In what sense is Idealism less explanatory? In what sense less ad hoc? In what sense less parsimonious? — PossibleAaran

Well Idealism obviously ad hoc because it's inventing a whole different understanding of reality from the ordinary one. That's the less parsimonious bit.

That would take us back to the line of thought about doubt requiring reason to doubt. Is there a reason to doubt the ordinary story? If not, then it's more parsimonious to go with it. Now of course Idealism pretends to have reason to doubt the ordinary story - but most of it's bogus, based on variants of the argument from illusion, etc.

The more general point is that there are many things that we continuously perceive without realising it, by which I mean that we would notice and pay attention if they were to suddenly cease. Other examples are a faint drone of an electric motor, which we only notice when it suddenly stops. Or one of the many instruments in a thick 'wall of sound' musical arrangement of a song, which one doesn't notice until the instrument stops, and thereby subtly alters the texture of the music. — andrewk

But what is the significance of this for our topic?

But he might not feel anything as well. Experience just ends. — Marchesk

Why is that a problematic account?

Well Idealism obviously ad hoc because it's inventing a whole different understanding of reality from the ordinary one. That's the less parsimonious bit. — gurugeorge

Is any theory which isn't the story which you already accept "ad hoc"? If so, is the mere fact that a theory is not the theory which you already accept a reliable means of determining that the theory is false?

That would take us back to the line of thought about doubt requiring reason to doubt. Is there a reason to doubt the ordinary story? — gurugeorge

Here is the simple reason to doubt the ordinary story which I have stressed already. The ordinary story includes the proposition that some things exist unperceived. There is no reliable method at all, for determining whether the paper in the drawer exists unperceived, and this same problem occurs for the vast majority of objects we perceive. In that way, the belief that things exist unperceived is sheer speculation. This doesn't depend on the argument from illusion.

You have conflated the problem I raised with the Cartesian evil demon/ Brain-in-a-vat/matrix problem. The problems are not the same at all, which is clear in the OP, or so I thought. The Cartesian problem requires one of two things. Either, you have to use a stronger definition of knowledge than mere de facto reliability or you can keep the reliabilist conception of knowledge and then have to assume that we are trapped behind a veil of perception. But I am not trying to discuss that problem, and my OP contained neither of those assumptions.

PA

Here is the simple reason to doubt the ordinary story which I have stressed already. The ordinary story includes the proposition that some things exist unperceived. There is no reliable method at all, for determining whether the paper in the drawer exists unperceived, and this same problem occurs for the vast majority of objects we perceive. In that way, the belief that things exist unperceived is sheer speculation. This doesn't depend on the argument from illusion. — PossibleAaran

Ah, I remember now, haven't we been through all this before? :D

In that case, IIRC my counter-argument was that while you can't perceive things that are unperceived, you can perceive things that prove beyond reasonable doubt that things presently unperceived exist unperceived by you. Remember my camera arguments? Well - camera in the drawer ;)

Pretty sure you're wrong about this. — Marchesk

You're not familiar with cosmology, are you?

You're not familiar with cosmology, are you? — Metaphysician Undercover

I'm familiar with the speed of light being a constant against which measurements of length and time are made across different inertial frames. Note the taking into account different observers making measurements.

I'm also aware that GR accounts for gravity across the cosmos and throughout time.

we can depict the world mathematically — Marchesk

Mathematical equations are meaningless symbolics until observations are substituted for variables.

Symbolics are meaningless. I could write this if I wanted:. %*&6&_*"+6. So what?

Symbols are tools that are invented by the Mind. They are used by the Mind to solve practical problems. The Mind invents new symbols when needed to help solve new problems (mathematics is an invention to represent patterns). The Mind makes observations and uses the tools it invented to solve problems. There is always some Mind (perspective) involved when observing and trying to understand or predict behavior(habits) in the universe.

