Brain in a vat

[Sarkus]

Im not lambasting anything.

To quote: "This assumption, even hypothetical of the brain in a vat is similar to the same argument of nonsense of any ideas with no evidence."
Sounds like a harsh criticism to me.

Im playing devil's advocate to point out that the brain in a vat could be true but there is no evidence.

Where is the devil's advocacy in this? This is no more playing devil's advocate than if you point out that "it could be raining at the moment although I haven't looked outside."

Where is the inconsistency? Same for many things. Now connect the dots. Touche.

1. "...similar to the same argument of nonsense of any ideas with no evidence". So it is nonsense to consider any idea without evidence.
2. "many things can be true with no evidence yet..." + subsequent comments about prejudice against certain types of evidence. So it is not nonsense to consider any idea without evidence.

Now connect the dots.
Ooh, is that a picture of inconsistency which I see before me, the paintbrush toward your hand?

 

[Sarkus]

Sorry, this is just quibbling. There isnt really a difference. You dont know the wider reality of the paranormal or tarot cards etc either.

Quibbling, you say?
Can you tell the difference between:
By playing the lottery I will win it; and
By playing the lottery I have a possibility of winning it. ?

With regard the paranormal - you are correct, I have no knowledge of the wider reality. But, and here's the difference you seem desperate to ignore, I am not making claims that it definitely exists, that it works.
Those who espouse the reality of the paranormal ARE making such claims.

Do you yet see the difference? Or do you still consider it to be mere quibbling?

Yes, some may believe something exists but the naysayers repeat its nonsense without proof.

It is nonsense to accept it as part of our "local reality" as it has been phrased, although one could quite happily discuss it as part of the "wider reality" about which we can not know.
Do you yet see the difference?

They cross that line just the same.

No, they don't. Although if you are blind to the differences, and consider them essentially the same, and to speak of differences to be mere quibbling, then I can understand why you might be mistaken.

Just like you are trying to get jan to admit he could be a brain in a vat or doesnt know he is and his logic is there is no evidence but there is evidence of his skull with a brain in it.

One does not need evidence to claim something as a possibility, one only needs it to not be impossible. One does need evidence, however, to claim someone is not just a possibility but the actual state of affairs.
All we are discussing in this thought experiment is the possibility that not just Jan but all of us are brains in a vat.

Even, doctors and pathologists have actually removed brains and studied them. There is concrete proof, see??

As it relates to the "local reality", yes. But we are not discussing the "local reality" but the "wider reality".
Just think to yourself: if our local reality is just a simulation, seeing a brain in a skull would simply be part of the simulation, in which we think our brains are in our skull. So how is seeing a brain in a skull proof that we are not in a simulation?
Or is this still merely quibbling from your perspective?

Your favorite go-to type of knock on wood logic for ya!

I'm sure you honestly think so, which speaks more about you than me.

Whats funny and ironic is if this was about ghosts, it would be the same flavor and type of argument except the roles would be switched. Lol

I fear you still haven't truly grasped what this discussion is about. Do you know the difference of claiming to know that something is real within our "local reality", and something is real within the "wider reality"? Do you know the difference between claiming something exists, and claiming something possibly exists?
Do you know where evidence would be required within these?
Or do you still think this is mere quibbling.

But tell you what, set up a thread to discuss ghosts in a similar philosophical framework (as opposed to merely the claims of existence we see within the fringe sections) and let's see how such a discussion fares, shall we. I would partake if you did so.

 

[James R]

birch:

Why examples? You do not know anyone is a brain in a vat versus jan's claim he knows he isnt but you are arguing he doesnt. Going by just the so-called evidence of logic so touted as absolute his logic applies more aptly, not that its my view.

I don't understand why you conclude that it is possible for Jan to know for sure that he is not a brain in a vat. My argument is that there's no evidence on which he could possibly draw such a definite conclusion.

Fundamentally, what is happening here is that Jan is claiming absolute certainty, and I am saying there is doubt. And you think Jan has the better argument? Why?

We may be a brain in a vat but there is no evidence. We may be ghosts in a simulation but there is no evidence. The universe may exist on the sweat of a larger being's brow but there is no evidence. Maybe its being flushed down a toilet, who knows?

