I disagree that the existence of objective reality is a matter of fact. To me it's a matter of viewpoint. Sometimes it's useful, sometimes it's misleading. If it's true, then the Tao doesn't exist, which of course it doesn't. That's what I like about Lao Tzu - he acknowledges the unspeakability of reality. The view that there is no such thing as objective reality is not an uncommon one. I've participated in several such discussions here on the forum. — T Clark

Do you hold that there is no such thing as objective reality or do you hold that there is no fact of the matter whether there is such a thing or not? The two aren't equivalent.

Incidentally, a debate about the existence of objective reality is exactly what I would call a metaphysical debate.

Those are matters of fact within a particular metaphysical system. — T Clark

In which metaphysical system do the facts which you listed belong?

Our disagreement is fundamentally this. I hold the modern conception of philosophy on which it is continuous with science and ordinary enquiry. Questions about objective reality and correspondence and such are the same kind of question as questions about protons and Julius Ceasar. They are just more straightforward questions about how things stand. By contrast, you hold that these "metaphysical" questions are completely different: they are questions about how it is useful to think, or about how we want to think about ordinary matters of fact. Is this an accurate portrayal of your side?

Hi,

For a minute, let’s discuss what I want metaphysics to be, but which it probably isn’t. At least not entirely – I want it to be the set of rules, assumptions we agree on to allow discussion, reason, to proceed e.g. there is a knowable external, objective reality; truth represents a correspondence between external reality and some representation of it; it’s turtles all the way down; the Tao that can be spoken is not the eternal Tao — T Clark

Most of these theses would be classified as metaphysical ones by tradition. The idea of an objective reality is usually called Realism. The idea of a correspondence between the world and thoughts is also metaphysical (although the debate about whether that's what "truth" is, is semantic). The Tao is much the same. They are all ideas that moderns would have called "special metaphysics". Modern philosophers would have added the existence of God, the nature of the mind, abstract objects and such. You say you don't want to include God because his existence is "a matter of fact" but then, the existence of an objective world is a matter of fact too, as is whether there is any correspondence between thoughts and the world; so would be the suggestion that "its turtles all the way down" if this refers to the myth about what holds up the earth. So I can't see how God's existence is different to any of those on your list.

So, anyway - Metaphysical questions cannot be addressed with yes or no answers. They’re not issues of right or wrong, what matters is usefulness. — T Clark

Why can't the question whether there is an objective world be answered "yes" or "no"? Why not the question whether there is any correspondence between thoughts and the world? You say in a reply to Moliere that these things are issues of "preference", but I don't see how they are issues of preference in any special sense which doesn't apply equally to any more mundane matter of fact.

For me it's not. The existence of procedural, foundational concepts that set the terms of all discussions is central to my idea of what philosophy is. I want to be able to talk about it — T Clark

...

I want a cudgel of metaphysics I can take out and beat my opponents with. (stomps feet, pounds table, face turns red). All you big boys and girls get to say "Kant said this" and "Aristotle wrote that," while all I get to say is "seems to me." — T Clark

You can talk about it, can't you? Several people here have mentioned Collingwood. If you want a philosopher you can quote in discussion who shares your perspective, he would likely be your man. He thinks there are these assumptions of any area of discourse, absolute presuppositions, which can't be proven or disproven, but they make the discourse possible, and he thinks of Metaphysics as the task of describing these for different areas of discourse.

Failure to understand that words are not reality. — T Clark

It seems to me that this is one of the greatest flaws of large swathes of philosophy, academic and otherwise.

So something that's credible is "worthy of our ascent?" Does that mean "true?" "Probably true." This is getting a bit circular. — T Clark

I am still not sure that you understand what I am trying to ask. It is usual to distinguish between beliefs which are, in some sense credible, and beliefs which aren't. Compare the creationist account of human beings with the evolutionary account; or compare me believing that there are exactly 3 million and two blades of grass in Birmingham city centre with your belief that you are looking at a computer screen (I haven't counter, and no one has told me about the grass). In some sense the latter beliefs of each pair are superior to the former; more credible. In what sense exactly? Your remark above accuses me of circularly defining "credible", but I'm not defining credible at all. I am asking someone to tell me the difference between these sorts of belief, and just stipulating that we call that difference "credibility".

Here's a definition of "justification" from the web - The action of showing something to be right or reasonable. In this context, justification is an answer to the question "How do you know that?" Example - I say "John stole the money." You say "How do you know that?" I say "He told me he did it." It doesn't mean it's definitely true, only that I have good reason to believe it. — T Clark

Sure, so the difference between the belief pairs above is that in each case, one item of the pair has "good reason to believe it" and the other doesn't. Is that what you are suggesting?

We are justified in holding a belief, or we are not. There is no percentage roll that makes a belief more or less justified. It simply is, or isn't. — Moliere

Interesting post Moliere. I am tempted to think you are right about probability. So you hold that the difference between, for example, me believing that there are exactly 3 million and two blades of grass in Birmingham city centre and you believing that you are looking at a computer screen (I haven't counter, and no one has told me about the grass), is that you are justified and I am not. Alright, what do you mean by justified?

Hi

If I say a possible event has a high probability I mean I am very confident it will happen, and that I will not be at all surprised if it does happen, and fairly surprised if it doesn't. — andrewk

credibility boils down to another measure of confidence. — andrewk

Thanks for the interesting thoughts. I began by trying to distinguish mere guess work type beliefs from credible beliefs. Contrast the belief that God created humans from nothing, as they currently are, with the belief that humans evolved from prior species over time. On your approach, the only difference between the two is our confidence. We are (I am?) more confident that the evolutionary story is true than the creation story. Evolution is credible just in the sense that we are (I am?) more confident that it is true. Of course, the creationist is more confident that the creation story is true and so the creation story is credible in the sense that he is more confident that it is true. Is this not quite a sceptical result? That no belief is more credible than any other except in the very weak sense that we believe some things and don't believe others? Perhaps you are happy with this.

The test is use, the criteria being, does it work? — tim wood

Is the suggestion here that a credible theory is just one that is useful?

you might try defining your terms — tim wood

Which terms do you want defined? I am trying to figure out whether it makes any sense to think of some beliefs as more credible than others. In what sense is any belief or theory ever more credible than another?

What does it mean that a belief is "credible?" Doesn't it mean there is justification for it? — T Clark

We can say that a belief is more credible - more worthy of our ascent - than another when there is justification for it, but what do you mean by "Justification"? You don't necessarily have to give a definition here, although you could do that. But you could instead illustrate the notion with some examples. That would be helpful.

Aren't you just recapitulating Descartes? I think I probably am therefore I am. — T Clark

I'm not making the cogito argument at all, and as far as I know, Descartes didn't write on probability.

