Sorry, the "that" was ambiguous. Better to have said, "A logical impossibility is so by virtue of its form. And we know that logical form is unaffected by tense." — J

And you know this I presume a priori.

Well, sort of. I'm invoking the standard construal of something like "p → q; p; ~q". This would be impossible by virtue of the assigned meanings of the logical connectives -- does that count as a priori? And there are no tensed versions of such a statement; it's meant to be false for all instances in the past and in the future.

I'm interested to know what's caught your attention here. Sometimes the most obvious construals can be wrong, so by all means tell me what you're thinking.

Just exploring this idea of “tense” and “affecting” logical form.

I will stop my inquiry into this since this may take the conversation in a direction the post may not have intended.

I think the conversation got away from PSR quite some time ago, but OK! Maybe another time.

There are two possible worlds that are accessible from today. — Banno

The concept of "possible worlds" itself violates the fundamental laws of logic. To predicate of "a world" that this world is possible violates the fundamental laws of logic. "Possible" implies that the world neither is nor is not and that is a violation.

Or, as argued earlier, determinism is false. — Banno

That's the best conclusion. But, if in fact determinism is false, then either the law of non-contradiction, or the law of excluded middle, both, or even identity, do not apply toward things of the future. This produces an important ontological question of what does the future consist of.

.To question the creator at all, we are assuming they exist to begin with right? So I see why the claim you make regarding Inherent existence is relevant here. Otherwise, bringing up the infinite regress aspect of design vs designer arguments as an acceptable position is assuming the existence exists in the first place..or is questioning how the existence was created apart of it's inherent nature? — Kizzy

An infinite regress signifies a logical impasse, a point where logic fails us. Assuming a final cause, as first cause, breaks the infinite regress of efficient cause, thereby pointing the mind in a different direction, allowing the logic to go to work from a different perspective, and possibly avoiding that failure.

So when I mention "the will to know" it involves the will to get beyond the logical impasse presented by things like infinite regress, (which appear to indicate that the object is impossible to know), and derive a new approach toward knowing it.

But there is a shwack load of situations with real possibilities. This would make the application of the law of excluded middle to be so infrequent that it would be no law at all. Which sounds absurd. — A Christian Philosophy

When you think about it, the law of excluded middle has very limited applicability. It's incompatible with probabilities. That's why modal forms of logic were invented.

Here is my alternative solution: There is ambiguity in the terms "there will be".
The statement "there will be a sea battle tomorrow" either means "there will necessarily be a sea battle tomorrow" or "there will possibly be a sea battle tomorrow". Both statements are either true or false. — A Christian Philosophy

Ambiguity just brings the violation of to a different level. Which of the two statements is true, and which is false? If we say "there will possibly be a sea battle tomorrow" is true, then the being or not being of that event, the referred sea battle, violates the law. This is exactly the tactic of Banno, by making "sea battle" a logical subject instead of an objective occurrence being referred to, it's existence becomes irrelevant, and the world of the sea battle is simply a possible world. Then whatever is said about it must follow the rules of that form of logic, rather than the rules we are discussing.

That's fine, within that logical structure which respects the fact that the subject, the sea battle tomorrow, is not a real object, but an idea created by a mind. The three laws, identity, non-contradiction, and excluded middle, make statements concerning what we can say about real objects. They do not apply to imaginary (or possible) objects, because we can say anything we want about these. The imagination is inherently unlimited. And since these imaginary subjects are beyond the applicability of those laws, we can just make up other laws, axioms, definitions, etc., which these imaginary things must obey.

The concept of "possible worlds" itself violates the fundamental laws of logic. — Metaphysician Undercover

Good grief.

Ok. There's not much point in reading your post any further.

Your replies are very predictable. When you do not understand the concept, walk away instead of learning.

"A possible world is a complete and consistent way the world is or could have been. Possible worlds are widely used as a formal device in logic, philosophy, and linguistics in order to provide a semantics for intensional and modal logic."

LOL.

"Although ‘possible world’ has been part of the philosophical lexicon at least since Leibniz, the notion became firmly entrenched in contemporary philosophy with the development of possible world semantics for the languages of propositional and first-order modal logic. "

A possible world is a complete and consistent way the world is or could have been. — AmadeusD

The basic laws of logic apply to the the way the world is. They are rules concerning what we can say about things. Adding to this, "or could have been". is a violation.

...and yet there it is.

Hehe I guess if all you go on it Wittgenstein, then yeah. But who would do that, when, yeah - there it is.

I don't think earlier Wittgenstein would exactly go along with this line of thought. Consider these sections from Tractatus,

“3.02. The thought contains the possibility of the state of affairs which it thinks. What is thinkable is also possible.

3.03 We cannot think anything unlogical, for otherwise we should have to think unlogically.

3.032 It used to be said that God could create everything, except what was contrary to the laws of logic. The truth is, we could not say of an “unlogical” world how it would look.”

And

“2.014. Objects contain the possibility of all states of affairs.”

