Moore's Argument Against Skepticism 

I want to criticize the example in 14:00. I am almost sure one can give a better one, but the one presented fails to demonstrate author’s idea. (A) There are more integers than even numbers.(common sense, very plausible) The thing is-this proposition is either true, or false, or meaningless. What do I mean? Very often in the introduction to set theory it is presented as if people tend to believe in a “false” statement A. However, first of all, in set theory you don’t have a “rigorous” concept of “set X is bigger than set Y”. You can compare cardinals-this is true, but it is totally different from any kind of propositions like “in set X there are more elements than in set Y”. We should ask ourselves: who said that people “commonsensly” think about the concept of “bigger than” in terms of mappings, bijections and so on? In fact, there is a totally fine partial order relation between sets, which is “X is bigger then or equal to Y iff X is subset of Y”(or vice versa, I don’t remember who is exactly subset of who in this relation, but you see my point). Maybe a common person thinks of set sizes in terms of this relation-in this case statement A becomes true. The whole point of what I wrote is to show that proposition A is a vague, non-mathematical, possibly translatable in different ways into mathematical language, while you and set theory lecturers quickly say that it is false based on the assumption that it is indeed a mathematical statement. At the same time Moorean statement “I have hands” at least at first glance does not seem to be something that you have first to translate into a formal language in order to check if it is true or not. So to summarize: when one says that A is false, he assumes that A is actually a mathematical statement, while in fact A is a pseudo-mathematical statement and so can’t be judged mathematically.

​@@timothytiberius487 Why are you interpreting (A) in terms of a "bigger than" relation? (A) just says that there are more integers than there are even integers. Anyway, (A) seems like a pretty straightforward mathematical statement to me. It's open to alternative interpretations, but that's the case for literally every statement. Translating it into more formal language might be helpful in checking whether or not it's true, but I'm not sure it's necessary. The arguments concerning the relevant property of infinity can be stated in nontechnical ways.

@@KaneB I did not interpret it; I said that you assume what is in a head of a common thinker while he might have absolutely different understanding in his mind. It is meaningless to say “more elements” before you say what it means(and we didn’t ask a common person what he has in mind when believing in A). As I said-common people may have different things in mind when they say “more elements”; they even might have different understanding of it with respect to final and infinite sets and I gave quite possible interpretation of proposition A. (You also mentioned that A and B are incompatible, but if we follow the interpretation I gave they become compatible) I mean that in case the interpretation I gave is in mind of a common person, then it is an example when a common sense, plausible believe is true-so it rather indirectly supports Moore's approach. Maybe better example can something like “Earth is flat”. I am almost sure that provided there was no institutional science and education, at least for lots of people it would an extremely intuitive, plausible statement.

@@timothytiberius487 I'm not sure why you brought up the "bigger than" relation in that case. "I said that you assume what is in a head of a common thinker while he might have absolutely different understanding in his mind" But that's true for every statement. It's possible that when I ask somebody whether or not the Earth is flat, they will have a deviant interpretation of the terms "Earth" and "flat" -- e.g. maybe they take "the Earth" to refer not to the whole planet but to the environment with which they are familiar, maybe they take "flat" to mean that the surface does not slope. In which case, it turns out that it's true that the Earth is flat! (or at least approximately true)

Why is there any need to prove the existence of an external world ? Moreover, what makes you believe that there could still be any real proof if an external world did not exist. A mind proving that only the mind exists based upon what evidence ? Not from any evidence apart from the mind, for if any evidence existing apart from the mind exists, so does a world external to the mind. No, it must be evidence from within the mind itself that proves the external world does not exist. What could this evidence be ? An idea, a thought, a belief, a sensation, an experience ? Of what ? The mind, of course -- what else is there? Is this real evidence ? An idea, a thought, a belief, a sensation, an experience of the mind ? Does this count as proof that only the mind exists ? No, it only 'proves' that the mind exists, not that it only exists by itself. But still, it is insisted that the existence of the external world be proven, yet by what evidence is not made clear by those who challenge its existence. For they will not accept that an idea, a thought, a sensation, or an experience of the external world will ever suffice to prove the existence of the external world. No, instead, they say that every idea, thought, sensation, experience depends upon the mind and, therefore, for all we know, there is only the mind. They want a piece of evidence, a proof, that in no way depends upon the mind. The only problem is that, supposing such a proof exists, as soon as anyone discovers it and believes in it, it will be part of that person's experience and beliefs, and thus it will no longer satisfy their irrational demand that the proof of an external world must not depend upon the mind in any way. Yet, these same people will still pretend to believe in the existence of real proof.