It's useless to look for a tool if you don't know what the job is. Especially for a tool that does everything: that tool doesn't exist. Also, belief is almost always a sign that both certainty and probability are out the window — tim wood

The "tool" I am looking for is one which distinguishes mere guess work from credible belief. A credible belief is one which is probably true, but in what sense of "probably"? We can talk of distinguishing speculation from credible theory if you don't like talk of belief. Can't we say anything more exact than "a credible theory is one which is probable. Probable in some sense or other, but not statistical and not subjective"? That's not particularly illuminating.

Aristotle covered this (from Nicomachean Ethics, but I can't find the quote I'm looking for): it's a mistake to look for more clarity than a subject matter will allow. — tim wood

I know the quote you want, and I agree with it. But it also makes sense to look for clarity wherever possible, if only to stave off the impression that the unclear ideas are really empty words.

Do we need a philosophy? — Philosopher

If only to combat bad philosophy, we need philosophy. People act and judge others on the basis of philosophical ideas. It is best to think about those ideas carefully for that reason.

What philosophical questions are you interested in and why? — Philosopher

Im interested in the idea that some beliefs or theories are more credible than others. I'm also interested in radical scepticism and arguments for /against the existence of God.

philosophy as a science. — Philosopher

It depends what you mean by this. Sometimes when people ask whether something is a science, they are presupposing that "sciences" are special in some way. That is itself philosophically controversial.

Are you suggesting that there's an alternative approach to the problem, or that the problem isn't really a problem at all? — Michael

In a way both. If you want to know what the usual meaning of "knowledge" is then go out and ask people. Do some surveys. Don't just consider thought-experiments among philosophers and assume that those judgements are representative. A number of philosophers have actually taken to using surveys for this recently.

But I also don't really see why some philosophers care so much about what regular people mean by "knowledge". Different people find different things interesting I guess.

Edmund Gettier made the following two assumptions:

1) b is a justified, true belief (JTB-definition of knowledge)
2) b is not knowledge
And therefore, JTB theory is false.

However, this is circular reasoning. Nowhere did Gettier actually prove that b is not knowledge. Gettier's own examples are evidence of knowledge being justified true beliefs. — BlueBanana

It isn't circular. What Gettier does is describe a number of thought-experiments in which the person has justified, true belief. But Gettier is inclined not to use the word "knowledge" to describe those cases. He thinks you will agree with him that it would be odd to use the word "knowledge" to describe those cases. Hence, "knowledge" does not mean "justified true belief".

Incidentally this whole method of doing philosophy I find unhelpful. Arguments of this sort produce vast and endless debates about the "ordinary" meaning of words. Empirical methods are better suited to figuring out whether there is such a thing as the "ordinary" meaning of "knowledge".

Count them. Seriously, just count them. Think of all the times when you've proceeded as if your sense perceptions have been correct, and your desires and expectations have been fulfilled by proceeding on the assumption that they're correct, versus the times you misperceived. You get up in the morning, you see what looks like a toothbrush, you pick it up and find you can brush your teeth with it. You reach for what looks like a door handle and find you can use it to open the door and get out of the house. You go to the train station, you step into what looks like a train and you find it's taken you to what looks like your place of work, which look like it has your workstation, where indeed the work is as you remember leaving it, etc., etc., etc. Maybe on the way home you encounter a situation like this:-

"I thought I saw a banker's clerk descending from a bus,
I looked again and saw it was a hippopotamus."

So there you have a whole slew of desires and expectations fulfilled by taking sense perceptions as veridical, and you have one misperception, one expectation baulked. The ratio I'd say is par for the course for the average day. — gurugeorge

This wasn't quite what I wanted. I understand that you think that one can use a track-record argument for the claim that sense perception is reliable. Sense perception got things right on occasions X, Y, Z, N, N+1... therefore sense perception is reliable. My question is, why believe, in any particular case, that sense perception got it right? I look into my bathroom and form the belief that there is a toothbrush on the sink. Why should I believe that there is? Remember, at this point we haven't established that sense perception is reliable, so we cannot appeal to that. Why, then, should I take it that sense perception is getting things right in this particular instance if I can't take it to be reliable yet? If the track record argument works, there must be some reason to believe its premises.

It's really more that the sceptic or the endless why-questioner isn't quite getting the game. "Why" questions have a limited ambit, always, they're delimited in a given universe of discourse, against a background in which some things are accepted as true. The extrapolation and extension is basically just continually moving the goalposts. — gurugeorge

I think that most sceptics knew perfectly well that they weren't playing the usual 'game' that is played in ordinary life. I don't think that Descartes was foolish enough to think that in ordinary life we pursue why questions all the way through. He even points this out himself in the Meditations. He saw that ordinary discourse involves taking many things for-granted. But his philosophy wasn't a description of discourse in London. It was an attempt to answer all of those why questions that aren't ordinarily answered. In doing this he recognizes that he's pursuing matters much further than they are usually pursued, but he has goals which he thinks are best achieved by doing this.

It seems to me that we are begging the question, as does the formulation 'I think therefore I am'.

What sort of argument is that? Plainly, the conclusion is entailed in the premise! So is the bit after 'therefore' telling us something new? Is 'I am' something more than 'this thought'? If it is, we need something more, some additional premise. Or is it only saying 'I' is synonymous with 'this thought'? — Londoner

When does an argument beg the question? It can't be just when the premise entails the conclusion, for then every deductive argument will be question begging and we will have to say that deduction is always unacceptable. Normally, philosophers say that an argument is question begging when the conclusion itself is the reason cited in support of the premise. The Cogito isn't like that. The premise, "I think" is supported by direct acquaintance. I am directly acquainted with the fact that I am thinking. Hence, the premise is not defended by appeal to the conclusion.

I expect you will be unhappy with this. You object:

Because, if it is only meant as a synonym, that 'I' seems to quickly take on extra meanings. For example, we shift to talking of 'consciousness', something that is distinct to the 'thought' , we have 'awareness', we have 'particular thoughts', all of which are assuming notions of perception, of personal continuity through time, that were not there in the single original 'a thought'. — Londoner

I don't think any of this is right. When I am directly acquainted with the thought "the bacon smells good", what this establishes is that there is a thought; whether or not it is mine is a further question. But what drives us to the further claim that "I am thinking" is that scepticism itself presupposes a subject. Scepticism is only an issue if it is possible that my beliefs might be mistaken, but if there is no "me" then there is no such thing as "my" beliefs and ipso facto no possibility of my beliefs being mistaken. Either I exist and am not mistaken that I exist, or I don't exist and (obviously) am not mistaken that I exist. I can't be mistaken that I exist. I have not here used the word "consciousness" or assumed continuity through time, as you say that the cogito must.