Right. But I'm not claiming I know that the universe is being flushed down a toilet, or that the universe is a simulation. Whereas Jan is claiming that he does know, by some magic that he declines to explain.

Lack of evidence doesnt negate the existence of something just because we arent aware of it or evidence is out of reach as you pointed out and is common sense which for some strange reason many on this forum forget.

Right. That's why I'm not negating the possibility of being a brain in a vat. But Jan is.

The fringe section is full of naysayers who are 'sure' none of that exists because there is no evidence.

Not in general.

What the "naysayers" say in the Fringe forums is that the evidence presented as proof of the paranormal by believers such as Magical Realist (to name one person) is not very convincing. That doesn't mean they are sure there is no paranormal.

For the record, I'm not sure there is nothing supernatural or paranormal. All I can say is that I've seen nothing that convinces me that the supernatural or paranormal is real.

Let me give you an example. I once had a bizarre experience with a Ouija board, where I was the only person in the room. I touched the glass that had been used to spell out messages and it literally flew off the table. I did not consciously push it, and nobody else was there to push it.

Now, Magical Realist, or somebody like that, would immediately say that this event is evidence of Spirits from Beyond the Grave, and conclude that a ghost from the sceance pushed that glass off the table. Moreover, they would say that my testimony that nobody else was there and that I didn't push the glass showed that I couldn't have pushed it, so it must have been pushed by some mysterious force from something else. Without more, I'd be one more anecdote for Magical Realist to add to his list of "proofs" of ghost activity.

But am I now convinced by my personal experience that sceances really do contact the spirit world, and the ghosts can telekinetically push things around? No. I can tell you that at the time, the experience was scary and I had no explanation for it. But it didn't make me believe in ghosts. In fact, when that happened I didn't believe in ghosts and I thought the whole seance thing was a silly game. This made me rethink, but I didn't end up as a ghost believer.

Why not? Because I knew there was probably a perfectly sensible explanation for what I experienced. A lot later, I learned that there is, and it has a name. It's called the ideomotor effect. So, mystery solved, without ghosts.

Does this mean that I now think that the existence of ghosts is impossible? No. In principle, they might exist. But I have seen no good evidence for their existence. So I don't believe in them, but I keep an open mind.

But when it comes to fringe areas that are not pet related topics of the science fora, its given utter hogwash treatment but computer simulations, brains in vat etc are such appealing speculations to some though could be deemed pseudoscience or fantasy.

The difference is, nobody (not me, anyway) is making the claim that we are actually brains in vats. I have no evidence that anybody is a brain in a vat, so I don't believe that people are brains in vats any more than I believe that ghosts exist. But does that mean I know that I'm not a brain in vat? No - no more than I know that ghosts don't exist. It is possible that I'm a brain in a vat. It is possible that ghosts exist.

Jan claims to know for sure about such things. I say he is pretending to have knowledge he doesn't have.

Sorry, this is just quibbling. There isnt really a difference. You dont know the wider reality of the paranormal or tarot cards etc either.

There's an important difference between brains in vats and tarot cards. The difference is that while there's no way to test whether you're a brain in a vat, there are ways to test whether tarot cards can, for example, predict the future.

That is, we can know that tarot cards don't predict the future. This can be tested scientifically. Using tarot cards is no better than guessing.

Yes, some may believe something exists but the naysayers repeat its nonsense without proof.

Not exactly. They say "If you believe something exists, show me some good evidence that it exists." That is, the onus is on the claimant to back up his or her claim. And, as the adage goes, extraordinary claims demand extraordinary evidence.

Just like you are trying to get jan to admit he could be a brain in a vat or doesnt know he is and his logic is there is no evidence but there is evidence of his skull with a brain in it.

The point is, if he was a brain in a vat, he would still think that there was evidence of his skull with a brain in it. I dealt with this early on in the thread. The fact that he believes his brain is in his skull isn't conclusive evidence that that is the case. it's an assumption he makes without actual proof.

Even, doctors and pathologists have actually removed brains and studied them. There is concrete proof, see??

