Knowing there's a difference between hallucination and perception doesn't depend on my being able to tell the difference when I'm hallucinating. — jamalrob

The problem is not that you can't tell the difference between the two when you're hallucinating. The problem is that according to your own account, you cannot tell the difference ever, even in principle. Do you see? It might help if you walk through how it is you figured out in the first place that there were two such types of experiences. I know what led you to that conclusion, but now think back a bit on how, given what you've sid, someone possibly could have discovered such a thing.

I don't want to be "the realist". — jamalrob

Then don't defend a realist position.

I don't know why my answers haven't been enough. Maybe I just don't know what you're getting at.

And I've already said I had no interest in defending realism as such.

You haven't answered my question, though.

Put it this way. You have claimed there are two metaphysically distinct, but phenomenologically identical, types of experiences. The question then arises: how did you figure out that such a distinction exists?

In other words, you are putting stock in a theory that requires you to make a distinction that, according to that very theory, you are incapable of making.

Like I say, subjective indistinguishability does not entail that I cannot successfully make the distinction based on what I know hallucination to be, what I know about it from experience, learning, and so on. There seems to be something very wrong about the question "how did you figure out that such a distinction exists?" I'm not prepared to start telling stories about how I once recovered from a hallucination and thereby "figured out" that hallucinations really are different from perception.

What if there really is no such metaphysical distinction? That is a worry for a certain kind of sceptic or his victims, but not for me. Again, I don't mean to be too blasé, because you're a serious interlocutor, but I just don't see the problem.

Like I say, subjective indistinguishability does not entail that I cannot successfully make the distinction based on what I know hallucination to be, what I know about it from experience, learning, and so on. There seems to be something very wrong about the question "how did you figure out that such a distinction exists?" I'm not prepared to start telling stories about how I once recovered from a hallucination and thereby "figured out" that hallucinations really are different from perception. — jamalrob

You don't have to tell a story. Your theory entails that there exists a distinction that you have to make in order for the theory to make sense, while at the same time the theory itself claims that you cannot make this distinction. So no 'stories' are required: you cannot make in intelligible how in principle you can make the very distinction you are required to make. In other words, it does not matter what story you try to give, because you have locked yourself out of making one.

What if there really is no such metaphysical distinction? That is a worry for a certain kind of sceptic or his victims, but not for me. Again, I don't mean to be too blasé, because you're a serious interlocutor, but I just don't see the problem. — jamalrob

This bewilders me. You can't just make claims and then deny that you're responsible for the consequences of them. I'm again only using what you have said. It is not as if some outside source, the 'skeptic,' is criticizing you. If your theory does not make any sense on its own terms, that is indeed a problem for your theory, and it can't simply be dismissed by saying 'I don't see the problem.'

In other words, it's not, again, like there's some lingering doubt, 'what if I'm wrong about the distinction?' It's that precisely the way you've made it rules out the possibility of determining there is one to begin with, yet you yourself are committed to claiming there is one.

When you say "your theory", do you mean the following claims taken together?

Subjectively, I can't tell the difference between a hallucination and a genuine perception.
Hallucination and perception are distinct.

I'm not playing games. I actually don't see the problem. So how can I possibly respond?

You don't see the problem between claiming that you can't make the distinction between two things, and then making that very distinction?

But I never said that I can't make that distinction. What I accepted was that there are times when I can't tell whether or not what seems to be there is there. Which is of the nature of hallucination, of course (and illusion).

Okay, so does that mean there are cases where you can tell whether you're hallucinating or not? If so, what differentiates the cases where you can from those which you can't? You seem to imply that there are no cases in saying that this is 'the nature of hallucination' (that is, the very possibility of hallucination entails the possibility of indistinguishability). Now surely you agree that if every instance of an experience is one that is in principle indistinguishable between the two types you've mentioned, there is a problem? Isn't it then of the utmost importance for your position to find a way that this can't be so?

TGW, do you think there is any contradiction involved in saying that we can be fooled by hallucinations some of the time but not all of the time? It is the fact that we are not fooled all of the time by dreams, hallucinations or virtual experiences that enables us to the make the relevant distinctions.

Now surely you agree that if every instance of an experience is one that is in principle indistinguishable between the two types you've mentioned, there is a problem? — The Great Whatever

No, I don't agree. I was hallucinating then, and now I'm not. But wait, I can't know that I'm not now hallucinating either: what if it's all hallucination? I really don't think the problem you've uncovered amounts to anything more than this.

There may be a contradiction, depending on what your other epistemological commitments are.