Indeed, there is no need for a 'you' to be involved at all, that reaction to the bacon need be no different in kind to a chemical reaction, where we find no need to posit that there is a 'you' within each chemical that is 'having' that reaction. Or, if we did extend 'you' to such things, that is not the sort of 'you' we were trying to get to, the one with 'consciousness'. — Londoner

I deny that thoughts are just chemical reactions, but that is really besides the point. Whether a thought is a chemical or not, that I exist is a preupposition of scepticism. That is why it is posited. If you don't like talking of consciousness and you like talk of chemical reactions, I think you miss something very important, but it doesn't really matter for this argument. For all that has been said, I might just be a mass of chemicals and lumps of flesh, but what is certain is that I, whatever I am, exist.

Hi, . Nice to meet you.

But if it is 'before your mind' then you are not directly acquainted with it. We would have two separate things, subject (your mind) and object (your thought). 'Consciousness' would then just be another object of perception and we certainly can doubt any object of perception. Or if we can't, why wouldn't it apply equally to any object before our mind? 'I see a doughnut, therefore I exist'. — Londoner

I did not intend to say that I am ever directly acquainted with consciousness (I think that I am, but it isn't part of my argument that I am). I meant to say that I am directly acquainted with a particular thought of mine. For instance, I can be acquainted with my thought "The bacon smells good", simply because the thought passes right through my conscious awareness. This is how one knows that one is thinking - by being directly acquainted with particular thoughts. It is true that in this act of acquaintance there are two relata - the subject (me) and the object (my thought), but I don't see why you would infer from this that I am not directly acquainted with my thoughts. You say that "we can certainly doubt any object of perception". I am not sure about this. Many philosophers think that it makes sense to doubt a proposition like "there is a doughnut", when you see one. I am not sure that it does, but I leave that aside. I would insist, however, that when you are acquainted with the thought "the bacon smells good", it makes no sense to doubt that you are thinking that thought. The thought is present to your mind in such a way as to make the suggestion that you are not having that thought unintelligible.

In practice I am always conscious-of some thing, I am always thinking-of some thing. — Londoner

Indeed, and that is how I know that I am thinking.

To conclude from 'I think' that 'I exist' — Londoner

As I rendered the Cogito, it doesn't involve inferring "I exist" from "I think". My position was that "I exist" is a proposition which it is logically impossible for me to be mistaken about (this is what Descartes is getting at when he says that "I exist" is necessarily true whenever it is entertained in my mind). I agree with your last point that this does not yet establish that the person who I am now is the same person as the person from one second ago, or even that there was such a person one second ago.

You are directly aquainted with the fact that you are thinking. It is right there before your mind, and when something is before the mind in this way, there is just nothing more you could want by way of proof. You consider whether it is possible that someone is controlling your thinking. It is possible, but it follows from that hypothesis that you are thinking! Otherwise, whose thoughts are being controlled?

I do not think that Descartes intended to infer deductively that he exists from "I think". He says as much in his replies to critics. Rather, that you exist is presupposed by the possibility that you might be mistaken. If you are mistaken, then you exist. Hence it is not logically possible that you are mistaken that you exist.

When it is usually asked what evidence there is that there is a God, noone ever says what sort of thing would satisfy them. I could offer the fact that many biblical authors say things which entail that there is a God, but critics will say that doesn't count because I didn't prove that the bible is reliable. I could say that many people claim to have experiences of God, but the critic says that there is no reason to think they aren't hallucinations. I can show that the existence of God follows from various premises, but critics will claim that the premisee haven't been proven. One wonders, then, what is wanted in asking for evidence?

It's deductive inference. This goes back to my point that we posit (punt, bet, conjecture) identities (natures, essences, etc.) for things, then we deduce what ought to eventuate for experience if we have identified the thing correctly (i.e. if the thing has the identity, nature or essence that we think it has) and then we check experience to see if things pan out as we'd expect them to if the thing has the identity we're positing for it.

So for example, if it's a piece of paper, which like all material things, is defined as having the property of existing while we're not perceiving it, then (we deduce that) a camera ought to inform us of the fact that it exists while we don't perceive it. — gurugeorge

This reminds me of Falsificationism. Make a hypothesis, deduce certain predictions. See if the predictions obtain by appeal to experience. If they do, retain the hypothesis. If they don't, the hypothesis is refuted.

Apply this to the view that things exist unperceived (unschmerceived if you like), and unphotographed. The thought would be that we have never experienced anything which refutes that hypothesis, although there is nothing by way of positive reason to support it. Is that your idea?

Now in all the above, I can sense you champing at the bit: you no doubt want to say, "But aren't sense perceptions being used in the very process of checking out whether sense perceptions are reliable?" This seems to be homing in on our disagreement even more: somehow, you think this is circular. But why?) — gurugeorge

Excellent stuff. I was tempted by this thought, and I did write a response explaining why I thought the argument was circular, but I don't think that's right after all. Your argument never uses the premise "sense perception is reliable" and so it isn't logically circular. I'm not sure that the argument is precise enough for me to disagree at this stage.

And you can show that sense perception is in fact reliable because you can distinguish reliable perceptions from unreliable ones, and show that we have more reliable ones than unreliable ones: — gurugeorge

How, exactly, can you distinguish veridical sense perceptions from non-veridical ones? And how can you show that we have more of the former than the latter?

This is the crux of it. If you can do that, then you have an answer to those pesky "why" questions.

Btw, I can't resist it: if Descartes relentlessly asks "why?" then ultimately he's in the position of the child relentlessly asking "why?" in the comedian Louis CK's skit, and his intelocutor is entitled to lose patience with him at some point: "WHY? Aw fuck you, eat your french fries you little shit, goddamit." — gurugeorge

My old supervisor criticized my conception of skepticism for being "childish". I agree that there is a parallel between the child's constant questioning and the sceptical one. But I don't see why that makes the sceptical questioning objectionable. It isn't as though if children do P, then necessarily P isn't sensible.

So why is it rational to doubt without reason, yet not to believe without reason? — Banno

The word "rational" is vague. I think a philosophical tradition that starts in Socrates and is carried through by various people to Descartes and - in some places - to Russell, defines rational belief as belief for which one has good reasons to hold. I don't think that is the "ordinary" meaning if there even is such a thing as that - I doubt it. But it is a good thing to have reasons for the things you believe and so good to strive to have them wherever possible.

But philosophy consists in words, so a philosophical discussion ought take words seriously — Banno

In one sense philosophy does consist in words. Philosophical doctrines are always expressed in words. But then, any doctrine is a doctrine expressed in words. Scientific theories are expressed in words. Should they also "take words seriously"? And what is involved in "taking words seriously" anyway? I agree if you mean that a philosopher should take great care to define his terms for his purposes and to be clear about what he is doing and what he is trying to say.