That might prove that those brains that they removed were in skulls, but it doesn't prove, for example, that your brain is in your skull. Nor, under the terms of the thought experiment, would an x-ray of your skull that shows a brain. I discussed this point earlier in the thread, too.

Does any of this make sense to you?

 

[birch]

Quibbling, you say?
Can you tell the difference between:
By playing the lottery I will win it; and
By playing the lottery I have a possibility of winning it. ?

With regard the paranormal - you are correct, I have no knowledge of the wider reality. But, and here's the difference you seem desperate to ignore, I am not making claims that it definitely exists, that it works.
Those who espouse the reality of the paranormal ARE making such claims.

Do you yet see the difference? Or do you still consider it to be mere quibbling?
It is nonsense to accept it as part of our "local reality" as it has been phrased, although one could quite happily discuss it as part of the "wider reality" about which we can not know.
Do you yet see the difference?
No, they don't. Although if you are blind to the differences, and consider them essentially the same, and to speak of differences to be mere quibbling, then I can understand why you might be mistaken.
One does not need evidence to claim something as a possibility, one only needs it to not be impossible. One does need evidence, however, to claim someone is not just a possibility but the actual state of affairs.
All we are discussing in this thought experiment is the possibility that not just Jan but all of us are brains in a vat.
As it relates to the "local reality", yes. But we are not discussing the "local reality" but the "wider reality".
Just think to yourself: if our local reality is just a simulation, seeing a brain in a skull would simply be part of the simulation, in which we think our brains are in our skull. So how is seeing a brain in a skull proof that we are not in a simulation?
Or is this still merely quibbling from your perspective?
I'm sure you honestly think so, which speaks more about you than me.
I fear you still haven't truly grasped what this discussion is about. Do you know the difference of claiming to know that something is real within our "local reality", and something is real within the "wider reality"? Do you know the difference between claiming something exists, and claiming something possibly exists?
Do you know where evidence would be required within these?
Or do you still think this is mere quibbling.

But tell you what, set up a thread to discuss ghosts in a similar philosophical framework (as opposed to merely the claims of existence we see within the fringe sections) and let's see how such a discussion fares, shall we. I would partake if you did so.

Yes, you wasted lots on quibble.

It does not matter if the threads in fringe sections on paranormal etc even discuss such speculatively, it is all lambasted with there is no evidence or evidence not accepted or can be recreated for others so therefore it doesnt exist or the very idea is lambasted period. If you pay attention to the threads it is all dismissed outrightly and even speculation is very strongly inhibited. Even trying to speculate is difficult because the whole subject matter has no respect from many here. The idea that events or things can exist not exactly within the confines of hard science because of its nature, fragility or randomness is dismissed as nonsense or unreal.

Pot/kettle and hypocrisy. And dont tell me i dont get the point because i do. You are not getting the point because the possibility is even met with derision and dismissal. Some here are refusing to see how hypocritical it is when the subject turns to paranormal, ghosts etc.

 

[Jan Ardena]

You can do it, Jan. You can understand this if you try.

If I can have knowledge that I may be a brain in a vat, can I similarly gain knowledge that I am not a brain in a vat?

jan.

 

[birch]

birch:


I don't understand why you conclude that it is possible for Jan to know for sure that he is not a brain in a vat. My argument is that there's no evidence on which he could possibly draw such a definite conclusion.

Fundamentally, what is happening here is that Jan is claiming absolute certainty, and I am saying there is doubt. And you think Jan has the better argument? Why?


Right. But I'm not claiming I know that the universe is being flushed down a toilet, or that the universe is a simulation. Whereas Jan is claiming that he does know, by some magic that he declines to explain.


Right. That's why I'm not negating the possibility of being a brain in a vat. But Jan is.


Not in general.

What the "naysayers" say in the Fringe forums is that the evidence presented as proof of the paranormal by believers such as Magical Realist (to name one person) is not very convincing. That doesn't mean they are sure there is no paranormal.

For the record, I'm not sure there is nothing supernatural or paranormal. All I can say is that I've seen nothing that convinces me that the supernatural or paranormal is real.

