But does temperature equate to (the sensation of) heat? — Banno

For a thermometer, or some sort of mechanical probe, seems so. For the human skin, its sensation is of more or less heat, or heat or no heat, temperature, as representation of a specific degree of heat relative to a standard, being irrelevant.

In my second re-read right after the molecular motion is heat part. So I'm sort of just thinking out loud here in quoting, I'm not sure if I have a point yet:

So, in this sense, the expression 'the inventor of bifocals' is nonrigid: under certain circumstances one man would have been the inventor of bifocals; under other circumstances, another one would have — pdf, page 10

What do I mean by 'rigid designator'? I mean a term that designates the same object in all possible worlds — pdf, page 11

...in talking about the notion of a rigid designator, I do not mean to imply that the object referred to has to exist in all possible worlds, that is, that it has to necessarily exist.

!!!

This one has turned all about in my mind.

So the property of necessary self-identity -- even if the object does not exist, the object is necessarily self-identical, that is, self-identical in all possible worlds -- is kind of trippy.

I'm wondering what on earth an object is at this point, other than somehow distinguishable from statements given Kripke's previous distinction.

Well, I think it is. That is, I'm now reading Kripke as suggesting that heat and the sensation of heat are somehow different things. Not too sure about that. — Banno

I'm good with distinguishing the sensation of heat from heat, even if Kripke doesn't. At least, a lot of my hesitation I think comes from knowing enough about heat to say it's a conceptual web that's slippery, if what we're trying to do is philosophy.

So my preferred notion of heat is "that which a thermometer measures". And I'm fine with a certain amount of loose use of "thermometer" (like, thermocouples and mercury thermometers are measuring the same thing).

And, from that, we can specify many ways of talking about heat.

One way is the kinetic theory, which is apt in the case of gasses at particular Pressure-Volume ranges we commonly interact with.

"molecular motion", however, would not pick out the very same atom in all possible worlds. It doesn't refer to any particular atom. It's an aggregate property.

So I suppose I'd have to say -- if molecular motion is a rigid designator, then it's at least picking out an unintuitive object -- a collection of particles that could have been different particles (and yet retained the same aggregate properties, i.e., it could be composed of oxygen atoms that come from Venus and still have the same properties) and yet is the same aggregate in all possible worlds.

Would you agree that how Kripke should have defined "rigid designator" is as the same subject (logical subject) in all possible worlds? So we could say X is a rigid designator, and X is the same subject in all possible worlds.

This puts X into the realm of possibility, and leaves X as possibly referring to an object, and possible not. This is where X needs to be if it is going to be the same in every possible world. That puts the judgement as to whether X corresponds to an actual object, and the important judgement as to which possible world corresponds with a presumed actual world, into a completely different category, i.e. a completely different type of judgement.

Under Kripke's plan, whereby X, as a rigid designator, represents the same object in every possible world, we have no real principles whereby we can separate the correct possible world (the one which best corresponds with the real world), and all the other possible worlds, because the real (actual) object is designated as within the possibility. This is because he does not allow for a separate real object, which we might compare the possible worlds to. The object is always as it is described in its possible world, but at the same time, the same object is in all possible worlds. This leaves no room for the real object, in a real separate world because the real object is designated as being within all possible worlds.

Those premises result in a dichotomy of Platonic realism, and anti-realism. It gives us the choice of those two ontologies. Either the real object is the very same thing as the logical subject (Platonism), having real existence in all possible worlds, or else we deny the reality of Kripke's "object", and say that the rigid designator does not reference a real object, only a possible object, but then we are left with anti-realism.

In other words, Kripke hands us the metaphorical "have you quit beating your wife?". If we affirm his premises, and accept the "object" indicated by the rigid designator, we are plunged necessarily into Platonism. If we deny the premise, saying that this is not a true object, we proceed into anti-realism, because there are no principles provided for any real object, and we are denying the reality Kripke's proposed "object". Therefore the correct response is to reject his premises altogether, as some sort of trickery, or at best, as simply incoherent.

That is, what is it that the sentence quoted above is about? It seems that it is about Hesperus. If one asks what it is that you are suggesting we remove the properties from, the answer is "Hesperus", and this is so even if the properties are removed. That is, in Kripke's terms "Hesperus" is a rigid designator, while it's various properties may not be. — Banno

I agree that "Hesperus" will continue to exist in language as a rigid designator even if all the properties of Hesperus disappeared from the world.

I will use the nomenclature that "Hesperus" exists in language and Hesperus exists in the world.