In another sense philosophy does not consist in words. Philosophy isn't about words - or maybe I should say, worthwhile philosophy isn't.

We use them at least in part, in combination with a desire, to provide explanations for behaviour. — Banno

I agree. Is this the kind of thing you want? A list of things that beliefs are used for?

the only reason why you think you were subject to an illusion (or why Descartes noticed he'd been in error about various things) is because of some corrective perception that reveals that your previous perception was an illusion. Therefore you're already implicitly allowing the validity of at least some sense perceptions: the corrective sense perceptions at least must be valid, for the illusion to be genuinely an illusion. Therefore you can't use the argument from illusion to globally doubt the validity of sense perception on the basis that sometimes you're subject to illusion. — gurugeorge

Thanks for the reply guru. It seems we are slowly isolating the key disagreements between us. Here is one of them. You think that what Descartes does is something like this. He first notices that he has sometimes been mistaken. From this fact he extrapolates that he might be mistaken in any given instance, and that is why he suspends judgement prior to finding his proof of God's existence and such. If this were how he was thinking, then I'd say you would be right that to get this started, he has to take fore-granted that at least some of his sensory experiences are veridical. It seems right to me to say that he can't really do that unless he is already assuming the reliability of sense perception, and so that assumption would be a presupposition of the possibility of his doubting it. A remarkable transcendental argument against scepticism!

My reply would be that even if Descartes did proceed in the way you think, he need not have done so. Descartes need not assume that sometimes he is mistaken, in order to ask "why believe that sense perception is reliable?". He can simply ask it, can he not? Of course, he cannot sensibly ask it if he is also assuming that sense perception is never mistaken or if he is assuming that sense perception is reliable. But he need not assume that. He can simply raise, relentlessly, with respect to every opinion he has, "why believe that?", until he reaches some beliefs for which this question cannot meaningfully be posed.

But, given your initial remarks about "getting the idea that there is an anomaly" in one's model, perhaps you think that for some reason Descartes cannot sensibly raise this question about the reliability of sense perception. It would be great if that were so, but how could it be?

Best
PA

I should say my piece in favour of Descartes' method.

I think it's right to say that Descartes was looking for indubitable truths to serve as foundations from which he could infer anything else he was going to believe. He begins the search by considering his cognitions in general and, in particular, his sensory experiences. He tries to locate cognitions that are self-certifying. An explication of "self-certifying" is best found by illustration. Consider the practice of gazing into a crystal ball in order to contact the dead. The gazer comes to form various beliefs about what the dead are saying. It is possible to ask why we should take what the gazer says at all seriously. Why should we think that what he says is true? He will likely retreat back to the claim that his crystal ball allows him to contact the dead, but we will immediately wonder why we should take this at all seriously. Why should we think that his crystal ball is reliable about these things? If we cannot find any answer to that question, there is a sense in which we will fail to assure ourselves that what the gazer says is true. That is, there will be a "why" question which he simply cannot answer.

All of these same issues arise for any and every method of belief formation. For example, I might answer a why question about my belief that there is a laptop in front of me by saying that I can see one, but this will lead to the question of why I should take sense perception to be reliable. I read Descartes as noticing this fact, that someone who is genuinely curious about the truth of their beliefs in general will raise why questions about any and every such belief. He seeks a way out of it - to satisfy his curiosity about the truth of his beliefs. To that end, he looks for beliefs about which a further why question makes no sense. He then tries to build the rest of his philosophy on top of those beliefs. His criterion for foundations ends up being clarity and distinctness. He thinks that when something is, in some sense, clear and distinct, there is no further question it makes sense to ask about why it should be accepted. He also thought that propositions that were clear and distinct were absolutely certain, but we should note that whether or not clear and distinct propositions are such that no further why question makes sense about them, and whether or not they are absolutely certain are logically two completely different matters.

Many people think something like the following about Descartes. Descartes is lead into solipsism because he requires absolute certainty for his beliefs. If you don't require absolute certainty, then you can escape and believe everything that you normally do. Doubt is thus just a silly game of demanding certainty when it isn't needed. It is true that Descartes pursues absolute certainty in the Meditations. His foundations are absolutely certain, and he insists only on deductive inference which would preserve certainty. But it isn't true that just by abandoning that standard you can avoid the issues Descartes gets himself into. Suppose that we relax the standard of certainty to probability. We could then, in principle, allow merely probable foundations and probable inferences. We are still limited, however, to propositions such that no further why question makes sense. Philosophers who have relaxed the standard seem to me to have failed far worse than Descartes ever did. They either fail to recognize that intelligible "why" questions can still be raised about their foundations or they simply don't see the regress of why questions; they only see certainty, and dismiss Descartes for being obsessed with certainty.

From this perspective, consider Gurugeorge's Model Building ideas:

you are creating an internally-consistent projection or model of how the world is, that you then test against eventuating reality. There's mathematical certainty, deductive certainty, within the model and the implications for testing that you can draw from it. But you can never be certain that the model you're using is the right model for the occasion. — gurugeorge

How does a model get "tested against reality"?

an anomaly crops up in experience, which means that there must be something wrong with the model you've been assuming to be true up till now; so then you figure out some other possible model for the world, and match your two models against each other, and filter the right one out on the basis of homely, perceptual level truths (measurements, meter readings, etc.) that you are less doubtful about. — gurugeorge

These ideas obviously assume that sense perception is reliable, and it is painfully easy to ask, why think that sense perception is reliable? And Gurugeorge seemingly has no answer to this question. The model building idea strikes me as very similar to Falsificationism, and I am attracted to that doctrine, but it has to be propped up by the claim that sensory experiences yield beliefs about which no further why question can be raised, and (since deduction is needed to deduce that a model is false given certain experiences) the claim that the rules of deductive inference have that status too. There may be ways to make these claims stick, but to do so one would have to employ either Descartes' idea of clarity and distinctness, or something which does the same job of answering that final why question. But those who say that Descartes' was just obsessed with certainty (perhaps guru doesn't hold this), never give such accounts. This is why I think they fail even more than Descartes did.

Now, it might be that part of the model we are building is the assumption that sense perception and deduction are reliable, but if it is, what sense does it make to say that the model itself is tested by appeal to sense experience? To test a model which contains the theory that sense perception and deduction are reliable by appeal to sense perception and deduction is clearly question begging. Thus, these ideas about models always leave one with an unanswered "why" question about the key assumptions of the model. It isn't just that the assumptions aren't absolutely certain. Its worse than that. Its that no reason at all has been given to think the assumptions are true, not even a fallible or probable one.