Let me give you an example. I once had a bizarre experience with a Ouija board, where I was the only person in the room. I touched the glass that had been used to spell out messages and it literally flew off the table. I did not consciously push it, and nobody else was there to push it.

Now, Magical Realist, or somebody like that, would immediately say that this event is evidence of Spirits from Beyond the Grave, and conclude that a ghost from the sceance pushed that glass off the table. Moreover, they would say that my testimony that nobody else was there and that I didn't push the glass showed that I couldn't have pushed it, so it must have been pushed by some mysterious force from something else. Without more, I'd be one more anecdote for Magical Realist to add to his list of "proofs" of ghost activity.

But am I now convinced by my personal experience that sceances really do contact the spirit world, and the ghosts can telekinetically push things around? No. I can tell you that at the time, the experience was scary and I had no explanation for it. But it didn't make me believe in ghosts. In fact, when that happened I didn't believe in ghosts and I thought the whole seance thing was a silly game. This made me rethink, but I didn't end up as a ghost believer.

Why not? Because I knew there was probably a perfectly sensible explanation for what I experienced. A lot later, I learned that there is, and it has a name. It's called the ideomotor effect. So, mystery solved, without ghosts.

Does this mean that I now think that the existence of ghosts is impossible? No. In principle, they might exist. But I have seen no good evidence for their existence. So I don't believe in them, but I keep an open mind.


The difference is, nobody (not me, anyway) is making the claim that we are actually brains in vats. I have no evidence that anybody is a brain in a vat, so I don't believe that people are brains in vats any more than I believe that ghosts exist. But does that mean I know that I'm not a brain in vat? No - no more than I know that ghosts don't exist. It is possible that I'm a brain in a vat. It is possible that ghosts exist.

Jan claims to know for sure about such things. I say he is pretending to have knowledge he doesn't have.


There's an important difference between brains in vats and tarot cards. The difference is that while there's no way to test whether you're a brain in a vat, there are ways to test whether tarot cards can, for example, predict the future.

That is, we can know that tarot cards don't predict the future. This can be tested scientifically. Using tarot cards is no better than guessing.


Not exactly. They say "If you believe something exists, show me some good evidence that it exists." That is, the onus is on the claimant to back up his or her claim. And, as the adage goes, extraordinary claims demand extraordinary evidence.


The point is, if he was a brain in a vat, he would still think that there was evidence of his skull with a brain in it. I dealt with this early on in the thread. The fact that he believes his brain is in his skull isn't conclusive evidence that that is the case. it's an assumption he makes without actual proof.


That might prove that those brains that they removed were in skulls, but it doesn't prove, for example, that your brain is in your skull. Nor, under the terms of the thought experiment, would an x-ray of your skull that shows a brain. I discussed this point earlier in the thread, too.

Does any of this make sense to you?

I never said he can know for sure but for now he has more proof than you that he is not a brain in a vat. Maybe science will find evidence at a later time but until then, its mere delusion. Sound familiar?

And there is no conclusive proof you are not a ghost according to this type of reaching logic. You can apply this to other scenarios but that's taboo heeby jeeby halloween stuff on this forum but brains in vats make total sense considering all the other make it up as you go explanations for that to be possible. Right.

 

[Seattle]

If I can have knowledge that I may be a brain in a vat, can I similarly gain knowledge that I am not a brain in a vat?

jan.

Let me help you with your logic so we don't go down this path for another 6 pages of "define that word".

"If I can have knowledge that I may be a brain in a vat, can I similarly have knowledge that I may not be a brain in a vat?".

See how that works? It's helpful to keep the terms the same on each side of the equation.

 

[Sarkus]

Yes, you wasted lots on quibble.

It certainly seems as though it was wasted, but not on quibble.

It does not matter if the threads in fringe sections on paranormal etc even discuss such speculatively, it is all lambasted with there is no evidence or evidence not accepted or can be recreated for others so therefore it doesnt exist or the very idea is lambasted period. If you pay attention to the threads it is all dismissed outrightly and even speculation is very strongly inhibited. Even trying to speculate is difficult because the whole subject matter has no respect from many here. The idea that events or things can exist not exactly within the confines of hard science because of its nature, fragility or randomness is dismissed as nonsense or unreal.

