But what is Scepticism as you have thought about it? What is its thesis, if it has one? What are its arguments, if there are any? For whom is Scepticism a problem? What is the value of studying it, if anything? — PossibleAaran

Interesting and well written. Small "s" skepticism is a mode of thinking I use all the time if I have to evaluate a claim. 1) Do I believe it? Is it plausible? 2) Does it matter? 3) Is there anything I can do about it? Should I do something about it?

A) If the answer to 1 is yes and the answer 2 is no, I'll accept the claim at least provisionally
B) If 1 is yes, 2 is yes, and 3 is yes, then I'd better get cracking and do something
C) If 1 is yes, 2 is yes, and 3 is no, I'll accept the claim at least provisionally
D) If 1 is no and 2 is no - bell rings - I'm skeptical
E) If 1 is no, 2 is yes, and 3 is yes - I have to put in more effort to figure it out
F) If 1 is no, 2 is yes, and 3 is no - bell rings again - I'm skeptical

As for big "S" Skepticism, I think that's a luxury for people whose problems all fall into categories C, D, and F.

There is supposed to be a general argument which enables us to do this, and it goes by the name Agrippa's Trilemma. The value of scepticism is that it produces first suspension of judgement (epoche) and then peace of mind (ataraxia). — PossibleAaran

This is not skepticism, this is apathy.
Skepticism is the ability to reject the endemic assumption, reject the easy answer, and to examine the question a fresh. Ataraxia is not the end result of skepticism.
Freedom from dogma is the reward of skepticism, but this also goes with potential uncertainty as so often skepticism leads to never allowing yourself the luxury of knowing.

Very well-written OP. I am interested in the theory that the historical origins of scepticism go back to Pyrrho of Elis who is said to have travelled East under the protection of Alexander. He is associated with Pyrrhonism of which Sextus Empiricus was the most notable exponent. I think the sophist-sceptics of the later Academy were of a different stripe.

Pyrrhonism’s main tenet was ‘the cessation of judgement concerning what is not evident’. It was not the positive claim that ‘no-one knows anything’ which results in inevitable contradictions, itself being a knowledge claim. I suppose in a pragmatic sense Pyrrhonism was more like not jumping to, or even drawing, conclusions. And here the significance of Pyrrho’s visit to the East is relevant, as he is said to have learned from what the Greeks called the ‘gymnosophists’, or yogis. The predominant school in Gandhara of those days (a region straddling Afghanistan and Pakistan) was Buddhist, and it was an early centre of what was to become Mahāyāna Buddhism. Buddhism is, perhaps paradoxically from our point of view, quite a sceptical religion; the Buddha himself was arguably a sceptic. And there is a teaching method in Zen Buddhism called 'only don't know', associated with the Korean Kwan Um school, which teaches adopting a 'don't know mind' as an outlook, by 'cutting off discursive thought'. I think that is possibly nearer the intent of the original sceptics than a lot of what is called scepticism nowadays.

Another interesting analysis is by a current professor called Katja Vogt, whose book 'Belief and Truth' is a sceptical analysis of Plato. 'Beliefs, doxai, are deficient cognitive attitudes. In believing something, one accepts some content as true without knowing that it is true; one holds something to be true that could turn out to be false. Since our actions reflect what we hold to be true, holding beliefs is potentially harmful for oneself and others. Accordingly, beliefs are ethically worrisome and even, in the words of Plato’s Socrates, “shameful." . Vogt also authored the piece on Early Scepticism on the SEP.

I think the value of scepticism lies in challenging what we take for granted. I think the inherent trust that modern culture places in naturalism is something certainly deserving of scepticism. But it's difficult to be sceptical about it, because the alternatives to naturalism have generally been dissolved by the 'acid of modernity'. The most common response is really a kind of nihilism - nothing really matters, and that doesn't really matter. And also the sense that the individual is the arbiter of what's real or important. There's a great deal to be sceptical about in this context, but it takes some careful analysis to understand how to go about it.

If I told you, I'd be telling.

Thanks for thoughtful replies

T Clark, I take it that you aren't so interested in Scepticism in any of the forms that I described in my OP? You draw a contrast between "big S Scepticism" and "small s scepticism" where the first, I suppose, is one of the forms of Scepticism I outlined in the OP (or all of them?).

A person is Small s Sceptical about a proposition, P, if and only if either (1) they do not believe that P and think it does not matter whether or not P, or (2) They do not believe that P, they do think it matters whether or not P, but there is 'nothing they can do about it'.

It would be good to get clear on some of this if you wouldn't mind. What is meant by there being 'nothing you can do about it'? Does it mean 'nothing you can do to make it true or false that P'? For example, I can act so as to make it true that I am eating an apple, or I can act so as to make it false. But in the case of Descartes being a Frenchman, there is nothing I can do to make it false that he was a Frenchman. Is that what you had in mind? Or did you mean 'nothing you can do about it' in the sense of there being no important implications for your actions whether or not P. For instance, it makes no difference to how I act whether or not Descartes was a Frenchman. These are just my two guesses. Perhaps you meant something else.