"Hesperus" may exist in language even if it doesn't exist in the world
1) Hesperus as an object in the world has millions of properties, most of which are unknown, but includes properties such as being 12,103km in diameter, having a solar year of 117 Earth days, has a central iron core, has a rocky mantle and has an atmosphere 96% carbon dioxide, 3% nitrogen, etc.

2) Hesperus has been named "Hesperus". If all the properties of Hesperus disappeared from existence, Hesperus would no longer exist. There is no example of an object existing in the world that doesn't have any properties. However, "Hesperus" would still exist in language. For a word in language to have meaning, it must have a set of properties, such as "being 12,103km in diameter", "having a solar year of 117 Earth days", etc. No word in language has meaning if it has no properties, for example a word such as "xxyyxx".

Nixon may be named "Nixon".
Similarly, Richard Nixon as an object in the world has millions of properties, most of which are unknown, such as born in 1913, family home in California, attended Whittier College, had a spot on his lung, a good debater, enthusiastic, etc. There are different approaches to how Nixon is named "Nixon".

1) For Ruth Barcan Marcus, proper names are tags which refer to an object which is the bearer of the name. Tags are directly referential and without descriptive content. For example, in the morning Nixon is tagged "Nixon". The tag could be a blue cross or a sheet of paper with the word "Nixon" on it. In the evening, the person with the tag is by definition "Nixon", even though the person may in fact be George McGovern.

2) For Bertrand Russell, in the morning Nixon is described as "born in 1913", "attended Whittier College" and "a good debater", Such a description, such a cluster of properties, is judged sufficient to pick out an individual uniquely. In the evening, the person that can be described as "born in 1913", "attended Whittier College", "a good debater" is by definition "Nixon", even though in fact it could be George Elmer Outland.

3) For Kripke, from (1), page 163, x may be identical to y and x may have the property F. For "Nixon" to be a rigid designator, for "Nixon" to be "Nixon" in all possible worlds, "Nixon" must have essential properties, such as having a spot on his lung. As with the example of the lectern, a non-essential property could be being in a different room. Whether a property is essential or non-essential can only be determined by human judgement, and then codified by social institutions, either fixed in a dictionary or similar or by daily use. For "Nixon" to be "Nixon" in all possible worlds, "Nixon" must have essential properties, such as having a spot on his lungs, where the property having a spot on his lungs is one designator of "Nixon", and as fixed in all possible worlds, is a fixed designator.

"Unicorns" exist in language and may or may not exist in the world.
1) I can define a "standard weight" as having the property 12.102kg, even before ever knowing whether or not 12.102kg exists in the world. Having the property 12.102 kg is an essential property of a "standard weight", is true in all possible worlds, and is a rigid designation. If I subsequently discover 12.102kg in the world a posteriori, I know a priori that it is a "standard weight", in that having the property 12.102kg is a necessary property of a "standard weight".

2) I can define a "unicorn" as having the properties the body of a horse and a single horn in its forehead even before ever knowing that unicorns exist in the world. Having the properties the body of a horse and a single horn in its forehead are essential properties of a "unicorn", and is true in all possible worlds as a rigid designation. If I subsequently discover in the world a posteriori the body of a horse with a single horn in its forehead a posteriori, I know a priori that this is a "unicorn", as having the body of a horse with a single horn in its forehead are necessary properties of a "unicorn".

Kripke's proposition that "identity statements are necessary" is true
1) Objects are observed in the sky. By observation, as "Phosphorus" has a diameter of 12,103km, and as "Hesperus" has a diameter of 12,103km, "Phosphorus" is identical in diameter to "Hesperus". Therefore, the identity statement "Phosphorus is identical in diameter to Hesperus" is true.

2) The property being visible is a priori defined as non-essential, and the property of diameter is a priori defined as essential. As "Phosphorus" has a diameter of 12,103km, having a diameter of 12,103km is a necessary property of "Phosphorus". As "Hesperus" has a diameter of 12,103km, having a diameter of 12,103km is a necessary property of "Hesperus". As "Phosphorus" has of necessity a diameter of 12,103km, and as "Hesperus" has of necessity a diameter of 12,103km, "Phosphorus" is of necessity identical in diameter to "Hesperus". Therefore, the identity statement "Phosphorus is identical in diameter to Hesperus" is necessarily true.

What do you make of this, pg 177-8:

“One could not say that though in fact every even number is the sum of two primes, there could not have been some extra number which was even and not the sum of two primes. So we certainly do not know, a priori or even posteriori, that every even number is the sum of two primes”.

