I agree with others that the point you are making is quite insignificant to the point of the discussion.

The OP wants to discuss this question: is there any reason to think that we are not brains in vats, and if not, on what ground can we dismiss that idea? It does not matter to this issue whether you call it a theory, a hypothesis, a thought experiment or whatever. The question still remains whether there is any reason to think that the world is like that.

The fact that Putnam uses the idea as a thought experiment does not matter. We can use the idea for a different purpose. It isn't as though Putnam's use of an idea is God's law, and any other way of using the idea is apostacy. In any case, Putnam too wanted reasons to believe we aren't BIVs. He gives arguments against that idea.

Jesus bloody Christ (to borrow a turn of phrase)

Any mention of the words 'brain in a vat' does not automatically and irrecoverably refer to to Putnam's Brain In A Vat Thought Experiment™.

presenting it as a theory doesn't magically turn it a theory. — Akanthinos

No, but it does turn it into a theory in a completely normal way, according to a perfectly understandable common usage of the term.

f Pattern-chaser can say with any semblance of rectitude that Putnam's brain-in-a-vat "theory" does not provide us any evidence to support either its conclusion or its contradiction, it is exactly because it did not even attempt at becoming an hypothesis. — Akanthinos

Pattern-chaser (to the best of my reading, apologies in advance if I've missed it) did not mention the name Putnam in his entire post. The only mention of the name I can find is actually your first post, so why would you think he's talking about Putnam's thought experiment? Why not Harman's original concept, or one of the many science fiction references before that? As I said, Putnam does not own the concept, not every reference to it is a reference to that which he had to say about it.

Putnam's BIV was never about what Pattern-chaser's want it to be. Not even close. — Akanthinos

Why are we still going on about Putnam's version when (as far as I can tell) no-one but you has even mentioned it?

...you are doing a serious disservice to philosophy by spreading this misrepresentation. — Akanthinos

This is the most interesting bit of your whole post. What service do you think I owe 'Philosophy' exactly? Let's, for that sake of this far more interesting point, presume Pattern-chaser had directly referenced Putnam's Brain in a Vat Thought Experiment by name, and called it a theory (in the scientific sense you're imagining), treated it as something designed to explain some phenomenon in a manner which could be falsified. In other words, let's presume he got it completely wrong, then I (or anyone else) come along and say "Yeah, he's right you know, it is a theory". What is it you imagine Philosophy is such that it would be harmed by that? Even if I managed to spread this 'misinformation' far and wide such that half the world believed it, I'm baffled as to what consequence you think that would actually have such that this level of indignation is required to stamp it out early lest it do...what exactly?

Is there any reason to think that we are not brains in vats...? — PossibleAaran

As a general rule any unmotivated question of the form 'is there any reason to think that such-and-such is not the case' can be readily dismissed out of hand. It is the conspiracy theorist's question: "is there any reason to think the Queen is not a lizard?; "is there any reason to think we are not ruled by aliens?"; these are not questions to be taken seriously. They are questions to be laughed at and ridiculed.

If BIV was a simplifying explanation of the way things are, it would be compelling. In fact, it is radically complexifying. — hypericin

:up:

As if the BIV thesis itself did not demand a radical profusion of things to be explained. Anyone who thinks it might function in an explanatory capacity in any sense fails to understand the English use of the term 'to explain'.

As a general rule any unmotivated question of the form 'is there any reason to think that such-and-such is not the case' can be readily dismissed out of hand. It is the conspiracy theorist's question: "is there any reason to think the Queen is not a lizard?; "is there any reason to think we are not ruled by aliens?"; these are not questions to be taken seriously. They are questions to be laughed at and ridiculed. — StreetlightX

In a broad logical sense of "can", any question "can" be dismissed, but it doesn't follow that they should be. I take it you didn't mean to make that claim. You compare the question about BIVs to the question "what reason is there to believe that the queen is not a lizard?", and the suggestion is that both questions are ridiculous. Because they are ridiculous, they should not be asked. Is that right?

