but did he also make the parallel with “Existence is not a predicate”? — J

I'm not sure if it predates Kant, but Kant is famous for making this assertion.

Thinking about a unicorn I know what properties it has, but thinking about a unicorn that includes existence as one of its properties adds nothing conceptually: the unicorn has to be "given", and so "existence" is not a predicate.

Thanks, we certainly find the existence question in Kant. (That's why I chose "a hundred thalers" as my example.) What I'm trying to pin down is whether anyone has addressed specifically the apparent parallel between "Existence is not a predicate" and "Truth is not a predication." Does it ring any bells?

I can say “It is true that there are a hundred thalers on the table” but this adds nothing to the proposition ‛There are a hundred thalers on the table’. — J

Basically, yes.

I can say “A hundred thalers exist” but this adds nothing to the concept ‛a hundred thalers’; — J

This is a bit different, as the latter possesses a conceptual existence which the former surpasses by asserting a super-conceptual existence, at least according to common language. As far as I can see things can only be true or false in one way, whereas things can exist in multiple ways. The domain of the former is propositions whereas the domain of the latter is ontological realities, and ontological realities are more variegated and complicated.

I’m looking for some source help — J

Aristotle's claim in the Metaphysics that to speak truth is to say of what is that it is or of what is not that it is not is very close to the truth predication question. I think the existence predication question is much more controversial, for reasons just noted. Much of that literature seems to revolve around Anselm's ontological argument. It is also related to your thread on Sider and univocal vs. analogical conceptions of being.

Aristotle's claim in the Metaphysics that to speak truth is to say of what is that it is or of what is not that it is not is very close to the truth predication question. — Leontiskos

Yes, quite close, and Kimhi is a hard-core Aristotelian if he's anything you could put a label on. But I assume Aristotle did not describe truth as a property that could or could not be predicated; that way of thinking wasn't available to him. Is there something he did say that would be more or less the equivalent of "To say of what is that it is, is not to provide additional knowledge about it"? Or maybe: "To assert of what is that it is, is the same act as identifying the being/existence of what is"? This is roughly what Kimhi wants to claim -- but again, I'm sure someone has done work on the "emptiness" question involved in predications of existence and truth, I just can't remember who.

But I assume Aristotle did not describe truth as a property that could or could not be predicated; that way of thinking wasn't available to him. — J

Intuitively, the reason I doubt this is because it seems that anyone involved in the analysis of arguments will need to wield truth and falsity as predicates. They will need to talk about propositions as being true or false. For example, if Plato and Aristotle differ with respect to the exact same proposition, won't this quickly lead to the recognition that one holds that it is true whereas the other holds that it is false? This ability to look at a proposition abstractly while prescinding from its truth value would seem to require the use of truth and falsity as predicates. Granted, this predication may still not mean much over and above simple affirmation and denial, but it does show that one can consider a proposition without assuming that it is true.

Is there something he did say that would be more or less the equivalent of "To say of what is that it is, is not to provide additional knowledge about it"? Or maybe: "To assert of what is that it is, is the same act as identifying the being/existence of what is"? — J

My hunch is that the answer to the two questions is no/yes, but I will do a bit of digging and come back to this. I also want to let the thread percolate a bit before posting overmuch.

In the Metaphysics, there is a lot of emphasis upon what can be isolated as a specific kind from what can only be only known by means of analogy. The difference between actuality and potentiality is placed firmly in the latter category. And yet that is where Aristotle rolled the dice on his theories.

The difference is brought out nicely in predicate logic. Three differing uses of "is" are used.
1. The "is" of predication - "The ball is red" - f(a)
2. the "is of equivalence - "Two plus two is four" - a=b
3. The "is" of quantification - "There is a ball" - ∃(x)f(x)

This last seems to be what you have in mind, where "existence" ranges over individuals, to whom it ascribes a predicate

Truth is treated somewhat differently. There's ⊤, a statement that is always true. But to get to what is going on with truth we need something like Tarski's T-statements, and talk in terms of metalanguages. That's because truth is a predicate, but of propositions. Here, truth ranges over propositions.

So generally, existence is not a first order predicate; nor is truth.

But also, there is the predicate ∃!, that does range over individuals... as used in free logic.

This doesn't answer your question, but might hint at why there may not be a literature of the sort you seek.

truth is a predicate, but of propositions — Banno

Staying within the Tarskian framework for the moment: If we say 'p is true in language L', are we ascribing a property to p? If not, exactly what are we predicating?