Hence, construed as an attempt to solve the problem Descartes tried to solve, the model building ideas are a failure. If, however, the model building ideas aren't an attempted solution to that problem, I admit that I have no real idea how to understand them.

I should apologize to for picking on his post as an illustration. I wanted some way to make the Cartesian perspective clear by contrasting it with some other ideas. His post was the most well thought out and lucid of those that seemed appropriate for this purpose.

Best
PA

Did you ignore the rest of my post intentionally? All of the substantive questions I asked were avoided.

I think philosophers in general ought to be more reluctant to take part in these discussions over "what is X?" questions. The debate about the meaning of the word can be endless and fruitless if there are no criteria for a succesful definition and no purpose served by the defining.

PA

I think that it's a little sloppy to split "tree" into types -- it's not like "dream tree" and "real tree" are species of the genus "tree". "Real" does not work exactly in that way. Even when it comes to a logical display of these terms it's not a matter of kinds and categories, but is an operator which ranges over a domain -- some set. — Moliere

But that's just a matter of words, isn't it? I am not particularly bothered whether it is not a "normal" use of the word tree to suppose that something I am aware of in a dream is a tree. I am defining "tree" as "thing which looks a certain way". Both things that I am aware of when asleep and things I am aware of when awake look that way, hence they are trees. I do not really care if the words are being used unusually. You can express the point in Descartes' way if you prefer, by saying that I cannot ever be mistaken that it seems to me that there is a tree, but I could be mistaken about whether there really is a tree or whether I am dreaming. I myself have no objection to his way of putting it either.

It still seems to me that we need to ask what the difference is supposed to be between "really seeing a tree" and "dreaming". My own explication is in terms of "reality" existing even when unperceived and capable of being perceived by other people, whilst dreams satisfy neither requirement. Again I'm not really bothered if that is an ordinary definition. It seems to me that if I could show that a tree exists even when unperceived by me and can be perceived by others, I will not be too bothered whether or not that tree is described as "a dream" or "real". If you think there is still some further question about whether I am dreaming which is important, I'd be interested to hear what it is.

I'd probably hesitate to use dreams as a contrast class to reality. — Moliere

This is my point exactly. Showing that something exists unperceived and such that others can perceive it settles the interesting issue. If a philosopher continues to ask "ah but am I dreaming it?", I don't really know what he wants.

Yes, I have read Quine. Why do you mention that?

I am not assuming that we mustinfer ourselves out of the present moment of experience, or what isnsometines called "solipsism of the present moment".

I make one assumption:

(A) To know whether something which you are presently aware of has a particular property, you must either be aware of that property or able to infer it from what you are aware of.

I add one premise. Say that the property "permenance" is the property something has if and only if it exists when noone is aware of it:

(B) I have never been aware of the property of permenance.

(A) and (B) entail that if I am to know that something has the property of permenance, I must infer it from what I am aware of.

I stress again that this problem doesn't arise for memory, since (A) is not an assumption about memory and the problem only begins given that assumption. I agree that you can raise all sorts of sceptical doubts about memory, but I'm not raising them here. I am only raising the local problem which begins with (A), and I can accept (A) and discuss problems that result from it without raising doubts about everything that I believe.

My earliest memory is of playing with a toy train at Christmas. Neither the train nor the room exist now; I'd have as much difficulty knowing about those things' non-existence outside my present experience as I supposedly have re. knowing about the existence of something outside my present experience. — gurugeorge

You tell me. How do you know that those items don't exist? I didn't raise that problem. There is likely an answer to that question, but I'm not presently discussing it. I have tried to constrain the discussion to the problem which springs from (A). I don't want to drag in all of these other issues because they are separate issues.

both the existence AND the non-existence of things outside my present experience are as problematic as each other - which is to say, not problematic at all. — gurugeorge

That X and Y are both as bad as each other does not entail that neither of them are bad! That Tom and Jones are both less than five feet doesn't entail that neither of them are less than five feet! Isn't this obvious?

you can know by inference. That's what happens with things like the camera test. You might have never seen the piece of paper in question, but be shown a photograph of it that demonstrates its existence. — gurugeorge

I agree you can know by inference. What is the inference? Is it inductive, dedective, inference to the best explanation, what? I've been trying to get you to spell out this inference for me for some time, but you never say what kind of inference it is. It is hard to evaluate the strength of an inference when one doesn't know what the inference is.

Best
PA

What is it, exactly that you want here? When you ask "what is a belief?", I am tempted to read the question semantically as a question about what the word "belief" means. But then, whos meaning is in question? Are you trying to work out what you alone mean? Or what people in general "ordinarily" mean? Or perhaps just what the members of the forum mean? Or perhaps you just want a definition such that everyone on the forum agrees with it.

In any case, what purpose is served by the excersice in defining? (I don't mean to suggest that there is no purpose to it, or that it isn't intrinsically interesting).

Best
PA

You understand what it is I am doing when I use words like "white". I am using them to label certain features of my field of awareness:

you're simply labelling portions of schmerception with tracking labels. ( — gurugeorge

What's wrong with doing this? Why can't I do it? Perhaps:

And then you get to Wittgenstein's point - you can't be sure you're using the same tracking label in the same way now as you did 5 minutes ago, in fact you can't even help yourself to any normal notion of time.) — gurugeorge

The reason I can't do it is because my memory might deceive me. I think I'm using "white" to track a particular feature, but, unbeknownst to me, I was using the label a different way just a moment ago.

Note, this doesn't stop me from using words as labels for parts of my conscious awareness. Rather, if I am a sceptic about memory then I am not entitled to the claim that my words at the moment mean what they did a moment ago, until I have a non-circular justification of memory. While this is an interesting point to make about radical scepticism, it has no bite here. It is possible to doubt whether things exist when I am not aware of them without doubting the reliability of memory. The considerations I put forward (that noone has ever... schmerceived... the property of unschmerceived existence) do not apply to memory. We can simply take memory forgranted and focus on the problem that arises for unschmerceived existence specifically. Here it is again. Say that a thing has the property of independent existence only if it is such that it exists even when noone is perceieving it.

(1) I can know that X has some property P only if I am/was aware of that property at some time (or I have testimony tracing to someone who was aware of if).

(2) I cannot be aware of the property of independent existence.

C. I cannot know that any X has the property of independent existence.

Notice that I can raise this argument without worrying at all about memory.

Hi again

Hrmm... I think you're coming close to contradicting yourself here. Either our perceptions are infallible, in which case I cannot be mistaken when I see a fire, or they are fallible, and I can be mistaken when I see a fire. — Moliere

There is no contradiction. Is Descartes contradicting himself in holding that although he might be mistaken about whether there is really a tree because he might be dreaming, but he cannot be mistaken about whether it seems that there is a tree? I hold the same view but put it differently. His 'seeming tree' is my 'tree'. I cannot be mistaken about whether there is a tree, since, even when I am dreaming, I am directly aware of a tree. I could be mistaken about whether the tree I am aware of is a dream tree or a real tree. I then have an explication of the difference between 'real' and 'dream'.

