Brain in a Vat.

[de_budding]

What is the connection between brain and body?

One thought experiment that allows us to explore the connection in a profound way is to imagine that the above picture is your brain. The vat of liquid stimulates your brain to perceive every thing you ever have and will experience.

What practical steps can we take to discover the truth from within the illusion?
What assumptions are reasonable within the context? And how cheap is it that The Matrix didn’t site Descartes in the credits of the film?

Well, let me start with...

'I think, therefore I am' –Descartes

If we are indeed within the illusion, I am still thinking about it and that is at least something I can be sure of.

Dan.

[boagie]

Y'all!!
Another entity has placed me in this tank---------Oh God!!! I care less than nothing for Zeus, let him do as he pleases!! Shelley's Prometheus.

[cjames]

Yay, this should be an interesting topic to follow, I have only recently begun to read about this theory myself(http://plato.stanford.edu/entries/brain-vat/), and while I was cycling home from school today I began thinking about the Evil Genius Hypothesis. If it is true, why should this Evil Genius want us to start doubting his manipulation of us? Why should he allow the brain to start questioning if it is merely a brain in a vat?

[de_budding]

Originally Posted by cjames

why should this Evil Genius want us to start doubting his manipulation of us? Why should he allow the brain to start questioning if it is merely a brain in a vat?

Well is it possible that the thought processes that lead to doubting are insuppressible. How would you go about it if you were the evil genius? You have an organic brain in a jar, the only control you have is via the simulation of reality, is there any way you could convince the brain not to question? I think the goal of ‘not allowing us to doubt’ would require stopping the subject from running comparisons of past experience with other past and new experiences and then projecting these as predictions- but this is self-consciousness right?

I have been thinking a lot about freedom recently and I want to say thanks for inspiring another 'fundamental freedom' which would exist in the vat as well as out the vat... the freedom to question, consider and doubt.

So if the case is that- no matter what- we will think, question, consider and doubt, then these would be the tools by which to start proving that we are a brain in a vat or not. If Arjen is about I would ask he remind me of how doubt can be used as a tool.

Dan.

[cjames]

Interesting theory Dan. So if I read you correctly we can't use the the freedom to question,consider and doubt to show that we are in fact not brains in a vat.

And I agree with you on the part of not allowing us to doubt would be impossible for the evil genius.

Now, it is time to go get some coffe, and start pondering over your questions. Thanks for taking the initiative to this discussion

[Arjen]

Say, guys,

Allow me to place things into context:

First of all de budding was quoteing René Descartes by saying "I think, therefore I am". The reason Descartes said that is because of his 'cartesian doubt'. He started questioning everything. That left nothing apart from his self doubt. So if nothing existed apart from his doubt there would still have to be something which was doubting. Thus Descartes proved his own existance: the only thing he was certain about. If an evil genius would somehow prevent the brain in a vat from doubting itselves it would leave no way for the brain to prove its own existence. That would be a silly mistake for an evil genius. Apart from that the evil genius would have made a noticeable difference between reality and the vat. The defining condition of our thought experiment was that there were no noticeable differences for the brain so it is right out (so to speak).

I would like to pose another interesting viewpoint though. Is it not true that no matter how convincing the illusion is which is being presented to the brain in a vat it remains an illusion? Say that the illusion is exactly equal to reality, and that we have a brain in the real world and a brain in a vat. Both are walking down the same lane, one in the illusion and one in reality and both are thinking of the same traffic light. Still there would be a very important difference: the thought-objects of the brain in a vat would be referring to the illusion and the thought-objects of the brain in reality would be referring to reality. The difference is there a priori.

Meaning just ain't in the head!
~Hillary Putnam.

[cjames]

Sure, the illusion remains an illusion. And there will be a diference between the reality and the illusion, because as you say they refer to two different things. The brain can't know if it refers to an illusion or reality though, can it?