Yep. More or less. Misusing "begs the question", Professor Dave Explains...


But, see also...

Seems to me a shame that the focus here is an the sensation. — Banno

So the property of necessary self-identity -- even if the object does not exist, the object is necessarily self-identical, that is, self-identical in all possible worlds -- is kind of trippy. — Moliere

...but it wouldn't make sense if it were otherwise...

If all the properties of Hesperus disappeared from existence, Hesperus would no longer exist. — RussellA

So in some possible world, Hesperus has no properties, and hence Hesperus does not exist in that world.

It doesn't follow that Hesperus does not exist in some other possible world.

The domain of discourse includes Hesperus - Hesperus is one of the things we can talk about. That domain of discourse has within its scope multiple possible worlds, some of which include Hesperus, others of which do not. But in all those possible worlds, Hesperus is Hesperus.

Lots of other issues. Let's stick to one at a time.

I think it worth quoting the following at length, since it summarises the last few pages.

Therefore, "Heat is the motion of molecules" will be necessary, not contingent, and one only has the illusion of contingency in the way one could have the illusion of contingency in thinking that this table might have been made of ice. We might think one could imagine it, but if we try, we can see on reflection that what we are really imagining is just there being another lectern in this very position here which was in fact made of ice. The fact that we may identify this lectern by being the object we see and touch in such and such a position is something else. — p.188

At stake is no more than our choice in parsing a sentence.

In the case of the demonstrative, "This lectern might not have been wood" can be understood in two ways. On the one account, this wooden lectern might have ben replaced by some other lectern, which was not made of wood. On the other account, this very wooden lectern might not be made of wood, and an inconsistency occurs, since we would have a wooden lectern that was not made of wood.

So the first is the better option. The demonstrative rigidly designates the lectern.

In the case of proper names, the name rigidly designates the individual. Cicero is necessarily Tully, and any properties that are attributable to one are attributable to the other. Of course Cicero might have not had that name, and might have done different things, but in such cases Tully would also have had a different name and done different things.

And, Kripke supposes, this goes for any equivalence between heat and the motion of molecules. If "heat" is a rigid designator for that sensation, and "the motion of molecules" is a rigid designator for molecules in motion, then if heat is the motion of molecules, it is necessarily so.

There are all sorts of issues wrapped up in this last. Not the least is the underlying assumption that there is the one sensation that is felt by each and every one of us when we feel heat. Now I do not think this is quite right, and hence I do not think this example is comparable to that of Cicero nor the lectern.

And I think this issue carries over to the next consideration in the article, mind-body dualism.

In the case of the demonstrative, "This lectern might not have been wood" can be understood in two ways. On the one account, this wooden lectern might have ben replaced by some other lectern, which was not made of wood. On the other account, this very wooden lectern might not be made of wood, and an inconsistency occurs, since we would have a wooden lectern that was not made of wood. — Banno

That's not what he said.

So the first is the better option. The demonstrative rigidly designates the lectern. — Banno

No, it doesn't. As he explains in the passage you quoted, it doesn't even make sense to say the lectern could have been made of ice. It's not even imaginable.

Kripke's proposition that "identity statements are necessary" is true
1) Objects are observed in the sky. By observation, as "Phosphorus" has a diameter of 12,103km, and as "Hesperus" has a diameter of 12,103km, "Phosphorus" is identical in diameter to "Hesperus". Therefore, the identity statement "Phosphorus is identical in diameter to Hesperus" is true. — RussellA

This is a similar issue which I went over with Banno already, concerning Kripke's premise that if the table is not made of ice it is necessarily not made of ice. That premise is a priori. And in your example, we need a similar a priori principle which states that one measurement of 12,103km is necessarily the same as another measurement of 12,103km. Kripke easily sidesteps this issue by implying that we can simply assume that 12,103km has the same meaning in each instance.

But this is not how meaning is in reality, each particular instance of usage has peculiarities unique to that context of usage. So in your example, the measurements might have been done in different ways for example, under different circumstances. These features, peculiarities which are unique to the particular circumstances, are known as accidentals. Therefore we remove, ignore, or make exceptions for the accidentals, and when two measurements are the same with respect to the apprehended essentials, we might say that the measurements are the same.

Of course two distinct measurements, even of the same object are never truly identical. Each act of measurement is unique, due to the difference in circumstances. Therefore we need to rely on an a priori principle to say that one measurement of 12,103km is the same as another measurement of 12,103km. Consequently, we compromise and say that the two measurements are "equal". And "equal" becomes a compromised sense of "the same", as it ignores the accidentals and applies only to what is determined as essential, depending on the purpose.

