I am right, this is a common misunderstanding.

It's a misinterpretation of Schrodinger's cat to think the cat is both dead and alive. You can never observe the cat in both states. And, once you do observe it, it's then in one state or the other, so no contradiction.

The measuring can happen in a variety of ways. It seems to be a kind of disturbance, conscious or otherwise. It's a disturbance of the wavefunction. The main point, though, is that there aren't contradictions happening, as far as I can see.

Does " belief' make any sense at all beyond the scope of personal meanings, and how can the idea of belief be seen in the wider scope of philosophy, especially in relation to objective and subjective aspects of thinking? — Jack Cummins

The idea that a belief is dependent on personal or subjective meaning is just nonsense. Meanings occur within a culture of rule-based linguistic use. However, don't confuse this to mean that there are no subjective experiences or mind-based states, they are two different things. If we are talking about beliefs as expressed in language, then we are referring to those beliefs that can be said to be true or false based on what we, as language users, mean by those words, viz., true and false. This doesn't mean that there can't be subjective truths. For example, "I like orange juice" is either true or false based on my preferences, but what we mean by true and false is not determined by your preferences or your subjective experiences. It's a matter of understanding the difference between conscious experiences and language about conscious experiences, or any language that describes reality. So, whenever we speak about anything, subjective or objective, the language we use as a community has an objective component to it, viz., the meanings of the concepts/words.

My own view is that there can be beliefs (states-of-mind) that are quite apart from language, and these are reflected in our actions (i.e., we know that such beliefs exist based on the actions of individuals). These kinds of beliefs are not true or false (true and false are reserved for propositions, states-of-mind are not intrinsically propositional, no more than a pain is intrinsically propositional). To speak of them as true or false is to bring them into a linguistic setting. Part of the confusion is that we don't always see the difference between these two kinds of beliefs, i.e., the different settings or environments in which they occur.

The electron is not in any state until it's measured, so there is no contradiction. One could think of it as the potentiality of states, or, there is the probability that it will be in this state or that state when measured. So, it's not that it's both up and down at the same time.

This reply is only meant to address some of your concerns. It doesn't address your comments or questions about Godel.

Yet I suspect that many philosophers are skeptical about Dummett's argument: it smacks too much of positivism and Wittgensteinianism

Something is odd here. — Banno

Yes, I noticed that too. Devitt seems to mischaracterize Wittgenstein, at least it seems that way from this statement. Positivism doesn't equate to Wittgensteinianism, if that's his point. Although I'm not completely sure of his point.

I'm now reading the paper by Devitt.

Dummett's arguments are confusing, to say the least. If you can't be clear, one wonders if you have a good argument.

So to the first section, in which Devitt characterises realism as the view that physical entities exist independently of the mental. Devitt notes with considerable glee that there is nothing in this definition about truth. He goes on to point out that truth is independent of the evidence at hand. "Truth is one thing, our means of discovering it, another". Hence, according to Devitt, "no doctrine of truth is constitutive of realism". — Banno

I read the SEP article, and if I was to align myself with anyone it would be Devitt. Truth it seems is a property of language (proposition claims). However, reality (that which exists independent of the mind) is not about what we claim (what we claim may or may not align with reality), but about facts or states-of-affairs (things that are generally considered to be independent of minds) quite apart from what goes on in language. This has been my understanding of this argument, and I believe it's why Devitt says, "no doctrine of truth is constitutive of realism."

Hell, some of Wittgenstein's comments confuse the hell out of me. They almost seem to break down at a certain point. I'm still learning Banno, maybe if I live another 71 years I might grasp some of his thinking.

