Was it a misquote, or an interpretation? I thought it was the latter.

Well, thanks for all your help.

So on to the top of p. 180, where we come across something that might be of further interest to @Mww.

That this table is not made of ice is known a posteriori - by examining the table. Yet that this table is not made of ice is a necessary fact about this table - if it were made of ice, it would not be this table.

We cannot know a priori if the table is made of ice or of wood. But given that it is not made of ice, it is necessarily not made of ice.

Yes, but let's move on.

Fair.

Was it a misquote, or an interpretation? I thought it was the latter. — Moliere

If it was an interpretation, it was a misinterpretation.

Well, thanks for all your help. — Banno

No problem.

The modus ponens on p. 180 shows how a necessary truth can follow from an a posteriori truth.

Is that a problem?

But given that it is not made of ice, it is necessarily not made of ice. — Banno

Correct. Not being made of ice is an essential property of the lectern. The basic idea here generalizes.

Wow!

I feel like it's a problem, but then I see the demonstration.

I think I'm tempted by @unenlightened's approach. It's necessary, yet our language of logic is what makes it so more than what is the case. We can say what we like, and define what we like, and while that will change how we talk about things that won't change whatever "stuff" is.

We can say what we like, and define what we like, and while that will change how we talk about things that won't change whatever "stuff" is. — Moliere

He makes the point that what we're doing is epistemology. It's about truth.

Again, I think it better to approach this sort of stuff as about choosing a grammar rather than a metaphysics. Yep, it won't change the way stuff is.

And all of this sits within the scope of the deranged epitaphs. Someone could create a divergent use that undermines it, but even in undermining it they will be acknowledging it.

Just to make sure we'll hate one another, that last paragraph sounds Hegelian. ;)

But your first paragraph gots me rethinking the paper. Guess I'll have to read it more than one time. Shit! :D

...that last paragraph sounds Hegelian — Moliere

Rude.

“Hesperus is Phosphorus” is a pure analytic proposition, hence necessarily true. — Mww

I agree that analytic propositions are necessarily true, independent of any empirical knowledge. For example, "all bodies are extended", as the notion of extended is implicit in the notion of body.

If we are given two analytic propositions "Hesperus is Phosphorus" and "Hesperus is not Phosphorus", how do we know which is true, if the truth of an analytic proposition is independent of any empirical knowledge ?

I am trying to understand the relevance of (1) and (4) on page 163, which is central to the article.

Kripke writes for any objects x and y:
(1) If x is identical to y, then if x has a certain property, so does y
(2) Every object is necessarily self-identical
(4) For every x and y, if x equals y, then, it is necessary that x equals y

Example one - let x by the Moon, and y be the Eiffel Tower

(1) If the Moon is identical to the Eiffel Tower, then if the Moon has a certain property, such as having a diameter of 3,476 km, so does the Eiffel Tower.
(4) For every x and y, if the Moon equals the Eiffel Tower, then, it is necessary that the Moon equals the Eiffel Tower.

Example two - let x be the object Hesperus, and y be an object that is not Hesperus

(1) If the object Hesperus is identical to an object that is not Hesperus, then if the object Hesperus has a certain property, then so does an object that is not Hesperus.
(4) For every x and y, if the object Hesperus equals the object that is not Hesperus, then it is necessary that the object Hesperus equals the object that is not Hesperus.

I may be misunderstanding, but I don't see any practical benefit to (1) and (4)

I hope this post isn't deleted as was my previous post for not being relevant to the OP.

If x and y are identical, that means x and y are two different names for the same object.

Like say John's nickname is Tweezer.

x is John
y is Tweezer

now plug that into the argument.

If x and y are identical, that means x and y are two different names for the same object. Like say John's nickname is Tweezer. x is John and y is Tweezer. now plug that into the argument. — frank

Taking x and y as proper names, whereby x is John, y is Tweezer. From (4), if John equals Tweezer, then it is necessary that John equals Tweezer.