I do remember your camera argument and I hoped that this thread would bring you back! I failed to make clear enough distinctions before and that lead me to make errors in our discussion.

What I should have said about your camera argument is this. It is true that I can put the camera in the drawer and take a picture and then view the picture. And you are right to think that this is a reliable method of figuring out whether the paper exists in the drawer when I am not looking. But what does it really show? It shows that the paper exists when photographed. Well alright. Lets grant that we can reliably establish that the paper exists when perceived and when photographed. What about when the paper is unperceived and unphotographed? After taking the picture I take the camera out of the drawer and sit on the couch to view the photo. I can see that the paper existed when the camera took its picture, but does the paper exist now? The camera is nothing more than an extension of the times at which I can view the paper; it cannot show that the paper exists unviewed tout court

What I should have realized before was that the spirit of Idealism as it was expressed by W T Stace isn't merely that when I am not literally looking at the paper, there is no way to tell whether it exists. Rather, when I normally suppose that the paper exists when unperceived, I suppose that it exists in such a way that its existence outstrips any mode of observation. Stace's Idealism springs from the claim that there is no way to reliably determine that this supposition is true.

There is another issue which springs to mind as well, but I'd like to proceed somewhat slowly if you are willing, and see what you make of these reflections first.

PA

I can see that the paper existed when the camera took its picture, but does the paper exist now? The camera is nothing more than an extension of the times at which I can view the paper; it cannot show that the paper exists unviewed tout court — PossibleAaran

What if you had a camera take a picture of the paper every nanosecond while it's in the drawer, and send that image to be processed by some software elsewhere. If the software sees that the image is a paper, it wires a cent to your bank account.

You step out of the room and check your account a minute later and notice that it's gone up by millions of dollars. The paper, drawer, camera and software doing paper detection and money wiring are all unperceived, but your bank account gains a lot of money very quickly, which if you calculated the time it took for the image to be taken, sent, processed and your count accredited would come out to having a picture taken every nanosecond by that camera with that software on the server it runs on at that time with your internet connection (the images would be buffered as they arrived, waiting for the software to check them).

Would that not establish the existence of the unperceived paper, at least every nanosecond (or however many nanoseconds got turned into cents)?

The point is that the perceived world is influenced by the unperceived world. You can't just say the rest of the world only exists when perceived given the way the world hangs together. The reason being that the perceived part of the world is being influenced by the unperceived world in countless ways.

Mathematical equations are meaningless symbolics until observations are substituted for variables. — Rich

That's why I said the world could be depicted by math. E=MC^2 means that the amount of energy in certain amount of mass is equal to that mass times the speed of light squared. That applies to any matter/energy conversion across space and time.

There is always some Mind (perspective) involved when observing and trying to understand or predict behavior(habits) in the universe. — Rich

Yes, but you're conflating how we know and represent things with the world itself. Are stars and galaxies dependent on telescopes and the software that processes those images? Of course not. That's just how modern astronomy gathers astronomical data.

Epistemology is not ontology.

I believe that there are items which exist when neither I nor anyone else is perceiving them. Examples of such items are pieces of paper, seas, mountains and apartment blocks. I believe it, but how could I possibly know it? — PossibleAaran

Know gets a bit complex here.

But it was suggested that I ask what reasons you have to doubt such things?

What reason is there to doubt that the coffee I just made is still on the kitchen bench where I left it? I can't see it, and there is no one else out there...

Doubt needs reasons, too.

Are you claiming though, for example, that the principles of aeronautical engineering are actually different in each aeronautical engineer's understanding, or merely that each engineer's understanding is different in having its own individual ways of representing and comprehending the principles, and also in being more or less comprehensive?

The camera is nothing more than an extension of the times at which I can view the paper; it cannot show that the paper exists unviewed tout court — PossibleAaran

That's true, but the salient question, given that objects always seem to remain reliably where we last encountered or put them is whether, in light of that obvious fact, it is more plausible to think that they persist regardless of whether we are perceiving them, or to think that they do not. For sure there can be no absolute proof, no absolute certainty; but why does that matter to you?