What Moore was really up to was making out the skepticism of folks like Hume for the Rationalists they were rather than the Empiricists they claimed to be. (They hold rationalisticaly to their abstractions about experience). Also involved is an implicit criticism of the reduction of reason to deduction alone, ie an argument for foundationalism. a

I think thats moores style in general I think, he was praised an critized for this style at times

Part of me wonders if it’s largely tongue-in-cheek

@@braden_m There are some passages in Moore that I think are charitably interpreted in that way. The humour is difficult to detect because Moore's writing is so bloated and dull. But for example, this incredible paragraph from his "Defence of Common Sense" is surely not to be taken entirely seriously: >> Some of these philosophers have brought forward, in favour of their position, arguments designed to show, in the case of some or all of the propositions in (1), that no propositions of that type can possibly be wholly true, because every such proposition entails both of two incompatible propositions. And I admit, of course, that if any of the propositions in (1) did entail both of two incompatible propositions it could not be true. But it seems to me I have an absolutely conclusive argument to show that none of them does entail both of two incompatible propositions. Namely this: All of the propositions in (1) are true; no true proposition entails both of two incompatible propositions; therefore, none of the propositions in (1) entails both of two incompatible propositions.

It is genuinely performative argument in nature because people to which argument was addressed for some reason adhered to skepticism only in the academy when they wrote skeptical texts, while rejecting skepticism in their ordinary life. So Moore just exposed this performatively error of maintaining skepticism and believing in ordinary world at the same time.

I don't have any current plans for that, but I intend to cover more arguments concerning skepticism in the future, so I might get around to it at some point.

Yes, the two arguments mirror each other. So it seems like we could just as well say that the skeptic is begging the question against the Moorean. On the other hand, it strikes me that there is a psychological difference, or a difference in the "force" of the arguments. In everyday life, I feel confident that I have hands. I have no cause to doubt this. But then, in a philosophical discussion, the skeptic raises the BIV hypothesis. Well, now I find myself doubting. I struggle to locate any grounds for what previously had been a confidently held belief. In practice, the situation I find myself in is that I do take myself to know that I have hands, but then I'm also very tempted by the premise that I don't know I'm not a BIV. This is not an unusual reaction to skeptical arguments. And it's not particularly satisfying to say to somebody in this position: look, clearly you *know* you have hands, so the skeptic must be wrong! If the skeptic has succeed in sowing doubt -- and for many people, the skeptic does succeed at this, even if not outright converting them to skepticism -- this response seems hopeless as a way of assuaging that doubt.

I can't promise when, or even if, the video will be done, but I'm planning on covering that article at some point!

As far as Moore is concerned, it doesn't make any difference. He would probably have been happy to use e.g. "here is a table" or "here is a tree". Though it's an interesting question whether Moore is right about this. I suppose that I do have a kind of direct, immediate experience of my own body, in a way that doesn't occur for objects like tables and trees.

By the end of the video, I realise that there's something that people do in practice that seems to have completely eluded epistemologists: Knowledge has a purpose, and people acquire knowledge in order to predict possible scenarios, and thus do things to make certain possible scenarios more likely to happen. (This using of knowledge need not be immediate or even be planned beforehand. It is simply there to be made use of if and when it becomes relevant.) For some reason, the points in this video seem to completely ignore the idea that a lot of knowledge isn't merely drawn from past observation or a priori principles, but the hypotheses derived from these sources are then tested again to see which ones are good and which are bad at predicting unknown (typically future) behaviour. A hypothesis that can't be tested - such as the hypothesis that the real world isn't actually real but is instead simulated to perfection such that we can't and will not ever be able to tell the difference - is useless as knowledge. If it never has any consequences then we might as well treat the real world as real anyway, regardless of the "truth". If it does have consequences then it becomes a scientific endeavour to figure out the regularity and the extent of its behaviour and ultimately conclude which hypothesis is more deserving to be "true"/"knowledge" than others.