If so, pursue the issue just slightly below the surface. Why is the question about the queen ridiculous? I am tempted to say that the question about the queen is ridiculous precisely because there is a very obvious and decisive reason for thinking that she is not a lizard. Namely, the queen does not look anything like a lizard normally looks, nor does she walk around on all fours (or slither!) sticking out a forked tongue laying eggs. That is the reason for thinking the queen is not a lizard, and if we did not have this reason, the question about what reason there is to think she is not a lizard would not be ridiculous. If you had absolutely zero information about the queen or about human social institutions, you might well wonder whether this random entity "the queen" is a human being or something different. So if the BIV question is analogous to the queen question, it can only be ridiculous if there are obvious and decisive reasons for thinking that we are not BIVs. In which case, I don't see the point of insisting that the BIV question should not be asked, when you could instead simply provide the answer.

PA

Silly PossiblyAaran doesn't know lizard people can grow human skin and impersonate us perfectly. :smirk:

I said the question can be dismissed at the level of its form: the fact that it asks for reasons why something isn't the case. Your reply, which quibbles over the content of the questions, is irrelevant. One can make up any bullshit one likes and then ask why it isn't the case, and then pretend like it's just a matter of being an impartial, rational inquirer. But if you don't have grounds to pose a thesis, then you don't have grounds to have anyone take it seriously.

Yeah how do we know they don't do this?! What reason do we have to think the lizard people don't do that??

So the problem is that the question is about what isn't the case as opposed to what is the case? If I had raised a question using the positive mood instead of the negative, would that have made the question acceptable? If so, instead of "what reason is there to believe that I am not a BIV?" consider:

What reason is there to believe that I am in my apartment?

Obviously, being in my apartment entails that I am not a BIV, so having a reason for the former also gives me a reason for thinking I am not a BIV.. This question doesn't ask why something isn't the case, so is this question acceptable to you?

If so, does this question not raise all of the same issues as the original BIV question which you tried to dismiss?

I note in passing that I didn't say anything about being an impartial rational inquirer, but I do not see why the mere fact that a thesis is, in your opinion "bullshit" means that it should not be taken seriously, although I'm not entirely sure what you mean by "take seriously".

PA

Silly PossiblyAaran doesn't know lizard people can grow human skin and impersonate us perfectly. — Akanthinos

Oh silly me! That could be so, but the simpler explanation is that the queen is what she looks like she is. A human.

PA

What reason is there to believe that I am in my apartment? — PossibleAaran

Well this can be answered quite straightforwardly: none. Maybe you're in your apartment, maybe you're in a library, maybe you don't even live in an apartment, maybe a million other things, but, from your posts so far in this thread at least, there is literally no reason - apart from you now intimating that you do - to believe that you are in your apartment. Speculation here is contained by available and public evidence, and does not begin out of thin air, without grounds. That's the difference.

--

Alternatively, if you're asking the question of yourself (while being in your apartment), then, pace Wittgenstein, you don't understand how the English language works.

I have good reason to believe that I am in my apartment. I look around and I see all of the furniture, the walls, the windows. Out of the window I see the hotel which is across the street from my apartment. I am categorically not in the library, because the library has very different things in it to the things I now see. This is also a good reason to believe I am not a BIV, since being in my apartment entails that I am not a BIV.

I don't know what reason you have to believe that I am in my apartment. Perhaps only the fact that I say that I am.

PA

I have good reason to believe that I am in my apartment. — PossibleAaran

I'm sure you do. Of course, this has nothing to do with being or not being a BIV and everything to do with having a proper grasp of the English language.

I'm sure you do. Of course, this has nothing to do with being or not being a BIV and everything to do with having a proper grasp of the English language. — StreetlightX

I am not sure I follow. If I am in my apartment then I am not a BIV. So if I have good reason to believe I am in my apartment I can simply deduce that I am not a BIV. Thus, I am not a BIV. The discussion has everything to do with BIVs after all!

PA

If I am in my apartment then I am not a BIV. — PossibleAaran

What kind of disjunction is this? What motivates it? Nothing. It might as well read: "if I am in my apartment than I am not a cloud; so this has everything to do with clouds". It's child's talk.