2.0141 The possibility of its occurrence in atomic facts is the form of the object.”

And

“2.201 The picture depicts reality by representing a possibility of the existence and non-existence of atomic facts.

2.202. The picture represents a possible state of affairs in logical space.”

Yes. Funnily enough, i actually picked up Tractatus for hte bus this morning, so read these exact passages before responding.
The point of Many Worlds is that you can think, logically, of a world which does not exist, but is coherent and possible.

Nothing illogical about that. My comment about Witty leading to the type of thoughts Meta is putting forward was about not contextualizing Wittgenstein as coming out of Russell per On Denoting. Not a great way to move from language use, to what 'can be'.

yeah - there it is — AmadeusD

Yeah, there it is. A relatively new type of logic which is not based in the fundamental three laws, and openly averts these laws. It's really not a big deal, but to deny that modal logic intentionally avoids those laws, because of a perceived need to violate those laws, is to demonstrate a basic misunderstanding of logic.

Yes. Funnily enough, i actually picked up Tractatus for hte bus this morning, so read these exact passages before responding.
The point of Many Worlds is that you can think, logically, of a world which does not exist, but is coherent and possible.

Nothing illogical about that. My comment about Witty leading to the type of thoughts Meta is putting forward was about not contextualizing Wittgenstein as coming out of Russell per On Denoting. Not a great way to move from language use, to what 'can be'. — AmadeusD

I am not saying it's illogical. No principles dictate that all forms of logic must obey those three basic laws, to be classed as "logic". Those three laws are ancient, and concern what we can say about a thing, starting with the law of identity, a thing is the same as itself. If, for some purposes, we find that we need a logic which applies to possibilities (possible worlds), then we would need a different set of laws, because possibilities are categorically different from actual things. However, the fact that one set of logical laws is not compatible with another, because the two apply to completely different aspects of reality, does not imply that one or the other is illogical. It simply demonstrates that there is a significant difference between the different aspects of reality.

If I understand correctly, the fundamental laws of logic exist in all possible worlds, and they are contravened only in impossible worlds. Is that right?

My point is that most people do not question that causes exist and do not ask what causes are because the word is already clear. I don't see a reason to defend a belief that is uncontroversially accepted. If you have a solid reason to defend the claim that causes are not in fact real, I'm ready to hear it. But if not, then I don't see a point of investigating this issue further.

If we say "there will possibly be a sea battle tomorrow" is true, then the being or not being of that event, the referred sea battle, violates the law. — Metaphysician Undercover

Not quite. Running the statement through the law of excluded middle gives: "there will possibly be a sea battle tomorrow" or "there will not possibly be a sea battle tomorrow (i.e. a sea battle tomorrow is impossible)". If, in reality, a sea battle is possible, then the first statement is true and the second one is false.

If I understand correctly, the fundamental laws of logic exist in all possible worlds, and they are contravened only in impossible worlds. Is that right? — A Christian Philosophy

An odd wording, but not wrong. It gets complex, of course.

As shown in the links above, the logic of possibility and necessity - modal logic - has a strong standing in modern logic. Those who restrict themselves to Aristotle still have difficulties.

Not quite. Running the statement through the law of excluded middle gives: "there will possibly be a sea battle tomorrow" or "there will not possibly be a sea battle tomorrow (i.e. a sea battle tomorrow is impossible)". If, in reality, a sea battle is possible, then the first statement is true and the second one is false. — A Christian Philosophy

The issue, is that you are making "possibly be" into a predicate. By doing this you violate the law of excluded middle, because the meaning of "possible" (what may or may not) is a violation.

The law of excluded middle is a law concerning predication. Now, we introduce a very special predicate named "possible", which we accept as being excluded from the applicability of this law. My argument is that we must respect the fact that this is an exclusion, and not attempt to represent "possible worlds", or "modal" logic as consistent with the fundamental three laws.

As shown in the links above, the logic of possibility and necessity - modal logic - has a strong standing in modern logic. Those who restrict themselves to Aristotle still have difficulties. — Banno

No one here is suggesting that anyone ought to restrict themselves to Aristotelian logic. What I am recommending is that we acknowledge the inconsistency between modal logic and the fundamental three laws, and not attempt to argue that there is consistency between them. Arguing for consistency signifies misunderstanding.

In ancient Greece the three laws were applied religiously, modal logic did not exist. Aristotle demonstrated how sophists (like Zeno who proved that motion cannot be real), could prove absurdities when those fundamental laws were strictly adhered to. He proceeded to expose the root of the problem as being the reality of potential, possibility, as the basis of change and becoming, and showed that we need to allow violation of either non-contradiction or excluded middle to understand this reality.

Aristotle's best examples were future possible events, which needed to be decided upon by human choice, like the sea battle. He determined that the way we understand human choice implies that the law of excluded middle must be violated to enable that understanding. However, he insisted that the law of non-contradiction must be adhered to avoid absolute unintelligibility. This violation of excluded middle, proposed by Aristotle, is the foundation of modern modal logic which is the manifestation of that violation.