Ya, I agree, how we refer to these experiences can be a bit muddled. However, I won't resort to saying your English is poor. :wink:

I mean, do you agree that the implausibility of a claim may tend to undermine the credibility of the witness who makes the claim? Do you agree that "extraordinary cases" like those you indicated typically involve claims that are considered prima facie "implausible", regardless of the general credibility and expertise of the witness who makes the claim; and that for this reason, something in addition to that testimony is typically required to support the claim in question? — Cabbage Farmer

Sorry it took so long to respond. I think we generally agree, with some clarifications, or maybe some disagreement. Yes, I do agree that generally "...the implausibility of a claim tends to undermine the credibility" of that claim. However, I don't think that because something seems implausible, that it follows that it is. Many discoveries have been overturned in science because people considered what most find implausible. So, there has to be the right kind of balance, we tend to get to invested in certain worldviews, which can impede new discoveries.

I do agree that more is needed than just a claim, i.e., we need some objective way to verify claims that seem implausible. I'm not sure you read my argument which was given further down on the first page, but I go into detail about what is needed to support my inductive argument, i.e., what drives good testimonial evidence.

What is philosophy? — Bret Bernhoft

Philosophy uses philosophical methods of inquiry (logic, language, epistemology, etc) to analyze beliefs or belief systems. You can't escape philosophy, we all do it, its just a matter of whether we do it well or not. If you have beliefs about life, morality, politics, science, mathematics, family, business, then you're doing philosophy. So, all of us are philosophers to one degree or another.

"Hmm. Internal... you mean private? Something is amiss."

It can't be completely private. What I mean by private is that it's me having the belief, just as I can have a private sensation. However, if we are to refer to beliefs or sensations as part of language, there must be something to refer to (something the community can get a hold of, which is not the internal private thing), and these can be linguistic, or just simple non-verbal acts (opening a door, building a hut, etc). We show (linguistic or otherwise) what we believe, or that we're in pain, i.e., there are outward signs. We don't believe a stone is conscious, because there is no sign of consciousness - there just isn't anything to latch onto. You seem to want to deny that there is or are private experiences (but I'm not sure). I think we both agree that we can't talk to each other in any meaningful way if meaning is dependent upon an internal thing or object - it has to have an external component for meaning to grab hold. That's my take. I think we're close, but there may be some differences. I think we can refer to the private, as long as we don't think meaning is solely derived from the private.

I think poetry escapes confusion because it is not trying to arrive at clarity, or at least any definite propositional kind of clarity, lacking any ambiguity. Perhaps by "confusion" you mean more uncertainty, and if this is the case I would agree with you because I see (at least much of the best) poetry as a celebration of uncertainty. Would you include the other arts in this judgement as well? — Janus

Ya, I think you could include dancing, acting, meditation, etc, - which are outward expressions of the inner self. Of course, even language is an outward expression of the inner self (this would have to be further clarified), but it's governed by rules, without which it would fall apart. Even poetry is still governed by grammatical rules, but it lends itself to more of the subjective. There is a kind of balancing act between the subjective world and the objective world around us.

I'm not sure what you mean when you say language is a muddled approach to reality. And again I'd ask whether you would include the language of music and the language of the visual arts in this. Perhaps you mean that what we say about reality is never reality itself? But then the very idea of reality would seem to be impossible without language. — Janus

When I say muddled, I mean reality, and talk about reality, it's a bit ambiguous. Even the word reality is a bit ambiguous. Hence, all the discussions about, "What IS reality?" Wittgenstein is certainly ambiguous in certain passages, i.e., it's difficult to get clear on what he's trying to communicate. I'm not saying it's all ambiguous, and I do think there is a correct and incorrect way of interpreting Wittgenstein.

Animals participate in reality - they use it, in Wittgenstein's terms. Calling this a belief is surely a retrojection. — Banno

All of us participate in reality. However, what that participation amounts to is where the disagreement occurs. My use of belief is no more a retrojection than your use of participate. All talk of pre-linguistic persons or animals is a retrojection, but this doesn't mean we can't describe what's happening in linguistic terms. All acts, whether pre-linguistic or not can be talked about. Why? Because of the acts themselves, be it non-linguistic or linguistic. Therefore, a belief for me is not just expressed in language, but is expressed in the way we act within the world. My beliefs are internal to me, just as my sensations are internal to me, so just as an expression of pain, which is something internal (the sensation) is expressed via ouch or a cry (external), so too, are our or my beliefs (internal) expressed via acts in the world (external), whether linguistic or not. So, just as we can have sensations apart from language, so too, can we have beliefs apart from language.

