Is it possible to perceive a world which is external to our perceptions?

[Paul C. Anagnostopoulos]

If a brain in a vat is percieving a chair, then there is no actual external chair.

But there are external signals, so it's not as if there is nothing external.

Then, there's the question of whether the cyber-chair was created using data from a real chair, thereby giving the cyber-chair a sort of supported meta-reality from that angle... or whether it was, in fact, wholly imagined, like some kind of unicorn or chimera. Yet even our tales of chimeras have roots in the real - that is, we compose these mythical beasts based on beasts we have some awareness of.

If the cyber-chair was generated from a real chair, then the BIV is perceiving the real chair, only through additional levels of mapping.

We still haven't agreed whether direct realism allows photons and/or stages of sensory perception.

~~ Paul

 

[Paul C. Anagnostopoulos]

Let's change the thought experiment so there's definately no external chair. We are just feeding nerve-data that corresponds to seeing a chair.

Somewhat like an animated cartoon. Yet the animation is created by analyzing, or even laser-scanning, an actual chair.

Why don't we make it a purely imaginary extraterrestrial craft and see where that takes us? Both the human and the BIV are picturing something that no one has ever seen, conjured up in someone's imagination and then fed to them either by word of mouth or by simulation of word of mouth. No "external object" at all to clutter up the thought experiment.

~~ Paul

 

[UndercoverElephant]

Somewhat like an animated cartoon. Yet the animation is created by analyzing, or even laser-scanning, an actual chair.

Why don't we make it a purely imaginary extraterrestrial craft and see where that takes us? Both the human and the BIV are picturing something that no one has ever seen, conjured up in someone's imagination and then fed to them either by word of mouth or by simulation of word of mouth.

~~ Paul

Word of mouth is no good. You can feed the BIV experiences of an ET. Telling you about ET's isn't quite the same.

 

[UndercoverElephant]

This is needlessly complicated. The evidence suggests that there is no single set of nerve-data that would correspond to seeing a chair; rather, the ability to recognize a chair is learned through unique interaction with the environment. Assuming that there is some sort of signal we could send--(yes, in a thought-experiment, we can specify that this BIV is sent this perceived history, whereas another BIV might be sent another...and as someone here has already mentioned, the BIV is not merely a B, but an interactive organ with the rest of a body, which is quite different from a V, but again it is a thought experiment)--is too complicated. Why not try a simpler real world example? We see illusions all the time. We look, see something, look again, it was not what we thought it was. Does this imply that the "existence" of the thing we thought we saw the first time has some sort of "real" quality to it?

Illusions aren't such a problem. If you see a stick in water which looks bent but is really straight, you are still percieving a stick. The last section of the essay I posted deals with this case. It's not the same as a BIV hallucination.

 

[UndercoverElephant]

But there are external signals, so it's not as if there is nothing external.

Yes, but that's not the point. We are trying to defend direct realism. There's no external chair - that is all that matters.

If the cyber-chair was generated from a real chair, then the BIV is perceiving the real chair, only through additional levels of mapping.

Yes, but this is just changing the thought experiment. It makes no difference to the original thought experiment.

We still haven't agreed whether direct realism allows photons and/or stages of sensory perception.

~~ Paul

I don't really know what you mean. Yes, there can be stages of sensory perception. This isn't the big problem with direct realism. The problem is that the chair doesn't exist!

 

[Bodhi Dharma Zen]

If a brain in a vat is percieving a chair, then there is no actual external chair.

mm, well, I disagree. There is an actual external chair; the input that the BIV is receiving.

 

[Bodhi Dharma Zen]

Yet, some would argue (and I would be among them) that the same data stored in a computer is, in essence, a form of reality as well. I'm very much a believer that we can create a wholly true reality within a virtual space a-la a very complex version of the Sims, perhaps. Hence, if the data about a chair exists in cyberspace, it is no less real with relation to its meta-reality than a chair in our space would be.

As usual, better explained that my own answer. I would like to add the fact that this chair will be as objective as the "real" chair. Both are independent to the perceiver. In fact, before any perception occurs, they can be argued to be "the noumena".

 

[UndercoverElephant]

mm, well, I disagree. There is an actual external chair; the input that the BIV is receiving.

That's not an external chair though, is it? That's a nerve input. The problem is if you want to argue that the BIV is perceiving nerve input then it looks like you've got to argue that you are perceiving nerve inputs right now. And in a way, you are - but not in the same way you percieve chairs. Whatever answer you give for the BIV, you must give for veridical perception - unless you've got a very good reason otherwise.

 

[Bodhi Dharma Zen]

Let's change the thought experiment so there's definately no external chair. We are just feeding nerve-data that corresponds to seeing a chair.

It is an external chair. The feeding is external, its configuration is what is interpreted as a chair.

 

[UndercoverElephant]

It is an external chair. The feeding is external, its configuration is what is interpreted as a chair.

That just makes it external. A "configuration of data which is interpreted as a chair" isn't the same as a chair. It's not a chair. Remember we have defined "objects of perception" as being like those things in front of you - like chairs. Neural configurations aren't like those things.

 

[hammegk]

From the view of one what we perceive as human BIV, we're just looking at neural signals.

I'd say the problem is, is perception of our universe all signals entering a BIV?

 

[Bodhi Dharma Zen]

That's not an external chair though, is it? That's a nerve input. The problem is if you want to argue that the BIV is perceiving nerve input then it looks like you've got to argue that you are perceiving nerve inputs right now. And in a way, you are - but not in the same way you percieve chairs. Whatever answer you give for the BIV, you must give for veridical perception - unless you've got a very good reason otherwise.