You say you can't give any definition of "real". That isn't necessarily a problem, but tell me this. Supoose in your dreams last night you saw a dream tree (or seemed to see a tree, if you prefer). It was 200ft tall and had large purple leaves with different animals on every branch. You wake up and go to see some friends. To your surprise, one of them starts telling you about this dream they had. They dreampt about a tree 200ft tall with large purple leaves! Another friend pipes up and begins to describe animals that were in the tree, exactly as you remember it. A last friend, getting very excited, explains that he dreampt the tree too, and he describes faithfully the buildings that surrounded the tree.

Over the next several days each of you dreams about the same tree again, each time sharing the same story with one another. If this happened, would you still insist that the tree which all of you keep dreaming about isn't a "real" tree? What would be the meaning of that?

Best,
PA

There can be no "paper" for schmerception, nor does "photograph" make any sense either. You might be able to single out some portion of the schmerceptual field (my "present kaleidoscope" idea) in some way (perhaps by awareness of shifting boundaries or something like that), but you can't help yourself to the idea that the "paper" portion of the shcmerceptual field has any physical qualities at all — gurugeorge

Of course I can say that the thing which I am aware of is a piece of paper. I am aware of something, and that thing is what I call a "paper". If you don't like my calling it "paper" because you think the ordinary meaning of "paper" presupposes the whole physical backstory, then call it schmaper. I will continue to use the word "paper" and stipulate that I mean the thing that I am aware of, without any physical presuppositions. (I do grow tired of these ordinary language arguments).

Of course I can say that the paper has qualities. It has the qualities I am aware of it having. Squareness, whiteness, thinness, for example.

Therefore the question of whether "it" "exists unperceived" doesn't even make any sense UNTIL you bring in the normal physical backstory — gurugeorge

I really don't see why not.

the normal meaning of "exists unperceived" applies, and the normal tests are sufficient. — gurugeorge

I was always using "exists unperceived" in the normal way". My whole case has been that the ordinary tests are not sufficient to determine that the paper exists unschmerceived and unphotographed. They show only that it exists schmerceived and photographed. Just as looking at the paper cannot establish that it is made of atoms, because merely looking at the paper does not reveal to you the atoms, so too being aware of and photographing the paper does not reveal to you that it exists when you are neither aware nor photographing it.

Another way of saying this might be that the more you chase absolute certainty — gurugeorge

I am not chasing certainty. I am saying that the ordinary test you propose isn't any reason at all, not even a probabalistic one, for thinking that the paper exists unschmercieved and unphotographed.

about which we're punting some possible nature or character, meaning that we've already left the narrow, presuppositionless realm of schmerception, we're already positing that there's more to the world than just schmerception, just the present kaleidoscope. — gurugeorge

I don't really know what "punting" is, but I don't think that is what I do when I say that I am aware of a thing which is white, thin and square. When I say that I simply report what I am aware of, and then I ask whether the thing I am aware of exists when I am not aware of it.

I see that I have spelt perceived several times woth an extra e. Replying on a phone is maybe not ideal.

I see you have continued to stress that the ordinary meaning of "perceived" entails that what is perceived exists when unperceived. I say again that I have never used the word "perceived" in that way, nor any of its relatives, "saw", for example. Wholly apart from that, what is ordinarily meant (by the population at large) by "perceieved" is an empirical question which I don't have the means to settle.

You know by now that what I mean by perceieved is what is given to conscious awareness, and you understand that notion perfectly well since you talk about it extensively in your last post. So I don't see the point of going over this ordinary meaning stuff again. Let's go back to calling it "schmerception".

Does the paper exist when unschmerceived and unphotographed? How can you tell?

We just throw possible natures, possible essences out there and see what sticks - and by this, I mean that we can devise tests on the hypothesis that the object has the nature we project for it, and if those tests pan out then we can say (with whatever degree of confidence, depending on the rigour of the tests) that the object has that nature. And howsoever rickety and lacking in absolute certainty that process is, well we're stuck with it — gurugeorge

It isn't merely that we can't be absolutely certain. It's worse than that. There is no means at all, even a fallible or merely probabalistic one, of establishing that the paper exists when unschmerceived and unphotographed. At least, that's the case if your above quote is a correct account of our situation. If that account is right, the best we can say about the paper is that it exists when schmercieved. It exists when photographed. Maybe it exists when neither of those things is going on. There is no evidence against that hypothesis, but no evidence for it either.

Forgive me for now. I will reply to you tomorrow, since I am out for the day and your post raises some difficult issues.

PA

I share the opinion that Descartes had - that if you doubt whatever cannot be justified non-circularly, you will see that you can use those doubts to discover new truths, or to understand old truths more clearly and distinctly.

I think this view was also held by Bertrand Russell and was the starting point for his logical construction of the world.

It is not so popular in philosophy today, and not on these forums either. Many people here prefer some dosage of "common sense" and Wittgenstein's view that legitimately doubting P requires some evidence against P or, alternatively, that our ordinary methods of verification are somehow exempt from criticism. I am not sure that I really understand these ideas.

PA

The resonance of your footsteps on the floor, and even the micro-audible vibration of the desk as air moves over it, will differ according to how many pieces of paper are in the desk drawer.

In order to talk about things that may have no effect at all on your sensory organs, you need to at the minimum change the focus to objects outside your past light cone, which means objects in distant outer space. There are difficulties there as well, but they are different difficulties. — andrewk

Ah yes, I remember you saying this before. I find that an interesting idea, but there are some issues. Stick with the paper example. Let's agree that the resonance of my footsteps on the floor will differ depending on whether or not there is a paper in the drawer. Well, then I could use specialized equipment to measure the resonance of my footsteps on the floor, and I could infer from observations about the resonance that there must be a paper in the drawer (this argument would be quite complicated I take it, but let's assume for now that it could be worked out cogently). Well that would certainly establish that the paper exists when I am observing those resonances, but clearly I am not always observing them. I am not observing them now, for example. My sensory faculties just aren't refined enough to detect them. Does the paper exist when I'm not observing the resonances? A further inference still seems to be needed.

So the dream-tree does not exist, even when I am seeing it. It is a dream. It doesn't pop in and out of existence. It never existed ever. Yet, upon my perception of it, I certainly believed it to be real.

So our perception of things is not infallible, at least, when it comes to determining if something exists or does not exist.

If you insist on the dream being real, then consider hallucinations, mirages, delusions, and so forth. Our perceptions are surely not infallible when it comes to determining if something is real or not. — Moliere

I am not sure about this, but it is interesting to think about.