Yes, but it's your problem. That is, your own positions requires you to say not only that everything could be a hallucination, but also that you have no way in principle ever of telling whether it is or not. This is turn means that, given any experience could be a hallucination, there is no way in principle for you to have ascertained, and so draw, the very distinction that you are relying on. This is what the Dreaming Argument amounts to. And if you believe the dreaming argument is absurd, then it reflects poorly on your position, since your position is exactly what makes it cogent.

I'd have thought that quantum mechanics has already shown that our sensory apparatuses are not causally related to anything like the objects we take ourselves to be perceiving... — Michael

I don't think that follows from quantum mechanics so much as it follows from reductionistic metaphysics/ontology: that is, from thinking that the objects that we encounter on a daily basis "are nothing more than" the parts out of which they are constituted at the smallest levels of scale, and that the only true descriptions of those objects are the ones given by a particular, "fundamental" physical theory.

we have one person who has taken some pills and found himself waking up in an apocalyptic future where his previous life was a computer simulation and we have another person who hasn't taken any pills and has found his life continue as he's accustomed. Which is the real world? — Michael

Well, if we are defining "real" as "not computer-simulated" then clearly the apocalyptic future is real and the other world is not. This is how the distinction between real and virtual objects is typically made and, in fact, it's kinda become the definition of the word "virtual". The distinction is an ontological one that is grounded in what we know about the causal structure and material composition of the respective objects. Real apples are things that grow on specific types of trees, virtual apples are things that you program into computer systems. When you eat a real apple your real body will be nourished, when you eat a virtual apple your real body will not be nourished. Etc., etc.

Now this doesn't mean that someone couldn't come to regard virtual apples as "real" and real apples as "unreal". The point is that there is a distinction to made here, and that it is not a phenomenological distinction but a causal/physical one.

But if your 'real' body was generally invincible in daily life, but damaging your 'virtual' body had terrible, painful consequences, you'd take liberties with your 'real'
body, not the virtual one. (And so functionally, the 'virtual' one would begin to take its place as 'real'). — The Great Whatever

Right, but the distinction is not grounded in the fact that the one body is invincible and the other is not. It's grounded in my understanding of what kind of thing each body is.

I think we need to distinguish between the two senses of the word "real" that are in play here. On the one hand we have an ontological distinction between "real" and "virtual" which is grounded in differences of kind. On the other hand we have a transcendental distinction between "appearance" and "reality" which is grounded in the way we justify our claims. Both distinctions seem perfectly legitimate to me. Could people disagree over what things to call real and what to call virtual? Sure. Is it possible that our claims could be wrong no matter how we justify them? Sure. I guess I don't see how either of these considerations undermine either distinction. In fact, it seems like neither of these considerations even make sense unless we are already making these distinctions. So like, @Jamalrob, I guess I just don't understand how you are connecting the dots.

This is turn means that, given any experience could be a hallucination, there is no way in principle for you to have ascertained, and so draw, the very distinction that you are relying on. — The Great Whatever

I know this was directed at Jamalrob, so I apologize for butting in and ruining the flow of the discussion, but I can't resist...

We can't have any idea of what it would mean to say that every experience could be a hallucination unless we can understand what it means to say that an experience is an hallucination. That's where the argument falls down, in my opinion, since it has to leverage the distinction between veridical/non-veridical perception in order to present the possibility that all perception could be non-veridical. So the argument from the possibility of global hallucination can't conclude that the distinction is meaningless/incoherent without undermining the meaningfulness/coherence of its own premises.

And if you believe the dreaming argument is absurd, then it reflects poorly on your position, since your position is exactly what makes it cogent. — The Great Whatever

The dream argument works against anyone who takes what is evident in experience to warrant belief in anything at all. It is cogent insofar as one thinks experience is intrinsically precarious and uncertain. But I don't want to argue against the dream argument or any of that stuff, and I don't know what position of mine you keep referring to that you think demands that I do.

No, I don't agree. I was hallucinating then, and now I'm not. But wait, I can't know that I'm not now hallucinating either: what if it's all hallucination? I really don't think the problem you've uncovered amounts to anything more than this. — jamalrob

The problem is the significance TGW is reading into the question of whether or not we are experiencing an hallucination. Asking that question, having doubt about whether we know an event is virtual or not, doesn't actually say anything about if we are aware of a real or virtual world. TGW's argument is really trying to ask this: if a distinction between the real and virtual world cannot be identified, how then is there a real and virtual world at all? If the real an virtual cannot be said to be different, how then can there be any difference at all? If real and virtual don't somehow talk about a difference about between states of existence, which we may know, experience and identify, then it is nonsensical to talks of such worlds. There would be no distinction of real and virtual. It would be outside what could be known and talked about. Direct realists are seeming arguing a contradiction in the very definition of their position- "States of existence are as we experience, even when they are outside our awareness. The distinction of real and virtual is something we cannot experience."