It can "gain a grounding" by building on that use - the same process as we see in showing rather than stating. After all, there is a way of understanding a rule that is not an interpretation - not a belief - but which is found in enacting the rule: §201 — Banno

Reality has to be a certain way, i.e., objects, persons, thoughts, etc., in order for there to be a language at all. The foundation, viz., reality (where we act), gives us the grounding. These are the arational beliefs that arise quite apart from language. It's not just that these beliefs are pre-linguistic, we (the linguistic we) also show that we have such beliefs, i.e., we open the door, we sit down, we do a myriad of things that show that we believe certain things. Things which are not expressed in language, but nonetheless, demonstrate what we believe.

I'm not saying there isn't a kind of grounding that takes place in language, via what Wittgenstein is referring to in PI 201, but I'm not talking about a linguistic grounding, I'm talking about what necessarily comes before what Wittgenstein is talking about. Wittgenstein alludes to what I'm talking about in several places. Again (as I've mentioned in other posts), though, I'm not pretending this is a Wittgensteinian idea.

I think this is right: it is only the language of poetry that can escape the mire; because it doesn't aim to be propositional but rather allusive and evocative. — Janus

For me, probably not Banno, there is a kind of mystical experience in poetry, music, art, and even prayer, that transcends language to a point, not completely. So, the mystical can be seen in, for example, an act of prayer, and it's not about being true or false, it's about what the experience shows us. Wittgenstein admired some of the writings Kierkegaard (I don't put that much value in Kiekegaard), but I think it had to do with admiring the transcendent reach, right or wrong. The mire I'm referring to is confusion, but I don't think poetry escapes this - depending on what you mean by the mire. As long as we use language, in whatever venue, we are in the mire. Don't think I'm saying something against clarity, because I'm not, I'm just saying that language is a muddled approach to reality. I do think that Wittgenstein's thinking helps to bring us one step closer to clarity, if clarity is the objective.

I'm not sure I communicated my point well, but there you have it.

I'd also like to hear something about what you think our use of language does exactly. Psychologists test how infralinguistic children model the world, and how crows do for that matter. Why language? — Srap Tasmaner

I think this is important, so I'll put my two cents worth into the mix. I believe there is something important to say about reality prior to language; and how children and animals model reality. This modeling (I talk about it in terms of pre-linguistic beliefs or states) is essential, and prior to the formation of language. In fact, it's hard to imagine how language would gain any kind of grounding without such a model (using your terminology). Language, it seems to me, builds a linguistic structure that allows us to structure reality in social ways, i.e., we can talk with others about epistemology, psychology, science, etc, which allows us to go beyond our pre-linguistic modeling.

If a poorly constructed building fails to meet certain criteria, we call it bad. We decide for ourselves what those criteria are depending upon the utility we seek from the building. There are no objectively good or bad buildings. It's just a matter of preference. On the other hand, the building itself exists regardless of my preference or opinion. — Hanover

I don't think we're going to make headway here. There's a sense where you are correct, viz., we do use the concept bad in a subjective sense, but we also use it to refer to objective reality, as I pointed out. Moreover, the statement that, "There are no objectively good or bad buildings" is or is not true depending on how we are using the concept (bad being of poor quality). There are obviously buildings, and from a structurally sound point of view, it can be said that they are poorly built, it's not a matter of opinion. On the other hand, one can use the word bad (obviously, not morally bad) in a subjective way, which would take into account its use as an opinion.

My point in bringing in the building example is to show the use of the word bad in reference to something objective, gives it an objective connection, which removes it from being purely subjective.