Would that not establish the existence of the unperceived paper, at least every nanosecond (or however many nanoseconds got turned into cents)? — Marchesk

Yes it would establish that the paper exists every nano second that it is photographed. But this wouldn't exhaust the content of what I believe about the paper. I don't just believe that if you took a picture of the paper every nanosecond it would be there, or that if I took the picture and the paper was there then a cent would transfer into my bank account. I believe further that even if you remove the camera and never take another picture of the paper again, the paper still exists in the drawer, unperceived and unphotographed. And this has yet to be established.

What reason is there to doubt that the coffee I just made is still on the kitchen bench where I left it? I can't see it, and there is no one else out there...

Doubt needs reasons, too. — Banno

The reason for the doubt is the one I stated in the OP. That is, the existence of the coffee when unperceived is something that nobody has any reliable means of determining to be true. No reliable means at all. The belief is (apparently) akin to the belief that there is a unicorn on mars. There is just no reliable way to tell. Is that not reason enough for doubt? (Incidentally, I am hoping that the belief about the coffee is not like the unicorn on mars belief, and that it can be reliably determined, but I've yet to see how it could be).

That's true, but the salient question, given that objects always seem to remain reliably where we last encountered or put them is whether, in light of that obvious fact, it is more plausible to think that they persist regardless of whether we are perceiving them, or to think that they do not. For sure there can be no absolute proof, no absolute certainty; but why does that matter to you? — Janus

Certainty doesn't matter to me at all. Any reliable means of determining that things exist unperceived is fine with me. It doesn't have to be a perfect method or a guaranteeing method or what have you. Just a plain old trustworthy method that gets things right more often than not.

The question is, what do you mean by "plausible"? If you mean, is it more psychologically convincing, yes it is. But what is that worth? Or what else could be meant by 'plausible'?

Best,
PA

PS, Apologies if this post contains any serious typos. It is quite late and I'm tired. I did try to proof read as usual.

E=MC^2 means — Marchesk

When you use the word mean, that brings the mind into it, and that brings perspective. To you it means one thing. To someone else it means something else.

The reason for the doubt is the one I stated in the OP. That is, the existence of the coffee when unperceived is something that nobody has any reliable means of determining to be true. No reliable means at all. The belief is (apparently) akin to the belief that there is a unicorn on mars. There is just no reliable way to tell. Is that not reason enough for doubt? (Incidentally, I am hoping that the belief about the coffee is not like the unicorn on mars belief, and that it can be reliably determined, but I've yet to see how it could be). — PossibleAaran

Basically, so what?

Is the argument that we don't have any reason to think it true, and therefore it is false? But that's obviously invalid.

The coffee was particularly pleasant. If I had decided to doubt it's existence, it would probably have gone cold before I re-discovered it.

Again, since I had no reason to doubt that it was still on the bench, things turned out well.

Now if i had gone out and not found it on the bench, then I would have had reason for further enquiry. But it remains irrational to doubt without reason.

I didn't make the obviously fallacious argument that you mention.

So, the belief that the coffee exists unperceived isn't one that can be reliably established by any method at all. It is like the belief that there is a unicorn on mars. Even despite this, you don't see the problem. Unless someone can give you an argument that the coffee doesn't exist unperceived then, regardless of the fact that the view that it does so exist is pure speculation, you continue to hold that belief. I am not sure how to respond to this. I suppose we have a difference in values. You are happy with speculation as long as there is no evidence against the speculation in question. I insist on having a reliable method of determining that the belief is true.

