A realist says the actual world contains true statements that are beyond our knowledge. — frank

Can you clarify this? What is a true statement that's beyond our knowledge? It doesn't make any sense to me.

I did this the other day, but it's easy enough to do it again. A possible world does not consist of stipulations, so much as a complete description of a state of affairs - which statements are true and which are false. In an informal sense it is convenient to think of possible worlds as stipulated, by setting out how, if at all, a possible world differs form the actual world.

The actual world can for logical purposes be set out in the same way, as statements setting out what is the case and what isn't. But of course the actual world doesn't consist of such statements, nor of stipulations. — Banno

The following is based on your latest description of possible worlds and actual world. Can you point out what's wrong with my reasoning?

A possible world consists of statements setting out what is the case and what isn't.
The actual world consists of statements setting out what is the case and what isn't.
Every possible world is the actual world.

I will count that as progress. But your views on realism appear similarly confused. But by all means, set out the account clearly and I might address it. — Banno

See below.

Take a moment to read through the first two paragraphs of the SEP article on possible worlds: — frank

Can you explain the point you are trying to make with that passage?

Anyway, the realist assumes that there is a world, and a way that the world is, which is independent from us, the human knowers.

So to reply to your SEP article, human beings think that "things might have been different in countless ways". These different ways that human beings think that things might have been different, are thought up by human beings, and so they are not independent from us. Therefore, "possible worlds" are worlds which are not independent from us, they are dependent on us. If, "the actual world" is said to be one of the possible worlds, then the actual world is not independent from us. Possible worlds are not independent.

That the actual world is a possible world is contrary to the realist assumption stated above.

Banno argues that Metaphysician Undercover fundamentally misunderstands modal logic and conflates distinct concepts. The core errors are: — Claude

1. "For example, it's true you read a post, but it's also possible you might not have read it."
That speaks for itself.
2. Just because we can consider counterfactuals, doesn't indicate that it's possible that what is false could be true.
3.No demonstration here, just appeal to authority, and disregard of my logical demonstration.
4.Doesn't make sense, or perhaps is just irrelevant.
5.False.

Poor effort Claude, so I'll have to give you an F for failure. And please do not try again.



In all that AI babble you haven't yet addressed my reasoning. Are you going to show me errors in my reasoning, or just continue with the misrepresentations.

Start with the following, which follows directly from your definitions:
Possible worlds consist of stipulations.
The actual world does not consist of stipulations.
Therefore the actual world is not a possible world.

Please show me where that reasoning is erroneous. Or, is it the case that your definitions are erroneous?

However solid your reasoning may be, you just have to accept the usage of whatever possible world semanticist you're reviewing. They generally say that actuality is a brand of possibility, the intuition being that all events of the actual world are logically possible. — frank

As I said to Ludwig V in the prior post, we can make the actual world one of the possible worlds, but this contradicts realism. Banno wants both, realism, and the actual world to be one of the possible worlds, and doesn't seem to understand the incompatibility. So he continues to define "actual world" in a way which contradicts how he defines "possible world", to support his realism, but also making it impossible that the actual world is one of the possible worlds.

And your reasoning has been repeatedly shown to be in error. — Banno

Point me to one place where you showed error in my reasoning please.

Your posts are becoming increasingly confused. — Banno

That's a direct reflection of what you are telling me. You are confusing me with nonsense.

Notice the two differing modalities, metaphysical and epistemic. Your account, as I've said before, fails to differentiate these. — Banno

From everything that I've read, one's metaphysics must be consistent with one's epistemology, or else there is contradiction within the person's philosophy. So the distinction between "metaphysical" and "epistemic" does not excuse your contradiction.

Note that in all cases the actual world is one of the possible worlds. — Banno

For the reasons I explained in prior posts, this is contradictory. You provided a distinction. Possible worlds consist of stipulations, the actual world does not consist of stipulations. Therefore it is contradictory to say that the actual is one of the possible worlds. Will I have to point this out to you an infinite number of times before you accept it?

If we apply Meta's logic to the example I just gave, then because it did not snow last night in Jindabyne, we cannot give any consideration to what may have been the case had it snowed in Jindabyne last night. — Banno

Why not? What's your problem here? We could give the very same consideration to "what may have been the case if it had snowed", while still acknowledging that it is impossible that it actually did snow. Is that difficult?

If we do not know whether it snowed or not, we consider that both are "possibilities". If we know that it did not snow, then that is known as an actuality; and the alternative is known as a counterfactual. There are no possibilities with respect to this situation in that case, because what is actual is known. I think that is what already pointed out to you

I'm sorry, but I don't understand what you mean by "the danger of contradiction". I'm used to contradictions existing or not - contradictions as a risk are new to me. — Ludwig V

There is an implied contradiction, in saying that the actual is also possible. This is the one I've been explaining to Banno, who continues to refuse to acknowledge this. Check the above. I called it a "danger of contradiction" because I am still giving Banno the benefit of the doubt, to see if he can provided definitions which would establish consistency.

The point is that "actual" can be made to be one of the possibilities, but that annihilates realism. We must instill principles other than realist principles to distinguish the actual from the possible, if the actual is to be one of the possible. This is the case with model-dependent realism for example, which claims "realism" in the name, but is not realism. The glaring problem being that realism denies the priority of the possible, therefore the actual cannot yield logical priority to the possible, which is required to conceive of the actual as one of the possible. The actual, real, must be distinct from, and logically prior to, the possible, for true realism.

Banno's problem is that he does not want to relinquish his realist ontology, but he wants at the same time to accept the priority of modal logic. Now he is starting to propose a division, a boundary, between metaphysical principles and epistemic principles, so he can hide the contradictory principles, one on each side of that boundary, thereby having an epistemology which is inconsistent with his metaphysics. "The actual world" means something different in Banno's metaphysics, from what it means in his epistemology.

Thanks, I think I'll take a look at his music theory when I get a chance.

Towards the end of the metaphysics lectures he mentions a manuscript he's published called "Reflections of metaphysics". I glanced at it, and there's a lot of talk about Kant, and what he calls "Kant's block". I'll probably read that, because I'm interested to see exactly how he manages to get around the block.