But the problem for TGW's argument is the direct realist has never argued there is no difference between the real and virtual world. They have NEVER take the position we can't tell the difference. We can, in fact, tell the difference all the time. We have experiences of "real" and "virtual" events. We know about them. Though it may be true there is no difference, in immediate sensation, between a "real" world event and a "virtual" world event, it is NOT true when is comes to our wider experience (and so our knowledge).

We notice the dragon the in the computer game doesn't touch our body, not matter how real it might look. It "virtual" nature is shown in our present experience. We know it can't roast us or eat us. The entire premise that there is no knowable difference between experience of the "real" world and hallucination is wrong. There is one. We just don't know it in the immediate experience of a sensation. It comes with a later experiences, where a sensation has been related to others we have had. TGW is ignorant of this because he isn't considering experiences other than the immediate sensation of an object.

I don't know what you are referring to here. Could you elaborate. I understand you are more focused on your exchange with jamalrob, so when you have the time...

Perhaps this is what you are referring to as "epistemological commitments": that everything could be an hallucination?

If everything were, or even could be, an hallucination then there could be no meaningful distinction between 'real' and 'hallucinated'. I think this possibility can be ruled out just on the grounds that we (apparently very successfully) make the distinction all the time and that the very coherence of the argument depends on the distinction.

PS. I just notice that Aaron has made substantially the same point above, so my apologies for not reading the thread thoroughly and inadvertently repeating it.

Well, if we are defining "real" as "not computer-simulated" then clearly the apocalyptic future is real and the other world is not. — Aaron R

I didn't say that the other world is a computer simulation. I moved away from the Matrix example for the reason I explained.

I don't think that follows from quantum mechanics so much as it follows from reductionistic metaphysics/ontology: that is, from thinking that the objects that we encounter on a daily basis "are nothing more than" the parts out of which they are constituted and that the only true descriptions of those objects are the ones given by a particular, "fundamental" physical theory.

It's exactly because a true description of the objects we encounter are not the ones that (always) describe the thing(s) that causally influence our sensory organs (and so experiences) that direct realism fails and indirect realism is a more reasonable account. Direct realism entails reductionism.

I didn't say that the other world is a computer simulation — Michael

I don't mean to be nit-picky, but I think you did:

However, The Great Whatever's point is perhaps better explained with a different hypothesis; we have one person who has taken some pills and found himself waking up in an apocalyptic future where his previous life was a computer simulation and we have another person who hasn't taken any pills and has found his life continue as he's accustomed. Which is the real world? (emphasis mine) — Michael

Perhaps you did not mean to say that?

It's exactly because a true description of the objects we encounter are not the ones that (always) describe the thing(s) that causally influence our sensory organs (and so experiences) that direct realism fails and indirect realism is more reasonable account. Direct realism entails reductionism — Michael

Hmm...I'm not convinced that's right, but I need to think it over a bit.

Perhaps you did not mean to say that? — Aaron R

By "found himself" I meant to suggest that this is what he experienced. One person experiences himself waking up in a post apocalyptic world and another doesn't. Who is having the real experiences and who is having the false ones?

The position that demands it is the position that (1) there are two metaphysically distinct kinds of experience, ostensible perception and actual perception, and (2) in any case, a hallucination is potentially phenomenologically indistinguishable from a veridical perception. I have already said this, many times.

The reason it forces you to confront the dreaming argument is that the result of these two propositions combined is that the dreaming scenario is not only a cogent one, but there is literally no way on your account ever to tell the difference, in principle, between that scenario and a waking one. In other words, there is no 'uncertainty' on your position, in the following sense: you are certain based on your characterization that you can never distinguish one from the other. You cannot adopt the position that makes the dreaming scenario possible, and then simply dismiss it! This is not a viable position. You have to deal with the consequences of your own position, and if your own position drives you into incoherencies you do not want to confront and/or cannot accept, it is not an option open to you to simply ignore them.

Yes, there would be a meaningful distinction on the position jamalrob is advocating: this is what he posits. The result is that he draws a distinction that in principle can't have any effect on the capacity to tell that distinction, which raises the question of how such a distinction can be drawn, if by his own admission he cannot draw it!

But the problem for TGW's argument is the direct realist has never argued there is no difference between the real and virtual world. They have NEVER take the position we can't tell the difference. We can, in fact, tell the difference all the time. We have experiences of "real" and "virtual" events. We know about them. Though it may be true there is no difference, in immediate sensation, between a "real" world event and a "virtual" world event, it is NOT true when is comes to our wider experience (and so our knowledge). — TheWillowOfDarkness

TGW is ignorant of this because he isn't considering experiences other than the immediate sensation of an object.