If someone in those forums claims the things don't exist then they should explain why they think it is, what evidence / justification for it not being possible. But usually one sees some people claiming that things do exist, and then others lambasting that claim for being based on nothing but anecdote, the odd photo here and there, etc. That is what is lambasted: the thought process that gets some people from such weak evidence to claims that the things exist.
What is also lambasted is the claim that some vague notion of a phenomena exists but with no actual idea of what it is, how it is observed, what mechanisms give rise to its manifestation etc.
Certainly some may come along with some justification as to why a claim might actually be impossible, but that is not the tendency in those threads. What usually happens is someone makes a claim and the claim is shot down. The possibility of such phenomena existing, however, never goes away until/unless proven to be impossible.

Pot/kettle and hypocrisy. And dont tell me i dont get the point because i do. You are not getting the point because the possibility is even met with derision and dismissal. Some here are refusing to see how hypocritical it is when the subject turns to paranormal, ghosts etc.

As said, feel free to start a thread in the philosophy section about the existence of ghosts... It as good an example as any to discuss issues of what is knowledge, what is belief, levels and types of justification, the nature of existence etc.
So put your money where your mouth is. Let's see what happens when ghosts are discussed in more depth than "ghosts exist!" "Prove it!" Heck, you may even be correct and people can not get past the issue when the subject of the paranormal is raised. But I doubt it.
So, are you game? Methinks perhaps you are not.

 

[Sarkus]

If I can have knowledge that I may be a brain in a vat, can I similarly gain knowledge that I am not a brain in a vat?

No.
Are you ready for the explanation of why not?
Okay, here goes (and I'd stand back if I were you; this could get messy!)...


Knowledge is required to be true (at least per the Justified True Belief notion of knowledge).
If it is true that you may be a brain in a vat, then there must be a possibility of it being the case.
As soon as you know that you are not a brain in a vat then there is no longer the possibility of you being a brain in a vat.
Okay so far?
Good.


So, if it was possible for you to have knowledge that you are not a brain in a vat then it is no longer true that you may be a brain in a vat.
Thus you can either have knowledge of maybe being a brain in a vat, or knowledge that you are/are not a brain in a vat.
Only one can be true.

The only reason it is true that we may be a brain in a vat is because we cannot ever actually know whether we are or not.
If we are able to know whether we are or not but just don't yet know, then strictly we can not know whether we may be or not. We simply wouldn't know, although we could say that "as far as we are aware" we could still be one or the other. Or even "as far as we know"... which indicates that we currently think of it as knowledge but that it is based on incomplete data and thus might not be knowledge after all.

So, in summary, no... you can not know that something is uncertain AND later know the something with certainty.
This ties in with Seattle trying to keep the wording the same on both sides... because as you can see it gets somewhat more complicated if you don't.

I'm sure that was all easy enough to follow.

 

[birch]

It certainly seems as though it was wasted, but not on quibble.
If someone in those forums claims the things don't exist then they should explain why they think it is, what evidence / justification for it not being possible. But usually one sees some people claiming that things do exist, and then others lambasting that claim for being based on nothing but anecdote, the odd photo here and there, etc. That is what is lambasted: the thought process that gets some people from such weak evidence to claims that the things exist.
What is also lambasted is the claim that some vague notion of a phenomena exists but with no actual idea of what it is, how it is observed, what mechanisms give rise to its manifestation etc.
Certainly some may come along with some justification as to why a claim might actually be impossible, but that is not the tendency in those threads. What usually happens is someone makes a claim and the claim is shot down. The possibility of such phenomena existing, however, never goes away until/unless proven to be impossible. As said, feel free to start a thread in the philosophy section about the existence of ghosts... It as good an example as any to discuss issues of what is knowledge, what is belief, levels and types of justification, the nature of existence etc.
So put your money where your mouth is. Let's see what happens when ghosts are discussed in more depth than "ghosts exist!" "Prove it!" Heck, you may even be correct and people can not get past the issue when the subject of the paranormal is raised. But I doubt it.
So, are you game? Methinks perhaps you are not.

Stop lying. There are and have been plenty of threads in the fringe section on these topics where many dont even try to contribute anything except to reiterate how its all nonsense.

