Every truth must be true

Then the president is no longer the president if he resigns. But he was (indubitably) the president when he was the president. The fact that he is no longer the president does not change that. I don't know what you mean by saying that Obama is no longer the same person he was, so I really cannot speculate about something I do not understand. But, whatever you mean, it is still true that Obama was the president when Obama was the president no matter who Obama was. (I imagine, however, that Obama has always been Obama. Wouldn't you?)I didn't say that if light is both undulatory and corpuscular (whatever that may mean) that is logically impossible. In fact, I don't think I mentioned light. But what I think is that it is logically impossible for light to be both undulatory and not undulatory; and what I think is that it is impossible for light to be both corpuscular and not corpuscular. I haven't the foggiest idea whether or not is is logically possible for light to be both undulatory and corpuscular. And neither, I bet, do you, or about 99% of the readers of your post. Why don't we stick to talking about something we understand rather than talking about something neither of us understands? Finally, I have no idea what point you are trying to make with all this stuff about Obama changing (how, I don't know) and this stuff about light neither of with either of us has much of a handle on.

guigus wrote:

jeeprs wrote:

I think the city of Quito should, at the very least, start levying a royalty on philosophical conversations in which they feature. Judging by the frequency of mentions in the Forum, I'm sure it would be a nice little earner.

And I think that, for the same reason, Obama should be elected president of the United States.

He was. Alas!

guigus wrote:

Suppose the vice-president assumes. Then, the president is not the president. Or imagine that Obama is right now no longer exactly the same person he was an instant ago. Then again the president is not the president. Despite not "logically possible," this is possible.

Only if you are using two different definitions of "president". If "president" is defined clearly and consistently, it is logically necessary that the president is the president. If two things are the same in some respect, they cannot be different in that very respect.

guigus wrote:

Suppose now light is both undulatory and corpuscular. Since for you this is a logical impossibility, you must throw away most if not all of current physics.

If any property of a wave is inconsistent with any property of a particle, then it is logically impossible for light to be both undulatory and corpuscular. If there is no inconsistency of properties, then it is logically possible.

Nope your claim that "if any truth were untrue, then it would not be a truth" is false because truth can be context specific. Interestingly, the opposite of a context specific truth (ie a universal truth) cannot be readily shown to have likelihood.

fast wrote:

He wants to say that if obama is president in 2010, then there is no longer a possibility that he is not president in 2010, and though he is wrong (since it's logically possible that he is not president in 2010), I want to make what he says correct by qualifying the word "possibility" with the appropriate adjective. I came up with the word, "real," but I was hoping that the word "epistemic" would be a better fit.

I can't really jump fifty feet up into the air unaided. It's not possible! Awe, but it is possible. It's logically possible, so when I say "It's not possible," I'm wrong; however, I want to say it anyway!, but to do so and not be in error, I need to know what word to use to qualify the kind of possibility I'm talking about.

But, I need to be careful. It's not physically possible, but the scope of "physical" is not wide enough to cover both examples. After all, what's not physically possible about obama not being president in 2010?

The problem is simple. Kinds of possibilities are being equivocated. I just don't know the label to apply to the kind of possibility that both he and I is talking about. I'm hoping "epistemic" will do.

But it isn't even epistemically possible for you to jump 50 feet into the air, since it is not true (I hope) that for all you know you can jump 50 feet into the air. But it is logically possible for you to do so, since the supposition that you do so is not logically impossible. It is not a necessary truth that Obama is president. and therefore, Obama might not be president, although he is president. What I don't understand is why anyone thinks that every true proposition is a necessary truth.
Of course, I understand why he thinks so. He has made clear that why he thinks so is that he commits the modal fallacy of confusing (1) Necessarily if p then p, with if p then necessarily p. Some philosophers, notably Spinoza, have held that all truths are necessary truths, but that is something they believe follows from their metaphysics. But the op is just confused. Why do you want to make what he says correct when it is false? Indeed how can you make what he says correct when it is false?

Particle/wave duality consists in a problem of description on the phenomena, not the actuality of the phenomena as a thing...

Of course, I understand why he thinks so. He has made clear that why he thinks so is that he commits the modal fallacy of confusing (1) Necessarily if p then p, with if p then necessarily p. Some philosophers, notably Spinoza, have held that all truths are necessary truths, but that is something they believe follows from their metaphysics. But the op is just confused. Why do you want to make what he says correct when it is false? Indeed how can you make what he says correct when it is false?