So how to tell reality from illusion, when you can't know it isn't an illusion, and we are kinda back to the start. This brain in a vat thing kinda annoys me a little :P so I hope we can prove it false somehow.

[Arjen]

Originally Posted by cjames

Sure, the illusion remains an illusion. And there will be a diference between the reality and the illusion, because as you say they refer to two different things. The brain can't know if it refers to an illusion or reality though, can it?

So how to tell reality from illusion, when you can't know it isn't an illusion, and we are kinda back to the start. This brain in a vat thing kinda annoys me a little :P so I hope we can prove it false somehow.

Our set-up was that we said that the difference would be unnoticeable by the the brain in the vat so I must concede that point. I do, however, have serious reservations on that.

1) There is a difference between what the thought objects refer to in and outside the vat a priori.

2) The machine the brain in the vat is linked to is taking the place of physical reality by thought waves. If this difference is unnoticeable, then the question comes to mind that this cannot be noticed in real life as well. I think, however, that there is a difference between my thoughts of rain and rain itself. I even think that there is a difference between "normal" thoughts and "delusions".

On the other hand all of value things in a different way. The pain we feel is different to each of us for instance.

[de_budding]

1) There is a difference between what the thought objects refer to in and outside the vat a priori.

2) The machine the brain in the vat is linked to is taking the place of physical reality by thought waves. If this difference is unnoticeable, then the question comes to mind that this cannot be noticed in real life as well. I think, however, that there is a difference between my thoughts of rain and rain itself. I even think that there is a difference between "normal" thoughts and "delusions".

Arjen,
Your highlighted comments triggered an idea that uses a priori logic… I think,
It’s based on two givens. (a) Is based on the idea that there is an unperceived world, this unperceived world in my opinion is going to be a dimensionless multiplicity of data in the form of waves (e.g. sound, light).

(a) Outside the vat, in reality, any thing we perceive is an interpretation via the senses.

Things don't actually look (or smell or feel or sound etc.) how they do to us, and this can be observed by looking at another animal with slightly different sensual equipment. Human eyes respond to light with wavelength in the range of approximately 400 to 700 nm but some birds see in the ultraviolet spectrum, also we can study when our senses confuse their interpretations of reality by looking at conditions like synaesthesia. Often people with synaesthesia will smell colors, taste sound etc.

(b) The BIV does not have any senses by which to interpret.

The brain in a vat has no means by which to interpret.

If (a) and (b) then the data fed to the BIV must be pre-interpreted for human consumption*. Therefore, if you remove your eyes now and can still see you are a BIV, if you go blind you are not a BIV.

*if the data fed to the BIV was ‘raw’ data which 100% matched that of the unperceived world the brain would not be able to interpret or absorb it without the human senses by which to convert it into usable data.

Is this use of a priori logic?

Dan.

[Arjen]

De budding, I think you are making a mistake somewhere. You point out that the BIV has no senses. I disagree. The machine the brain is linked into is taking the place of the senses. Apart from that every human has a "knowapparatus" which are the senses combined with the brain, connected by the nervoussystem. The sum total of this system is what makes us "see" (<--think) what we "see" (<--think). In that sense it does not really matter if I use ultrasonics, infrared or just plain touch; I "see" what my mind tells me I "see".

So what happens is that through our "knowapparatus" we form "thought-objects" ("judgements"). We do not know that our senses have been replaced by a machine. However, it is a priori true that the thought-objects in the two respective brains (in the vat and in reality) refer to two different things. The thought-objects in the BIV refer to illusions and the thought-objects in the BIR refer to something in reality.


To answer your question:
I do not think a priori logic is really implied in your post de budding. It uses thought objects and a priori intuitions are what form thought objects. Try to realise that the thoughts you have are formed by combining a priori intuitions with a posteriori judgements or perceptions. In that sense logic itself: the existence of the combinations that can be made, is a priori. The moment a judgement is formed it leaves the a priori field so to speak.