That's not what he said. — frank

That's right. It's what some call an explication.

As he explains in the passage you quoted, it doesn't even make sense to say the lectern could have been made of ice. It's not even imaginable. — frank

Yes. That's right.

That's right. It's what some call an explication. — Banno

I agree that you have some reading comprehension issues.

, if we all simply quoted or paraphrased, there would be no point to this thread.

If you have a substantive reply, I'm all ears.

But as it stands, your post looks again like passive-aggressive posturing.

It wasn't for your benefit. It was in case someone reading along was thrown by your bizarre interpretation. I was confirming that you're intentionally veering from Kripke's thinking and inserting your own untenable views.

SO justify that: what is it that Kripke is thinking? How does it differ from what I wrote? Set out your case.

Correct me. Set the record straight.

Put your balls on the anvil.

Say something substantive.

I don't debate MU, and I don't debate you, for pretty much the same reason.

I'll respond when you're inserting your own garbage in Kripke's mouth, for the reason I mentioned.

Are piss-ants common out your way?

I don't debate MU, and I don't debate you, for pretty much the same reason. — frank

So Banno and MU on the same thread are double trouble?

So Banno and MU on the same thread are double trouble — Metaphysician Undercover

Yep. :scream:

What do you make of this, pg 177-8: — Mww

Kripke asks on page 177: "Is everything that is necessary knowable a priori or known a priori?". He writes page on 178: "So we certainly do not know, a priori or even posteriori, that every even number is the sum of two primes”.

There is a difference between knowable a priori and known a priori.

Taking a simpler example of cardinal numbers, 1,2,3,4 etc. If numbers are invented, and only exist in the mind and not the world, it is certainly true that not every cardinal number is known a priori, because there are an infinite number of them. However, if numbers are invented, every cardinal number is certainly knowable a priori.

We may not know something that is necessary a priori, even though it is knowable a priori.

And in your example, we need a similar a priori principle which states that one measurement of 12,103km is necessarily the same as another measurement of 12,103km. — Metaphysician Undercover

I know The Red Sox will win their next game, I know The Eiffel Tower is in Paris and I know that I am looking at the colour red. The word "know" is being metaphorically, in that it has degrees of certainty, because language is inherently metaphorical

Similarly, the word "same" is being used metaphorically having varying degrees of certainty.

I know a priori, before using language, that language is metaphorical. The a priori principle is that language is metaphorical. that "same" is being used metaphorically.

...but it wouldn't make sense if it were otherwise... — Banno

I'm not sure about the general case, but in the case of this paper I agree. I think I'm just marking where things are becoming strange for me. At this point I realized I wasn't sure what Kripke really meant by object.

One way in which this makes sense is that he's speaking to people who emphasize predication as how a person picks out an identity, at least explicitly in the talk. So in that way of looking at the logic I think I agree -- certainly every object is necessarily self-identical, insofar that necessity can be quantified over propositions at all.

However, the belief that non-existent objects have properties is at least unintuitive. Not that it's wrong, I'm just not sure what objects are now. Also, there's something funny about applying negative predicates to names, I think, even though logically there's no difference given negation is always a primitive.

... Yeah, just marking things that seem different -- not just to criticize (though maybe at some point), but to figure it out.

I know The Red Sox will win their next game, I know The Eiffel Tower is in Paris and I know that I am looking at the colour red. The word "know" is being metaphorically, in that it has degrees of certainty, because language is inherently metaphorical

Similarly, the word "same" is being used metaphorically having varying degrees of certainty. — RussellA

I would say, that your example shows the existence of ambiguity rather than metaphor. Although metaphor often makes use of ambiguity, the two are not the same. And in logic, we ought to make an attempt to reduce ambiguity, as this will increase the degree of certainty. We can reduce ambiguity and increase certainty by employing axioms which leave no room for ambiguity.

There are varying attitudes with which we can approach the production of logical axioms in relation to ordinary language use. At one extreme we try to adapt axioms to match the habits of ordinary language use. At the other extreme we attempt to curb the habits of language use, conforming them, and even producing new habits, to match contrived and artificially created axioms.

Language use is an habitual activity. Habits may be judged as good or bad. So the question of whether an existing habit of usage ought to be incorporated into a logical system requires a judgement as to whether it is a good or bad habit. And, the question of whether a new habit ought to be encourage or produced, as the result of introducing a new axiom, requires a judgement as to whether it would be a good or bad habit.