I don't know how I could get you to see things my way. One thought which comes to mind is that if you are happy with speculation in the absence of counter evidence, then any and every speculation no matter how wild is acceptable. I am beyond criticism in holding that there is a unicorn on mars; beyond criticism in holding that great warriors go to Valhalla upon death; beyond criticism in holding that a meteor will strike the earth tomorrow and obliterate the entire of the UK. After all, there will be no difference in evidence between these beliefs and the belief that the coffee exists unperceived. Obviously this won't suffice as a proof that you are wrong, since if you have the strength of your conviction, you will just accept these consequences. Still, I think they are odd consequences.

Best,
PA

So, the belief that the coffee exists unperceived isn't one that can be reliably established by any method at all. It is like the belief that there is a unicorn on mars. — PossibleAaran

It isn't like a belief in a unicorn on mars at all. We do have good reasons for thinking objects exist unperceived:

1. They're still around when we do perceive them again.
2. They can undergo change in our absence.
3. They can influence things we do perceive.
4. The perceived world is dependant on the unperceived for being the way it is.
5. We have no reason to suppose that things stop existing when we're not around.

A unicorn on mars doesn't fit any of that. It's like saying we have no reason to think unperceived paper doesn't turn into a unicorn or teleport itself to Mars. Why must it not exist? Why not anything fanciful? We're not perceiving the paper, so it could be anything or anywhere in addition to not existing, logically speaking.

Why is your doubt fixated on non-existence instead of any of an infinite number of unperceived scenarios?

1. They're still around when we do perceive them again.
2. They can undergo change in our absence.
3. They can influence things we do perceive.
4. The perceived world is dependant on the unperceived for being the way it is.
5. We have no reason to suppose that things stop existing when we're not around. — Marchesk

Well, 1 doesn't entail that things exist unperceived. So what is the inference from 1 to the view that things exist unperceived? You haven't said, and I keep trying to get you to tell me. I suspect you want to give an inference to the best explanation, but you shy away from doing this in any degree of detail, which is what is problematic.

2 blatantly presupposes that things exist unperceived. I observe a fire burning. I go away and come back later. I observe a burnt out fire. These events are only connected as 1 fire undergoing change on the assumption that the fire exists unperceived and the law of causation operates unperceived, and this is what has to be proven.

3 equally presupposes the view that things exist unperceived. I don't at present perceive the sun, but it is partially responsible for the present temperature in this room, so the story goes. But that story obviously is not a proof of, but assumes, that the sun exists unperceived and, again, that causation operates unperceived, and these need to be proven. Now, I don't suppose that there is no way at all of making something like 2 and 3 into an argument, but what you have suggested won't do. We need to start with a non-question begging account of the observations which make us think that 2 and 3 are true, and perhaps we can infer that they are true from those observations. But 2 and 3 can hardly be the argument, since they presuppose the view in question.

5 doesn't entail the view that things exist unperceived either. So what is the inference from 5 to the view that things exist unperceived? You haven't said.

Best,
PA

But what is the significance of this for our topic? — PossibleAaran

That everything is connected to everything else, so all the examples given here of things that are unperceived, followed by the question 'do they then exist?' are not unperceived. They are perceived, so the question is moot.

One thought which comes to mind is that if you are happy with speculation in the absence of counter evidence, then any and every speculation no matter how wild is acceptable. — PossibleAaran

Well, no. If there is reason to think the speculation wild, there is reason to doubt it.

Thankfully speculation about my coffee not existing was subsequently shown to be false.

The fact that things are generally where we expect them to be is as reliable a means as you can get. What more reliable kind of means can you imagine might be available?

[Delete] @Baden

Personally, I think you're getting hung up on the story, not the behaviour. We all know that time does not exist in the way we think it does, we all now know that atoms are made mostly of empty space. But we act as if time were an immutable straight line (unless we're doing physics) because it works. We act as if the table in front of me is solid because it works. The story we tell as to why it works is irrelevant, it's post hoc, just a soothing picture for us. What matters is what we're going to do next.