I disagree. Skepticism does not merely amount to the view that we cannot be certain that there is an external world. It's the view that there is no justification whatsoever for the belief that there is an external world. At least, that's the case for any interesting form of skepticism. In any case, Moore actually *does* claim to know various common sense propositions with certainty. He explicitly states this numerous times. In his "Defence of Common Sense", he begins by listing "a set of propositions, every one of which (in my own opinion) I know, with certainty, to be true", and throughout the article he emphasizes the claim to certainty.

I agree with your general point -- it's not enough to simply note the mere possibility of deception -- but I think you're understating the power of the skeptic's argument. In the ice core example, we take it that we know how ice cores are collected, we know what would be required in order to create a convincing forgery, etc. This background knowledge justifies the claim that ice cores have probably not been faked, at least in the absence of any reason to think otherwise. By contrast, the external world skeptic will argue either that there are no grounds on which to make any judgment about the prior probability of the common sense hypothesis that perception provides access to the external world, or that there are such grounds, but that the common sense hypothesis turns out to be improbable. Now we could try to meet the skeptic's argument by supplying reasons for thinking that the common sense hypothesis is more probable than any skeptical hypothesis. But notice that if we do this, we are abandoning the Moorean response in favour of something more like the explanationist response. Suppose we have 30 ice cores. I then discover evidence that 10 of these ice cores are forgeries. Moreover, the means by which these 10 ice cores were forged could easily have been done for the other 20. Even if I've been using ice cores that are not currently known to be forgeries, it seems like my justification for the conclusions based on the ice core data is undermined. The skeptic will argue that we are in a similar position with respect to perception. We know that our sensory impressions are sometimes deceptive: during dreams and during certain types of drug trips, the appearance no longer correspond to an external reality. But our sensory impressions during normal waking life could have been generated in the same kind of way; there is nothing special about our normal waking experiences. Of course, we could dispute this claim. We might argue that there are certain features of sensory impressions during normal waking life that are better explained by the common sense hypothesis. Again though, if we take this line, we're abandoning the Moorean response.

​@@KaneB I'm not sure that's my intuition: if I discover that those 10 are forgeries I would start to find the signs in the other cores but I would not assume they're forgeries; if a professor finds out a student cheated he doesn't therefore suspend judgment on everyone's test. The dream and the drug induced illusion do have clear signs that they're forgeries: I've done something to get in a different state of consciousness(I'm not sure I'm using the term in the same way a psychologist would but I hope my message comes through anyway); do I have evidence of the same happening for real life? No, or at least not off the top of my head. It's like there are two area of the lab and I find signs of a break-in only on the door of the area A: if I don't find those same signs in the the door of the area B I would not suspend judgment on the results of experiments made with samples from that area. This answers also doesn't seem to me to deviate from the moorean perspective. I want also to spend a line or two to tell you how much I appreciate your work and the fact that you spend time to answer to people at such length.

​@@federicobondi3038 I wouldn't assume that they're all forgeries either. But if the all the cores had been extracted by the same team, on the same expedition, I would at least suspend judgment about the veracity of the others, and this would undermine the support that they provide to the CO2 hypothesis. Re the professor example, what if the professor had discovered that some students had got hold of an answer sheet before the test, where this would have been easily accessible to the other students? I think in that case, he should suspend judgment about everybody's test. >> The dream and the drug induced illusion do have clear signs that they're forgeries: I've done something to get in a different state of consciousness We are in a position to make that judgment now, from the point of view of normal waking life. But in many cases where somebody is actually in a dream or a drug-induced hallucination, there are no such clear signs. Most people, when they dream, are not aware that they are dreaming. >> I want also to spend a line or two to tell you how much I appreciate your work and the fact that you spend time to answer to people at such length. Thanks a lot, glad you like the videos!