Ok. Thanks.

So in some possible world, Hesperus has no properties, and hence Hesperus does not exist in that world. It doesn't follow that Hesperus does not exist in some other possible world. — Banno

My next post will be about heat and the motion of molecules. One could easily become paranoid about being thrown off TPF for not sticking to the OP.

Regarding "possible worlds"
Kripke wrote: 1) What do I mean by ‘rigid designator’? I mean a term that designates the same object in all possible worlds. 2) All of this talk seems to me to have taken the metaphor of possible worlds much too seriously in some way 3) And if the phrase ‘possible worlds’ is what makes anyone think some such question applies, he should just drop this phrase and use some other expression, say ‘counterfactual situation,’ which might be less misleading.

IE, one can use the phrase "possible world", as long as one takes it metaphorically.

Existence
I proposed that if in this actual world, all the properties of Hesperus disappeared, then Hesperus would also disappear. You made the point that even if Hesperus didn't exist in one possible world, it may still exist in another possible world.

I agree that even though Hesperus no longer existed in this actual world, it could still exist in a possible world.

However, these are different kinds of existences. The first refers to something physically existing in the actual world and the second refers to a possible world existing in the mind.

We can reduce ambiguity and increase certainty by employing axioms which leave no room for ambiguity. — Metaphysician Undercover

Agreed. Which returns to I think a major bone of contention in Kripke’s thesis, with respect to classes of statements of knowledge and of metaphysics, where he says, pg 177, “Now I hold that neither class of statements is contained in the other”.

This is to categorically deny the validity of a priori knowledge, the statements of which are always metaphysical, and by such denial the very possibility of purely logical truth disappears. And if that is the case, then purely logical conceptions, in particular, the modal relations under which this entire thesis is constructed, are empty.

Your “leave no room for ambiguity” is the very same thing as the validity of principles, and the “increased certainty” arises from the subsequent employment of them in deductive inferences, which are only and always from pure thought, a quite metaphysical enterprise, I must say.

Just in passing…..rhetorically speaking.

And, Kripke supposes, this goes for any equivalence between heat and the motion of molecules. If "heat" is a rigid designator for that sensation, and "the motion of molecules" is a rigid designator for molecules in motion, then if heat is the motion of molecules, it is necessarily so. — Banno

Heat and the motion of molecules independent of any observer

Kripke wrote: "First, imagine it inhabited by no creatures at all: then there is no one to feel any sensations of heat. But we would not say that under such circumstances it would necessarily be the case that heat did not exist; we would say that heat might have existed, for example, if there were fires that heated up the air."

Beginning with this lectern, this lectern is made of wood. If it had not been made of wood it would have been a different object, so this lectern is necessarily made of wood. This sounds reasonable.

This raises the question as to whether objects such as this lectern exist over and above their properties, in that if all the properties of the lectern were removed, would this lectern remain. Would Hesperus remain if all its properties were removed. Would heat remain if there were no molecules in motion. As no example of an object existing having no properties can be found in the world, it must be concluded that an object cannot exist in the world independently of its properties.

Kripke would say heat has essential properties. These essential properties exist in all possible worlds, and as such heat is a rigid designator. Objects have properties, and for Kripke, some properties are essential and some non-essential. This can only be a human judgement. Human judgement cannot exist independently of any observer. In a mind-independent world the motion of molecules cannot be judged to be essential or non-essential, meaning that heat cannot be a rigid designator, as the world has no means of judging which properties are essential and which non-essential.

IE, heat cannot be rigid designator in a mind-independent world.

I proposed that if in this actual world, all the properties of Hesperus disappeared, then Hesperus would also disappear. — RussellA

Since an object with no properties is beyond imagination, it's not so much that Hesperus would disappear as that we're no longer talking about a possible (or the actual) world. We would just talking nonsense.

This is not what Kripke intended by specifying rigid designators. He was just adjusting some old assumptions about necessity to allow for our use of hypotheticals.

I would say, that your example shows the existence of ambiguity rather than metaphor — Metaphysician Undercover

I more or less agree, but my long-term project is to show that language is fundamentally metaphorical. "Time is a thief" is a metaphor in that time is not the same as a thief. "Object A is object B" is a metaphor in that object A may be similar to object B, but object A can never be the same as object B. "Hesperus is Phosphorus" is a metaphor in that Hesperus may be similar to Phosphorus, but Hesperus can never be the same as Phosphorus.