Use of (spatiotemporal) distinction is not seeing something as distinct? — Janus

No. Motion detectors do not see something as distinct but they make use of spatiotemporal distinction nonetheless.

That doesn't answer the question. "Because they tell me" or something like that would be an acceptable answer. But the toddler you have in mind can't speak yet; so I could be forgiven for thinking you are indulging in projection.

No they don't they simply detect movement.You're projecting again!

I'm done with this side issue Janus...

It amounts to differences in our frameworks.

It's really a side issue only because you brought in motion detectors when we were discussing human beings, their practices and what those practices consist in and rely upon..

But if you're done, that's fine with me.

Ok, I looked up "Afla and Ateb" and I see what you are saying. But again, absent description, or a map (which amounts to a visual description) the two people who are familiar with one or the other side of the mountain are so based on direct experience (observation). They may have found their way up the mountain by trial and error, without relying on any description. But once they know how to get up the mountain they would then (provided they are competent language users) be able to offer someone else a description of the mountain they call either Afla or Ateb.

And it seems to be on the basis of such a description that someone who was following their directions would be able to recognize whether or not they were on the right mountain; the one called Afla or Aleb (as the case may be). I don't want it to seem like I am being provocatively deflationary, but all this seems very commonplace, quite easy to understand for pretty much anyone and lacking in any real paradox or mystery to me.

I'm trying to grasp the challenge to Kripke's necessary a posteriori brought by Kripke himself in A Problem of Belief:

If Hesperus=Phosphorus is necessary a posteriori, then these two proper names can't be de jure rigid designators, which one can grasp without any descriptive content.

If they are such rigid designators, then the identity statement can't be necessarily true.

This is because in order to be both (rigid designators and a posteriori necessary) the names have to be substitutable in epistemic contexts, and they weren't prior to the discovery that they're co-referential.

If Hesperus=Phosphorus is necessary a posteriori, then these two proper names can't be de jure rigid designators, which one can grasp without any descriptive content. — frank

This is false, because the rigid designator is the same across all possible worlds where Hesperus and Phosphorus denote the same entity. If what you mean to imply that the post hoc ergo propter hoc fallacy is being committed then, I agree to some extent.

Rigid designators are graspable without any descriptive content.

There's a whole story about a French guy who is kidnapped and held in London. It makes it a little easier to see the problem. I dont have time to explore it at the moment.

Rigid designators are graspable without any descriptive content. — frank

Yeah, they just are. Hence, I don't see your argument as legitimate, unless treating their descriptive content as necessary a posteriori to establishing their necessity, which isn't true, I think. Perhaps some disambiguation is required here.

It's Kripke's argument, not mine. :razz:

This?

http://www.uvm.edu/~lderosse/courses/lang/Kripke(1979).pdf

Maybe after the last lecture?

Sure. I just thought Kripke's own challenge to the necessary a posteriori would help me flesh out the idea.

I got stuck. I'll be back soon to play catch up, with what we're covering. @Banno, what page are we on?

I'm working my way through Lecture Three. But my comments here so far only go to the end of Lecture Two.

The unexpected part for me has been the role that his criticism of Wittgenstein's comments about the standard metre play in his thinking.

For Wittgenstein, language starts with use, and so a metre is defined by its use in the game of comparing stuff to the standard metre.

For Kripke, the Metre is a rigid designator for a certain length, and hence the same in all possible worlds.

Prima facie, these might be compatible views.

For Kripke, the Metre is a rigid designator for a certain length, and hence the same in all possible worlds. — Banno

Prima facie, this looks to be plain false, given that 'we' (scare quotes because I was not consulted) have changed the designation. Presumably, the new designation is more rigid than the rigidity of the lump of stuff that was previously designated. We can now measure what was immeasurable.

"One Metre" once referred, in every possible world, to the length of the stick.

We now use "One Metre" to refer, in every possible world, to a different length determined by vibrations and stuff.

Two different uses of "One Metre", talking about different lengths. But one Metre is the same in all possible worlds. You might sometimes have to specify which one you are using.

It's a worthwhile account; I commend it to you.

I'm trying to grasp the challenge to Kripke's necessary a posteriori brought by Kripke himself in A Problem of Belief:

If Hesperus=Phosphorus is necessary a posteriori, then these two proper names can't be de jure rigid designators, which one can grasp without any descriptive content.

If they are such rigid designators, then the identity statement can't be necessarily true. — frank

It logically follows from them being rigid designators that the identity statement is necessary. Per definition, a statement is necessary if and only if it's true in all possible worlds. But if the statement is true in the actual world, and a proper name refer to the same object in all possible worlds, then, since both names refer to the same object in the actual world, they also refer to the same object in all possible worlds.

[/quote]This is because in order to be both (rigid designators and a posteriori necessary) the names have to be substitutable in epistemic contexts, and they weren't prior to the discovery that they're co-referential.[/quote]

If they were substituable in epistemic contexts, then, the identity statements would be known a priori, and not a posteriori. If I don't already know that Hesperus is Phosphorus, then, one can't substitute salva veritate Hesperus for Phosphorus in the epistemic context: "I believe that (Phosphorus) is yellow".

Prima facie, this looks to be plain false, given that 'we' (scare quotes because I was not consulted) have changed the designation. Presumably, the new designation is more rigid than the rigidity of the lump of stuff that was previously designated. We can now measure what was immeasurable. — unenlightened

Just to supplement what @Banno already said, remember that the claim that a name is a rigid designator doesn't mean that there are no possible worlds at which the name has a different use, neither does it mean that the use of the name can't evolve in the actual world (or vary across different linguistic communities). It rather means that this name, as used by us, today, in the actual world, refers to the same object in (our talk of) all possible worlds.

Banno suggested waiting till after the third lecture to discuss A Puzzle of Belief. I hope youre still around to help clarify. :grin:

Banno suggested waiting till after the third lecture to discuss A Puzzle of Belief. I hope youre still around to help clarify. — frank

Hopefully I will not have been run over by a bus or hit by lightning.

Or kidnapped and held in an ugly part of London.

Or kidnapped and held in an ugly part of London. — frank

You're right. I had forgotten about this scary possible world.

It rather means that this name, as used by us, today, in the actual world, refers to the same object in (our talk of) all possible worlds. — Pierre-Normand

Yes, I understand. But it is still a strain to say that 'all possible worlds' of yesterday excludes the actual world of today.

If - in the actual world - positing hypotheticals, counterfactuals, and/or possible world scenarios is itself an activity that is existentially dependent upon reference by description, then it cannot follow that description is not necessary for reference even if it is the case that we can often drop the descriptions and retain identity and/or still successfully refer to an object with proper name alone when positing such scenarios.

Reference fixing could be ostensive. But some sort of fixing needs to happen.

You may. I'm here, but right now am generally limiting myself to posts that involve parts of history or the law I'm interested in, so not to be tempted to use the H word disrespectfully.

Cheers.

It doesn't. It was possible that we might change the referent of the word "metre" before we actually did.