You must either act as if the paper will still be there when you re-open the drawer or not. If you have an important document which will lose you your job should it be lost, do you keep it in vision at all time, set a camera up next to it to photograph it every nanosecond to ensure it remains in existence? No, you simply act as if it will continue to exist unperceived, and this works. You cannot not act, there is no 'wait and see' option, so scepticism doesn't help us here, you must choose one behaviour or another.

The important job having been done, you can tell whatever story you like to yourself about why the paper turned out to still be in the drawer when you came back to it, so long as that story provides you with useful predictions about how to act in future. If you choose to believe that the paper simply carries on as it were even whilst you're not looking, that works, because it provides the useful prediction that if we were to go to that drawer at any point in time, the paper would be there. If you want to tell yourself that an absolutely reliable and 100% consistent demon puts the paper back every time anyone or any thing tries to perceive it, then that's fine too as it provides you with the same useful predicting power.

What's not fine is if you tell the story that a real evil demon, a capricious wilful demon, puts the paper back whenever you look at it. That provides you with the very unhelpful prediction that its re-existence when you come to look at it again can't be trusted, that valuable objects must be constantly observed lest they fail to re-exist when we need them. It leads to the very unhelpful prediction that we cannot chart a rocket to the moon simply on the basis of our mathematical assumptions about where it is, because it might well have simply dropped out of existence since we last observed it.

Hume's problem of induction aside, this is the difficulty with your approach, it becomes an entirely semantic, story-telling exercise. There is no utility to the result. Whatever the reason, we experience that the paper does indeed, reliably re-exist when we open the drawer. Whatever the reason for this, it is entirely consistent and reliable. So tell yourself whatever story about it you like, so long as it does not contradict the evidence we have. If you think you have a story that will provide predictions that are different from the standard model then think of a way of testing it, but I'm not sure what value you're seeing in pointing out that we could use different words to describe the phenomenon we experience.

What I should have realized before was that the spirit of Idealism as it was expressed by W T Stace isn't merely that when I am not literally looking at the paper, there is no way to tell whether it exists. Rather, when I normally suppose that the paper exists when unperceived, I suppose that it exists in such a way that its existence outstrips any mode of observation. Stace's Idealism springs from the claim that there is no way to reliably determine that this supposition is true. — PossibleAaran

Again, I'd go back to the deeper sorts of arguments I put forth in our previous discussions. If you're accepting that what you're doing when you've got object x in view truly is that thing we normally call "perception" or "observation", whether mediate (camera, videocamara) or immediate (MK-1 eyeball), then plumping for calling what you're doing "perceiving object x" in the immediate case carries with it your implicit acceptance of whole backstory about physical objects in causal concatenation, such that they can't just pop into and out of existence.

In that case, the camera/video evidence ought to be good enough to prove the object's existence outside your present eyeballing. If you then want to check the video, that too is subject to doubt and the possibility of error (perhaps a mischievous friend is interjecting a false feed), but then in the same sense, so was your initial eyeballing perception (subject to errors of illusion, etc.).

On the other hand, if you want to strip away all presuppositions and go the non-dual/Ernst Mach route, as above, and you're contemplating present experience as a you-know-not-what, then the thing that's happening right now in and as present experience has no name, and it's not perception or observation either. It's not even experience, the blandest possible thing you could normally call it. The seeming of an "object x" in it, carries no connotation of existence or nonexistence outside of just being part of that "subjective" (again, problematic, because normally working in tandem with "objective") kaleidoscope hanging in the void, it doesn't even carry any connotation of existence outside perception (external existence) while you're perceiving it, far less while it's not in view.

You get out what you put in, GIGO. Strip away all presuppositions, then you can easily get the universal doubt, but at the cost of not being able to call the thing you departed from in your investigations "perception." The stripping away of presuppositions works hand and hand with the degree of universality of doubt, they're just two sides of the same coin.