But this is a logical implication, which says nothing about the reality of what is being expressed. I could say that if I lived on Mars, then I would open a pizzeria, or if I was a nuclear scientist then I would work on small modular reactors.

The possibilities are almost infinite. If John equals Bill Gates, then it is necessary that John equals Bill Gates, or if John equals Alison, then it is necessary that John equals Alison or if John equals the President of France, then it is necessary that John is the President of France, etc, etc.

We learn nothing significant from these logical implications, other than if two things are equal then they are necessarily equal, which seems a redundancy. Why not just say that two things are equal.

You're asking what earth shattering consequences follow from Leibniz's law. Kripke is just setting the stage to show off a contradiction. That's all. Keep going.

That this table is not made of ice is known a posteriori - by examining the table. Yet that this table is not made of ice is a necessary fact about this table - if it were made of ice, it would not be this table.

We cannot know a priori if the table is made of ice or of wood. But given that it is not made of ice, it is necessarily not made of ice. — Banno

The first premise expressed at 180 ("given that it is not made of ice it is necessarily not made of ice") is a priori. It is directly derived from the law of identity, and a priori principles of "being" as described by Aristotle. When a thing comes into being, it is necessarily the thing which it is, rather than something else, as indicated by the law of identity. This a priori principle, along with the (empirically) given fact that a thing displays an order, is what leads us to conclude that the Form of the object necessarily preexists the material object.

The second premise, which supports the asserted "given", that the table is not made of ice, is a posteriori. The "given" that the table is not made of ice, is provided by empirical observation, therefore a posteriori.

The mistake which Kripke makes is to attribute to the conclusion the character of only one of the premises. One premise is a priori and the other is a posteriori, but he says the conclusion "it is necessary that the table not be made of ice", is a posteriori. Since the conclusion is stated as a necessity ("it is necessary that...") we must enquiry as to what validates this claim of necessity.

Kripke's conclusion is a mistake, because the necessity of the conclusion "it is necessary that..." is derived from the first premise which is a priori, "given that the table is not made of ice it is necessarily not made of ice". It is only the "given" aspect which is a posteriori, and the "given" is not at all necessary, and cannot provide the necessity required for the conclusion.. So it is very clear that the conclusion "it is necessary that..." is a priori, because the "given", or what is taken for granted (which is the a posteriori aspect of the argument), could be replaced with absolutely anything, Any possibility whatsoever, provided by empirical observation could replace "not made of ice", and the necessity of the conclusion would not be altered. We could still conclude "it is necessary that... (with the replacement empirical fact). Kripke simply employs smoke and mirrors sophistry, to make it appear like the conclusion "it is necessary that..." might be a posteriori.

You're asking what earth shattering consequences follow from Leibniz's law. Kripke is just setting the stage to show off a contradiction. That's all. Keep going. — frank

No, Leibniz's Law states that if two objects have all the same properties, they are in fact one and the same.

My question is, why does Kripke need to add the word necessary to Leibniz's Law. What does "if two objects have all the same properties, they are in fact necessarily one and the same" add to "if two objects have all the same properties, they are in fact one and the same"

What does "if two objects have all the same properties, they are in fact necessarily one and the same" add to "if two objects have all the same properties, they are in fact one and the same" — RussellA

I'd say necessity is implicit in Leibniz's law. He's just making it explicit because he's about to challenge the notion that apriori=necessary, and aposteriori=contingent. He's going to show that there can be a statement that is known aposteriori, but is necessarily true.

our language of logic is what makes it so more than what is the case. We can say what we like, and define what we like, and while that will change how we talk about things that won't change whatever "stuff" is. — Moliere

Reformed analytic philosophers like Rorty will argue the opposite. Once we divest ourselves of our temptation to assume intrinsic features of the world, all we have is our changing performances of language as they simultaneously express and shape our material
interactions with each other. Formal logic and its various notions of ‘truth’ depends for its sense on faith in intrinsicality. Even those at the very progressive edge of the analytic tradition, like Hilary Putnam, who is a conceptual relativist, hold onto a valuative realism
On the one hand, he argues “So much about the identity relations between different categories of mathematical objects is conventional, that the picture of ourselves a describing a bunch of objects that are there "anyway" is in trouble from the start.” “…what leads to "Platonizing" is yielding to the temptation to find mysterious entities which somehow guarantee or stand behind correct judgments of the reasonable and the unreasonable.”