Take the dream tree, does it exist? Well, if it doesn't exist then what is it that you are aware of when dreaming? Nothing? But it sure seems like you are aware of something doesn't it? Some qualities are there before your consciousness are they not? If I were to ask you about the dream tree, couldn't you tell me about it? You could tell me "it had a trunk 500 metres high and purple leaves", for example. If you told me that, you would be describing what you were aware of when you dreamt, and you couldn't do that if there were nothing you were aware of when you dreamt, could you? This is what leads me to insist that the dream tree does exist and that the only difference between it and a real tree is that a real tree can be perceived by others and exists unperceived also. In fact, I would go as far as to say that what I mean by "real tree" is " a tree that can be perceived by others and which exists even when no one is perceiving it".

Our perceptions aren't infallible. I can make mistakes in perception, as when I think that a tree is 'real' but it isn't. But what this mistake amounts to is that I thought the tree was such that it could be seen by others and existed even unperceived, and I was wrong on both counts. But, even when I was hallucinating, I couldn't be mistaken that I was seeing a tree - even if it turned out to be a mere hallucination tree. This is essentially Descartes' view that he cannot be mistaken that he seems to see a fire, even though an evil demon might trick him into thinking that there 'really is' a fire. I have just tried to explicate what I mean by 'real' and used this concept instead of Descartes' terminology, because I think his terminology encourages the veil of perception doctrine (I do not think that he actually espoused that doctrine, but his phrasing in an English translation makes it very tempting). Whether you mean the same thing by 'real' I am not sure. It would be interesting to find out what you do mean by 'real' if not my explication, and equally interesting to determine whether dream trees or ordinary trees are 'real' in your sense, and what bearing this would have on our present subject matter.

Thanks for the reply. It seems that you are of the view that I cannot really get what I am asking for. You might be right.

PA

What you are doing is asking for a justification for your belief, and following each suggestion with "But I am still not convinced".

Your failure to be convinced is not our problem. — Banno

I didn't ask for a justification, if that means some proof from premises which I accept. I asked for someone to tell me a story such that, if true, the belief that things exist unperceived was produced by a reliable method or process - a method or process which makes it objectively likely that things exist unperceived. Any story will do, so long as you can convince yourself that it is actually true. You can postulate a special magical faculty deep in your brain that allows you insight into the unobservable, if you can convince yourself that you have such a faculty.

I didn't say I'm not convinced that things exist unperceived either. As it happens I am convinced of it.

So, what difference does that qualification make? — Janus

Induction, deduction and inference to the best explanation vastly increase our knowledge beyond mere perception.

I'm asking whether you regard seeing something as perceiving it, but do not regard hearing something as perceiving it. That seems to be implied by your statement (at the top of this post: ↪PossibleAaran) that we do not perceive a motor that we hear, but that we do perceive a table that we see.

If that is your position, do you think it stands up to scrutiny? I wonder what a blind person would think about the suggestion that they don't perceive anything.

If that is not your position then which side would you alter? Would you agree that we do perceive things that we hear, or that we don't perceive things that we see. I can see no other way out of the difficulty, than one of those two options, although I am open to suggestions. — andrewk

I see your point. Previously I maintained that hearing the motor was not sufficient for reliably detecting its existence. I should not have maintained that. Still, that I hear the motor only establishes that it exists when heard. The paper in my drawer is not heard.

The paper in my hand could very well be a dream paper, after all, which doesn't exist. But it can seem very real. The possibility of error -- the probability -- is close enough to the same (I'm not sure how we could even come up with an actual number here, but just by judgment on my part) that there isn't a difference. — Moliere

What is the difference between a merely dreamt tree and a real tree? I think the answer is two-fold. First, a real tree is a tree which can be perceived by other people, and second, a real tree is a tree which exists even when I am not aware of it. The tree that I see when dreaming cannot be seen by other people and exists only when I am seeing it. When I wake up, the dream tree no longer exists. Now your other question:

what kind of certainty would actually make the existence of the perceived any more certain that the existence of objects after they have been perceived? — Moliere

While an object is being perceived I am directly aware of it. When I am directly aware of P I am - to say the very least - in a good position to tell that P exists. When I am no longer perceiving P, how can I reliably tell that P is still there?

Not sure how you can accept chemistry as scientifically valid without conceding the existence of the atomic world which makes the periodic table what it is. Same with the germ theory of disease, cell biology or neuroscience.

Sure, we have equipment that can make those things perceivable to us, but most of the time atoms, microbes and cells are unperceived. The molecules science says you are made might never have been perceived by anyone. — Marchesk

Didn't we already go over this Marchesk? The existence of atoms can be inferred from things which can be perceived. This suffices to establish that atoms exist whenever we observe ordinary objects like trees, tables and the like. Do the atoms exist when we don't perceive the tree? If they did, the tree would also exist unperceived, since the atoms compose the tree. But my question all along has been how this can be known, even assuming all of our usual methods of confirming things.

Or maybe, just maybe, classical physics works so well precisely because its assumptions about macroscopic objects are accurate! — Aaron R

Perhaps. That sounds like quite a strong argument to me. One issue which I am thinking of is this. Classical Physics can be interpreted in an Idealist fashion, so as not to posit anything which exists unperceived. Doing so would not conflict with any of the available evidence. Presumably then, the Idealist interpretation of classical physics would work just as well as the Realist one would. It is just a contingent truth that we happen to use the Realist interpretation. But then, couldn't this argument of yours be made in favour of Idealism? The fact that the Idealist interpretation works so well is best explained by the hypothesis that it is correct - that things do not exist unperceived. That sounds like just as strong an argument to me. Unless, in some sense, the Realist interpretation works better than the Idealist one. I can't see what sense of 'works better' would be involved though.

You seem to be haunted by the the prospect that you might be wrong. Get used to it. Such is life! — Aaron R

Not at all.

I think our discussion has spun off in too many different directions to be useful. I'll try to simplify, if you will follow me in this. Imagine a dialogue between you and I:

PA: What reliable method is there for determining that things exist unperceived?

GG: If you want to know whether a piece of paper in the drawer exists when you aren't perceiving it, put a camera in the drawer and take a picture.

PA: A camera is an extension of perception. Your camera procedure shows that the paper exists when photographed. Does the paper exist when unperceived and un-photographed? How can that be reliably determined?

I am not sure what you would say at this juncture. Here are some of the things you have said (Or I have interpreted you as saying). I don't know which, if any, fits at this point:

GG1: It is part of the meaning of "perceived" that things perceived always exist unperceived.

GG2: Things perceived do exist when unperceived (and that can be checked by the camera test).