The actual world is the one in which we may empirically verify statements as true, as opposed to other possible worlds, where we stipulating them to be true. — Banno

So "the actual world" is not the world we live in, (where we live, work, and play, does not consist of statements), it is a world of empirically verifiable statements. And the actual world is not one of the possible worlds which consist of stipulations rather than empirically verifiable statements. Therefore the actual world is not a possible world. Agree? Obviously, it would be a mistake to say that what is actual is also possible, because you've provided clear principles to distinguish the two, and the actual is known to be actual, and distinct from the possible.

But are your principles really clear? "We may empirically verify statements"? Are you saying that "the actual world" consists of statements which are possible to verify empirically, but are not necessarily verified empirically? If we do not actually verify the statements, how would we distinguish a statement of the actual world, from a stipulation of a possible world? Suppose I present you with two statements/stipulations, S1 "it snowed here yesterday", and S2 "it did not snow here yesterday". How would we know which one is an empirically verifiable statement of actuality, and which one is a stipulation of possibility?

Furthermore, if we do actually empirically verify the statements, then how are the "stipulations" truly "possible"? Do you see the dilemma? If we do not empirically verify S1 or S2, then we have two stipulations of possibility. If we empirically verify S1 or S2, we have a statement of actuality, but the other has been ruled as contrary to actuality, and no longer possible.

Your proposal of empirically verifiable statements sucks, as completely useless.

I'll have to read it. — Jamal

Definitely a very good read. It's a bit simpler than ND, so it flows well, but it provides very good background material. This is especially so, concerning the concept "mediation". But it's like an incomplete concept in those lectures so I'm looking forward to seeing how he develops it further in ND.

Keep going. — Banno

Going where? I've laid bare your contradictions and now you say no more. Seems you can't write anything without it being contradictory, so you've shut up.

Banno said we are int he actual world. He also said that we can stipulate that we are talking about the actual world - a bit of semantics. We do not get to stipulate that we are in the actual world. — Banno

What do you mean we don't get to stipulate that we are in the actual world? You personally, have stipulated that we are in the actual world, numerous times just today.

You are playing on the difference between the metaphysical truth that we are in the actual world, and the semantic truth that we can stipulate whatever possible world we want. That failure to recognise the difference between semantics and metaphysics runs right through the confusion you show here. — Banno

If you stipulate (say) that we are in the actual world, which is an unstipulated world, and you also stipulate (say) that the actual world is one of the stipulated possible worlds, you very clearly contradict yourself.

Which do you have it to be? Are we in the actual world, or is the actual world one of the possible worlds? You cannot have both without contradiction.

Near the beginning of these lectures on metaphysics, he distinguishes between metaphysics and theology. Metaphysics is the broader field, so that theology is a branch of metaphysics. He then explains how even criticizing and denouncing metaphysics is self-defeating, because that is itself metaphysics. In this way we can't really avoid metaphysics, because to reject metaphysics is to do metaphysics. That sort of sets the stage for the idea that metaphysics is something natural, which human beings will do, and it cannot be prevented.

After going through Aristotle's metaphysics, he provides some ideas for modern metaphysics. We need to consider the possible reality of life without meaning, and if that can even be life. Also he mentions something worse than death, torture. These both point toward suicide and the question, "Is it still possible to live?". People, have become superfluous, the meaning of one's life is that the person has no meaning.

Further, we find joy in philosophy because thinking is an illusion which takes us away from this reality. But by the same illusion we rationalize ourselves away from real feeling, physical pain etc.. The true basis of morality is to be found in bodily feeling, but this is the opposite direction to those who rationalize ideals. Then he speaks about the narrow mindedness of culture and how it suppresses nature.

So in lectures 16 17 he discusses the intertwining of culture and metaphysical questions. And this gets difficult. The two are in a way, inseparable, each being mediated by the other, but he speaks of them as if they are somehow separate things. What comes out in Lecture 17 is that death is what distinguishes them. Death relates to each of these in a completely different way. He says for example "culture has not integrated death", while "death is the true spur to metaphysical speculation".

So he discusses the failures of the metaphysics of death, the inability to make us "conscious of death", and then turns to the ideas of time, and wholeness, in relation to death, and his paradoxical notion of immortality.

The important, and final point seems to be that thought is always mediated by history. In other words, it is never the case that thought is a pure abstraction, as if floating free from all time and space, it always has a spatial-temporal context in the world, and it is always mediated, conditioned by that context. This plays into what he calls metaphysical experience, and Hegel's principle of determinate negation, which he rejects. He says that if negation of the negative produced something positive, this would create a deceptive type of certainty which would make mistake appear to be impossible. That would leave us hopelessly lost because the truth of the idea is its fallibility.

There's something wrong with saying that the actual world is possible and something wrong with saying that it is not possible. — Ludwig V

That's what I said, it's categorically distinct.

You are missing the point. You cannot stipulate which possible world is actual. — Ludwig V

That's Banno's claim. Banno said we stipulate which world is the actual world. I addressed that in my last post. If one of the possible worlds is supposed to represent the actual world, this needs to be justified rather than stipulated. But then the justification will be be judged.

That is why Banno's claim that modal logic gives us a rigorous way to talk about the actual world is incorrect. To apply rigor to the way that we talk about the actual world requires strict rules on the use of descriptive language, and also for justifying the claims of "actual". But this is outside the purveyance of modal logic.

A god logician will understand that they can only know what it is possible to know. — Banno

Sure, all of us atheists will agree with that. We know that "god" itself is inherently contradictory.

This is a metaphysical point. — Banno

A very important metaphysical point, I might add. Failure to recognize this might lead one to think that the actual world is one of the possible worlds. And one might think that what is actually known is also possibly known. But a good metaphysician will recognize the category division, and the danger of contradiction if we allow that the actual is also possible.

Speaking semantically, the actual world can be stipulated. Which is just to say we can talk about the actual world as one of the possible words. — Banno

Sure, but this is problematic due to the possibility of mistake. If we stipulate that a specific possible world represents the actual world, then we take that special status assigned to "the actual world", for granted, even though it might not be a correct representation. Therefore, the title "the actual world" requires more than simple stipulation, it requires justification.