On the topic of Big S Scepticism, I am not sure what you meant by that at all. Like I said, it would have been taken to mean any one of the types of Scepticism which I outlined in the OP, but you didn't say which; or it could be taken to mean all of them. What you did say about Big S Scepticism is that you think:

that's a luxury for people whose problems all fall into categories C, D, and F. — T Clark

Big S Scepticism about P, then, is an issue which arises if and only if (1) you believe that P, it matters whether or not P, but there is nothing you can do about it, or (2) you don't believe P and it doesn't matter whether or not P, or (3) You don't believe that P, it does matter whether or not P, but there is nothing you can do about it. The troublesome phrase enters here again, 'nothing you can do about it', but that aside, if Big S Scepticism only arises in these conditions, I am not sure it is any of the types I outlined in the OP. Just one example, my last kind of scepticism which arises for Realism when combined with Empiricism. If its true that no one has ever observed the property of unperceived existence, and it can't be inferred from things which can be observed, it will turn out that we have no reliable means of establishing Realism at all. It would be a mere guess, akin to if I were take a stab in the dark at how many blades of grass are in Birmingham city centre. That issue doesn't seem to presuppose (1), (2) or (3). It might be an issue only if I believe Realism, but I'm not sure of the relevance of the other conditions. I think this same kind of thing can be said about all of the other kinds I sketched, which leaves me unsure what Big S Scepticism is, as you understand it.

Charleton, I doubt that its useful to argue over 'what scepticism is'. Philosophers often refer to 'the' problem of scepticism, but I doubt there is such a thing. As my OP illustrates, philosophers have discussed quite different things under the label 'scepticism' and for quite different purposes. You quote my summary of ancient scepticism and write that:

This is not skepticism, this is apathy. — charleton

But this was what scepticism was for the ancients, and certainly for Sextus.

Your substantive remarks were:

Skepticism is the ability to reject the endemic assumption, reject the easy answer, and to examine the question a fresh. Ataraxia is not the end result of skepticism.
Freedom from dogma is the reward of skepticism, but this also goes with potential uncertainty as so often skepticism leads to never allowing yourself the luxury of knowing.

Scepticism as you understand it is an ability, much like for the ancients. For you it is the ability to reject 'the endemic assumption and examine the question a fresh'. Again, I think you are much closer to ancient scepticism than your initial remarks suggest, since this is just what they did. I do agree with you that you can't get Ataraxia through this kind of thing, but you can get freedom from dogma.

Wayfarer, Sextus, at least, idolizes Pyrrho as the originator of scepticism. As I understand it, the Pyrrhonian school was a splinter of the Academy. The Academy immediately after Plato held that nothing could be known and, even more radically, that nothing was any more plausible than anything else. The early leaders of that school, Arcesilaus and Carneades were thought to be capable of arguing equally well on either side of any question, and they frequently did just that in public. They had both also been heavily critical of the Stoics, who had originally held both that some things could be known for certain and that some things were more plausible than others, and supplied a criterion for this. The later Academics interpreted Carneades less sceptically, and this lead to a weakening of the doctrine and to the acceptance that some things were more plausible than others. Aenesidemus and a number of others are thought to have dissented from the weakening, and split off, taking Pyrrho as their hero, and embracing an even more radical scepticism than even the early Academy. All this, if you believe the account in Bailey's 'Sextus Empiricus and Pyrrhonian Scepticism'.

Pyrrhonism’s main tenet was ‘the cessation of judgement concerning what is not evident’. — Wayfarer

But then, Sextus' account of what 'the evident' is amounts to the beliefs, traditions, laws and customs of the society in which he belongs. About these, Sextus will not suspend judgement, but this is only because he has to live his life and cannot do so in complete suspension; a criticism which was pressed by the Stoics and Aristotle and just about everybody! But, although Sextus will not suspend judgement on those things, he denies that he accepts them in the same sense that dogmatists do. He just 'goes along with' these things for the sake of life, without making any claim to their absolute truth. I am not sure what you would make of this interpretation of Sextus, but it seems to me right.

You also drew some parallels between forms of Buddhism and ancient scepticism and I think you are spot on about that. Most thinkers have lost that element of scepticism these days. See Charleton above, as a case in point. I tend to agree with him/her that you can't get the kind of peace of mind those Buddhists and sceptics thought you could get from the 'don't know attitude', but I have found that the freedom from dogma that comes with the attitude does, at least, lessen my anxiety about certain topics, to wit, religion, morality and politics.

