The so called 'laws of physics' are not really 'laws' in that physical entities are compelled to follow those laws. What you actually have in the 'laws of physics' are a description, and often a very accurate description, of the way that physical entities behave.

The only 'justification' required for a distinction is that it proves useful for the understanding of the world.. such as the difference between mammals and fish so that dolphins belong to one but not the other.

As for Hume's distinctions.. I was referring to his famous quote regarding 'matters of fact' and 'relations of ideas' and that if a book in a library said nothing about either it should be burnt.

I am just extrapolating, or perhaps bringing up to date this distinction, so that it differentiates between ideas or statements that refer to the real world or those that refer to an abstract world.

All too often in philosophy people conflate the two and arrive at false conclusions about the real world.

The so called 'laws of physics' are not really 'laws' in that physical entities are compelled to follow those laws. What you actually have in the 'laws of physics' are a description, and often a very accurate description, of the way that physical entities behave. — A Seagull

We can't describe events in the future because we dont have access to them. Laws of physics are expected to predict events, so in what sense could we say they're descriptions?

That's all the average person thinks of as a physical law: predictability, the compulsion angle is funny.

We can say that the laws of physics can be used to predict a description of the future.

Let me re-emphasize my thought-experiment: Suppose the world changes overnight so that it becomes impossible to model an implication (per se and of course especially for our human minds). It's hard to see why and how, but just bare with me. Wouldn't that mean that MP becomes impossible as well, in contrast to a day before where it was not only possible, but necessary? Doesn't that prove the induction problem for logic as well? — Pippen

If you lived in a world where nothing followed necessarily from anything else, then MP wouldn't apply. Perhaps, for example, a quantum vacuum where particles just pop into and out of existence and you are a Boltzmann brain.

However that wouldn't be a case of MP failing, merely that it has no application or use in that scenario. Whereas the rule p; p ->q; not q is inconsistent and so couldn't apply to any scenario.

Nowadays, Hume's intuition about the sun is considered to be quite right:

The Solar System will remain roughly as we know it today until the hydrogen in the core of the Sun has been entirely converted to helium, which will occur roughly 5 billion years from now. — alcontali

The sun will still be around in five billion years, therefore Hume was right that the sun might not rise tomorrow? :-)

The sun will still be around in five billion years, therefore Hume was right that the sun might not rise tomorrow? :-) — Andrew M

Technically, yes. Some day it will be true.

We can say that the laws of physics can be used to predict a description of the future. — A Seagull

So we dont predict future events, we predict descriptions of future events?

:chin:

Yes, but the difference is subtle. Physicists might well consider that they are predicting future events, philosophers predict descriptions of future events.

Again: Why is it impossible that we wake up tomorrow in a world where one tiny particle has the property to be and not to be (which would make the whole world inconsistent)? That would make MP invalid and kill all our logic, right?

Again: Why is it impossible that we wake up tomorrow in a world where one tiny particle has the property to be and not to be (which would make the whole world inconsistent)? That would make MP invalid and kill all our logic, right? — Pippen

No, we would just look for ways to model the world that avoided inconsistency. Which is just what occurs in quantum mechanics where the state of a particle in superposition is represented as the sum of two or more distinct states.

What that means is a separate question.

No, we would just look for ways to model the world that avoided inconsistency. — Andrew M

But your answer implies that it could happen and so we'd need to adjust our logic and math, but that means the problem of induction also applies to logic and math so why did Hume not agree? For him only our experiences are inductive, not logic and math, but we see that it's wrong. We can easily imagine a scenario where our world of tomorrow has different logical/math rules than the world of today. Was David that blind?

But your answer implies that it could happen and so we'd need to adjust our logic and math, — Pippen

As I see it, if the world seemed inconsistent then that would point to a problem of representation, not that the world was inconsistent. That's the approach physicists have taken with quantum mechanics since it is standardly represented using classical logic and algebra (though, of course, new mathematics such as matrix mechanics was developed).

but that means the problem of induction also applies to logic and math so why did Hume not agree? — Pippen

As you may know, Hume drew a distinction between "relations of ideas" and "matters of fact and real existence". For the broad ramifications of that, see Hume's fork. If one inquires whether the "relations of ideas" are themselves "matters of fact" then the distinction starts to break down or become circular. So the problem of induction only makes sense in a context of deductive certainty per Hume's distinction.

If that distinction is rejected, then you are left with something like an Aristotelian view (or pragmatic view) where the meaning, or use, of terms like "possible" are understood in the context of the law of non-contradiction or ostensive demonstration. In turn, accepting inconsistency seems to take one out of the bounds of meaningful language. But one needs meaningful language to state one's position in the first place.

In turn, accepting inconsistency seems to take one out of the bounds of meaningful language. — Andrew M

Not really. It just means trivialism, i.e. everything becomes true, but I can still talk and be understood on an ostensive level. That sounds enough meaningful to me.

Back to Hume. How does he prove that logic is not a matter of fact but something higher? IMO he can't, so his "fork" is pretty much made up from speculation and tradition.

In turn, accepting inconsistency seems to take one out of the bounds of meaningful language.
— Andrew M

Not really. It just means trivialism, i.e. everything becomes true, but I can still talk and be understood on an ostensive level. That sounds enough meaningful to me. — Pippen

On trivialism, the statement of mine that you are disagreeing with is trivially true. So your disagreement assumes non-trivialism (i.e., you think my statement is false). Can you give an example of ostensive talk that doesn't assume non-trivialism?

