You're using "introspection" so loosely it's worthless, bert. I rely on a lack of grounds to doubt and, where otherwise, use hypothetico-deductions tested by observation (Popper et al).

The underlying assumption here is that if something can be imagined then it must be taken seriously as a real possibility.

We have no reason beyond perhaps entertainment value to take seriously the possibility that we are brains in a vat.

If it is possible that I am a brain in a vat then it is possible that we are all brains in a vat, including those who allegedly put our brains in vats. But then they are not really brains in vats at all.

You're using "introspection" so loosely it's worthless, bert. I rely on a lack of grounds to doubt and, where otherwise, use hypothetico-deductions tested by observation (Popper et al). — 180 Proof

Oh, OK. If you're a BiV all you have is introspection, loosely defined or not.

There are no grounds for me to doubt that I'm not a BiV so the point's moot. The idle doubts upon which 'the BiV speculation' is raised show it's vacuous.

There are no grounds for me to doubt that I'm not a BiV so the point's moot. The idle doubts upon which 'the BiV speculation' is raised shows it's vacuous. — 180 Proof

I don't think I'm a BiV either. But I'm not sure why. You haven't established a prima facie reason for thinking you're not.

EDIT: I agree it's somewhat idle. It's not something I seriously worry about. But it's a philosophical niggle. It's like the New Riddle of Induction. I'm totally sure the grass I'm looking at is green and not grue, but justifying that is not straightforward.

I have but, apparently, it's not good enough for you. Well, my uncontested (or unfalsified) "reasons" persuade me, which is all that matters. "Justification", btw, is not my game – I'm a freethought 'pragmatist-falsificationist-foundherentist' with respect to epistemology.

The idea that you are a BiV is coherent, founded in experience and unfalsified.

Foundherentism is a theory of justification.

Foundherentism is a theory of justification. — bert1

Oh yes, I know, which is why I'm not exclusively or primarily a foundherentist (as I point out in my previous post). And I append it to the end my broader epistemic position because foundherenism is inherently fallibilist and focused on beliefs more so than knowledge (i.e. explanatory theories).

As for BiV, there aren't any grounds to doubt 'I'm not a BiV' or for believing 'I am a BiV'. Feel free, however, to share such grounds one way or the other if you can, bert.

Today I got up, heard the birds singing, smelled the toast, trod on a nail. If the computers had not stimulated my brain I would not have had those experiences. I did have them, therefore the computers stimulated my brain just so.

'pragmatist-falsificationist-foundherentist' — 180 Proof

If this is some kind of irreducible compound, I have no idea what you mean by it.

Okay. I await your BiV reasoning though.

And I append it to the end my broader epistemic position because foundherenism is inherently fallibilist and focused on beliefs more so than knowledge — 180 Proof

But you explicitly said you knew you were not a BiV.

Okay. I await your BiV reasoning though. — 180 Proof

Scroll up

180, your posts are in code. I don't have the codec.

No. There is no reason to believe we are a brain-in-a-vat, but there is equally no reason to believe we are in base reality - the experience would feel "real" either way. — Down The Rabbit Hole

That is, your answer to the question "Do you know whether or not you're a brain-in-a-vat whether or not you're a brain-in-a-vat ..." is actually Yes. You do know. Right? :)

No. There is no reason to believe we are a brain-in-a-vat, but there is equally no reason to believe we are in base reality - the experience would feel "real" either way.
— Down The Rabbit Hole
That is, your answer to the question "Do you know whether or not you're a brain-in-a-vat whether or not you're a brain-in-a-vat ..." is actually Yes. You do know. Right? :) — Alkis Piskas

My answer is No I don't know whether or not I'm a brain in a vat. On the basis that there is no reason to believe either way.

My answer is No I don't know whether or not I'm a brain in a vat. On the basis that there is no reason to believe either way. — Down The Rabbit Hole

If there is no reason to believe we are a brain-in-a-vat and also there is no reason to believe we are in base reality, it means you know that neither of them is true. If there is no reason to believe that I am a fool, it means I know I am not a fool. So the answer is anyway "Yes, I know".

What's the essential difference between a skull and a vat? — Olivier5

The brain = "us"

The skull = The vat

What's the essential difference???