I think the value of scepticism lies in challenging what we take for granted. I think the inherent trust that modern culture places in naturalism is something certainly deserving of scepticism. But it's difficult to be sceptical about it, because the alternatives to naturalism have generally been dissolved by the 'acid of modernity'. The most common response is really a kind of nihilism - nothing really matters, and that doesn't really matter. And also the sense that the individual is the arbiter of what's real or important. There's a great deal to be sceptical about in this context, but it takes some careful analysis to understand how to go about it. — Wayfarer

I largely agree with this. Naturalism has far too easy a time these days, with few sceptical challengers. Your acid metaphor is apt, since what tends to happen these days is alternatives to Naturalism are scoffed at and treated as absurd. I cannot count the number of articles I have read in which Idealism is dismissed as unbelievable, incredible, 'dead', or just plain silly. Theism gets a similar treatment, though to a lesser degree because it has been defended as of late by some capable philosophers. What tends to happen with Naturalism is that anyone who dares raise a challenge to it is insulted and discredited ad hominem. Thomas Nagel is an excellent philosopher, and there are few who would deny it. But his book 'Mind and Cosmos' puts principle tenets of Naturalism under serious pressure and for that he got a number of reviews with remarks like 'what has gotten into Thomas Nagel?', 'irresponsible', 'ignorant of science' and 'dangerous to children'. This, together with the vagueness of Naturalism itself, make challenges to it difficult.

Thanks. I am an admirer of Nagel also, and often bring up that book on the Forum. I also like his book The Last Word, which contains an essay on Evolutionary Naturalism and the Fear of Religion that I also reference frequently.

He just 'goes along with' these things for the sake of life, without making any claim to their absolute truth. I am not sure what you would make of this interpretation of Sextus, but it seems to me right. — PossibleAaran

A sensible approach, close to pragmatism. Again from Buddhism, and also found in the medieval Islamists, there is a device called 'the two truths' (called in Averroes the 'double truth'). This refers to the idea that there is a domain of conventional truth, (samvrti satya), which is the realm of conventional understanding, laws and even science (bearing in mind this was an ancient philosophy). The realm of transcendent truth (paramartha satya) was the domain of the Buddha's understanding. I think it enabled that kind of pragmatic adjustment to the realities of conventional life whilst still maintaining the proper relationship between the sacred and the profane.

In my reading about the life of Pyrrho, there are interesting anecdotes about his demeanour when he came back from the East - that he had to be looked after as he showed no sense of concern for his physical well-being, and also that he was highly tolerant to physical pain and discomfort. I think it's a hint that the 'suspension of judgement' went far deeper than simply the discursive.

According to an early Bertrand Russell, Scepticism arises because of the veil of perception. What we are aware of in sense perception is an image or 'sense datum', which only exists whilst we are aware of it. If this is so, we are never aware of physical objects - since these are supposed to exist independently of us. Since no one has ever seen a physical object before, but only an image of one in the mind, how does anyone know that there is a physical object which is like the image? On the empiricist assumption that our basic reliable belief forming methods are sense perception and inference, if we cannot infer physical objects from sense data, we cannot establish their existence by any reliable means. (Notice that I put this point in terms of reliability and not knowledge. This is to illustrate that you cannot escape the sort of scepticism Russell faced just by defining 'knowledge' as 'reliably produced true belief', as some philosophers have done. — PossibleAaran

Or one could attack the veil of perception and the notion that we perceive sense datum instead of the objects themselves. Direct realism has an easy answer to external world skepticism. It denies the starting point for getting skepticism off the ground. And you don't need idealism as an answer to skepticism if we're already perceiving physical objects, obviously.

The difficulty for direct realism is accounting for various aspects of perception and experience that led to skepticism in the first place. But this effort has continued to the present day. Direct realism is defended by some modern philosophers. It was never actually defeated, just called into serious question.

Wayfarer, I haven't read The Last Word, but I just did a quick google. It looks like it contains critiques of both Naturalism and Relativism, and that interests me greatly. I agree with Nagel on many things, and so I'm surprised I missed this one. Thanks for pointing me that way.

In my reading about the life of Pyrrho, there are interesting anecdotes about his demeanour when he came back from the East - that he had to be looked after as he showed no sense of concern for his physical well-being, and also that he was highly tolerant to physical pain and discomfort. I think it's a hint that the 'suspension of judgement' went far deeper than simply the discursive. — Wayfarer

The story I find most entertaining is that Pyrrho had to be protected by his friends at all times even just walking down the street because of his complete disregard. He would walk without stopping toward deep lakes and refuse to move out of the way of horses! I think you are right that his suspension was perfectly general. Most of his followers thought his style of life was ultimately unmanageable and undesirable, which I think is what lead to the 'going along with' beliefs of common life. This attitude of 'going along with' seems to give the sceptic who practices it a kind of hollow appearance. He says officially that he does not believe these things, but behaves for all the world as though he did. I don't know how much force a criticism like this really has. I suspect such a sceptic wouldn't be too concerned by the charge of hollowness.

Marchesk

Or one could attack the veil of perception and the notion that we perceive sense datum instead of the objects themselves. Direct realism has an easy answer to external world skepticism. It denies the starting point for getting skepticism off the ground. And you don't need idealism as an answer to skepticism if we're already perceiving physical objects, obviously.