As to morality, are you claiming that bad buildings are akin to bad acts, and saying that rape (for example) is bad if it meets our criteria for badness based upon whatever social objectives we might have,? Or, do you subscribe to the position that rape is bad regardless of what I think, much like the building exists regardless of my opinion? — Hanover

No, I'm not saying that bad buildings are akin to bad acts. As I said above, I'm saying that the use of the word bad is not always subjective, it depends on what our point of reference is.

I do, believe rape is bad or morally wrong because of the objective nature of the harm done. It's just as objective, in my view, as the existence of the building. And ya, rape is bad regardless of what anyone thinks.

No, there are two things (1) badness and (2) suffering. #2 is an emotional state. #1 is a judgment about that emotional state. If I say "you are suffering," that will be true if the event of your suffering is occurring. If I say "your suffering is bad," that will be true if your suffering is bad. What is "bad" here other than an opinion? Your suffering is occurring (or not) regardless of my opinion. Why doesn't this apply to "bad"?

I can't dictate whether your pain is real, but can I dictate whether your pain is morally bad? If I can't, how do I know? — Hanover

It's not my opinion that the suffering is bad, my use of the word bad or immoral is directly connected to the objective truth of the statement that, "Bill is suffering," if he is indeed suffering. Are you trying to tell me that bad has no objective meaning in relation to what Bill is experiencing? What about my use of the word bad in relation to "That building is poorly built (as an engineer looks at the placement of beams)," is this an opinion? My use of the word bad, in both examples, connect to something objectively true, and is not based on some internal opinion.

But where is the moral judgment? I get that the suffering is occurring in the world as an objectively identifiable event, but where is the badness of it except in your opinion? — Hanover

The "badness" IS the suffering. Not all suffering is bad, but when it comes to moral right and wrong, it's the objective harm done that gives it it's reality. This is true apart from any religious appeal.

I have no quarrel with the above post.

There is no way to resolve the many interpretations of Wittgenstein, because the interpretations are as varied as language itself. Even people who have studied Wittgenstein all their life can't agree on how to interpret some of Wittgenstein's passages, and especially their implications. It seems the more we explicate what this or that passage means, the further apart we get. This is not to say that there aren't important points to be made about meaning within social contexts for example, but it is to say that we still have much to learn when it comes to thought, language, and the world. It would be wrong to try and pigeon hole Wittgenstein into this or that interpretation. Only Wittgenstein could clear up some of these mischaracterizations of what he's saying.

Language and thinking, by its very nature is a bewitching thing. Hence, Wittgenstein's warning, "Philosophy is a battle against the bewitchment of our intelligence by means of language (PI 109)." For myself, I hope that I've learned a methodology from Wittgenstein that will help provide some clarity, but definitely not complete clarity. Complete clarity may be a phantasm. It seems that any thought or theory can be pushed to the breaking point using language. This breaking point can be seen in the changing nature of language and knowledge. Language in some sense is a kind of fog that is more or less dense given this or that understanding. This isn't to promote a kind of skepticism, although there are things to be skeptical about, but only to point out that language traps us into a kind of mire from which we cannot escape. There is a kind of mysticism to my point, and I think to Wittgenstein's thinking.

I gave you my response, now you're going to lecture me. If you don't like the way I respond move to a different thread.

Basic courtesy dictates that you respond to someone you has replied to your topic and in fact in length ... — Alkis Piskas

I don't always have the time to respond to every post. Life just has a way of getting in the way of my responses. Sometimes I can put more effort into these threads than other times. I would like to respond to every post, but sometimes I just don't have the energy. There are a lot of things that can get into the way of responses, like an illness for example. So, it's not always that someone is being discourteous. When I'm distracted I tend to make mistakes, so I try not to force myself. So, don't take it personally.

Sorry, I read that rather quickly, and didn't read it all. When I get a chance I'll read more closely. Life is getting in the way right now. I'm a bit busy with something else.