Indeed, I tried to make that point in various ways, but it doesn't satisfy TG.

Isn't the distinction just a logical one based on our understanding of different categories of experience?

There is a difference between the possibility that the experience I am having right now might be a dream or hallucination and the possibility that my entire experience might be. The possibility that my entire experience might be dream or hallucination is senseless without the accompanying possibility that I might wake up from the dream or come to realise that I had been hallucinating.

The idea that it is possible that there is nothing but dream or hallucination is senseless because there could then be no reality to distinguish it from.

Everything being dream collapses into the "dream" being real because reality is defined as 'all that is'.

By "found himself" I meant to suggest that this is what he experienced. One person experiences himself waking up in a post apocalyptic world and another doesn't. Who is having the real experiences and who is having the false ones? — Michael

Hi Michael. I must apologize in advance for the length of this post. I usually try to keep my posts to a more modest length, but this issue is complicated enough that, in order to do it some kind of justice, I felt I had to be somewhat explicit in explaining my take on it. So here goes...

In my opinion, the question of which world is real cannot be answered in a justificatory vacuum. We have to have reasons for thinking that our perceptions might be in error. So the man who wakes up in the post-apocalyptic world might initially question the veridicality of his perceptions just in virtue of the sheer incongruity between what he currently thinks he knows to be true about the world and what he is now perceiving. Each new perception confronts him with a new reason for either revising or persisting in what he already takes himself to know.

After a while the contents of what he takes himself to know will inevitably be altered by what he has subsequently perceived and inferred. At some point he will presumably learn about the "matrix". He'll learn that the matrix is a computer-simulated reality that is used by an artificial intelligence for the purposes of harvesting humans to generate electro-magnetic energy, and he'll learn that his previous perceptual experiences had all occurred while plugged-in to the system. He'll may or may not come to accept this story, but if he does, he'll likely come to regard the objects that he perceived while plugged-in to have been "virtual" as opposed to "real" and, again, this assessment will be based on what he takes himself to know about the kinds of things those objects are.

So for instance, he takes himself to know what kind of thing an apple is, and nothing he has perceived so far has prompted him to revise his criteria for what does and does not count as an apple. He now knows that the "apples" he had perviously encountered while plugged-in were, in fact, patterns of electro-magnetic fluctuations coursing through the channels of some ultra-sophisticated computer system, and as such, were not really apples at all (again, according to his understanding of what kind of a thing an apple is). And in general, he will upon this basis likely come to regard the beliefs of those still plugged-in to the matrix to be in error insofar as they take themselves to be perceiving and interacting with real, rather than simulated apples, etc.

So in order to answer the question of which world is real, we each need to ask ourselves who's reasons we'd be willing to endorse and defend. To me this seems like a perfectly legitimate question, and this is where I can't really make heads or tails of @The Great Whatever's position on this matter. He apparently wants to deny the coherence of the distinction on the grounds that the man who took the pills could have just as easily persisted in his initial skepticism regarding the veridicality of his perceptions, and could have alternatively interpreted each new perception as just another reason for thinking that the post-apocalyptic world he now finds himself in is, in fact, not real. So we're faced with a kind of equipollence regarding the hypothesis that this world is real and that these perceptions are veridical, etc., and it supposedly follows from this that there is no grounds for making the distinction in the first place.

But I don't see how that follows. For one thing, the argument seems to be premised on the very possibility that it seeks to deny, namely the possibility of questioning the veridicality of one's perceptions. But, perhaps more fundamentally, equipollence is something that can be achieved by asserting the negation of any claim whatsoever, so if we're prepared to reject the legitimacy of one distinction on that basis, then we ought to be prepared to reject the legitimacy of all distinctions on that basis, which, as far as I can tell, amounts to a reductio of that position.

I am definitely open to the possibility that I am fundamentally misunderstanding what's being said. So, if you have any insight into the matter please feel free to share it. I'd be interested to get your take on it.

I really don't see how you think this isn't a problem, jamalrob, nor can I believe that after the posts I've made you don't know what I'm talking about. I literally don't know how to say it any clearer.

If the distinction is senseless, then this is a problem for the realist, who is the one who wants to secure the distinction. An idealist, for example, would not be able to make sense of the idea that every experience one has is illusory. It is only a commitment to realism, which posits a distinction between two kinds of experience, real ones and fake ones, to whom such a possibility is intelligible.