Again, this is the core problem with Idealism and phenomenalism as I see it: they want to keep their cake and eat it. They want to call what's happening in the present moment "experience", "perception", "observation", etc., etc., but they want to retain universal doubt. But if you're universally doubting, then you can't call what's happening right now "perception", "experience", "observation" etc in the first place. But then as soon as you accept those terms, you implicitly accept the physical backstory, so there's no place for universal doubt any more.

Esse est percipe doesn’t strictly imply that things pass in and out of existence. The idea of them doing that, depends on assuming a perspective from which you are able to see them going out of existence, or alternatively imagining them being non-existent. And again all of those imaginings assume a realist stance. But that form of realism, which is essentially hard-wired into us, is itself a mental construction, a notion of the meaning of existence. We are imputing to the objects of consciousness the very quality which the idealist argument seeks to demonstrate is unwarranted. In that sense, many of the objections here beg the question.

To me, what no contributor to this thread sees is the foundational role of the observing mind in ascertaining what the term ‘existence’ means, for any object whatever. We have a native sense of the reality of the perceived universe, in fact for most of us the reality of the perceived universe is the very definition of what is real. But that forgets why the question is asked in the first place. The question can only arise on the basis of a deep sense that the perceptual domain, the common-sense world that we all take for granted, is not what it seems to be. That is the original motivation for scepticism and it is actually a deeply unsettling realisation.

In 1958, Schrödinger, inspired by Schopenhauer from youth, published his lectures Mind and Matter. Here he argued that there is a difference between measuring instruments and human observation: a thermometer’s registration cannot be considered an act of observation, as it contains no meaning in itself. Thus, consciousness is needed to make physical reality meaningful.

Read more at: https://phys.org/news/2009-06-quantum-mysticism-forgotten.html#jCp

The act whereby any judgement is made about what exists - whether a piece of paper or anything else - is part of that process of ‘making physical reality meaningful’. That’s the sense in which we live in a meaning-world, not a world of objects as such. There are objects, but the nature of their reality is imputed by the observing mind on the basis of perception, sensation, judgement, and the rest. But, as I think has become clear through physics itself, objects have no absolute or intrinsic reality, as to all intents they are endlessly divisible. What they ultimately are, if anything, is still the subject of a vexed debate in physics over the nature of matter (which is the subject of the investigation by the most expensive, largest and most complex apparatus in history.)

So the reason idealism is significant, is to remind us that knowledge is always conditional, dependent, and in some sense subjective. Not in the sense of there being simply no objective truth, but that there is no ultimately objective truth.

Kant's introduced the concept of the "thing in itself" to refer to reality as it is independent of our experience of it and unstructured by our cognitive constitution. The concept was harshly criticized in his own time and has been lambasted by generations of critics since. A standard objection to the notion is that Kant has no business positing it given his insistence that we can only know what lies within the limits of possible experience. But a more sympathetic reading is to see the concept of the "thing in itself" as a sort of placeholder in Kant's system; it both marks the limits of what we can know and expresses a sense of mystery that cannot be dissolved, the sense of mystery that underlies our unanswerable questions. Through both of these functions it serves to keep us humble. 1.

Again, this is the core problem with Idealism and phenomenalism as I see it: they want to keep their cake and eat it. They want to call what's happening in the present moment "experience", "perception", "observation", etc., etc., but they want to retain universal doubt. But if you're universally doubting, then you can't call what's happening right now "perception", "experience", "observation" etc in the first place. But then as soon as you accept those terms, you implicitly accept the physical backstory, so there's no place for universal doubt any more. — gurugeorge

That's a really excellent critique. It undermines much of the bite of the hardcore idealist means of arguing where it's just one experience followed by another and nothing can be said of what happens in between.

So the reason idealism is significant, is to remind us that knowledge is always conditional, dependent, and in some sense subjective. Not in the sense of there being simply no objective truth, but that there is no ultimately objective truth. — Wayfarer

But this conflates epistemology with ontology. Just because there is a process by which we come to know about the world doesn't mean the world is constituted of that process.