Dont need to start one now just because someone or in this case, is all of a sudden game or with pretense of appearing more fair to discuss it potentially because the hypocrisy was called out.

 

[Sarkus]

Can I suggest you take the chip off your shoulder, birch. If you think I'm lying feel free to point out where, provide some examples so that I may get a better idea of what you're talking about, 'cos at the moment you come across as simply whining. I'm assuming that when you claim psychics or ghosts are genuine in those threads you offer more evidence than you're providing of me either lying or of being hypocritical? And since when in those threads do you discuss the mere possibility rather than someone claim the truth of their existence. Again, evidence please. Otherwise stop being so pathetic.

 

[Jan Ardena]

I appreciate the summary. Thanks.

You make the claim that it is true that we may be a brain in a vat only because we cannot ever know whether we are or not. Is that correct?

Why is it true that we can never know?

Jan.

 

[Xelasnave.1947]

Why is it true that we can never know?

Most brains be they in a vat or in a skull can not accept the truth.
Try convincing a brain in a vat that it is indeed in a vat and that brain will refuse to accept it is in a vat.
And a brain in a skull will not necessarily accept its reality.
I could offer examples but I will hold back on that aspect.
Alex

 

[Seattle]

I appreciate the summary. Thanks.

You make the claim that it is true that we may be a brain in a vat only because we cannot ever know whether we are or not. Is that correct?

Why is it true that we can never know?

Jan.

A brain in a vat may invent an imaginary skull with which to house itself.

 

[Sarkus]

I appreciate the summary. Thanks.

You make the claim that it is true that we may be a brain in a vat only because we cannot ever know whether we are or not. Is that correct?

To clarify, in my explanation above I did not intend to make any claim as to the truth of whether we can know or not. My explanation was all conditional, and merely to express how we can not know both that we may be a brain in a vat (i.e. knoweldge of uncertainty) and also know that we are (or are not) - i.e. knowledge of certainty.
Your question, after all, started with the context as being conditional: "If I can have knowledge..." etc.
Where I stated "The only reason it is true that we may be a brain in a vat is because we cannot ever actually know whether we are or not.", while I appreciate comes across as being a claim of knowledge, was intended to be still within the context of the conditional. So it would have been better I had I written "The only reason that it could be true that we may be..."
So apologies for any confusion.

Why is it true that we can never know?

It might not be true - afterall our death in this "local reality" might result in our brain in the vat being placed back in a physical body within the "wider reality".
But to all intents and purposes - i.e. as far as we know - our universe (i.e. our "local reality") is closed... internally consistent, conservation of energy and all that lovely stuff. So under this assumption we can not know what is outside it. We can but guess, educated or otherwise.

 

[Yazata]

Isn't this brain in a vat scenario the justification for absolute / ultra-hard agnosticism?

I think that it's the most recent incarnation of ancient skeptical doubts. Since the Academic and Pyrrhonian skepticism of Hellenistic Greek times, philosophical skeptics have long wondered how we could ever know whether what we take to be reality is just a dream from which we will soon wake. We are all familiar with the possibility that we might be mistaken about particular things in our experience. But what about the possibility that we might be mistaken about everything, such that our experience is entirely misleading? In that case, any evidence we cited to determine whether we are or aren't living in an illusion might itself be illusory.

The notion that we can know absolutely nothing at all, other than perhaps "I am"?

Yes, Descartes tried to address these kind of universal skeptical doubts in his 'Meditations' by arriving at something that he believed that he couldn't be mistaken about, something that couldn't be an illusion, his famous'cogito'. (I think, therefore I am.)

At best we can only ever "know" what is in our local reality with us, not the wider reality in which our local reality may reside.