The error I mean is to treat the "observer" as in a separate world from the "observed." — Ciceronianus

It is a mistake to separate the observer from the observed. The nature of an experiment is that we do something to the world, in a precisely designed way, and we observe how the world responds. Understanding the design, and the procedure, is just as important as observing the effects.

We are in the actual world. Metaphysics. — Banno

OK, let's get this straight. I hope you are not trying to confuse me.

We are in the actual world.
Possible worlds are stipulated though.
The world we are in is not a stipulated world
Therefore the actual world is not a possible world.

Agree?

This shows your error nicely. Semantically, we can of corse stipulate that we are talking about the actual world - one in which Branson's wife is dead. Metaphysically, the actual world is the one we are in. Your neat syllogism mixes the two. — Banno

You stipulate that you are talking about the actual world, and this means that the world you are talking about is a possible world, it is stipulated. By your own words, the actual world is "not stipulated".

What you propose here is just ridiculous, because one could just as easily stipulate that the world which Branson's wife did not die, is the actual world. How do you propose that in any stipulated world (possible world), stipulating "I'm talking about the actual world", makes that stipulated world (possible world) into a not stipulated world?

Well, the actual world is either possible or impossible (necessarily not actual) - this is the equivalent of the law of excluded middle in standard modal logic. It would be absurd to maintain that the actual world is impossible, so you are left with the actual world being possible (indeed, this is a theorem in all but the weakest modal logics). And yes, the actual world is different from all the other possible worlds - it is actual! — SophistiCat

What is actual is not possible in the sense that it is a distinct category. Since "impossible" is defined relative to "possible", what is actual is just as much not impossible as it is not possible. If we try to bring "actual into the category of "possible" as Banno does, and you do, this results in the contradiction which I've been demonstrating to Banno.

That seems to me a bit confusing, because it suggests that the actual world is merely a possible world. Surely one needs to say something to the effect that the actual world is different from all the possible worlds. — Ludwig V

This is the issue. Banno's been arguing that if it is actual it must be possible. I've been trying to show him how we must accept that this is contradictory. But Banno seems to be influenced by some sort of common language intuition which makes him think that it's nonsense to say that what is actual is not possible.

You are already in the actual world, Meta. — Banno

Possibly, as that is what you stipulate, but we're right back to where we were, days ago. Remember, I told you how "actually known" is distinct from "possibly known", incompatible because the two are contradictory? You could not understand that and kept arguing otherwise. Maybe you'll understand the logic now:

Possible worlds are stipulated.
The actual world is not stipulated.
Therefore the actual world is not a possible world.

While semantics talks about many possible worlds, metaphysics tells us that only one is the actual world - the one that is fixed by empirical facts. The actual world is one in which Branson's wife died. — Banno

By the logic above, if there is an actual world, it is not one of the possible worlds. That would be contradictory.

You seem to think that somehow the actual word ought be deducible form a modal logic. — Banno

If the actual world is one of the possible worlds, then it ought to be deducible from modal logic. However, the actual world could not be one of the possible worlds because that would be contradictory. That appears to be a problem with your metaphysics, you accept contradiction.

The best way to think of possible worlds is not as imagined, but as stipulated. — Banno

Sure, "stipulated". But I don't see how this change of words makes any significant difference. A stipulated world is nothing other than a special type of imagined world, one put to words, and proposed for agreement. But I'll use your word if you think it adds some significance.

We can consider the possible world in which we did not know Bransons wife had died, and consider the consequences thereof - such as that I would not be using it in this example. That's quite sensible. — Banno

So you are suggesting two distinct stipulated worlds, one in which Branson's wife died and one in which Branson's wife did not. I have no problem with this, those are two possible worlds.

The question is how do we get to an actual world?

And, to add to your confusion, we make such stipulations in the actual word... As indeed, I just did. — Banno

Yes, that definitely confuses me. The way you phrase that, "to add to your confusion", creates the appearance that you are doing this intentionally. Why would you strive to confuse rather than to clarify?

You are stipulating that we make such stipulations in the actual world. But that stipulation you make, just produces another stipulated world. Just because you stipulate that we make stipulations in the actual world, doesn't give that stipulated world any special status as anything other than another stipulated world, just like all the rest of the stipulated worlds. I could stipulate that there is another world, "the real world", within which you make the stipulation that we make such stipulations in the actual world. Then someone might stipulate that there is a "physical world" within which I made the stipulation about the real world. And someone could stipulate an "existing world" within which the stipulation about the physical world was made. As long as people could keep coming up with new terms, we'd approach an infinite regress. All the while, we'd only be dealing with stipulated worlds, which are just a special type of imaginary world.

The difference with the actual world is that it is not stipulated. It's already there. — Banno

I don't understand this at all. How could that even be a "world", what's already there? Very clearly, a world is what is stipulated. If there is anything which has not been stipulated, then this is very obviously categorically distinct from what "a world" is. We cannot now use "world" to refer to something "not stipulated", when "a world" very clearly refers to what is stipulated. I agree that there is much more to reality than what is stipulated, but if worlds are what is stipulated, we sure as heck cannot talk about what is not stipulated as if it is a world. That would be extremely confusing.

That's pretty hopelessly confused. — Banno

Now I think I understand very clearly why I am hopelessly confused. You use the word "world" in an extremely confusing way. You suppose worlds which are stipulated, and also a world, or perhaps a multitude of worlds (I really can't know, because everything you say about this "world" would just be stipulated, therefore a stipulated world) which is/are not stipulated. How could we even know that there is such a world, or worlds?

Can you see the inherent contradiction here, which is confusing me immensely? You are stipulating that there is an actual world, which is not stipulated, but is already there. If we remove this stipulation, of an actual, not stipulated world, which is already there, because it is self-contradicting, a stipulated not stipulated world, how can we know, or even say, anything about this supposed contradictory world, because that would be to make the contradiction of stipulating the not stipulated?

What I suggest to you Banno, is that it is actually you who misunderstands modal logic. In modal logic there cannot be any such thing as the actual, not stipulated world, which is already there. This realist assumption contradicts the very principles of modal logic. This is why we have ontologies like model-dependent realism, which the adherents recognize is not consistent with traditional realism, but they give it that name anyway, to create the illusion of consistency. And, you either get deceived by this illusion, or grasp it, and propagate it in intentional deception, by insisting that modal logic is consistent with realism.