Back to Hume. How does he prove that logic is not a matter of fact but something higher? IMO he can't, so his "fork" is pretty much made up from speculation and tradition. — Pippen

I think you're right.

Can you give an example of ostensive talk that doesn't assume non-trivialism? — Andrew M

I can't, you are right.

My line of thinking goes like this: Imagine tomorrow the proposition "p & ~p" becomes somehow true! At that point our logic would collapse, we couldn't even talk or think about it (trivialism), we'd be literally insane. But we can today - under the assumption that our logic still holds - verify that this very scenario could happen tomorrow and that it would destroy our logic. Isn't that a proof by example that logic is not necessary?

Imagine tomorrow the proposition "p & ~p" becomes somehow true! — Pippen

A possible analogy: The rules of chess specify that players can only move a bishop along the diagonal. Moving the bishop vertically would be invalid. Suppose, tomorrow, a player moves the bishop vertically. One response is to reject the move. Another response is to change the rules of chess to accommodate the move.

The conventional rules of logic include the law of non-contradiction (LNC) which specifies that it is impossible for states-of-affairs p and ~p to obtain simultaneously. Or, propositionally, that propositions p and ~p can't be true simultaneously.

Suppose per hypothesis that, tomorrow, "p & ~p" becomes true. One response is to reject the hypothesis. That is, to say that such a scenario is impossible and thus cannot obtain. Another response is to change the rules of logic to accommodate the scenario.

Now the "changing the rules" response - rejecting the LNC - collapses to trivialism. (Note: unless explosion is also rejected, as with paraconsistent logics.)

Whereas under the existing rules the hypothesis that, tomorrow, "p & ~p" becomes true is, per the LNC, provably false. Thus, according to the existing rules, this scenario couldn't happen tomorrow.

Isn't that a proof by example that logic is not necessary? — Pippen

Not if the rules of logic include the LNC. But note, as with the chess example, one can always propose one's own rules. However they may have undesirable consequences (such as trivialism).

The problem of induction stems from our ignorance and lack of any clear definition of what knowledge is.

How do we know there is a problem with induction when the problem itself is empirical and based on experience? You're using induction to prove the problem of induction exists.

The problem of induction isn't much different than the paradox of knowing that you know nothing. We need a better definition of knowledge to solve the problem of induction and the paradox.

I think to answer this question you need to understand the difference between inductive and deductive. I would advise you read this article about Difference Between Inductive and Deductive | Differencebtwn

Suppose per hypothesis that, tomorrow, "p & ~p" becomes true. One response is to reject the hypothesis. That is, to say that such a scenario is impossible and thus cannot obtain. Another response is to change the rules of logic to accommodate the scenario. — Andrew M

Both impossible if p & ~p becomes true because then we couldn't talk/think straight/meaningfully.

More and more it seems that the main difference between induction and deduction is this: If we imagine an induction to be false tomorrow then we can at least comprehend what it would mean for tomorrow while with deduction we could only say that if it happens then tomorrow would 'black out' for us. But that's not enough for me to exclude such a possibility. It would be like if you would exclude the possibility to get insane tomorrow just because you couldn't say anything about that tomorrow.

What prevents us from imagining that we all wake up tomorrow and a circle is no longer round

The same thing that prevents you, or should prevent you, to imagine our planet is actually called Penis, while knowing for a fact it is named Earth. Nonsense.

The same thing that prevents you, or should prevent you, to imagine our planet is actually called Penis, while knowing for a fact it is named Earth. Nonsense. — Zelebg

Interesting theory. How does it deal with the fact of me (or some Humpty) claiming to call it whatever I like?

The problem is semantic, it is about constructing a formal system for common meaning to help us communicate. Imagining then some other system of reference meanings does not speak about actual change in the outside world, but about personal interpretation module. Dealing with it would manifest with difficulties in communication.

The problem is semantic, it is about constructing a formal system for common meaning to help us communicate. Imagining then some other system of reference meanings does not speak about actual change in the outside world, but about personal interpretation module. Dealing with it would manifest with difficulties in communication. — Zelebg

Sure. My difficulty was with making sense of,

knowing for a fact it is named Earth. — Zelebg

How to know such a fact. Perhaps you meant, agreeing to assume?

How to know such a fact. Perhaps you meant, agreeing to assume?

Something like that, but calling circle “round” is not about making assumptions, it is about putting a label on a specific and certain geometrical relation.

Nonsense in imagining that circle is no longer round is due to using two terms from one formal system which are linked together and then moving one of them to the context of some new undefined reference chart of meanings. This is just an exercise in messing with the English dictionary and produces gibberish. Imagine a flower is a vacuum cleaner.

:up:

Imagine a flower is a vacuum cleaner. — Zelebg

Ok. I did that.

Ok. I did that.

It makes sense in some abstract fantasy context, as a painting for example. But circles that are not round you can not even paint because the two terms are semantically linked so strongly they are almost synonyms. It’s like trying to paint a flower that is not a flower. It's gibberish, a contradiction, it does not compute, and being semantically invalid statement it can not be sanely reasoned about.

It's gibberish, a contradiction, it does not compute, and being semantically invalid statement it can not be sanely reasoned about. — Zelebg

So, on waking that morning (OP), we might all seize and catch fire like confused robots.

But we might do that anyway if we took any logic too religiously, and felt obliged to believe all the consequences of our (inevitably) inconsistent beliefs.