The difficulty for direct realism is accounting for various aspects of perception and experience that led to skepticism in the first place. But this effort has continued to the present day. Direct realism is defended by some modern philosophers. It was never actually defeated, just called into serious question. — Marchesk

That is the way many philosophers attack the sort of scepticism which Russell sets up with his veil. But I suggest that you have made a mistake if you think that there is no problem of external world scepticism once you reject the veil. I briefly indicated this in the last paragraph of my OP, but let me try a little more carefully. Suppose Direct Realism is true. In that case, this, which I am looking at right now is a 'physical object' and not a 'sense datum'. It is also what I call a 'laptop'. I can observe that my laptop has various properties. It is black. It is rectangular. It has a screen and keys. All of this I can observe and reliably believe. But now suppose I close my eyes. I am in this room alone at present. Is there still a laptop there even though no one is perceiving it any longer? If I am a Realist, I want to say 'obviously yes', but by what reliable method can I sensibly believe that? If Empiricism is true, my only reliable sources of belief about the world outside of my mind are sense perception and inference. I have never observed that the laptop exists unperceived, like I have observed that it is rectangular. So I cannot sensibly believe this on the basis of sense perception. But now we are back to the problem which is set up by the veil. That is, now I need some means of inferring that the laptop exists when unperceived; an inference starting with the data that I do observe. The problem of inferring mind-independent objects from the data we observe reappears, but this time we haven't presupposed a veil of perception.

Thanks to both of you for your replies.
PA

ut now suppose I close my eyes. I am in this room alone at present. Is there still a laptop there even though no one is perceiving it any longer? If I am a Realist, I want to say 'obviously yes', but by what reliable method can I sensibly believe that? — PossibleAaran

When you close your eyes, is the room still there? The floor beneath your feet? The Earth hurtling around the Sun? Radiation from the sun keeping the atmosphere warm? Is anyone or anything there? Or just what you feel or hear or smell when you close your eyes? Does the back of your head even exist when you're not seeing it in a mirror?

Does it all come back just because you opened your eyes? Do things only exist for you as you perceive them? Does the starlight and dinosaur bones and tombstones and picture of your birth only exist when you look at them? Does whatever is causing that smell only exist when you finally see or touch it?

You can adopt that form of skepticism just like you could argue that we can't know everything popped into existence five minutes ago with the appearance of age and memories intact. And to use Russell, you could also say there is a giant orbiting teapot. But what's the point of that sort of skepticism? To demonstrate that you can be a doubting Descartes?

The much more likely answer is that our perceptions are possible because there exists an entire world full of people, objects and events to perceive that persists over time. That world is primary, not our perceptions of it.

Marchesk

Thanks again,

This reply which you have given is a common and understandable one, but I think it makes some subtle confusions which once made clear, reveal that a much more careful analysis is needed to deal with scepticism than this one that you have given.

The questions you ask beginning "when you close your eyes" and ending "finally see or touch it" are more ways of raising the same sceptical issue I raised about my laptop, so these are not at issue. But you go on:

You can adopt that form of skepticism just like you could argue that we can't know everything popped into existence five minutes ago with the appearance of age and memories intact. And to use Russell, you could also say there is a giant orbiting teapot. But what's the point of that sort of skepticism? To demonstrate that you can be a doubting Descartes? — Marchesk

Now these questions are very different. My original question was "by what reliable method can you believe that the laptop exists when it is unperceived?". What creates the difficulty is the Empiricist claim that there are only two reliable sources of belief about the physical world - sense perception and inference. Sense perception is reliable with respect to things which can be sensed. Sense perception does not reliably yield true beliefs about unobservables. I cannot use sense perception alone to reliably form the belief that there is exactly one alien insect on the furthest planet from earth. I have never observed any such thing, and sense perception is only reliable concerning things which have been sensed. That is why sense perception cannot deliver a reliable belief that the laptop exists unperceived - because the property of unperceived existence is unobservable. This only leaves inference, which is why there needs to be an inference from the observed laptop to its unobserved existence.

Notice crucially that the way I framed the issue above is not me being a 'doubting Descartes'. I am not simply doubting everything that can be doubted for the sake of it, regardless of whether it is probable or not. When I, playing the role of sceptic, doubt that the laptop exists unperceived, I doubt something which, if we cannot provide an inferential argument for it, there is absolutely no reliable basis for accepting. If no inference is provided, human beings have no reliable means of establishing that any object exists unperceived, not even with the slightest probability. So much for your criticism that I am pointlessly being a 'doubting Descartes'. I am being no more a 'doubting Descartes' than someone who refuses to accept the existence of atoms on the basis of plain unaided observations of trees and rocks. Without a scientific inference, such a person has no reliable means of figuring out that there are atoms at all.

You also raise a number of issues about memory. Your thought is that perhaps the world popped into existence 5 minutes ago with the appearance of age. Well, I seem to remember that the world existed at least ten minutes ago, when I ate meatballs. Of course, a doubting Descartes might question the reliability of memory. He might say "oh but maybe your memory is deceiving you and the world was created 5 minutes ago". He could say that, but that would be to raise a very different kind of sceptical problem than the kind I am trying to raise. My problem is that, even assuming all of the usual human faculties are reliable sources of belief, there is no reliable basis for the belief that an object exists unperceived, unless an inferential argument can be given. Hence, the issue I raise for sense perception has no parallel for memory. Memory is a reliable source of belief about the past. Sense perception is reliable about things that can be sensed, but is not a reliable source of belief about unobservables, and the property of unperceived existence is an unobservable. Hence, there is a difference between the radical sceptical issue you raised about memory and the issue I raised about sense perception.