But then he insists there are intrinsic non-relative valuative grounds for scientific and ethical truth. This belief allows him to uphold ideas of warranted justification and truth.

Rorty , however , believes the following about warranted justification as it is used in formal logic:

“The metaphysician thinks that there is an overriding intellectual duty to present arguments for one's controversial views - arguments which will start from relatively uncontroversial premises. The ironist thinks that such arguments - logical arguments - are all very well in their way, and useful as expository devices, but in the end not much more than ways of getting people to change their practices without admitting they have done so. The ironist's preferred form of argument is dialectical in the sense that she takes the unit of persuasion to be a vocabulary rather than a proposition. Her method is redescription rather than inference. Ironists specialize in redescribing ranges of obiects or events in partially neologistic jargon, in the hope of inciting people to adopt and extend that jargon. An ironist hopes that by the time she has finished using old words in new senses, not to mention introducing brand-new words, people will no longer ask questions phrased in the old words. So the ironist thinks of logic as ancillary to dialectic, whereas the metaphysician thinks of dialectic as a species of rhetoric, which in turn is a shoddy substitute for logic.”

Rorty is just an ontological anti-realist. There's a whole spectrum of that including various hard and soft options. It's all analytical philosophy, though. If you want to read an article about it, it will be an analytical philosopher you're reading. Nothing particularly reformed about it, I don't think.

But we are substituting this into an opaque context - whether they are empirical facts. — Banno

If you want to use logical shorthand, we have P = V, H = V, therefore P = H. Regardless, there was a time when it was a fact this thing in the sky was called P, and there was a time when it was a fact this thing in the sky was called H, and in these times, P was not known to be H. At some later time, experience informed that P, H and V were all the same thing in the sky, P = V at one time, H = V at a certain other time relative to the first time. After that, after the facts changed due to new experience, the thing in the sky was just V.

P never was equal to H, the proposition P is H never occurred to the Greeks, as Kripke said of something else and thus misspoke**, “surely no amount of a priori ratiocination on their part could have conceivably made it possible for them to deduce P is H”, so why are we belaboring the nonsense of it now?
** He said it of astronomers who discovered the distinction, when he should have said it of those who never considered there was one. Besides, one needs no a priori ratiocination when he’s got a telescope and a camera.

So it seems we are left with empirically discovered necessities. — Banno

Ehhhh…..maybe. I’d say we have empirically discovered relations, the relations we understand as being so because they necessarily conform to the laws we invent to describe them.
—————-

WHere's the argument? — Banno

In the text, which as you must well know, is a convoluted mess, requiring some presuppositions, and wouldn’t benefit this discussion.
—————-

Knowledge is experience, experience is always changing with time, so knowledge is always changing with time, therefore knowledge is contingent on time.
— Mww

Well, we know 4=2+2, but that doesn't change over time... an we know water boils at 100℃, at any given time; that doesn't change. So that doesn't work. — Banno

By “knowledge is experience”, the term knowledge is tacitly understood to be empirical knowledge. Mathematical propositions are not empirical knowledge in their construction, but only in their proofs. Mathematical propositions change over time only insofar as the system that constructs them changes; the human cognitive system that constructs mathematical propositions hasn’t changed so the propositions won’t change.

We knew once a liquid substance; we knew later a liquid substance we deemed to label water; we knew later the liquid substance we deemed to label water, boiled; we knew later water boiled at 100C, we knew later water boiled at different temps relative to pressure. Hell, we knew later, not only do things float in water, but water itself floats!!! How cool is that?? Knowledge changed over time.