But your "rigorous way to talk about it" assigns truth to the talk not the actual world, and it provides no principles to even support the reality of an actual world. Look at the definition of "possibly" you gave me:

In Kripke semantics, “possibly p” means that p is true in at least one world about which we can talk. — Banno

Clearly these are "imaginary worlds". Consider that I may produce a world based on my experience, and you may produce a world based on your experience. Despite each of us claiming that mine is the actual world, based on my experience, they are both imaginary worlds derived from our memories and other parts of our minds, and there may very well be contradiction between us. So we may establish modalities, and ways to cross reference between your world, my world, and numerous others, to produce "a model". This model which is produced is just another imaginary world though.

You say "The whole point of model-theoretic semantics is precisely not to replace the actual world, but to give us a rigorous way to talk about it", but that is not correct. It gives us a rigorous way to talk about our experiences, compare them, apply logic, and seek consistencies and inconsistencies. It does not give us a way to talk about the actual world, nor do the principles of modal logic claim we talk about the actual world. That's why it leads to ontologies like model-dependent realism. It provides principles to talk about possible worlds, and produce conclusions concerning these possible worlds, and then we might stipulate some principles whereby we'd choose the best possible world (the one we think could qualify as the actual world), but it is not working with descriptions of the actual world. Nor does it claim to be. It cannot, or the possible worlds structure would be negated.

Notice the inversion. Modal logic does not provide a way to talk about the actual world. It provides a way to talk about possible worlds. Then, through principles, and logical proceedings, it stipulates "the actual world". So instead of the classic approach, talking about the actual world (propositions judged for truth and falsity), and proceeding logically from there to determine what is possible within that actual world, modal logic talks about possible worlds, and proceeds to make a logical determination about the actual world. That is not a matter of giving us a rigorous way to talk about the actual world. It is a way to make logical conclusions about the actual world. The descriptions, therefore what we are talking about is possible worlds, not the actual world. Therefore, a rigorous way to talk about the actual world is what is really missing here.

Can you explain how you think it isn't? — Banno

I did that already.

https://thephilosophyforum.com/discussion/comment/1027665

Truth is determined by the model,, The model is a product, imaginary. Unless you are assuming something like model-dependent realism, (which isn't actually realism, it just has that word in the name), there is no place for a real, independent world.

Here you go: Boxes and Diamonds: An Open Introduction To Modal Logic. Sections 1.5 and 1.6 cover truth at a world and truth as a model. There's a couple of sections on accessibility relations, but you might find 15.5, "Accessibility Relations and Epistemic Principles", most useful. — Banno

OK, so truth is defined as within the model, so we haven't gotten to anything to support the assumption of a real, or actual world, or truth by correspondence to the actual world. How do you claim to be realist if you believe in the principles of modal logic? How do you assume to make modal logic consistent with realism?

The definition provided is not mine; it is the standard definition in modal logic. It has nothing to do with correspondence, since truth in such systems is model-theoretical. — Banno

That's right. It's exactly what I pointed out in my post.

This does not claim that there are multiple concrete universes out there and that truth “corresponds” to each. It is a semantic model, a mathematical structure used to evaluate formulas. Model-theoretic “worlds” are not metaphysical worlds. They are semantic devices, exactly like the points on a truth table are not little universes. — Banno

I don't care what you call it, a "semantic model" if you want. However, if you choose to use "true" in that way, we must adhere to that for the purpose of our discussion here, so that we do not equivocate. That is the reason why I asked you to provide some principles or definitions, so that we have something concrete to go by.

That's exactly what the accessibility relation is for. — Banno

Well give me the "accessibility relation" then. I don't think it's going to change the meaning of "true".

Frankly, your attempts to show that modal logic, and possible world semantics, which are accepted fields of study in mathematical logic, are somehow inconsistent, is just a bit sad. — Banno

I am not trying to show inconsistency in modal logic, I am trying to show incorrectness in your presentation of it. And, in case you didn't notice, that is what I did in my last post.

You are here confusing "true in a model" with "true in reality".

Again, a bit sad. — Banno

Ha ha, I'm staying consistent with "true in a model". From here, there is no such thing as "true in reality", because that would be equivocation. That's the problem, your realistic tendencies make you want a "true in reality", while you argue modalities. That is your inconsistency, your incorrectness, which I am trying to help you to understand.

Are you ready to proceed with the "accessibility relation" now?

The way that antirealism usually avoids omniscience is by rejecting classical logic. That for instance is the approach in Kripke's theory of truth, which has some merit.

In effect, in talking about the medium-size goods around us, we have a choice between using classical logic and accepting that there are truths we don't know on the one hand; and supposing that there are no such unknown truths and rejecting classical logic on the other.

Ether will do, but the former seems more intuitive, less sophistic and simpler. — Banno

In the way that "true" is used in your definition of "possibly", how does "truths we don't know" say anything meaningful? Since truth is relative to the specified world, and "true" means what is consistent with that world, and we can imagine any type of world, than anything, and everything is true. How does "truths we don't know" say anything meaningful, when everything and anything is a truth?

Yeah, I did, you missed it. It's the standard Kripkeian definition:
In Kripke semantics, “possibly p” means that p is true in at least one world about which we can talk.
— Banno — Banno

From the perspective of truth by correspondence, these appears to be incoherent. How can we talk about things being true in more than one world, when "true" is determined by what corresponds with "the world"? I thought you were realist. No? Are you saying that there is a whole bunch of contradictory truths depending on which world we are talking about?

Regardless, I'll accept this definition as a working platform. But I'll warn you that it will be very hard to support any type of realism which could be consistent with this definition. So a "world" is a product of the imagination, and "true" means consistent with that specific product. This is a reflection of the basic idealist assumption covered in the thread called "The Mind Created World". The difficulty with this approach is to find principles which would provide "correctness". that is because my proposed world produced from my experience may differ from your proposed world produced from your experience. Each is " a world about which we can talk".

We cannot us "true", to talk of the "true world", or "real world", in the sense of correspondence, because "true" is already used in the sense of coherence, as consistent with the proposed possible world. Furthermore, we cannot refer to an independent "actual world", because all we have is the different proposals from different people, based on their experiences. By what principles would we say that one person's experience represents "the actual world", over another's, when they contradict?