Lastly, you write:

The much more likely answer is that our perceptions are possible because there exists an entire world full of people, objects and events to perceive that persists over time. That world is primary, not our perceptions of it. — Marchesk

But what makes it more likely? There are many alternative hypotheses which explain the observable data, and I'm sure you are familiar with them. The dream hypothesis. The evil demon hypothesis. Etc. What makes these worse off than Realism?

PA

Let's say your laptop is performing some computation that you can't carry out in your mind. You close your eyes and when you open them, the laptop has an answer for you. How did it compute that answer while it no longer existed?

We can make the thought experiment more involved. Let's say your survival depends on the laptop performing some computation. If it fails to when you close your eyes, then a bomb goes off, killing you. You close your eyes. No laptop, no bomb, except for that ticking sound.

That's why idealism is silly. You either end up with an extremely gappy world in between perception where events somehow still appeared to have happened, or you have to invoke something like God to keep the laptop and everything else in existence. We know what Berkeley opted for.

But what makes it more likely? There are many alternative hypotheses which explain the observable data, and I'm sure you are familiar with them. The dream hypothesis. The evil demon hypothesis. Etc. What makes these worse off than Realism? — PossibleAaran

The dream hypothesis fails because dreams are not like waking experience. The evil demon hypothesis has nothing empirical in its favor, unlike laptops and trees and what not. We can't infer an evil demon, a simulation, or being a brain in a vat from what is perceived. But we can infer a physical world. The laptop performs the computation when you close it's eyes because it's still there. Simple as that.

Kuddos for a well thought out OP. As you mention, Skepticism as term and denotation carries with it a multitude of often divergent meanings, each endowed with its own bundle of understandings. Many paradigms—be they adopted or rejected—thereby become expressible via this one word.

In relation to the OP’s questions, as for myself, I liken philosophical skepticism with the simple, commonsensical affirmation that no one is ever perfectly infallible. It doesn’t prove the unmitigated certainty of any belief—regardless of whether these are positively or negatively affirmed. Instead, it endows the intellect with tools via which emotively held, non-contemplated absolutes (or, in this sense, dogmas) become replaced with beliefs upheld on grounds of their greater quality of justification—justified beliefs that then, in turn, become emotively lived until even more coherent beliefs may be established through similar noncontradictory justifications. So, as I interpret it, the stance opens up the doorways of the intellect, of cognitive perception, to most everything holding conceivable alternatives—and the alternative one upholds to be true, this at expense of all other alternatives then being judged false, becomes so upheld due to coherent reasoning—and not, for example, due to blind bias (again, dogma in this sense of the word). In other words, it makes one more perceptive by comparison to the tunnel vision of not mentally seeing the alternatives that otherwise can be discerned.

BTW, to me this stance has no bearing on the possession of knowledge … not unless one denotes knowledge as something that is directly or indirectly equivalent with some epistemological absolute: be this absolute certainty, absolute justification, absolute awareness of what is true and/or real, etc. To me the lack of epistemological absolutes does not then signify the lack of reliable epistemological givens. It is only in this equivocal sense that phrases such as “I know I know nothing,” can make any sense to me.

As I have been thinking of it the last few days, Scepticism is a problem for Realism - the view that there are objects which exist even when no-one is perceiving, thinking or talking about them. — PossibleAaran

That there factually is an external world can well be upheld by a Skeptic on grounds that it is the most cohesive means of justifying most of the whys and hows that apply to any particular experience of the external world. This especially when considering issues of causation.The reality of an external world, in other words, can be well upheld to provide the greatest explanatory power to the greatest number of questions that could be asked of something experienced to pertain to an external world. Still—in contradiction to some of my good natured nemeses here about—for a Skeptic to uphold the factual reality of an external world is not for him/her to also necessarily uphold that the external world is metaphysically primary to the metaphysical reality of psyche; i.e., just because individual minds are subject to the physical external world does not then entail that physicality is primary to psyche at metaphysical levels of reality (nor does the latter alternative entail theism).

Basically wanted to mention that this was a nice OP and add some comments. If I’m replied to, though, it might take a while till I answer in turn.

didn’t all philosophy start off as direct realism?

Marchesk, I thought that you were maintaining that no inference was needed? In any case, I am not sure that the argument you suggest is subtle enough to do the job. Here is what you said:

Let's say your laptop is performing some computation that you can't carry out in your mind. You close your eyes and when you open them, the laptop has an answer for you. How did it compute that answer while it no longer existed?

We can make the thought experiment more involved. Let's say your survival depends on the laptop performing some computation. If it fails to when you close your eyes, then a bomb goes off, killing you. You close your eyes. No laptop, no bomb, except for that ticking sound.