I guess a better question is: how can we differenciate between the external pattern that it is interpreted as a chair from "a real chair"?

Well, its impossible. Both are external patterns, both are, for every account, a real chair.

 

[Z]

That's not an external chair though, is it? That's a nerve input. The problem is if you want to argue that the BIV is perceiving nerve input then it looks like you've got to argue that you are perceiving nerve inputs right now. And in a way, you are - but not in the same way you percieve chairs. Whatever answer you give for the BIV, you must give for veridical perception - unless you've got a very good reason otherwise.

But that's the point - we DO perceive nerve inputs, which we translate to equal chairs. That's the whole point - all of our knowledge of the world external to us is translated by the brain via our sensory organs. If all sensations appear consistant and congruous, we have a reality.

So the perceived chair (via reality) or the perceived chair (via computer-generated fantasy) are the same, with regards to perception.

 

[UndercoverElephant]

But that's the point - we DO perceive nerve inputs, which we translate to equal chairs. That's the whole point - all of our knowledge of the world external to us is translated by the brain via our sensory organs. If all sensations appear consistant and congruous, we have a reality.

The argument is not about whether or not an external reality exists. The argument is about whether we can directly perceive it.

 

[UndercoverElephant]

I guess a better question is: how can we differenciate between the external pattern that it is interpreted as a chair from "a real chair"?

Well, its impossible. Both are external patterns, both are, for every account, a real chair.

BDZ,

A pattern of nerve inputs is NOT a real chair. It just isn't. This argument is a non-starter.

Geoff

 

[Ichneumonwasp]

The argument is about whether we can directly perceive it.

Depends on what you mean by "directly". Isn't the perceiver, by definition, in the form of direct realism you have posed a homonculus? Immediate perception is possible only for a little guy with all the perceptual ability immediately available to him sitting in your head.

That isn't how the brain works. This form of "direct realism" is simply a badly formed idea having nothing to do with the way perception actually occurs. The pathological cases demonstrate this. Awareness isn't even one "thing".

 

[Paul C. Anagnostopoulos]

Word of mouth is no good. You can feed the BIV experiences of an ET. Telling you about ET's isn't quite the same.

What? Having an ET craft described to you is just another sensory experience.

Yes, but that's not the point. We are trying to defend direct realism. There's no external chair - that is all that matters.

But external signals are just as "real" as an external chair. We don't want to end up with a thought experiment where an external physical object produces different conclusions that external physical signals, do we?

I don't really know what you mean. Yes, there can be stages of sensory perception. This isn't the big problem with direct realism. The problem is that the chair doesn't exist!

But how about the fact that the chair isn't directly crammed into our senses, but rather mappings of the chair such as photons, sound waves, odors, etc.? Is that okay in direct realism, or does that make it indirect or something else?

That's not an external chair though, is it? That's a nerve input. The problem is if you want to argue that the BIV is perceiving nerve input then it looks like you've got to argue that you are perceiving nerve inputs right now. And in a way, you are - but not in the same way you percieve chairs. Whatever answer you give for the BIV, you must give for veridical perception - unless you've got a very good reason otherwise.

It is precisely the same: Both the BIV and I are "perceiving" sensory inputs, which are usually presented to the brain as nerve inputs. No one is directly perceiving the chair, whatever the hell that would mean. The question is simply how the nerve inputs are driven.

~~ Paul

 

[Paul C. Anagnostopoulos]

The argument is not about whether or not an external reality exists. The argument is about whether we can directly perceive it.

But what does directly mean? This is what we keep asking you.

It is okay for there to be a complex sensory pathway between my sensory apparatus and my brain.

Is it okay for there to be transduction processes between the external chair and the signals reaching my sensory apparatus? I hope so, or this thought experiment is irrelevant.

Given this incredibly complex causal chain, I'm not sure what the word direct actually means, and exactly how it differs from indirect realism. From what I can tell, it has something to do with what goes on in my brain, and so the exact reality of the external chair doesn't matter.

~~ Paul

 

[UndercoverElephant]

Depends on what you mean by "directly". Isn't the perceiver, by definition, in the form of direct realism you have posed a homonculus?

I haven't mentioned "a perceiver".

Immediate perception is possible only for a little guy with all the perceptual ability immediately available to him sitting in your head.

Didn't understand this sentence.

That isn't how the brain works. This form of "direct realism" is simply a badly formed idea having nothing to do with the way perception actually occurs. The pathological cases demonstrate this. Awareness isn't even one "thing".

I do not need to know anything about neuroscience in order to be able to make the statement "I perceive a chair".

 

[UndercoverElephant]

What? Having an ET craft described to you is just another sensory experience.

I think you may be confusing perception and imagination.

But external signals are just as "real" as an external chair.

Yes, but they're not a chair!

We don't want to end up with a thought experiment where an external physical object produces different conclusions that external physical signals, do we?

Didn't understand question.

But how about the fact that the chair isn't directly crammed into our senses, but rather mappings of the chair such as photons, sound waves, odors, etc.? Is that okay in direct realism, or does that make it indirect or something else?

Direct realists do not have to believe there is a chair inside their skull.

No one is directly perceiving the chair, whatever the hell that would mean.

~~ Paul

Why don't you tell me what you think of my own defence of direct realism.