We know that Branson's missus has died. But it could be the case that we did not know she'd passed on. — Banno

You are mixing up tenses and not properly representing what I said. I said "we know X" means that it could not be the case "that we do not know X". You have replaced "do not" with "did not". Sure it is possible that we did not know what we do know now, but that's not what I'm talking about. If we know X right now, it is absolutely impossible that we do not know X right now. Of course if we allow different imaginary worlds, we could have one of each, but those two different cases would not be in the same world.

Here's the problem, then - your incapacity to understand a simple situation; or is this the doubling-down I spoke of earlier? We can happily consider what might have been the case had you not read that post. I would not be writing this, for starters. That does make sense. — Banno

Your claim here is incorrect. What you insinuate is contrary to your definition of "possibly". Notice, "possibly" refers to what is true "in at least one world". It does not provide the principles to cross from one world to another. In one world I read the post. In another world I did not read the post. "True" refers to consistency within the referred to world. Therefore if it is true that I read this post, (meaning in that world where it is true) it is not possible that I did not read it. So your claim that what I said was wrong is incorrect. Your incorrectness is the reason for my doubling down.

You seem to misunderstand "true" in the context of your proposed modal logic. Notice in your definition of "possibly", "true" is relative to the specified world. Therefore if it is true that I read the post, it cannot be the case that I did not. "True" indicates what is the case within a specified world. You can go ahead and talk about other worlds, in which I did not read the post, but in those worlds it is not true that I read the post.

What to make of that. Modal logic not relevant to possibility and necessity. — Banno

The words "possibility" and "necessity" were being used long before modal logic was invented, so it is clear that those words can be used in ways not at all related to modal logic. If you want to limit use specifically to modal logic, then to avoid ambiguity we need principles or definitions. So, if you want to bring a specific form of modal logic to bear on this discussion, you need to provide some principles or definitions, as you did with "possibility" above.

However, you need to respect the consequences of these principles. Notice for instance what becomes of "true" under your definition of "possibly". "True" becomes relative to the specified world, it is not absolute, or relative to any sort of supposed independent actual world. If you use "true" in a number of different ways you likely equivocate.

And the answer, overwhelmingly, is "yes". If we know something then by that very fact it is possibel for us to know that thing. — Banno

You have not yet defined "possible" to support this, as I asked. What you are saying here is that "it is possible that we know X" is implied by "we know X". I've already explained to you over and over, why this is incoherent. The two actually contradict each other because "it is possible that we know X" means that it could be the case that we do not know X, while "we know X" means that it could not be the case that we do not know X.

I've shown you the logic. Continuing to assert something completely illogical is pointless. You need to back up your claims, show how you understand the meaning of "possible" in such a way which allows what you assert to somehow be coherent.

No — that conflates truth with necessity. “p is true” does not mean “p cannot be false.” It means only that p is not false in the actual world. Something can be true without being necessary, and false without being impossible. — Banno

Your mention of necessity is a distraction of sophistry. If p is true it very clearly does mean that p cannot be false. Notice "is" and "be" imply the present time. If p is true, p cannot be false, because that would mean that p is true and false at the same time.

Furthermore, truth and falsity are determined by the actual world, as correspondence. I'm very surprised that you, a self-proclaimed realist would suggest otherwise. If truth is not determined by the actual world, realism has no standing.

But that issue is which I told you about yesterday, your tendency to say one thing, then argue principles which explicitly undermine what you claim. It's a sort of hypocrisy on your part.

It is true that you read this post. It is also possible that you might not have read it. — Banno

What? How does that make sense? If it is true that I read this post, how is it possible that I did not read it?

'Did' marks what happened, not what had to happen. Saying 'Jill did push Jack' tells us what actually happened, not that her pushing him was necessary, inevitable, or impossible to be otherwise. Confusing tense with modality is exactly the same mistake as treating 'true' as meaning 'cannot be false.' — Banno

I agree, "did" marks what actually happened, and this is the truth. As it is the truth, it is impossible to be otherwise. If Jill did push Jack, then that is the truth, and it is impossible to be otherwise. True does mean, precisely and exactly, "cannot be false". If what is true could be false we would have contradiction. If you really believe otherwise, you have some explaining to do.

And I don't know how "modality" is related here. You haven't provided any definitions or principles of relations. All you have done so far is made absurd assertions.

Unfortunately, no. Your ignorance of modal logic stands alongside your denial of instantaneous velocity and insistence that 0.9... ≠ 1. — Banno

You keep bringing up "modal logic" but you have done nothing to show how this is relevant. We have been talking about what it means to know p, not to know p, and the possibility of knowing p. That is what we are talking about, what these propositions mean. If you want to apply modal logic, then you need to provide some principles, definitions, and structure. To simply keep on asserting that what I say is contrary to modal logic is pointless if you cannot prove your claims with reference to some principles or definitions.

If we know shit at time t, then clearly at some time prior to time t it must have been possible to know said shit - otherwise there's no way we could know said shit at time t. This is the plain language interpretation. — EricH

That is not the issue. The question is whether at the same time, "We know shit", and "It is possible that we know shit", could both be judge to be true.

So I'm trying to figure out how P1 would not automatically imply P3 at time t. Are you saying that prior to time t we were somehow able to figure out the shit, but that at time t the situation has changed and we whatever means/mechanism we used to determine the shit prior to t is no longer applicable - and thus P1 no longer automatically implies P3? — EricH

The issue is if, when you judge that p is true, you can also judge that it is possible that p is true. I think that this is dishonesty and contradiction because "it is possible that p is true" contradicts "p is true". This is because "p is true" means that it is not possible that p is false, whereas "it is possible that p is true" means that it is possible that p is false. Therefore contradiction.

No, it doesn't. It might have been the case now that we didn't know stuff. In some other posibel world we might not have known stuff. Tensed logic, if needed, is constructed separately to modal logic. But your not seeing this is yet another example of your eccentricity. — Banno

For God's sake Banno, what are you talking about? "Did" is the past tense of do. "Did not know" refers to the past. It does not refer to the present, which would be "does not know".