That's why idealism is silly. You either end up with an extremely gappy world in between perception where events somehow still appeared to have happened, or you have to invoke something like God to keep the laptop and everything else in existence. We know what Berkeley opted for. — Marchesk

The first thing to note is that your characterization of the data is already biased in favour of Realism. You presuppose that the object which is before me when I look the first time is numerically the same object as the one which is before me when I look the 2nd time, and that already screams out that the object existed when I wasn't looking, or else, how could the same laptop have changed state while not existing, as you point out? But this isn't a fault with Idealistic hypotheses. It is a bias in your description. Describe the data without the assumption that the laptop is the same each time and the difficulty disappears:

My eyes are open at time T1 and I see that a laptop is in state X. I close my eyes and reopen them at T2 and I see that a laptop is in state Y. It is a Realistic bias to interpret this by saying that 'it looks like something happened when I wasn't looking'. Neither what I see at T1, nor what I see at T2, yields this information. So what explains the fact that I see something different each time? It could be that there is no explanation. That I see something different at T1 and T2 might be a brute fact about the universe. There might not be a single object, the laptop, whose different states I see at T1 and T2 which has some state or other even when I'm not looking. This doesn't require that the laptop changed over time when I wasn't looking even though it didn't exist. The Idealist doesn't postulate the laptop at all. Hence, Idealism doesn't lead to the kind of gappy absurdity that you suggest.

The dream hypothesis fails because dreams are not like waking experience. The evil demon hypothesis has nothing empirical in its favor, unlike laptops and trees and what not. We can't infer an evil demon, a simulation, or being a brain in a vat from what is perceived. But we can infer a physical world. The laptop performs the computation when you close it's eyes because it's still there. Simple as that. — Marchesk

Concerning alternative sceptical scenarios, it is true that ordinary dreams aren't like waking experience in a sense. But they are alike in an important respect. When I dream, I see things which do not exist when I am not seeing them. For dream objects, esse is percipi. Moreover, my mind is the cause of the dream and all of the dream objects. The dream hypothesis is the idea that (i) the objects seen while awake only exist when I am sensing them and (ii) my mind is the cause of the existence of all of those objects. The evil demon hypothesis is (i) together with (iii) an evil demon is the cause of the existence of all of those objects. What exactly is wrong with these two hypotheses? Why can we sensibly infer Realism as opposed to them? Sure, you say that Realism can be inferred and these can't, 'simple as that'. But that's just saying, and I could just say that the dream hypothesis is better than Realism, or that all of them are equally likely. Why is Realism to be preferred?

Javra, it pleases me to hear someone give the explanatory defence of Realism. I think if anything can answer the scepticism I alluded to in my OP last paragraph, it is this. But difficulties do remain. You say that Realism:

provide the greatest explanatory power to the greatest number of questions that could be asked of something experienced to pertain to an external world — javra

Which questions can be answered by Realism? Can they also be answered by Idealism, the dream hypothesis or the evil demon hypothesis? If so, in what sense are the Realist answers superior? Does the superiority of its answers entail that Realism is more likely to be true than the alternatives? I am quite confident that there is no question about experience that Realism can answer which the alternatives cannot, but the question of the adequacy of those answers is an interesting issue.

Do not worry if it takes some time for you to reply Javra. Thanks for your thoughts.

PA

There seems to be an excessively binomial use of the term 'Skepticism' here - either one is skeptical or one is not, but surely skepticism, by whatever definition, is a matter of degree?

I struggle to think of any example where one believes entirely beyond all doubt that some proposition is true (even priests have doubts), nor equally where one allows absolutely no bias whatsoever in one's behaviour in favour of some belief or other. Are we not really saying, when we talk about the decline of skepticism (in something like the approach to naturalism that had been mentioned) that the thinker is not being skeptical enough? If that is the case, then skepticism itself is not the issue, it is how can we justify a belief about the degree of skepticism that is appropriate in any given case.

Otherwise we end up in circular logic. We might say proponents of modern naturalism are not skeptical enough, but that in itself is a belief about which we could then be accused of demonstrating insufficient skepticism.

Which questions can be answered by Realism? Can they also be answered by Idealism, the dream hypothesis or the evil demon hypothesis? If so, in what sense are the Realist answers superior? Does the superiority of its answers entail that Realism is more likely to be true than the alternatives? — PossibleAaran

As one example, were a single light in the home to no longer turn on when I flick the light switch, the realism of an external world would indicate that there is something physically amiss with the light switch, the respective lightbulb, or with the wiring that dwells in between. The real problem might not be perceived nor thought of at first, yet the web of causal relations which such realism affirms facilitates my being able to discover what is wrong so as to resolve the problem. Other hypotheses, such as a Cartesian evil demon (or the materialist counterpart of being a BIV), could be conceived as alternatives to the reality of an external world. Yet, devoid of upheld belief in the very same external world, these alternative hypotheses would at best only encumber my ability to remedy the stated problem. This then can be expanded to why electricity operates the way that it does, to the question of where the electricity in my home originates from, etc.