GG3: Perception is the very standard of reliability. Perception and other ordinary procedures like the camera test are "where reliability lives".

GG4: The idea that things might not exist when unperceived is just an imaginary notion. There is no reason to think that it is true, and all the reasons we do have (the camera test) militate against it.

Which of these would you insert in our dialogue, if any? Would you insert something different, or some combination of them?

On your other point about language. I agree that language in ordinary use does not usually have very precise meanings. I also agree that there are relatively stable meanings of words, at least, if we confine ourselves to specific groups of people or cultures. Remember, it is you that insists on the empirical hypothesis that the ordinary meaning of "perceive" entails that things perceived also exist unperceived. It is you that thinks ordinary language is very clear on at least that one point. I am simply pointing out that this is an empirical hypothesis which you have given no evidence for. You have simply assumed that this is part of the ordinary meaning of "perceived" as most people use it, perhaps because that is how you use the word.

To all I am thinking at this point that it is not as clear as I had hoped what the question is that I am asking. I am thinking that perhaps putting the point in terms of "reliability" is not as helpful as I thought it would be. I will try to think of another way to frame the issue. I am open to suggestions.[/b]

Best,
PA

I do take the scientific method to be reliable (dropping issues about "the" scientific method). But it seems to me perfectly possible to interpret the findings of science in an Idealist way, without doing anything that contradicts the evidence. That classic scientific theories assume that things exist unperceived is a kind of bias of those theories. It isn't needed to make sense of them, so far as I can tell. It just requires imagination and the willingness to entertain views which are different to what we ordinarily accept.

There is no knowledge of the world apart from perception. — Janus

Inference from sense perception.

Even perceiving the piece of paper is insufficient to convince some folk that it exists - they suggest brain vats and daemons and such.

What you are convinced by, and what you believe, are up to you. If you refuse to believe that the cup was still in the kitchen that's entirely up to you. — Banno

I know some folk say "well but what if we are brains in a vat", and this possibility is supposed to be an obstacle to my knowledge that there is a piece of paper at the very moment when I am looking at it. Those arguments always assume either (a) a very high standard of knowledge - either absolute certainty or proof from no assumptions, or (b) the veil of perception doctrine. Assuming that we aren't adopting a very high standard, but are sticking to simple de facto reliability, I say that brain-in-a-vat arguments will always presuppose the veil of perception doctrine, and that doctrine is false. Once that is put aside, there is no issue with knowing that there is a piece of paper. The piece of paper is immediately there before my consciousness. When I can see the paper so plainly and clearly in good light at a reasonable distance, I can reliably determine that it is there. I am aware that there are sceptics who question the reliability of sense perception, but I don't do so in this thread. I grant the reliability of sense perception with respect to things perceived, and I say even still there is a difficulty - which I have tried to bring out.

Be aware of what your rejection of such obvious stuff tells us about you. You are one step away from Bedlam. Given your opinion on such arguments as this, we should take care with whatever else you say.

You are following a classic philosophical garden path. It leads to much more poor thinking.

So why should we pay you any attention? — Banno

Take care what PossibleAaran says - he's a real crackpot! Anyway, it isn't 'obvious stuff' at all, except in the weak sense that you and I both believe it with conviction. I asked what reliable method there was for determining it to be true. I still haven't been told what that method is.

At any one time there will be one or two threads here in which some neophyte explains patiently to we dullards that we can't prove anything. — Banno

I never called you a dullard, nor even implied it, and I never maintained that we can't prove anything.

No one is forcing you into this thread Banno. If you don't think the topic is worthy of discussion, you don't have to discuss it. If you think people who discuss it are poor thinkers on their way to bedlam; or crackpots whom you should pay no mind; or worse still, neophytes who aren't as wise as you; there are plenty of other interesting threads.

How is that any different from saying that when you see a table in front of you, you 'blatantly' assume that the table exists - that you assume that there is a cause of the visual sensation that you have of a certain shape, because the visual sensation and the table are not the same thing? By what argument can you move from the visual sensation to the table?

Taking that approach, one has to conclude that every non-mental thing is unperceived, because we only ever perceive the phenomenon, not the noumenon 'behind' it. — andrewk

Thanks for this Andrewk. I think this is an important topic.

You are assuming the veil of perception in these remarks. When the table is in front of me, it is given to my conscious awareness, or more plainly, I see it. I don't merely assume it to be so. Assuming that sense perception is reliable, I can reliably tell that it is there. My point in the OP is that, even assuming that all of our usual methods are reliable, there is still no way to tell that anything exists unperceived. So that's the difference.

That you have assumed a veil of perception is shown by your thought that the table is the "cause of my visual sensation of a certain shape". I don't see a visual sensation of a certain shape. I see a table and the mental process I undergo in seeing it is called a visual experience. And again in your last sentence, "every non-mental thing is unperceived, because we only ever perceive the phenomenon, not the noumenon behind it". But the whole sentence is a mistake, because I can perceive tables and tables aren't mental. There is no noumenon 'behind' the thing which I see, because the thing I see isn't just a picture on a mental screen behind which may or may not be the 'real' table. The veil of perception doctrine - a fascinating doctrine held by many great philosophers. I think it was Austin who said in another context, "it is a very great mistake, and it took a very great philosopher to make it". I apologize if these remarks come across as only cursory. I am happy to have a more lengthy discussion of the veil of perception if you want to defend it, or if you think you haven't presupposed it in the above remarks. For now I am just pointing out what I take to be the difference between scepticism about the objects of sense perception in general and scepticism about things which exist unperceived. The former requires the veil of perception doctrine. The latter doesn't.

Best,
PA

Where all humans with human brains and if some of us are Philosophers than aren't we all? — René Descartes

This was an idea which I was friendly with in my previous post, but I am now doubting the point of saying it. We could count as a philosopher anyone who thinks about certain topics. Then almost everyone will count as a philosopher. But then we could also define "scientist" as anyone who thinks about the nature of the physical world, and then almost everyone will count as a scientist. Perhaps a more careful distinction is one which insists that being a Philosopher requires spending a substantial amount of ones time thinking about certain topics, where "substantial" is left un-explicated.

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.

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

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

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

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.

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

I like 's list of kinds of philosopher. It is pretty inclusive. I'm a philosopher of type A. That is, I read, study and teach philosophy as an academic career. I don't think that's the only sort of philosopher, nor are the people in A always the most interesting on philosophical matters!

In some measure, I suppose everyone is a philosopher. Pretty much everyone you talk to has opinions about what the world is like, the existence of God, the soul, freedom, how we ought to live, what we can know and so on. Some people think about those things more than others. A philosopher is a person that thinks about certain topics. I don't think those topics have much in common, except that answers to some of them naturally encourage certain answers to others.

PA

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

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