It's interesting (to me, anyway) that while today the skeptical doubts are usually the province of those who identify with science and the atheists (there are anti-"woo" magazines with 'Skeptic' in their titles), back in Renaissance times (when the ancient skeptics' writings were first widely circulated), the theologians made use of them too. They argued that if this created realm (as they put it) was analogous to the dream, no experience inside the dream/created world will allow us to be certain whether or not its creator God and his heaven exist apart from it on a higher metaphysical plane, so to speak. (The analogy of wherever it is that the brains are in the vats.) So in a odd way, today's 'brains-in-vats' thought-experiment is an analogy to some 500 year old arguments in philosophical theology. The theological skeptics of the 1500's argued that faith is necessary either way, that atheism is no more justified by experience than theism. So the Catholics among them argued that in this essentially agnostic situation the best thing for people to do is to go with long established tradition, while the newly emerging Protestants argued for fideism. (The emphasis on faith.)

My remarks above are strongly influenced by Richard Popkin, and his The History of Skepticism from Savanarola to Bayle. A Sample of the introduction and part of the first chapter are here. (Popkin's multivolume history of skepticism is one of those rare works that will change a reader's life. The whole intellectual history of the West is revealed in a new light.) This particular volume starts with Savanarola (the Renaissance dictator of Florence who overthrew the Medicis, tried to suppress secular art and culture, and was a religious nut) because he wanted the ancient skeptics be published with the new printing presses in defense of "The True Faith". Popkin calls the Renaissance revival of ancient skepticism 'the intellectual crisis of the reformation'.

Descartes was influenced by that intellectual environment but he was a mathematician. Probably influenced by the Platonic tradition, he believed that even if the possibility exists that sensory experience is systematically misleading, humans can still acquire true knowledge through 'theoria', the inner eye-of-reason. (Arguably mathematical proofs should be equally valid inside and outside the vat-reality.) So he tried to concoct a logical argument for his own existence, the most fundamental thing that he thought that he (or the brain in the vat) could be certain about.

Personally, I don't think that Descartes' cogito is convincing. It seems to me to depend on the subject-predicate structure of our language, where actions seem to linguistically imply actors, but might not metaphysically imply them. Instead of starting out with 'I think' in his 'I think, therefore I am', he probably should start out with 'thought is occurring', without presupposing the 'I' that supposedly has the thought. The Indian Buddhist philosophers actually made that kind of argument, that the thought process generates a false concept of a metaphysical self in which the thought resides.

And there's a deeper problem too. Descartes is accepting (for the purposes of argument) the skeptical idea that sensory experience might be systematically misleading. But why stop there? Why not go all the way? He probably should also be skeptical about whether our logical intuitions are correct and valid. Just because we possess his 'clear and distinct ideas' and have a subjective feeling of logical rightness about them, doesn't mean that our reasoning process really is valid and truth-preserving. After all, the logic of dreams can be pretty bizarre, but it seems fine to us while we are dreaming.

 

[C C]

The fringe section is full of naysayers who are 'sure' none of that exists because there is no evidence. What is the difference here?

In some (if not most) instances the comparison might be warranted. But "suspension of belief" about, say, a particular ghost claim (due to the evidence being insufficient, but the claim not being debunked either) should be distinguished from universal declarations that "ghosts do not exist" and "ghosts do exist" grounded in preset ideologies or worldviews (or even informal, personal preferences).

The gist of Wittgenstein's spiel below might be invoked so as to discard "brain in a vat" type possibilities on the basis of their being inutile. But this as well falls out of a pre-established belief that all hypotheses can be judged as testable or non-testable without possibility of the future rendering such judgements false / wrong.

Also, it's covertly propelled by a desire / wish to "let's prescribe a way to eliminate certain proposals from consideration so we don't have to expend mental resources upon them". While any narrow strain or broad school of thought will have such preset conditions and rules -- i.e., how things should be done within its jurisdiction-- outside of that it should be recognized that such is simply the properties of that sub-credo or whole system of thought rather than being a literal non-artificial directive / doctrine which is "prior in rank" to human inventions and needs (so to speak).

Wittgenstein: [Bertrand] Russell said that remembering cannot prove that what is remembered actually occurred, because the world might have sprung into existence five minutes ago, with acts of remembering intact. We could go on to say that it might have been created one minute ago, and finally, that it might have been created in the present moment. Were this latter the situation we should have the equivalent of "All that is real is the present moment".