It isn't a disjunction its a conditional, isn't it? Anyway, what motivates it is quite simple. A brain in a vat is, obviously, a brain in a jar of chemicals being electrically stimulated to hallucinate that it is in an apartment (for example) when it is not. A human being in an apartment is not a brain in a vat. Therefore, if I am a human being in an apartment, I am not a brain in a vat. QED.

PA

Yes, and you can make up a million other bullshit scenarios and call it philosophy too; but they'll all be bullshit and they'll all be made-up, and of each of them you could say: "but it's all about that...".

I don't understand your point. Do I have a good reason to believe I am in my apartment or not? If I do, I have good reason to believe I am not a BIV. If I don't, then for all I know maybe I am a BIV. Calling the BIV hypothesis "bullshit" is... well a lot of things. Its irrelevant. Its ad hominem. Its unnecessary. I just don't see what point it serves. I guess we are back to that: What is the point of saying that we should not ask the OPs question, when it obviously interests him? The mere fact that you think a hypothesis is bullshit is just not a good argument for the idea that it shouldn't be discussed.

PA

Calling the BIV hypothesis "bullshit" is... well a lot of things. Its irrelevant. Its ad hominem. Its unnecessary. — PossibleAaran

It is as necessary as the the very idea of BIVs: arbitrary and irrelevant. It's a response equal to the status of the question. I'm not saying don't discuss it; just to be aware that whatever will be discussed about it will be a bunch of crap, because the question itself is a bunch of crap.

And what I can't help continue to ask is: why do you think the question is "a bunch of crap"?

PA

Because it's entirely arbitrary. If you don't get that, then go ahead and speculate all you like; even dredging the toilet bowl can be fun if you squint.

"Entirely arbitrary"? You mean that there is no reason to believe that we are BIVs?

That's your question; if you think there's anything to the idea, that's for you to answer. Better, at least, than the trivial idiocy of 'why don't you think...'.

I see. I think you miss all of the historical and philosophical significance of discussions about BIVs. The hypothesis isn't discussed because some fantastical philosophers actually think it might be true, or because they like to think about wild stories. It plays a crucial role in a long philosophical tradition which tries to build a worldview only on the basis of what there is some reason to believe.

Consider the Realist hypothesis that I am in a physical and mind-independent world. Trees, rocks, rivers and such are all physical and exist independently of my thoughts and perceptions. Many philosophers - and non-philosophers too - have wanted to affirm Realism. So they have looked for a reason to believe it and usually always appealed to sense perception. The role of the BIV hypothesis is that, because it is compatible with all possible sense perception, it is supposed to illustrate that the information given in sense perception cannot be straightforwardly taken to support Realism (note the qualification 'supposed to').

Again, the significance of this isn't meant to be "uh oh, maybe we are BIVs after all". It is meant to be that there is no reason to believe Realism and so, if you want a worldview that is based only on good reasons, Realism cannot be a part of it, even though many of us are initially attracted to it.

Maybe you don't care about building a worldview that sticks to such standards, but I think you miss the point if you think its just for 'over-imaginative children'.

PA

Right, so the idea of the BIV is not a thesis nor any kind of 'explanation', but a limit-concept - in truth, nothing more than an updated and technologized version of Descartes' demon - meant to provoke thought. And that's probably fair enough. But treating it on its own terms is indeed a non-sense too stupid to contemplate.

Outside of metaphysics the brain-in-a-vat theory is not as striking. — BrianW

It was never my intention to promote a discussion of whether the brain-in-a-vat speculation is true or not. It's only here as a good example of speculation which are possible, but that come without evidence. And let's be clear: I am not proposing BIV as being true (or false). Please can we leave the correctness of BIV alone? :wink:

I choose to accept a theory which states that illusion is a part of reality — BrianW

Yes, of course. A real illusion is, of course, real. :up: :wink:

So, how should we treat these speculations? As a critique of our own belief. You do not need to provide evidence to build a critique -- use the other person's evidence if you'd like. — Caldwell