We can analogize this to modern astronomy where sophisticated telescopes feed data to software that produces results for astronomers to analyze. There is a process in constructing knowledge of the cosmos.

But that doesn't mean the cosmos is therefore constructed by telescopes and software! It's a fallacious move to make. This is where Stove's worst argument gets it right.

That everything is connected to everything else, so all the examples given here of things that are unperceived, followed by the question 'do they then exist?' are not unperceived. They are perceived, so the question is moot. — andrewk

This view, that "everything is connected" blatantly assumes that things exist unperceived. Take the drone of an electric motor example. When I hear the noise, if I come to believe that anything more than the noise exists at that time I will have to assume that the cause of the noise exists unperceived, since the noise and the motor are not the same thing. By what argument can I move from the noise to the motor?

Even if this difficulty can be worked out, it is of no use in coming to know that the paper in the drawer exists unperceived, since none of the paper's effects are perceived either.

Well, no. If there is reason to think the speculation wild, there is reason to doubt it.

Thankfully speculation about my coffee not existing was subsequently shown to be false. — Banno

How was it shown to be false? You went and looked at the coffee? This establishes that the coffee exists when you looked the first time, and that it exists when you look the second time. It doesn't establish that the coffee existed in between, when you weren't looking. I have been pointing this out since the very beginning.

The fact that things are generally where we expect them to be is as reliable a means as you can get. What more reliable kind of means can you imagine might be available? — Janus

As I have said to Banno, perceive the piece of paper as many times as you like, this is never sufficient to show that it exists unperceived. Perception is only a reliable guide to things that are actually perceived, and obviously nothing is ever perceived while unperceived. So in answer to your question, any actually reliable method would be what I imagine available - not a method for which it is contradictory to suppose it could reveal the alleged fact.

but I'm not sure what value you're seeing in pointing out that we could use different words to describe the phenomenon we experience. — Pseudonym

They aren't 'merely different words', since there is an obvious difference between something existing at a time, T and something not existing at that time. Thus, there is an obvious difference between something existing at some time, T, when unperceived, and that things not existing at T, when unperceived. That you think that the two hypotheses have no difference in meaning because they have no difference in empirical predications is the result of your Verificationism, but there is no reason to think that Verificationism is the correct account of meaning, and in fact many reasons to think that it isn't, which by now are very well known. One of these is the one which the Verificationists themselves raised, which is that Verificationism has no conditions of verification and thus is, by its own lights, meaningless. But I'm sure you have heard this before.

Again, I'd go back to the deeper sorts of arguments I put forth in our previous discussions. If you're accepting that what you're doing when you've got object x in view truly is that thing we normally call "perception" or "observation", whether mediate (camera, videocamara) or immediate (MK-1 eyeball), then plumping for calling what you're doing "perceiving object x" in the immediate case carries with it your implicit acceptance of whole backstory about physical objects in causal concatenation, such that they can't just pop into and out of existence. — gurugeorge

They want to call what's happening in the present moment "experience", "perception", "observation", etc., etc., but they want to retain universal doubt. But if you're universally doubting, then you can't call what's happening right now "perception", "experience", "observation" etc in the first place. But then as soon as you accept those terms, you implicitly accept the physical backstory, so there's no place for universal doubt any more. — gurugeorge

Are you saying that there is no understanding of 'perception' which doesn't entail that the thing perceived exists unperceived? If so, some of the modern theories of physics are literally incoherent. Does Schrodinger's cat exist when unobserved? Well, you would have to say, it follows from the meaning of the word "observed" that it must exist unobserved, and any attempt to doubt this means that you can't meaningfully say that you ever "observed" the cat.

Moreover, if it were so, then there would never be a need for me to check whether something I saw earlier is still there now. It would make no sense, for example, to see a sand castle at T1 and then wonder later about whether it exists when you are in the coffee shop, or whether it has blown away in the wind. I can just say "well, it follows from the meaning of the word 'perceived' that the sand castle I perceived earlier must still exist". It is plain as day to me that my own ordinary understanding of the word 'perceived' entails only that the thing perceived must exist at the moment I am perceiving it. It says nothing about any other moment.