He has made clear that why he thinks so is that he commits the modal fallacy of confusing (1) Necessarily if p then p, with if p then necessarily p.

kennethamy wrote:

Of course, I understand why he thinks so. He has made clear that why he thinks so is that he commits the modal fallacy of confusing (1) Necessarily if p then p, with if p then necessarily p. Some philosophers, notably Spinoza, have held that all truths are necessary truths, but that is something they believe follows from their metaphysics. But the op is just confused. Why do you want to make what he says correct when it is false? Indeed how can you make what he says correct when it is false?

If you don't understand what I think, how can you understand why I think it? And believe me, you don't understand what I think. But I know why: it is because you take a truth out of a statement and puts it into the state of affairs from which that statement gets its truth. You are not inventing anything: this is what classical logic does, and you are only reproducing what you have learned. By relocating truth from the statement to the state of affairs, you make that state of affairs an equivalent statement, a self-expressing truth whose independence from us is absolute. Or, which is the same, you create a statement whose independence from us is absolute, a "logical possibility" that exists in a world of its own. Hence, when you read the statement "every truth must be true," you already have in mind a statement-like state of affairs, with its absolute existence, to which you have no choice other than attributing an absolute necessity - the infamous "modal fallacy." If you just put the truth back into the statement, making it the true statement it is, which depends on the state of affairs from which it gets its truth, that fallacy would simply vanish. All you have to do is remember that the statement "water is liquid" is true inasmuch water is liquid. By examining this carefully, you will clearly see where truth belongs.

hence the inevitable circularity of the correspondence theory of truth, would you say?

kennethamy wrote:

He has made clear that why he thinks so is that he commits the modal fallacy of confusing (1) Necessarily if p then p, with if p then necessarily p.

Putting things this way, that is, reading me by means of symbolic logic, you will never understand what I am saying. The reason is simple: symbolic logic by definition takes all truth as meaning whatever is true. When you write "p" to mean "every truth" you already turn "truth" into an object named "p," which is no longer what refers to a state of affairs, but rather that state of affairs itself. Or, what is the same, a statement that is neither true nor false, a "logical possibility," since "p" makes no distinction between a true statement and whatever state of affairs makes it a truth. To me, a truth is an already true statement: something symbolic logic has no representation for. Symbolic logic is like classical physics: there is no room for us, only for the natural world. It is different from quantum physics, which incorporates the observer. Symbolic logic admits no subjectivity, there is only objectivity there, so "p" will never be a truth as meaning its own "truthness": it will always be whatever is true in the world, as if truth were "out there" waiting for us to find it - an object, like a chair. Which is why the only kind of necessity it knows about is "natural" necessity: necessity as a property that "applies" to things and comes out of nowhere. The necessity I refer to is a relation linking an already true statement and a state of affairs that makes that statement a truth.

You and I are not exactly the same persons we were yesterday.

guigus wrote:

You and I are not exactly the same persons we were yesterday.

I'm the same person I was! I'm a day older today than I was yesterday, just as my car is a day older today than it was yesterday, but both I am my car are exactly who and what we were yesterday. There may be things about me that is different today than yesterday, just as there are things different about a river today than it was yesterday, but we should not think that all these things are not the very exact same things they were yesterday just because things about them are different today.

Ok, ok. But I think he still deserves to be honored in some way. Perhaps a Nobel Prize or something.

If you believe you can define something so well so as to eliminate all ambiguity of it, then you are just dreaming, no matter how pleasing is your dream.

@ Kennethamy:

kennethamy wrote:

Ok, ok. But I think he still deserves to be honored in some way. Perhaps a Nobel Prize or something.

Suppose he does deserve to be honored in some way. A Nobel Prize would not be appropriate, for as we have learned, one need not earn it to receive it.

I must reiterate what I am not saying: that no truth is contingent. Again, I am not saying that, you are. It is your interpretation of my words, which is the only one you seem capable of, that leads to it. Just clarifying.

guigus wrote:

I must reiterate what I am not saying: that no truth is contingent. Again, I am not saying that, you are. It is your interpretation of my words, which is the only one you seem capable of, that leads to it. Just clarifying.

You announce what you are not saying, but you are saying the very thing you deny that you are saying, so I'm led to believe that you do not say what you mean to say. An interesting question is, "are you correct?" If what you say is incorrect, and if what you mean to say is correct (e.g. that not all truths are necessary truths), then given that what you mean to say is true while what you say is false, then should I be led to think you are correct or incorrect?