[...] By examining Russell's hypothesis that the world was created five minutes ago I shall try to explain what I mean in saying that it is meaningless. Russell's hypothesis was so arranged that nothing could bear it out or refute it. Whatever our experience might be, it would be in agreement with it. The point of saying that something has happened derives from there being a criterion for its truth. To lay down the evidence for what happened five minutes ago is like laying down rules for making measurements.

The question as to what evidence there can be is a grammatical one. It concerns the sorts of actions and propositions which would verify the statement. It is a simple matter to make up a statement which will agree with experience because it is such that no proposition can refute it, e.g., "There is a white rabbit between two chairs whenever no observations or verifications are being carried out." Some people would say that this statement says more than "There is no white rabbit between the chairs", just as some would say it means something to say the world was created five minutes ago. When such statements are made they are somehow connected with a picture, say, a picture of creation. Hence it is that such sentences seem to mean something. But they are otiose, like wheels in a watch which have no function although they do not look to be useless. --Wittgenstein's Lectures, 1932 - 35

 

[Yazata]

The fringe section is full of naysayers who are 'sure' none of that exists because there is no evidence. What is the difference here? Nothing essentially except you are arguing on the other side.

The difference is that the 'brain-in-a-vat' (along with 'this is all a dream', 'perfect virtual reality' and similar things) are epistemological thought-experiments.

Nobody is insisting that we really are brains in vats. We (or some of us at least) are discussing the implications of the possibility that somebody might be. Philosophically speaking, 'brains-in-vats' introduce the issue of total-skepticism, skepticism not only about particular items of knowledge, but skepticism about all knowledge.

Playing devil's advocate, there is no evidence for a simulation but there is evidence that one has a body, brain and skull which it resides. Thats the type of evidence most here go by but not on this topic.

If we accept even the possibility that all of our experience might be systematically misleading, then (so the skeptical argument goes) no evidence from experience will suffice in distinguishing whether or not that total-illusion possibility actually is the case. That's because, hypothetically, all evidence might be part of an illusion. Our evidence that we have bodies and skulls might be fundamentally bogus.

But when it comes to fringe areas that are not pet related topics of the science fora, its given utter hogwash treatment but computer simulations, brains in vat etc are such appealing speculations to some though could be deemed pseudoscience or fantasy.

It's a thought-experiment meant to explore the strongest form of empirical skepticism. Brains-in-vats and computer simulations are just one way of conceptualize how that might happen. Descartes' 'this might all be a dream' idea in his Meditations was another. We aren't being asked to believe in the literal truth of either one. We are being asked to explore the implications of the possibility that something like them might be true. How could we ever determine whether it was?

It seems to me that people like you should think about this a bit and not fight so hard against it. As I mentioned in my last post up above, skeptical arguments can be used to argue for belief in supernatural realities as well as against them. If a higher plane of metaphysical reality exists (call it 'heaven') from which some entity (call it 'God') generates the cosmic 'Matrix' illusion that we are embodied beings in a physical world, then arguably no experience that we have in this physical plane will allow us to distinguish the real state of affairs. Historically, it was philosophical theologians in the 1500's who first made use of these kind of ancient Greek skeptical arguments (after they were first widely circulated with the new printing-presses in the Renaissance). They used them to argue that if no experience can distinguish true reality from the 'vat' simulation (not having heard of computers or sensory nerves, they would have called it 'the dream'), then belief that we live in one is just as much a matter of faith as belief that we live in the other. We see that kind of argument recurring over and over, such as in William James' pragmatic version of it in The Will to Believe.

 

[DaveC426913]

The fringe section is full of naysayers who are 'sure' none of that exists because there is no evidence. What is the difference here? Nothing essentially except you are arguing on the other side.

No. There is a very big distinction between
I may be a brain in a vat
and
I am not brain in a vat.

The first one is true unless proven false (and it is impossible to prove false).
The second one is false unless proven true (and it is impossible to prove true).

 

[Michael 345]

No. There is a very big distinction between
I may be a brain in a vat
and
I am not brain in a vat.

The first one is true unless proven false (and it is impossible to prove false).
The second one is false unless proven true (and it is impossible to prove true).

Still thinking my brain is in a jam, Raspberry, jar.

Still get jam on my pillow in the morning.