Hegel's logical dialectics, on the other hand, allows that being and not being are subsumed within becoming. This is a violation of non-contradiction, which provides the foundation for dialectical materialism. Notice, that Aristotle's violation of excluded middles is based in the potential associated with human choice, while Hegel's violation of non-contradiction is based in the potential of matter.

My point is that most people do not question that causes exist and do not ask what causes are because the word is already clear. I don't see a reason to defend a belief that is uncontroversially accepted. — A Christian Philosophy

'Course not. People believe it; it must be true. And anyway, they believe it! Case closed!

What nonsense!

I'm sorry, Meta, but your post is again risible. You say no one is restricting themselves to Aristotle and then go and do exactly that. This is on par with your rejection of instantaneous velocity and 0.99...=1. This is the reason I do not usually read nor reply to your posts.

Modal logic has been demonstrated to be consistent. You are simply mistaken.

I'm sorry, Meta, but your post is again risible. You say no one is restricting themselves to Aristotle and then go and do exactly that. — Banno

You seem to have a limited capacity for understanding.

What I said was:

What I am recommending is that we acknowledge the inconsistency between modal logic and the fundamental three laws, and not attempt to argue that there is consistency between them.

I then proceeded to explain the reason why the two are inconsistent.

If that produces for you, the conclusion that I am restricting myself to one or the other, then you have a significant problem in your ability to interpret a simple piece of writing.

You seem to have a limited capacity for understanding. — Metaphysician Undercover

Well, to be sure, I do not understand how you can maintain such views. There are formal proofs of the consistency of S5, for example. Google it. So again, I'll leave you to it.

Cheers.

I don't doubt the consistency of S5. Did I say that one system of logic, or another is not consistent? No, I pointed out two systems of logic which are not consistent with each other.

Fine.

It's good to see that we agree, once in a while.

In ancient Greece the three laws were applied religiously, modal logic did not exist. Aristotle demonstrated how sophists (like Zeno who proved that motion cannot be real), could prove absurdities when those fundamental laws were strictly adhered to. He proceeded to expose the root of the problem as being the reality of potential, possibility, as the basis of change and becoming, and showed that we need to allow violation of either non-contradiction or excluded middle to understand this reality.

Aristotle's best examples were future possible events, which needed to be decided upon by human choice, like the sea battle. He determined that the way we understand human choice implies that the law of excluded middle must be violated to enable that understanding. However, he insisted that the law of non-contradiction must be adhered to avoid absolute unintelligibility. — Metaphysician Undercover

But rhetoric certainly existed, with its own logic in which even as a matter of necessity both sides of a contradiction are "entertained." There will be a sea battle; there won't. The ultimate reduction being either-or, to which A. added also neither-nor. And Achilleus, "in the division of his heart," weighting competing courses of action.

The division, then, between on one side matters that are necessarily so and not otherwise, and proving them as needed, and on the other matters that may be this way or another way, often enough concerning future actions. To be sure, the logics can overlap, but in main subject and acceptable practice different.

But rhetoric certainly existed, with its own logic in which even as a matter of necessity both sides of a contradiction are "entertained." There will be a sea battle; there won't. The ultimate reduction being either-or, to which A. added also neither-nor. And Achilleus, "in the division of his heart," weighting competing courses of action. — tim wood

We are not talking about the situation after a future reduction though, we are talking about the current situation now. At the present time, neither "there will be a sea battle tomorrow" nor "there will not be a sea battle tomorrow" is true. "It is possible that there will be a sea battle tomorrow" is true, but obviously this violates the law of excluded middle. However, under the principles of determinism, one or the other is considered to be true, even at the current time. But this leaves "it is possible that there will be a sea battle tomorrow" as false. (Note to Banno: this use of "possible" is not consistent with modal logic, but there is a number of different ways "possible" is commonly used). Also, determinism leaves deliberation as superfluous, so only a fool would accept that perspective.

We are not talking about the situation after a future reduction though, we are talking about the current situation now. — Metaphysician Undercover

Exactly so. And the right logic for this is Rhetoric, in which we consider both alternatives, sea battle or no sea battle. And resolution relies not-so-much on a voiceless demonstration of an apodictic certainty, but instead on persuasion that considers contradictory possibilities to determine a best course of action.

Imagine just before D-Day, Eisenhower deciding whether to chance the weather, and an advisor telling him that it was not true that the next day the invasion would take place, nor true that the invasion would not take place the next day. I think he might make that advisor first person on the beach!

And the right logic for this is Rhetoric, in which we consider both alternatives, sea battle or no sea battle. — tim wood

The problem though is that "Rhetoric" is not necessarily logic, it is language intended to persuade. If we class the language which deals with what is possible, and this includes what is named "modal logic", as simple rhetoric, @Banno will not be happy. However, "rhetoric" is the larger category, and logic can be used as rhetoric. But this leaves your statement as meaningless.