Are you suggesting that the past tense "did" can refer to the present, but in another world? So that "we did not know" doesn't refer to us in the past, but it refers to us at the present, but in another world? So right now, we know shit, but in another world there's another us that does not know the same shit, right now. And somehow it seems reasonable to you to say that this other "we", at the present time "did" not know shit right now, because the usage of the past tense creates the illusion of a temporal separation between one thing referred to with "we" and the other as if it's a temporal extension of one thing referred to with "we". But the illusion of the temporal separation only really helps to veil the absurdity of two versions of 'we" existing at the very same time. Why not just say what you mean, there's one "we" which knows, and another "we" which does not know.

In my last post I warned you about using ambiguity. See here, "we" refers to two distinct groups of people, one which knows stuff, and the other which does not know stuff, both at the same time. Can you see that you are intentionally proposing ambiguity? That fills the criteria of sophistry.

"My eccentricity"? Is that meant as a joke? You are the one talking about the 'we" which know stuff at the present time, and another "we" which does not know the same stuff at the same time. And to cover up the absurdity of this you say that the one "we" does know stuff right now, and the other "we" did not know the same stuff right now. Don't you admit that that is very strange "stuff" which you are on about?

Please Banno, try to provide something more reasonable.

I think it's actually about drugs... — frank

Check this:
President Donald Trump said Friday that he will be pardoning former Honduran President Juan Orlando Hernandez, who in 2024 was convicted for drug trafficking and weapons charges and sentenced to 45 years in prison.

...the bit where if you know stuff, then it thereby is possible to know stuff. Yes, it might have been that we did not know stuff, but as things turned out, we do know stuff. Either way, it is possible - that is, not impossible - to know the stuff that we do indeed know. — Banno

Look at the temporality of your statements; "it might have been that we did not know stuff", refers to past time. All three of the propositions refer to current time. The propositions refer to our knowledge of "shit" at the present time. That we might not have known, in the past, what we do know now, is completely irrelevant.

Statements like "if you know stuff, then it thereby is possible to know stuff" indicate to me that common usage has corrupted your understanding of "possible". Common usage propagates ambiguity, so "the stuff" which you refer to as the stuff that is known, is not the same stuff as "the stuff" that it is possible to know. If I know 10 cars (stuff known), you might conclude that it's possible for me to know another 40 cars (stuff possible to know), but clearly "stuff" refers to something different in each case, the 10 cars that are known , and the 40 cars that are not known, are completely different things. That's ambiguity in "cars", just like the ambiguity in your use of "stuff".

So I think you need a good clear definition of "possible" which would support your usage. I've already explained my usage. The proposition "it is possible to know p" indicates that we have judged that p could be known, but is not known. This is because "it is possible that p is known" would indicate that we do not know whether p is known or not, and that would be somewhat incoherent, implying that we know without knowing that we know. So we must settle on an altered version, "it is possible to know p", but "possible" maintains the same meaning. "Possible" indicates that we do not know whether p is true or not. That is why it is inconsistent with the judgement "p is known", as this implies that we know whether p is true or not.

Can you provide me with a definition of "possible" which supports your position, so I can understand what you are trying to say?

Note that it's "shit may not be known", which is quite valid, and not your "shit is not known", which implies that you only know shit that it is not possible to now. — Banno

This is an indication of the ambiguity which is disturbing you. Shit is the subject, and known is the predicate. I believe, "Shit is not known" is a valid predication. The ambiguity described above, is making you think of "shit" as a multidimensional object, in which each dimension is called "shit", and some dimensions may be known while others not. That is very confused shit, which you are proposing.

This is tedious, Meta. But good for my post count. — Banno

Personally I don't give a damn about any thread counts or anything like that. But if it pleases you, it makes me happy too. The pleasure is ours, and it may help you to overcome the tediousness. I'm tedious by nature, so I'm pleased that you give me the opportunity to be that way. Therefore I suggest that we keep the posts short and to the point, quicker reply etc., as that would be preferrable to you. The next point would be for you to provide a definition of "possible" so that I can question you on it, to gain an understanding of what you mean. Then I can examine and analyze your usage to see if your definition is coherent and consistent with your usage.

For anyone watching on, (well, there may be some...) Meta's argument relies on treating “◊Kp” as if it meant “we do not know p, but could.” But that is not what the modal operator means — not in Aristotle, not in modern modal logic, not anywhere. — Banno

OK, so let's see what "the modal operator means". Can you define "possible" in a way which makes sense of what you are claiming, without the appeal to ambiguity demonstrated above? Can you keep the subject (or object if you wish) which is referred to, as one subject, and not make it refer to many things (as you do above). After you've been informed of this ambiguity, it would be a case of intentional ambiguity if you continue to utilize it. Intentional ambiguity will surely support the charge of sophistry.

It does, for your purpose. Perhaps that's the issue... I think what you're getting at is essentially the problem of other minds. I don't even know that 'red' is the same for you, as me. — AmadeusD

It's you who has insisted that knowledge is the property of a single subject. Look, I am happy to discuss with Banno, propositions like "we know...", which implies that knowledge is a property of "us". However, we must keep these two discussions separate, because "know" refers to two very distinct things in the two cases of "I know...", and "we know...".

So I am not bringing up any "problem of other minds", just informing you of the obvious, that the knowledge in my mind is different from the knowledge in your mind. And if you make claims, like you did, which indicate that you think that you and I have the same knowledge, I will ask you to justify such claims because they are inconsistent with your starting premise, that knowledge is the property of an individual subject.

Banno, on the other hand has started with a use of "know" which indicates that knowledge is a property of us, "we". So if Banno starts to say that I can know different things from what you know, then I can likewise ask him to justify those assertions, as they are inconsistent with that starting premise.

Curiously, Aristotle was at pains to disagree. — Banno

I don't see how any of your free floating quotes from Aristotle are relevant, because you and I are discussing epistemic possibility, and your quotes from Aristotle concern ontological possibility. These two are very different. Clearly Aristotle believed, as you indicate ""If a thing is or has been, then it is necessary that it was possible for it to be". But Aristotle was very interested in change, and the temporal aspect of reality, physics. So he was concerned with how a specific possibility is actualized, rather than some other possibility, and he also stipulated that the possibility of a physical thing is always prior in time to the actual existence of that thing, as your quotes indicate.