We didn’t know water boils at 100C at any given time, as you say, until we learned at one time water boils at 100C. We know post hoc and a priori, as mere inference, water under a certain set of conditions will always boil at 100C. Just like, because you put it there at one time, you know a priori that stupid cup is still in the stupid cupboard at any other time, as long as nothing happened to alter the initial conditions.

It is possible the set of conditions under which water boils at 100C changes, such that water no longer boils at 100C. Some would like to proffer that this is sufficient reason to claim physical law is tentative, and in so doing, imply human intelligence is schetchy at best, insofar as it is human intelligence alone which determines physical law. Which is tantamount to those some slapping themselves in the face, getting nothing from it but a ruddy cheek.
————-

Kant and Kripke. There is obvious disagreement, but they are doing different philosophies, so no big surprise there. The idea was probably, if Kant was brought into this era would he find current philosophy noteworthy. While it is patently unjustified to speak for him, personally I think he would find it unapologetically superficial, there isn’t a particular philosophical doctrine these days a majority of thinkers support, and, there’s a conspicuous dearth of cognitive metatheories.

Nowadays, people who philosophize at all are apt do so regarding what’s said and its communal effect, rather than what is thought and its private effect, and his magnum opus concerned the rational subject over the empirical object, and even with the spectacular advances in physical science, the rational subject is still pretty much just as he was in the 18th century, so I think CPR would be written pretty much as it was. His other sciency stuff would probably be different, and there’s reason to suppose he might have come up with stuff that set the tone for other scientists, just as he did on the 1700’s.
————

might be of further interest to Mww.

That this table is not made of ice is known a posteriori - by examining the table. Yet that this table is not made of ice is a necessary fact about this table - if it were made of ice, it would not be this table. — Banno

All that’s fine, but what’s the point? That this table is made of this substance immediately precludes it being made of any other substance. I rather think that if this table is made of, say, wood, wood isn’t so much an essential property, as being a given property. It would seem the essential property of a table is merely is spatial extension, its shape, without regard to the substance of its construction.

Of more import, methinks: Kripke says, “…this table, if it exists at all…”. If he talks of a table, isn’t its existence given? Otherwise, shouldn’t he be talking of a possible table? Minor quibble, one of many, and overall, irrelevant, other than to exemplify differences in philosophical ground.

Then he says, “this table if it exists art all was not made of ice is necessary…”. Taken as a complete sentence, shouldn’t that have been “…was not made of ice is necessarily true”? Continuing, and under the assumption he means necessarily true, he says, “was not made of ice is necessarily true, it is certainly not something we know a priori”.

Hmmmm…..I don’t think that’s quite right. He’s asking about what we know. So we have a thing we know, a table, made of something we know, say, wood, so we can say with certainty it is not made from anything else, but the ask concerns only what we know, not what we can say.
(Recall the quote, “ Experience no doubt teaches us that this or that object is constituted in such and such a manner, but not that it could not possibly exist otherwise…”)

Experience cannot tell us the table could not have been made of something else, but if it is necessarily true it couldn’t have been made of anything else, because it isn’t, we must have known that necessity a priori.

It isn’t that we know it isn’t made of ice, it’s that we know it is necessarily true it isn’t made of ice. Given that there are only two ways for a human to know anything at all, experience and reason, and the former is from experience but the latter is not, therefore the knowledge in question must be from reason alone, which is, of course, a priori.

I’m not going to apologize for the length of the post. Peruse or not as you wish.