:chin: :chin:

If I'm a brain in a vat, everything I perceive is an illusion generated by simply stimulating the right combination/sequence of neurons. I cannot trust my perceptions.

If I'm a brain inside a skull, my perceptions correlate with an external reality that provides the stimuli to my neurons. In other words, there's an external reality of which I become aware of through my sensory apparatus. I can trust my perceptions, relatively speaking (see vide infra)

Intriguingly, if a person is experiencing a complete all-modality sensory hallucination (sounds, sights, touch, taste, smell) then there's no difference between a brain in a skull and a brain in a vat! In both cases, the brain is being fed an illusion.

If I'm a brain in a vat, everything I perceive is an illusion generated by simply stimulating the right combination/sequence of neurons. I cannot trust my perceptions. — TheMadFool

You can trust your perceptions to tell you something about this supposedly virtual reality in which you find yourself. Just like if you are a brain in a skull, you can trust your perceptions to tell you something about the supposedly non-virtual reality in which you find yourself. There is no real difference. A skull is essentially the same thing as a vat: a brain container.

If there is no reason to believe we are a brain-in-a-vat and also there is no reason to believe we are in base reality, it means you know that neither of them is true. If there is no reason to believe that I am a fool, it means I know I am not a fool. So the answer is anyway "Yes, I know". — Alkis Piskas

No. What's the name for someone that sees no reason to believe there is a god and no reason to believe no god exists? An agnostic. And that doesn't mean an agnostic knows that neither option is true.

As no evidence would prove one way or the other whether we are in reality or an illusion, it's reasonable to be agnostic on the question.

As to your fool analogy. Just because you, the potential fool, see no reason to believe you're a fool, it doesn't mean you know you're not a fool.

You can trust your perceptions to tell you something about this supposedly virtual reality in which you find yourself. Just like if you are a brain in a skull, you can trust your perceptions to tell you something about the supposedly non-virtual reality in which you find yourself. There is no real difference. A skull is essentially the same thing as a vat: a brain container. — Olivier5

There's a difference. In the brain in the vat scenario, conscious experience is no different from an all-modality hallucination. Suppose I'm a brain in a vat and the "evil genius" stimulates my eye neurons and I see an image of a house. Once the stimulation is terminated, there is no house.

If I were a brain in a skull, the image of a house can only form in my eyes if there really is a house. Looking away (terminating the eye stimuli) has no effect on the house - it still is even when my eyes aren't looking at it.

If I were a brain in a skull, the image of a house can only form in my eyes if there really is a house. Looking away (terminating the eye stimuli) has no effect on the house - it still is even when my eyes aren't looking at it. — TheMadFool

You can dream of a house; you can imagine a house; you can see a picture of a house; so there are ways in which the image of a house can form within a brain in a skull without an actual, real house being there, outside of same skull.

Vice versa, in a well-conceived and coherent virtual reality, houses would not vanish just because you don't look at them. Otherwise, you could tell that something's not quite right. E.g. when you play a video game, villains don't disappear just because you look elsewhere. They are still able to game you over, even if you pay no attention to them.

If there is no reason to believe that I am a fool, it means I know I am not a fool. — Alkis Piskas

Since when has a mere contingent cognition (belief) justified a certain cognition (knowledge)?

(Sigh)

You can dream of a house; you can imagine a house; you can see a picture of a house; so there are ways in which the image of a house can form within a brain in a skull without an actual, real house being there, outside of same skull.

Vice versa, in a well-conceived and coherent virtual reality, houses would not vanish just because you don't look at them. Otherwise, you could tell that something's not quite right. E.g. when you play a video game, villains don't disappear just because you look elsewhere. They are still able to game you over, even if you pay no attention to them. — Olivier5

Regarding the firsr paragraph of your post.

Yes, the brain can independently generate conscious experience. I mentioned hallucinations.

Regarding the second paragraph of your post.

Yes, a sim would be designed to give you the illusion of coherency. So, the sim would, like you said, give you the impression that a villain persists even when the villain is outside the field of your consciousness.

However, there's something terribly wrong in saying/believing a brain in a skull = brain in a vat.