You gallantly attempt to make a coherent account in which knowing that p is possible is logically incompatible with knowing that p. But this requires a reversal of modal logic and the standard view of the last 2300 years - that what is actual must be possible. — Banno

It's not my fault if the so-called "standard view" is misguided and obviously incorrect. Your appeal to authority does not stand up very well to my well-formulated logical argument. Look again:

P1. We know shit.
P2 We do not know shit.
P3 It is possible to know shit.

If we judge 1 as true, then we know that we know shit. Further, if we then proceed to judge 3, we already know that we know shit, and 3, "it is possible to know shit" implies that shit may not be known. That shit may not be known is impossible by our judgement of 1, a judgement which makes it necessary that we know shit. So 1 and 3 are incompatible. However, if we judge 2 as true, then we know that we do not know shit. But even if we judge that we do not know shit, it might still be possible that we could know shit. So 2 and 3 are compatible.

As for your use of Excluded Middle, "It is possible that we know that P" is not a third state between "We know that P" and "We don't know that P". It is a different proposition about the modal status of Kp. It is ◊Kp. — Banno

OK, now we're getting somewhere. I will agree, that "It is possible that we know that P" is a different type of proposition, categorically distinct from the pair "we know that p", and "we do not know that p". So, you need to treat them that way, and stop declaring that one is "derivable" from the other. That is your category mistake, Look:

Kp is read "p is known", and ◇Kp, "it is possible that p is known". They are not the "represented by the same proposition". But the latter is derivable from the former. — Banno

I'm happy to concede that both "we know that p" and "we do not know that p" are categorically distinct from, and incompatible with, "it is possible to know p", but then you must agree that we cannot draw inferences across that category boundary.

This is why I "double-down". You say things like "It is a different proposition about the modal status of Kp", and "This is a category error", which indicates that you actually recognize the principles. But you refuse to apply these same principles to your own erroneous statements. So it's a type of hypocrisy. You make claims and assertions which are contrary to the principles which you employ in arguments against others. Doubling-down is necessary to help you to reflect.

That category mistake is what Sirius pointed out to you.

"Every Truth is knowable" is subject independent. It does not presume the existence of knowers.

"Every truth is known" is subject dependent since it presumes the existence of knowers.

Note : I'm not making a tensed argument.

So you can't claim both are represented by the same propositional form "kp" without justification. — Sirius

The consequence of this is the term k will be different for one of the two.

To illustrate,

(K(p),x) =: There exist x which knows p, for truth is known

K(p) =: p is knowable, for truth is knowable


Now, there is no way to draw an inference from the latter to the earlier since the total variables are different

If this argument isn't mentioned in SEP (I haven't checked it yet) then it doesn't show it's invalid. It could be out there, somewhere else. I don't think I'm the first one to ever raise this rather obvious objection. — Sirius

The alternative... if we know that p, and yet it is not possible that we know that p... is risible. — Banno

Another fine example of sophistic abuse of language. The correct statement would be ... if we know that p, it is not possible that we know that p is possible. This is because logically, if we know that p is possible, then it is the case that we do not know that p. "We know that p" is not consistent with "we know that p is possible". Difficult to understand? I think not. Common sense will tell you that if we know that P is possible, this is consistent with "we do not know that p", and it is inconsistent with "we know that p".

This is the problem with your representation, from the start, which @Corvus very adeptly points out. You start with the subject "we", and the predicate "know that p". Then you unsoundly step outside that predication, to qualify it with "it is not possible that". Nothing that I said supports this strawman representation. The "knowable" in your representation is not a predication of any subject, because you attempt to remove it from "we". In fact, this representation is illogical, being excluded by the law of excluded middle if we adhere to the need for a subject in predication.

The two alternatives are "we know that p", and "we do not know that p". Representations such as, "possible that we know that p", are explicitly excluded by the law of excluded middle. For the umpteenth time, do you recognize this reality, that "possible that we know that P", in this basic form, violates the law of excluded middle? Therefore, if it happens to be the case that the truth of the matter must be represented with "we know that p is possible", then we must categorize this as a form of "we do not know that p", in order to remain consistent with the law of excluded middle. That is because, if you stipulate that "we know that p is possible" is consistent with "we know that P", as you do with "If we know that p, then it is possible that we know that p", you implicitly contradict yourself, because because knowing that p is possible is not knowing that p. Therefore "we know that p is possible" must be classed as a form of "we do not know that P".

This is such simple, basic reasoning, developed thousands of years ago, so I cannot honestly believe that you actually do not understand it. And especially after its been so thoroughly explained to you numerous times. Therefore I can only conclude that you intentionally deny fundamental logical principles for the sake of sophistry.

...without the curtesy of flagging mentions of me... — Banno

You tend to ignore mentions, so I've reverted to reverse psychology. It seems to be working.

"known" cannot apply except to an S. — AmadeusD

Yes, I assumed that was the perspective you were taking from the start.

I don't think the rest needs treating with this in mind. — AmadeusD

The rest of my post assumes that position, that knowledge is particular to the individual subject. I described the problems with this, what is known to me is not the same as what is known to you. Reread the post.

Or you're barking up a really weird and uninteresting tree. To say "the colour of the surface of Mars is known" doesn't mean anything. Known by whom? — AmadeusD

Look, I say that I know Mars is red, and you say that you know mars is red. The fact that we use the same words, "Mars is red" doesn't mean that we both know the same thing. The words represent what is known as proper to each subject who uses the words. What I know as "Mars is red" is completely different from what You know as "Mars is red".

I see you're still having difficulty understanding. Either that or you've retreated into some form of denial. So, let me lay it out very succinctly.

Take any proposition, "the cup is red" for example. The truth of this proposition means that the situation cannot be otherwise from the cup being red. Now take the alternative proposition, "it is possible that the cup is red". This means that the situation can be otherwise from the cup being red. One says it can be otherwise, the other says it cannot be otherwise. Therefore the two contradict each other in meaning, an implicit contradiction.

We can see a very similar situation with "p is known", and "p is knowable". Truth of the former indicates that the situation cannot be otherwise from p is known, while truth of the latter indicates that it can be otherwise from p is known. Therefore one contradicts the other and they cannot both be true at the same time. One is not derived from the other, it implicitly contradicts the other.