What evidence? The point of this discussion is to ask how we deal with speculations for which there is no evidence. It seems that logic takes us so far, but no farther. And when we reach that point, we must stop. The temptation is to draw conclusions anyway, instead of having the courage to admit that we don't know, and that the only logically-justified conclusion we can draw is ... that we don't know. :chin:

Putnam's BIV was never about what Pattern-chaser's want it to be. Not even close. It's not an earlier version of the Simulation "theory", never was anywhere close to it, and you are doing a serious disservice to philosophy by spreading this misrepresentation. — Akanthinos

With all due respect to Mr Putnam, I just picked up ('stole', if you like) a speculation that I used for illustrative purposes only. I make no attempt to show that BIV is true or false. In fact, I believe that it cannot be demonstrated to be true or false. That's the issue that I'm trying to focus on.

Philosophy is about thinking, and thinking about thinking. Almost any subject can be considered philosophically - that is to say, using careful consideration and structured thought - and I see no reason why this particular topic should be different. A "serious disservice to philosophy"? No. A simple application of philosophy, to discuss something that is usually ignored. :chin:

In short, It falls to Occam's razor. — hypericin

You seem to have mistaken Occam's Razor for something authoritative. :chin: It's just a rule of thumb, a way of guessing when we can think of no better way to proceed with our reasoning.

As a general rule any unmotivated question of the form 'is there any reason to think that such-and-such is not the case' can be readily dismissed out of hand. It is the conspiracy theorist's question: "is there any reason to think the Queen is not a lizard?; "is there any reason to think we are not ruled by aliens?";these are not questions to be taken seriously. They are questions to be laughed at and ridiculed. — StreetlightX

[My highlighting.]

Well that's great news! :up: Now, if you could just offer a logical justification for dismissing such things...? Seriously, some of these things just look ridiculous, and we dismiss them without a second thought. But are we justified in doing so, or are we just hiding from the uncomfortable truth, that we have no logical justification at all for dismissing such things? Is it all just to avoid admitting to ourselves that there are things - many things - that we just don't know, and that we can never know? :chin: :razz:

Now, if you could just offer a logical justification for dismissing such things...? — Pattern-chaser

Why? What grounds do you offer that could be rationally engaged with? Ex nihilo nihil fit. Rationality is not your - or anyone's - play-thing.

I think your question is worth answering directly. As a preliminary venture. Consider:

BIV Hypothesis (BIV): I have lived a normal life on earth for many years. Last week I was, without realizing it, removed from my body. My brain was placed in a vat of chemicals and hooked up to various electrodes which produce in me sensory experiences just like those I would have if I were still in the ordinary world. For example, I have sensory experiences as if I am in my apartment; as if I am in my office; as if I am eating by the lake. But really, I am never in any of the places my sensory experiences show me to be in. I am a brain-in-a-vat, and I have been for a week, but I never noticed it.

Real Life Hypothesis (RL): I am now in my apartment having sensory experiences of my apartment. In general, my sensory experiences as a fairly accurate guide to my present surroundings. I have never been en-vatted. — PossibleAaran

Thank you for this, @PossibleAaran! :smile: With two examples, we can make the whole thing a little more interesting. I start from the position that both BIV and RL are possible, and that they both come with the same amount of evidence: none at all. Here's an interesting question:

Can we compare the two?

Odd as it seems, no. :chin: Having no means to assign probabilities of correctness to either speculation, we have no means to compare them. We can say that they are not both correct, as they contradict one another. We can say that one or both of them could be incorrect. Logic allows no further justified conclusions, isn't that so? :chin:

Also, a treat for those concerned that unlikely speculations are given equal weight with more likely scenarios: we cannot logically justify saying that BIV and RL are equally likely. This is because we can't establish a numerical probability for either one. :up:

My (unjustified!) conclusion is that we should never dismiss these things, but instead we should use them as it suits our convenience. RL offers me utility, so I use it. BIV is a teaching-story that I find otherwise useless, so I don't use it. But it remains a possibility, and I continue to remember this as my reasoning progresses. I'm not leaving lies behind me, to confuse me later. Isn't this the only practical and honest way of proceeding?