The question to me is one of why uphold something like the Cartesian evil demon rather than an external world? I.e., what justifies the upholding of such a conviction?

Tangentially, to be more explicit about my understandings of idealism and realism, granting that these terms hold different meaning to different people:

The umbrella term of idealism does not equate to any particular subclass of belief which can be so classified, such as that of Berkley’s immaterialism. One can, for example, uphold a real, physical, external world as effete mind within an idealist system. Charles Pierce is known for so upholding. Thinking of more Eastern perspectives which we would likely term idealist, one could alternatively choose to uphold the external world to be a waking dream that is—in one way or another—resultant from the unconscious processes of all individual minds (the philosophy of Jung here also comes to mind) … yet even when so doing, and when presuming it to be the veil of Maya for one example, the external world would yet be real in the sense that it occurs in all its causally linked intricacies even when its intricacies are not perceived or thought of (what occurs at quantum levels, for instance … or, better yet, what occurs behind your back when you're neither looking nor pondering the matter).

On the other hand, realism, as I interpret you to have defined it, can well apply to both idealistic and materialistic systems of belief, as well as to anything in between—with the leading disagreements here concerning what is fundamentally real, upon which all other reality is founded. For example, it is common knowledge that Plato, an idealism-leaning philosophical skeptic, was a realist. It seems logically sound to me that Buddhists, by virtue of upholding Nirvana to be, are all realists--regardless of possible divergences as concerns other aspects of ontology—for Nirvana (and the four Noble Truths) would yet be even if all sentience were to somehow be, or become, unenlightened (in the Eastern sense of this term) … in other words, the Buddha didn’t invent an axiom of Nirvana but, instead, discovered Nirvana's existential presence via enlightenment (this, of course, in Buddhist worldviews). Materialist realism is, of course, yet another variant of realism—one that strictly upholds an underlying physical reality (here thinking of QM, the vacuum field, etc.). In all cases, there are one or more things postulated to be even when not perceived, thought of, or talked about by anyone.

didn’t all philosophy start off as direct realism? — Wayfarer

I don't know, but it's the default naive view people have. It would seem as if we're looking out at the world through the windows of our eyes. Of course it's not that kind of direct.

But then again, philosophers tend to get rather hung up on vision, which might be a tad misleading. We do have other senses and ways of interacting with the world. Not everything is a visual metaphor.

I don't like the term "naive realism" when applied to philosophical direct realism, because of course philosophers defending direct realism are aware of the criticisms and the biological underpinning for how our senses actually work.

Skepticism is the tendency for beliefs in representational theories of perception to collapse into beliefs in direct-perception and vice-versa.

I don't like discussions of skepticism in relation to idealism or realism, since both idealism and realism have been interpreted through the lens of representational metaphysics, and it isn't clear that either position constitutes a substantial ontological thesis.

My eyes are open at time T1 and I see that a laptop is in state X. I close my eyes and reopen them at T2 and I see that a laptop is in state Y. It is a Realistic bias to interpret this by saying that 'it looks like something happened when I wasn't looking'. Neither what I see at T1, nor what I see at T2, yields this information. So what explains the fact that I see something different each time? It could be that there is no explanation. — PossibleAaran

The problem with this is that we understand computation to be a process. The laptop at T2 can't complete a computation without having undergone the process of computing starting at T1.

You're right that it is an inference, when we bother to philosophize about it, but it's also the common sense view we all have on a daily basis. We don't really think there are different objects every time we close and open our eyes. We just think it's one object that we don't see when our eyes are closed.

But given that we're doing philosophy, a strong reason to trust the realist inference is because when we do watch our laptops, they undergo a process of computation from one state to the next. So we have no reason to think they don't just because we've closed our eyes.

If we adopt that form of skepticism, we might as well say the entire universe and everyone else disappears the moment we shut our eyes. That it only appears things continued on without us when we open our eyes back up.

philosophers defending direct realism are aware of the criticisms and the biological underpinning for how our senses actually work. — Marchesk

Thereby viewing philosophical questions through the perspectives of the biological sciences, which in turn assume scientific realism.

Sure, but I consider that a good reason.

Plainly, as you and I have been debating basically the same question for about 6 years. X-)

Plainly, as you and I have been debating basically the same question for about 6 years. — Wayfarer

Yeah, but you're not nearly as frustrating as Landru, no offense.

T Clark, I take it that you aren't so interested in Scepticism in any of the forms that I described in my OP? You draw a contrast between "big S Scepticism" and "small s scepticism" where the first, I suppose, is one of the forms of Scepticism I outlined in the OP (or all of them?). — PossibleAaran

Yes - When I say large "S" skepticism I mean what you described. When something new comes along, I generally check it out on my plaus-o-meter. If the bell rings, I'll tentatively accept it. If the red light flashes, it gets the boot. This is true except when it has significant potential consequences, then I have to put more thought into it.

Big "S" skepticism seems lazy and cowardly to me. Come on Rene - don't give me this "cogito ergo sum" bullshit. Make up your damn mind. As I said previously, that type of skepticism is a luxury for those who can afford to sit around on their asses.