Another point to make is that your view about the ordinary meaning of "perceived" is an empirical hypothesis. It says that ordinary members of the population use the word "perceived" such that perceiving X entails that X exists unperceived. Recent experimental philosophy has made it clear that ordinary language users don't always agree with philosophers about what a word means and made even more clear that the best way to figure out what ordinary words mean isn't just to take a guess from the armchair, or even to talk with other philosophers about what it is 'intuitive to say'. The best way to find out is to actually go out and ask questions to ordinary folk which indicate the meanings of their words (you could see, for example, any study by Stich, Machery or Weinberg). Hence, my suggestion is that we cannot really tell whether the ordinary meaning of 'perceived' is what you say it is, or even that there is a ordinary meaning.

Even if the ordinary meaning of 'perceived' were as odd as you suppose it to be, I don't think that is of any importance at all. I would simply reformulate in new terms. I held previously that humans have two reliable sources of belief about the present and future (memory has to be included for the past, but this can be omitted for now): perception and inference from sense perception. If perceiving X entails that X exists unperceived then I shall reformulate my view. Instead, I say that humans have two reliable sources of belief, Schmerception and inference from schmerception. Schmerception is what is happening when various properties and/or objects are brought before your conscious awareness. We could say that Schmerception 'gives' items to you in awareness. Schmerception doesn't entail that what is schmercieved exists when unschmercieved, since being consciously aware of some object or property at T does not entail that the object exists at any time T1, when it is not something you are consciously aware of. Perception is not, although I thought it was, a reliable way to learn about the world, since "perception" turns out to mean this odd and mysterious thing where perceiving something at one time entails that it must exist at other times. Perception, so understood, has nothing to do with my conscious awareness of the world, since that conscious awareness doesn't entail that the things I am aware of exist unperceived. I am not really sure that perception is, if that's what it means. Perhaps perception is just Schmerception of things which also exist when unschmercieved. Perhaps, but then the fundamental method of finding out about the world is schmerception, and perception is a thing I can do only if there are things which exist unschmercieved.

I understand the attempt which you are trying to make. You are trying the ever popular method of building our ordinary worldview into the meaning of our ordinary words. Doing this is supposed to make us feel better about those views. It is supposed to somehow prevent sceptical challenges to those views, since the sceptic will be unable to meaningfully state any challenge to those views using ordinary language. Thus, I can't meaningfully ask whether there is any reliable way to determine that things exist unperceived while using the ordinary notion of 'perceived'. The problem is, if I am really sceptical about ordinary views because those views don't meet a standard which I deem important (reliability), I won't be impressed by the thought that those views are built into my language. So what if they are built into my language? Other cultures use other languages and their language might not be such as to have my ordinary views build into it. If so, how can we reliably establish which culture is right? The appeal to language obviously won't do. This was made very clear in a paper by Stich entitled Reflective Equilibrium, Analytic Epistemology and The Problem of Cognitive Diversity.

Best,
PA

I suppose I'd first ask, what is it about perceiving the paper that makes you believe you know, in the same sense that you're asking about knowing how the unperceived paper exists, that the perceived paper exists?

Clearly if you believe that then there's some kind of method you're already accepting as a path to knowledge of what exists. What constitutes that method? — Moliere

Sorry for skipping over you Moliere!

The method I am accepting is quite straight forward. When I look at the piece of paper its existence is something of which I am immediately aware. It is there right before me in conscious view. When this is so, I have reliably established that the paper exists. I am tempted by the thought that this is more than reliability, and more like certainty, but I feel like that might be problematic and so I hesitate. Let's just say that when the paper is right before my conscious view, it is more likely than not that the paper exists.