experiences. The brain in the vat is supposedly experiencing something indistinguishable from a veridical experience.

Any way what you see is not the object but light reflected off the outside of the object. You can feel the outside of an object. You can smell the outside of an object. What is inside you mind makes a judgment or interpretation. The object has properties much more complex than your senses detect or your mind can understand.

That is a version of yet another argument against direct realism:

The Partial Character of Perception Argument:

First Premise. Direct Realists hold that we are able to (directly) perceive physical objects.

Second Premise. But to perceive a physical object, we must be able to perceive all of its parts at once.

Third Premise. But we are not able to perceive all of a physical object’s parts at once. At best, we are able to perceive a spatial part of it (e.g, a portion of its outer surface), but not all of its spatial parts at once.

Conclusion. Direct Realism is false. We do not directly perceive physical objects. The proponent of the argument may then take a further step and infer that “there is no part even of the outer surfaces which I see; for, with respect to any such part, there is, surely, some part of it which I do not see. What I see, therefore, cannot be a part of any physical thing.

NOTE FOR ALL:

The above quote comes from a paper detailing of the arguments against direct realism, and claims to be able to defeat them all. Personally I think the argument supplied that is supposed to defeat the argument from hallucination fails, even though I also believe the argument from hallucination fails.

http://www.tcnj.edu/~lemorvan/APR_Proof.pdf