Skepticism

That really makes my head spin. What's to say this is not a computer generated reality a la the Matrix?

JBrian said:

This is also posted in GA.

Epistemological skepticism states that one cannot know that he is not a brain-in-a-vat, or controlled by creatures from another planet. Therefore, the skeptic claims that one cannot have knowledge.

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Actually epistemological skepticism would deny that claim outright, because the "brain in a vat" claim is a metaphysical claim not an epistemological claim.

But, for what its worth, if I really was a brain in a vat, its really a mystery why all of my perceptions and experiences are exactly what I'd expect in a materialistic universe. Whereas in a dream state, I can do anything, break all the laws of physics if I feel like it, but in my conscious state I am bound by the very laws I created despite logically I should be able to unbound myself at any time.

And also, it would appear that I am the creator of all things, from Einstein's Theory of Relativity to the Mona Lisa. The only problem is that I have no memory of creating these things, and if I was given the chance to create them again it would be impossible for me. The brain-in-a-vat scenario supposes that I am the creator of things which I am unable to concieve right now, and I can only create these things (unknowingly mind you) one time - in short, I produced things unknowingly and with no exercise of effort, but it would be impossible for me to reproduce knowingly and with all of my effort. For some reason, this idea seems to beg questions to the extreme, and if the implausibility of this doesnt cause the philosophical speculation of the brain-in-a-vat scenario (or the foundations of solipsism and idealism) to crumble altogether, then I dont know what better reason there is. At least in this respect, the assumption that people who are not me who are responsible for every scientific theory, philosophical conundrum, musical composition, and work of art that I could never hope to reproduce (let alone produce the first time) is not unreasonable.

FSTDT said:

And also, it would appear that I am the creator of all things, from Einstein's Theory of Relativity to the Mona Lisa. The only problem is that I have no memory of creating these things, and if I was given the chance to create them again it would be impossible for me.

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Those are not things created by you (the brain-in-the-vat). They are things, as are all artificial things, programmed into your pseudo-perception with a mnemonic backstory.

JBrian said:

Since there is no reason to believe that it is, we should not believe it. Also, it is not a real problem based on evidence, but rather one that has been made up.

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Perhaps, but the point is it could be true. We don't believe it as we see no evidence for it, but we can never disprove it so we can never be 100% certain.

JBrian,

What do you mean when you say that the brain-in-a-vat hypothesis is not "practically possible"? Do you mean that you think that it is probably false, or do you mean that you don't think it would be practical to believe it?

I ask, because it seems that you mean the former, and it seems to me that you have no reason to believe that the brain-in-a-vat hypothesis is false. This is what the skeptic would say in this situation -- there is no reason at all to believe or disbelieve in the BiaV hypothesis. Since it is unfalsifiable and unverifiable, you have to evaluate it on other grounds than "true" and "false." One such ground might be whether it is "practical" or "impractical."

To base something on no evidence is irrational. Hence, skepticism is irrational.

Why do you assume skepticism is not based on evidence?

JBrian said:

This is also posted in GA.

Epistemological skepticism states that one cannot know that he is not a brain-in-a-vat, or controlled by creatures from another planet. Therefore, the skeptic claims that one cannot have knowledge.

While it is logically possible for one to be a brain-in-a-vat, that is, not logically contradictory, it is not practically possible. Lots of things are logically possible. For example, it is logically possible that Jupiter is made of wax. However there is no reason to believe this, so we should dismiss it as a theory.

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As a theory, yes. But not as a possibility. Just because a conclusion is not reasonable does not mean that it is impossible. I am skeptical of the existence of God because there is no evidence -- but I don't deny it as a possibility. Likewise with the brain-in-a-vat idea.

JBrian said:

The same should be done with skepticism. There is no reason to believe that one is a brain-in-a-vat, so no one should believe that he is. To believe this would be to base a theory on a lack of evidence. To base something on no evidence is irrational. Hence, skepticism is irrational. It is also a false problem. It is not a problem discovered via evidence, but rather a made up problem.

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JBrian, this has been explained to you at very great length in the GA thread. Epistemological skepticism does not contend that our perceptions are inaccurate, but that the possibility exists.

You have clearly stated in the GA thread that you do not deny the possibility exists. Thus, you agree completely with the epistemological skeptic. However, you apparently don't wish to agree, even though you clearly do, so you try to refute epistemological skepticism by refuting something that epistemological skepticism does not state and, in fact, rejects utterly: that we are brains-in-vats.

An epistemological skeptic will tell you exactly what you are telling us -- that it is ridiculous and unreasonable to believe that one is a brain in a vat. How, then, do you imagine that you're refuting epistemological skepticism by agreeing with the e-skeptic? Explain that, please.

Ophis said:

Perhaps, but the point is it could be true. We don't believe it as we see no evidence for it, but we can never disprove it so we can never be 100% certain.

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His reasoning, as taken from the GA thread, is as follows:

1) It is possible that we are brains-in-vats (yes, he said so explicitly in the GA thread).
2) This possibility is a very small one that is not supported by any known evidence.

C) Therefore, it is impossible that we are brains-in-vats (compare to premise (1)).

I wonder if he can spot the flaw in his reasoning, now that I've distilled it to the actual argument?

JBrian said:

Since there is no reason to believe that it is, we should not believe it.

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Very funny, Seeker. Rep for you!