Rorty is just an ontological anti-realist. There's a whole spectrum of that including various hard and soft options. It's all analytical philosophy, though. If you want to read an article about it, it will be an analytical philosopher you're reading. Nothing particularly reformed about it, I don't think — frank

Except that on one side are those who find the symbolism of logical formalism important, perhaps indispensable , because it gets at the root of all those things that are relevant to philosophy ( the nature of language, meaning , truth, justification ) and on the other those who find it not very useful and certainly not engaging with the fundamental issues of philosophy. They side with the later Wittgenstein who found formal
logic to get in the way of a clarified understanding of such fundamental issues. Would you call someone who had almost no use for formal logic , and thought ‘ truth’ was a confused idea an analytic philosopher? Even Putnam said analytic philosophy had reached the end of its relevance .

I'd say necessity is implicit in Leibniz's law. He's just making it explicit because he's about to challenge the notion that apriori=necessary, and aposteriori=contingent. He's going to show that there can be a statement that is known aposteriori, but is necessarily true. — frank

Necessity is being used in two different ways, between objects and between an object and its property.

Necessity between objects - between a lectern and a rostrum
As regards (4), necessity is being used between objects. He writes: "For every x and y, if x equals y, then, it is necessary that x equals y."

(1), (2) and (4) make use of Leibniz's Law, where "if two objects have all the same properties, they are in fact one and the same".

It seems to me that the use of the word necessary is redundant between objects, in that what does "if two objects have all the same properties, they are in fact necessarily one and the same" add to "if two objects have all the same properties, they are in fact one and the same"

Necessity between an object and its properties - between a lectern and its property wood
As regards the lectern, necessity is being used between an object and its properties, where he writes "So we have to say that though we cannot know a priori whether this table was made of ice or not, given that it is not made of ice, it is necessarily not made of ice.

As he persuasively argues, this lectern, if made of wood, is necessarily made of wood, because if not made of wood it would have been a different object, and it wouldn't have been this lectern.

However, necessity between objects is irrelevant to the question of necessity between an object and its properties. Therefore, necessity may be removed from (1), (2) and (4) without affecting his argument about necessity between an object and its property.

Would you call someone who had almost no use for formal logic , and thought ‘ truth’ was a confused idea an analytic philosopher? — Joshs

If someone described truth as a confused idea, I'd say they're not any kind of philosopher. Want to start a thread on it?

The necessity we're talking about is with regard to the truth of statements. Some statements are necessarily true, some are contingently true.

Note that I won't debate this with you. It's explained by Kripke in the essay, and that's the scope of his interests.

If we are given two analytic propositions "Hesperus is Phosphorus" and "Hesperus is not Phosphorus"….. — RussellA

What if we are given one proposition, and its negation?

….how do we know which is true…. — RussellA

Does it matter which, if there can be only one?

….if the truth of an analytic proposition is independent of any empirical knowledge ? — RussellA

The analycity resides in the relation of the conceptions. Doesn’t matter if the conceptions are empirical. It is only after experience informs that P and H are in fact V, is it the case that all the conceptions which comprise V are found in both P and H, and it is necessarily true that either P or H represent V without any possible contradiction. The next step, then, says that there is nothing contained in the conception of P that does not belong to the conception of H, therefore, P and H are the same thing, or, that P is H is a necessarily true statement. We don’t need the experience those conceptions represent, only that all of them are thought to co-exist equally in one object.

And here is the support for the claim that time is not a property of objects, which just might be the reason the whole shebang rears its head in the first place.

Tangled web and all, doncha know.

If we are given two analytic propositions "Hesperus is Phosphorus" and "Hesperus is not Phosphorus", — RussellA

Why would anyone consider these analytic? They look to be synthetic.

Hesperus is the evening star; phosphorus, the morning star. It is not clear from the sense of these worlds that they are the very same thing.

Similarly, that Tully and Cicero are the same person is not analytic.

(4) For every x and y, if x equals y, then, it is necessary that x equals y — RussellA

Well, one consequence is that, that x=y may be discovered empirically - examples are give - but has necessary implications. While this may seem obvious now, it is contrary to both Kant and Quine, fir different reasons. The notion that an empirical fact implies a necessary truth is one of the novelties of this paper.

Yep.