It's like this. For a brain in a vat, the body, the skull is part of the sim. Thus the body, the skull, the brain you (can) see - possible with available surgical techniques & fiberoptics - is not your actual body, skull or brain!

If the brain in the skull is a brain in the vat, the body, the skull is not a sim. Your body, your skull, the brain inside it is the real McCoy!

Still not convinced. Your body is not, actually, the same thing as the way you perceive your body. We have this Kantian incapacity to reach reality as it is, we only see phenomena. In the world out there as theorized by physics, there are no color, only wavelengths. So what you see is NOT what there is, but a representation of it.

The images you see, they are in your head, and you know it.

This is precisely why it is so hard to get rid of the brain-in-a-vat idea: because it is basically true that we ARE brains in skulls watching algorithms, which is much the same thing as brains in vats.

From https://plato.stanford.edu/entries/abduction/

"In the philosophical literature, the term “abduction” is used in two related but different senses. In both senses, the term refers to some form of explanatory reasoning. However, in the historically first sense, it refers to the place of explanatory reasoning in generating hypotheses, while in the sense in which it is used most frequently in the modern literature it refers to the place of explanatory reasoning in justifying hypotheses. In the latter sense, abduction is also often called “Inference to the Best Explanation.”

No argument; I just thought this was interesting..

If there is no reason to believe that I am a fool, it means I know I am not a fool.
— Alkis Piskas — Mww

Since when has a mere contingent cognition (belief) justified a certain cognition (knowledge)? — Mww

You must not interpret arguments the way you like, because it looks like you either don't really undestand them or that you avoid admitting that yours are false. And in the process, the discussion becomes a game in semantics.
So I will help you by rephrasing my argument: "If I had some reason to believe I am a fool, it would make me doubt about what I currently believe, namely that I am not a fool. Which means I could not claim that I know I am not a fool." Makes better sense?
And please, do not use terms like "contingent cognition". Plain English please. That is, "speak" in the same terms as I do.

Still not convinced. Your body is not, actually, the same thing as the way you perceive your body. We have this Kantian incapacity to reach reality as it is, we only see phenomena. In the world out there as theorized by physics, there are no color, only wavelengths. So what you see is NOT what there is, but a representation of it. — Olivier5

So, you wouldn't be sure about being a brain in a skull just because you look like a brain in a skull! Right? But then you claim brain in a vat = brain in a skull which implies you've seen your actual self (a real brain in a real skull). It doesn't add up.

No. What's the name for someone that sees no reason to believe there is a god and no reason to believe no god exists? An agnostic. And that doesn't mean an agnostic knows that neither option is true.

As no evidence would prove one way or the other whether we are in reality or an illusion, it's reasonable to be agnostic on the question.

As to your fool analogy. Just because you, the potential fool, see no reason to believe you're a fool, it doesn't mean you know you're not a fool. — Down The Rabbit Hole

(Re 'agnostic': I asked you please not to bring up such terms. For one thing, we may have different definitions of them, which means we couldn't discuss on same grounds. That is why I avoid them, except when they are necessary in some way. But here we can very well do without 'agnostic'! :))

Right. If I have no reason to believe that there is a god, I can't say that god doesn't exist. No evidence about something cannot lead to any kind of knowledge about that something, positive or negative in nature.

Yet, this has nothing to do with my "fool" example. (Please notice my quotation marks. Otherwise a fool example means that the example is fool (i.e., foolish, silly)! :)) Because in that case, I am talking about something I know and about which I can bring acceptable (reasonable, conventional, etc.) evidence. So, not only myself but also others would know that I am not a fool.

But then you claim brain in a vat = brain in a skull — TheMadFool

No no no, I'm just saying there's no essential difference between the two situations.

If the sim that the BiV is fed looks exactly like some sort of reality that a BiS would possibly live in (it is coherent, rich in details, etc., as you agreed that it could be or even should be for the illusion to work), and if "they" don't wake you up from your sim, whence come the difference? You live in a sim which happens to be your reality. It is as real as any other reality will be.

If in addition there is in a BiS situation a structural, unavoidable epistemic gap between your mind's view of the world and the world itself; if you cannot really access the latter but only images of it (or any other senses' mental output/representation of it), then you DO actually live in a sim even in a BiS situation. Your mental world is a sim of the real world around you.