@@federicobondi3038 Also, re this point: >> This answers also doesn't seem to me to deviate from the moorean perspective. If our response to skeptic involves evaluating the relative merits of the common sense hypothesis vs various skeptical hypotheses, or judging the prior probability of the common sense hypothesis, etc., then we're no longer giving a Moorean response. The Moorean doesn't think that any appeal to explanatory criteria is required for a response to skepticism. I'm not saying that you're response isn't Moorean. Just something to bear in mind.

hmmm, but maybe this remark is hypocritical, eh? does the negation of my argument work as well? negation: perhaps BIV is possible we should not assume we are not BIV we should not assume that we might not be BIV -> (we should assume that we are/might be BIV) until it can be demonstrated that it's impossible hrm. one might have an issue with both arguments, but this one does not seem quite as convincing.

still though, we don't need to establish that it's impossible to be persuaded. it's possible that donald trump is in my closet, but that doesn't give me good reason to suspect as much. so for this approach to work, the optimist would have to establish that ~BIV is more plausible than BIV. how might one do this? that's a very interesting question. it seems as though one might have to argue that what it is like to be ~BIV is more similar to our current experience than BIV, but why? hmm, the more i think about it, the more i don't like the question. this seems categorically similar to questions like the world being made exactly as it is 5 minutes ago, as was touched on in the video. so now it seems more like the means to answer the question, one way or another, have been define outside the scope of what's possible to discern. i'm satisfied with that conclusion for now.

Yes, the standard skeptical argument assumes that there could be a BIV whose experiences are indistinguishable from those of a person with a real body, living in the real world. We might respond to the skeptic by denying that this kind of scenario is possible. However, bear in mind that the BIV is only one among many skeptical hypotheses. Other popular ones are the dream hypothesis (maybe I'm just dreaming) and Descartes' evil demon (maybe a malicious all-powerful entity is creating sensory impressions to deceive me).

what we need is meta skepticism!

👍

"'i don't know whether I have hands' is asking for absolute truth which is unattainable" Are you sure? Is it absolutely true that absolute truth is unattainable? "'i don't know whether I have hands' is asking for absolute truth which is unattainable and frankly irrelevant." Irrelevant to what? The "practical concerns" of a fake world? "Simulated or real makes no difference here. Until hands stop producing predictable hand-like results I'd say we can shelve this topic." It only makes no difference if you're just not interested in the truth. Which is fine, not everyone is into it, but if you're not then why are you even here commenting on it?

So what's real is what's perceived?

@@saintsword23 That's not the spin Moore would put on it. Rather, you could say (using later terminology) that those are paradigm examples of the concept of being real. Other things can ve, and are real, but If these trivial cases are not real, what does "real" even mean?

@@whycantiremainanonymous8091 That's the question. Just imo, "real" is a concept that could be retired from the philosophical vocabulary and we'd be better off for it. There's certain concepts, like "real" or "justice" for which we're always better off using another term or phrase if our goal is clarity. Quine's paper "On What There Is" is a perfect example. Saying "God doesn't exist" leads to the confusing debate about "well, how can God possess the quality of non-existence if he doesn't exist?" The question is all wrong because the term "exists" is vague. When I say "minotaurs don't exist" what I really mean is something like, "a creature with the head of a bull and the body of a man is not present in the labyrinth (or anywhere on Earth)." When we try to go back and apply this to God we see that the entire debate arises due to the vagueness of our terms. So, I regard the debate over what spin one should place on the word "real" to be pointless. One should just use more precise language. And when we start doing that, it's going to become apparent that what Moore is doing is failing to examine what's really going on when he says, "I have a hand" or "My hand is real."

this argument loses to the modified BIV scenario where 'I don't know if I'm a BIV put in the vat yesterday'. Clearly your 'reality' has been shifted (even if it's from one simulation to another), but the language you use remains unchanged.

Thanks!