If I know X, then it is trivially possible that I know X. — Banno

How can you honestly say something like this? If you know that Jill pushed Jack down the hill, and someone asks you about what happened, then you are being untruthful if you say that you believe it is possible that Jill pushed Jack. Obviously you do not believe that at all, because you know that Jill actually did push Jack. To say that it is possible that Jill pushed Jack, is to be deceitful, because it contradicts what you know. To insist that "I know X" and "It is possible that I know X" are consistent with one another is blatant deception.

"Known" indicates that some S knows it. It also indicates that another S could also know it but does not currently. — AmadeusD

How does "known" indicate these things to you. If it indicates that some S knows it, it doesn't in anyway indicate that another S could know it. That would require another premise. So your argument is based in hidden premises.

The problem I see with this approach, is that if we define "known" as the property of one S, then when we introduce other Ss we have no way of validating whether what one S knows is actually the same thing as what another S knows. So, S knows something, and teaches it to another, T. Now what T knows is not the same thing as what S knows, even though S taught T. It doesn't make sense to say that another knows the same thing that S knows, in any logically rigorous sense of "same".

Any piece of information can be known many times over by different people or animals. So I'm with him here. — AmadeusD

This is not true, for the reason i just explained. The information I receive is not the same as what you receive, because we each have distinct spatial temporal perspectives. Therefore it is false to say that many different people know the same piece of information.

If this were so, you would not know any things that are knowable. — Banno

That's exactly right. "Knowable" excludes "known" because knowable allows for "not-known". Every proposition which I know, is actually known, that's what "known" means. However, "knowable" means that it is possible that the proposition could be known, and this implies that it is not actually known. Therefore I do not know any propositions which are knowable, (possible to be known) because every proposition that I know is actually known, therefore not-possible that it is not-known, and knowable implies that it is possible that it is not-known.

You are treating “Possible to be known” as if it meant “not known”. — Banno

Of course, "possible to be known" is categorically distinct from "known". Therefore it is a form of "not-known", in the sense of other than known. To allow otherwise would create all sorts of epistemological problems.

Consider your example. I know something, and it is possible that I know it. We can represent these as the two following propositions P1, "I know X", and P2, "It is possible that I know X". Clearly, if we judge P1 to be true, we cannot honestly judge P2 to be true, because the truth of P2 allows that P1 may not be true. We cannot say that it is true that I know X, and also that it is true that it is possible that I know X, because the latter judgement implies that it is possible that I do not know X, thereby ruling out the possibility of former judgement, that I know X.

Therefore "it is possible that I know X" must be taken as a form of "I do not know X", because "possible that I know X" implies necessarily that I may not know X. So "I know X" and "it is possible that I know X" cannot both be true at the same time, because the latter allows the possibility that "I know X" may be false, and that would contradict "I know X". In other words, claiming both provides the premises which allow for contradiction.

Or do you know only things that are impossible to know? Perhaps you think you do. — Banno

Who said anything about "impossible"? Like you, and everyone else, I only know things which are known. I do not claim to know things which are possibly known, because possibly known implies possibly not known as well. Then I would be claiming to know things which are possibly not known, thereby allowing for the potential of contradiction.

It is very obvious that the difference between actual and possible indicates that if p is knowable (possible to be known), then p is not known. Conversely. if p is known, then p is not knowable (possible to be known) because it is already actually known. I illustrated this very clearly in my reply to Sirius, which it appears that you did not take the time to understand. To conflate these two is an abuse of language, which you do with the intent of sophistry.

Back to ignoring you. — Banno

You obviously didn't address what I wrote. And, it appears like you didn't even attempt to understand what I wrote. Despite pretending to consider what I wrote, and adding your two cents worth, your ignorance is continuous.

@Sirius
Here's an illustration to demonstrate what I'm talking about. Suppose we take a simple proposition P, and say that it is possible. We therefore must also allow that not-P is possible. In the basic form, we have a relation of equality between them, each is equally possible. This equivalence between the two allows us to apply mathematics, 50% probability at the fundamental level. It is fundamental to the nature of "a possibility", that there is at least two, and this allows us to apply the mathematics of probability.

Now, we can add secondary propositions which would alter the weighting, making one possibility more probable than the other. We can add as many secondary propositions as we like, and apply formulae to figure probability. However, if we go to the point of saying either P or not-P is true, that it is what is actually the case, then we assign 100% probability to it. This negates all other possibilities, and since the one assigned 100% is necessarily the one and only, it loses it's nature of being a possibility.

So in Banno's example, P is actually known. But Banno wants to derive from this truth, that P is also possible to be known (knowable). But of course, by the logic of the above example, if P is knowable, (possible to be known), it is impossible that P is actually known.

If not, then it's the worst case of question begging & the formal logic showpiece is nothing short of sophistry. Symbols can only take you so far, what matters more is semantics, epistemology & metaphysics at a deeper level. — Sirius

Now, there is no way to draw an inference from the latter to the earlier since the total variables are different — Sirius

After years of explaining very similar issues to Banno, Banno simply chooses to ignore, rejecting Aristotelian bullshit. As you accurately point out, "known" and "knowable" are defined by distinct relations, with distinct variables. You say, one is subject dependent, the other is subject independent. This makes them categorically distinct. Therefore there is nothing within :"known" which implies "knowable". And since "knowable" is supposed to be subject independent, it must be defined by some other relation.

I explained this problem thoroughly to Banno already, as the incompatibility between what is actual, and what is possible. If, for instance, we say that X is actually the case, we cannot say also that X is possibly the case, due to contradiction. What it means to say that X is an actuality contradicts what it means to say that X is a possibility. The principles required to make it true that X is an actuality, negate the possibility that X is possible. But Banno continues to insist (sophistically), that the latter is "derivable" from the former.

You may regard this as an outdated Aristotelian objection, but it has actually inspired modern relevance logic [which extends to modality] — Sirius

That's Banno's usual, reject outdated Aristotelian principles, in full ignorance of the fact that these principles were established for the purpose of combatting very similar sophistry.

Two men, two goals, same means, kill two birds with one stone.