I haven't really considered this before, I'll have to give it more thought. Thanks for the reply.

"Someone said so" is not in general an adequate justification for an inference or belief. — Cabbage Farmer

Did at any point I make such a claim? You didn't pay close attention to what I said over the course of this thread. You are correct, that "someone saying this or that" is not in itself always sufficient to justify a belief. However, it depends on context, if you're in a class being taught by an expert in biology, that can be a justification for believing what the person is saying. Much of what we believe comes in the form of testimony from trusted people. When you read a book by an expert in a particular field of study, this is a form of testimonial evidence. You certainly aren't involved in the experiments of scientists, so you take their word for it. Obviously not all testimony is worth considering. It's a matter of knowing the difference between kinds of testimonial evidence.

Dividing the world up in accord with our language does not place any limits on what can be addressed. I could for example, by a combination of language, demonstration and practice, teach you the technique of holding the stem of a mugwort so as to twist it over your long finger and pull out the several inches of root without breaking it. Language does not work independently of the world, nor of the body that is speaking or hearing. Cognition is the same. It does not happen in one's mind alone, but in one's hands, in the feel of the root and the soil. Cognition is in the doing, language is a part of that doing. — Banno

Good points @Banno not just this quote, but that post is very well said. It would be interesting, in light of what's being debated about consciousness, to talk of what we mean by consciousness in the light of some of these thoughts. It would seem that our consciousness, and the consciousness of others, shows up in the same way that cognition does, viz., in the doing, language or otherwise. This is one of the reasons I have a problem with others saying that consciousness or the self is an illusion.

You can "say what [ you ] want" but you can not make what you say mean what you "intend". — Antony Nickles

Not sure I follow this statement. I understand that we can say what we want, even if it's just babbling. However, the latter part of that sentence seems confusing. viz., "...you can not make what you say mean what you intend." If my intention is to mean something totally private (as in the PLA), then this makes sense, but if I intend to mean something within the framework of public meaning, then I can intend what I mean, if that intention is a public conveyance. So, I'm transporting, so to speak, my intentionality into the public domain where my intention gets in line with public meaning (is evaluated publicly) and rule-following. So, whether the latter part of this statement is true, depends on the source of the meaning of intend. Unless I completely misunderstood your point.

But I see through Wittgenstein's sham, to see that true principles are derived from the minds of individuals, not from the public judgement of "correct". — Metaphysician Undercover

I'm mystified as to why you come in these Wittgenstein threads, especially given that you see through the "sham of Wittgenstein." I'm genuinely curious, are you trying to convince us of your particular interpretation? You seem to be privy to some special knowledge of W. that none of us possess. I know I create these threads because W. really interests me, and sometimes I get new insights into his thinking. Sometimes I even revise my interpretation because my interpretation is just incorrect.

According to what I described above, Wittgenstein's PLA, 253-270, demonstrates very clearly that one can never be certain concerning one's own sensations, if certainty requires justification. Do you not agree, that Wittgenstein has created a model that shows we can doubt being in pain? — Metaphysician Undercover

You are correct to think that Wittgenstein is talking about doubting one's pain in these passages, but there's a huge difference between these examples, and the examples where one cannot doubt that one is in pain. The difference is this: In these examples, Wittgenstein is referring to the PLA, as you correctly pointed out, and the point of the PLA is that one cannot privately create a language that correctly identifies sensations (of course it's more than sensations that goes terribly wrong). Hence, the doubt, but in this contrived situation (viz., the PLA context), which is, it seems to me, logically impossible. Why? Because language dictates a social environment, which is lacking in the PLA. Actually, one would wonder if even the concept doubt would have a foothold in the PLA, because the same argument being made about sensations could be made about doubting.