It would be good to get clear on some of this if you wouldn't mind. What is meant by there being 'nothing you can do about it'? — PossibleAaran

Let's use the example of climate change:

[1] Is climate change happening? I say yes based on my understanding of the scientific consensus. Many others say no.
[2] Does it matter? Will it have significant consequences. I vote yes on this, but I'm less sure. The scientific consensus predicts consequences, but the effect of those consequences depends on social and political factors too.
[3] Is there anything we can do about it? Some say yes. Some say it's too late. Some say we shouldn't do anything.

Did that answer your question?

Big S Scepticism about P, then, is an issue which arises if and only if (1) you believe that P, it matters whether or not P, but there is nothing you can do about it, or (2) you don't believe P and it doesn't matter whether or not P, or (3) You don't believe that P, it does matter whether or not P, but there is nothing you can do about it. — PossibleAaran

I guess I wasn't clear. The problem with big S is that it always calls for skepticism, even when we can't afford it, i.e. when we have to decide based on the information we currently have what to do next. Skepticism as a general acknowledgement that we can never know everything about things that are important and that what we do know may be wrong is fine.

I largely agree with this. Naturalism has far too easy a time these days, with few sceptical challengers. Your acid metaphor is apt, since what tends to happen these days is alternatives to Naturalism are scoffed at and treated as absurd. I cannot count the number of articles I have read in which Idealism is dismissed as unbelievable, incredible, 'dead', or just plain silly. Theism gets a similar treatment, though to a lesser degree because it has been defended as of late by some capable philosophers. — PossibleAaran

Aren't you and @Wayfarer mixing up two different types of skepticism? When Descartes says "cogito ergo sum" he is talking about facts. Do I exist? Does the world I see exist? Is the capital of France Paris? When you talk about skepticism about Naturalism, you are questioning the metaphysical basis of a whole system of belief. Those seem fundamentally different to me. The only problem I really have with Naturalism is that its proponents seem to believe it provides some sort of privileged outlook on the nature of reality, which I strongly believe is wrong.

None taken. I found Landru pretty frustrating myself.

The only problem I really have with Naturalism is that its proponents seem to believe it provides some sort of privileged outlook on the nature of reality, which I strongly believe is wrong. — T Clark

That's more or less what I meant. The 'privileged access' is the presumption that science is the only way of knowing. In pre-modern philosophy, there was a distinction between science and sapience, the latter being 'wisdom', which I think overall has been lost sight of.

Sense perception does not reliably yield true beliefs about unobservables. I cannot use sense perception alone to reliably form the belief that there is exactly one alien insect on the furthest planet from earth. I have never observed any such thing, and sense perception is only reliable concerning things which have been sensed. That is why sense perception cannot deliver a reliable belief that the laptop exists unperceived - because the property of unperceived existence is unobservable. This only leaves inference, which is why there needs to be an inference from the observed laptop to its unobserved existence. — PossibleAaran

Is this an acceptable inference - To the best of my memory, every time I saw something and then closed my eyes, one of two things happened when I opened my eyes again. Either it was still there or I could find an explanation of why it wasn't there. If there were times I don't remember when I couldn't find an explanation, I am confident enough in my understanding of the world to believe that there was an explanation even if I couldn't figure out what it was.

That seems trivial to me.

The dream hypothesis fails because dreams are not like waking experience. The evil demon hypothesis has nothing empirical in its favor, unlike laptops and trees and what not. We can't infer an evil demon, a simulation, or being a brain in a vat from what is perceived. But we can infer a physical world. The laptop performs the computation when you close it's eyes because it's still there. Simple as that. — Marchesk

It seems to me that the evil demon hypothesis or one where reality is just a program running on a computer are metaphysically equivalent to realism as long as we can never step outside the universe/program/demon's imagination to see what is really going on. If Morpheus, Neo, and the crew had never escaped the Matrix, could never escape it, what difference would it have made that it existed?

This is a fun thread.

It seems to me that the evil demon hypothesis or one where reality is just a program running on a computer are metaphysically equivalent to realism as long as we can never step outside the universe/program/demon's imagination to see what is really going on. — T Clark

Since we can't step outside, there's no reason to suppose we're inside a simulation. It's merely a philosophical exercise in what sort of wild scenarios we can imagine which aren't incompatible with our experiences. Brains in vats, evil demons, computer simulations, God's dreaming are flights of fancy. Something being merely possible isn't saying much. Maybe a cosmic unicorn farted and started the Big Bang.

If Morpheus, Neo, and the crew had never escaped the Matrix, could never escape it, what difference would it have made that it existed? — T Clark

You're asking this question by starting out saying the Matrix exists. We're not in a situation were we can do that. We can only imagine the possibility.

But to answer your question, it would matter when the machines decided to shut down the Matrix, or something happened to them such that the power could no longer be maintained, or a meteor struck the heart of Machine Ciy.

Anyway, the point is that realism doesn't require stretching the imagination like that. It can just borrow from science and experience.