Now the contrast - the PLA must be seen against, and in the light of how we normally learn a language. So, in our normal everyday language-games about sensations and/or pains, which is not by the way, the PLA, can we doubt we're in pain? Emphatically, No! We can see how far out such doubts are, especially if we compare this with what Wittgenstein is doing in the OC. If we compare Moore's proposition "I know this is a hand," at least Wittgenstein gives a reasonable example of how a doubt can occur here, although one has a difficult time understanding how a doubt could arise in Moore's context. However, in the case of doubting one is in pain, Wittgenstein constructs a contrived example (the PLA), which cannot be done (a totally private language cannot be done), as he rightfully points out. It's only done to point out how language logically works, and how that logic falls apart in the PLA.

Finally, it must again be pointed out, that even the doubt in the PLA is not a doubt.

It's difficult to follow what you're saying Isaac, because it's not that clear. On the one hand, you seem to agree about the use of the words sensation and pain, but on the other you deny the existence of sensations and/or pains. Not only do I think you're making it more complicated than it is - you also seem contradictory at points. You seem to be adding to social meaning, i.e., adding a thing that's not needed. Also, I don't think it's likely that you have created a model that shows we can doubt being in pain. Moreover, doubting as you seem to present it, as some physiological model, seems not to line up with how we learn to doubt. I don't doubt based on some inner physiological happenings. Doubting was just fine (at least generally), even without your model. Adding your model confounds the issue, and is especially problematic.

If you are talking about learning new things about physiology, and creating a language-game base on these new discoveries, that's one thing, but you seem to be drawing inappropriate conclusions about what's happening linguistically (based on your model). It's not clear to me, and it seems it's not clear to others, so your idea needs more work.

Well, it's nice to have some company, but as ever I can't really make much sense of what you're saying, you may have to be a bit more explicit for me. — Isaac

@Metaphysician Undercover

It should give you some pause if MU is on your side. Of course it could be that MU is right and everyone else is wrong, it's logically possible. Sorry MU, but it's just so funny how your thinking on this subject is so different. And, by different, I mean that I know of no one who interprets W. the way you do, but I could be wrong. There might be some one somewhere, after all the universe is a huge place.

I'll have to commend you on a couple of things MU, you're consistent, and you're, on the whole, very respectful of others, which is probably more important than being right. I, on the other hand tend to be a bit cranky.

Who is to have authority here, in our new language game? — Banno

Only me Banno, only me. :wink:

Modern science can find no such thing that answers to 'the sensation of being in pain'. That's the problem I'm attempting to address. — Isaac

That's just the old problem of trying to identify some thing that corresponds to the word. Obviously, not all words function like that, and sensation, is just one such word. Are you saying that when someone says, "I feel a weird sensation in my big toe," that that sentence is meaningless? It's correct use is what gives meaning to the word, so it has an ontology based on that use. This reminds of people trying to argue that consciousness is an illusion, or that the self is an illusion, therefore, they don't exist. You say, there's "...no such thing that answers to the 'sensation of being in pain' - but this just isn't true, we answer to it all the time. How? By what we say and do. You seem to be confusing the grammar of "This is a cup" (as you point to it), with the grammar of "This is a pain." One's tendency, and this is what Wittgenstein points out as a mistake in the Tractatus, and what he is fighting against in much of the PI, is to want to find that thing. What exists here is not some kind of object, be it physical or not, that corresponds to the pain, but a family of actions and statements that create its ontology. Where is the thing that corresponds to the word the? Should I say the word is meaningless, or that it doesn't exist because I can't find some thing to point at?

it seems to me that Isaac is really adding a new language-game to the mix based on new information. It could be that the example (not sure at this point) of pain and doubting that one is in pain, is generally senseless, but that there are exceptions.
— Sam26

Yes, that's exactly it. Banno and I have been here before. When we talk about cognition, in the scientific sense, we need a language-game to talk about what we find, but that's often not the folk psychology that gives us many of the terms we use day-to-day. — Isaac

Ya, but when you say things like this,

There's no such thing as 'sensations'. They don't exist. No representation on earth, Non-entities...* — Isaac

then you lose me. Also, you can't look at X, Y, and Z happening in the brain, and say, that's pain. Moreover, if someone isn't feeling pain, then they're not in pain, regardless of what the body is doing.

@Isaac @Luke
I haven't been following closely, but it seems to me that Isaac is really adding a new language-game to the mix based on new information. It could be that the example (not sure at this point) of pain and doubting that one is in pain, is generally senseless, but that there are exceptions. It makes me think of Moore's claim, "I know this is a hand," i.e., can Moore doubt in this context? He's holding his hand up in a well lit room before an audience. Doubting in Moore's example, is a doubt that lacks justification. However, as Wittgenstein points out, there are situations where the doubt would be justified (make sense), then he goes on to explain how that can happen. So, the point with Isaac's example is that it could be just such a counter-example, but this really does nothing in terms of Wittgenstein's overall points about language.

Isaac brings up really interesting points.

Sam26, if this is too far off topic I am happy to move it to another thread. Just give the nod. — Banno

You don't have to go to another thread. I don't mind at all.

Is it even worth it to engage with these people?

They're immune to facts and they will not change their minds no matter what happens, which is interesting psychologically. But should we engage for the sake of others who are rational yet "on the fence"?

I struggle with this.

[Edit: I added flat earthers to the original list.] — Xtrix

Why people believe what they do is much more complicated than one might imagine. There is a whole range of things that affect our beliefs (genetics, culture, family, friends, group dynamics, politics, intelligence, etc, etc), it's not always about evidence or reasons. In fact, much of the time it's not about evidence or facts. Moreover, if we think we're immune to these kinds of psychological factors (it's just a matter of degree), then we become part of the problem. You have to keep engaging with people, generally speaking, obviously there are some people who are more difficult to talk to than others, but most people will listen.

I'm currently attending a class at a church on faith and reason, and I'm not at all religious, but I do it to keep engaged. I was straight forward about what I believe with the class, but I was respectful. I challenged their beliefs, but I take my time and allow them to approach me, and I don't try to make them feel stupid. I'll have to admit, I'm more respectful in this class than I am in this forum. Some of the people in this forum are much more respectful when engaging with people in here than I am, but for the most part, I try, but with mixed results. Anyway, this class is going well so far, and they often ask me questions about their epistemological views, and I try to answer their questions gently and with humor. This is disarming, and it allows me to get my point across without trying to tell them that they're being irrational about this or that belief. I believe they enjoy having me there, it's a chance for them to hear other points of view. Now this doesn't always happen, there are some churches that wouldn't take kindly to someone challenging them, especially in this setting (Sunday school class). Years ago I was kicked out of someone's house for my disrespect of Cornelius Van Til, so I'm very familiar with how these situations can go sideways. In this class they always ask me questions, so basically I just wait for them to ask me, and then I simply share what I believe about the topic. Last Sunday I shared why I don't believe in the resurrection, and they listened intently.

The point is that we should stay engaged where possible, don't let it become us against them. Also, you may find that some of your own beliefs aren't as reasonable as you might think.

We got way off topic, but that's fine.

Your belief that the cup is red is not justified by anything. The contention is that it is insufficient to count as knowledge, because doing so fudges the very useful distinction between belief and knowledge.

But further, if "the cup is red" were to count as knowledge by acquaintance, it must be justified by appeal to our common use of those words. — Banno

My view is that another way we justify beliefs is by linguistic training, i.e., we learn how to use words. How do I know that that is a cup and that it's red? First, we learn to use the words in social contexts, so (as I point to a cup) it's what we mean by cup, red, etc. Whether it makes sense to say "I know this is a cup," depends on the context. If someone was learning a language, we could imagine where one might appropriately doubt whether X is a cup or something else. In other words, the doubt is about the use of that particular word, and its referent.

So, I wouldn't claim that the cup example is an example of knowledge by acquaintance, you're making this assumption. This would be an example of justifying a belief based on linguistic training.