This ability to look at a proposition abstractly while prescinding from its truth value would seem to require the use of truth and falsity as predicates. — Leontiskos

Peeking at Kimhi's book at the library, this is very close to the same idea:

In other words, [for Frege and Geach] a propositional sign manifests, through its symbolic composition, the semantical character of each actual occurrence of the proposition, but not the force character of any [of] those occurrences. — Kimhi, Thinking and Being, page 39

In a recent thread I was trying to get people to consider the difference between the "force character" of an assertion vs. the "force character" of a reductio's supposition, but everyone in the thread proved incapable of these metalogical distinctions. As Kimhi points out through Geach on p. 38, the context of a proposition has implications for its meaning (see my post here).

But again, I have not found anyone on this forum who is interested in or even open to discussing the metalogical issues that Kimhi is interested in. Given the subtlety of such a topic, that's not surprising. Deep dives into the basis for Aristotelian realism (which necessarily involves the realism of propositions and assertions) produce the same incomprehension on this forum. The logicians on TPF tend to be what I would term 'logical pragmatists', and they have little interest in the inner workings and meta-workings of logic itself. In some places it is even assumed that some sort of isomorphic mapping between logic and language obtains.

are we ascribing a property to p? — J

Yep.

That's what I thought. Now, returning to the "is" of quantification, when we say "∃(x)f(x)" we are not ascribing a property to f, namely the property of existing, correct? It's the reverse -- we're saying of some putatively existing individual that it has the property of f. (Bear with me, this is going somewhere, I hope. :smile: )

It's the reverse -- we're saying of some putatively existing individual that it has the property of f. — J

"putatively existing"?

"∃(x)f(x)" says something in the domain of discourse is f. Does that thing exist? Well, "Frodo has hairy feet" predicates hairy feet to Frodo - does that mean he exists?

Trouble is, "exists" is used in various and incompatible ways.

But ok, with "∃(x)f(x)" we are not ascribing a (first order) property to f.

Understanding Truth by Scott Soames

I can say “It is true that there are a hundred thalers on the table” but this adds nothing to the proposition ‛There are a hundred thalers on the table’. — J

Basically, yes. — Leontiskos

I can say “A hundred thalers exist” but this adds nothing to the concept ‛a hundred thalers’; — J

This is a bit different, as the latter possesses a conceptual existence which the former surpasses by asserting a super-conceptual existence, at least according to common language. As far as I can see things can only be true or false in one way, whereas things can exist in multiple ways. The domain of the former is propositions whereas the domain of the latter is ontological realities, and ontological realities are more variegated and complicated. — Leontiskos

Maybe QM can tell us something pertinent herein: When that tree falls in the forest without a witness, does it make a sound? No. It makes a potential sound, and in so doing, it takes its place among all of sound in its potentiality.

“Truth is not a predication.” That is, neither existence nor truth add anything, conceptually, to what they appear to be predicating ‛existence’ and ‛truth’ of. — J

I suppose Frege was the first to have pointed out the “emptiness” of the “It is true that . . .” prefix, but did he also make the parallel with “Existence is not a predicate”? — J

Aristotle's claim in the Metaphysics that to speak truth is to say of what is that it is or of what is not that it is not is very close to the truth predication question. — Leontiskos

Truth/existence predication adds something conceptually entangled: the existential_cognitive entanglement of superposition resolved, or, to put it another way: decidedness.

In quantum mechanics, Schrödinger's cat is a thought experiment concerning quantum superposition. In the thought experiment, a hypothetical cat may be considered simultaneously both alive and dead, while it is unobserved in a closed box, as a result of its fate being linked to a random subatomic event that may or may not occur. This experiment viewed this way is described as a paradox. This thought experiment was devised by physicist Erwin Schrödinger in 1935[1] in a discussion with Albert Einstein[2] to illustrate what Schrödinger saw as the problems of the Copenhagen interpretation of quantum mechanics.

In Schrödinger's original formulation, a cat, a flask of poison, and a radioactive source are placed in a sealed box. If an internal radiation monitor (e.g. a Geiger counter) detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison, which kills the cat. The Copenhagen interpretation implies that, after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead, not both alive and dead. This poses the question of when exactly quantum superposition ends and reality resolves into one possibility or the other.

Schrödinger's Cat

A thing is potential and undecided until it is witnessed by a sentient. Therefore, when a sentient says: It is true of what is that it is or, it is existential of what exists that it exists, s/he adds the decidedness of witnessing the superposition of the cognitively decided thing.

- Yes, and this is a good demonstration of how the propositions, assertions, and knowledge of intellectual agents are not ontologically neutral, even though they are stipulated to be ontologically neutral within the logical frame. @J could easily respond by restricting his sphere of discourse to the logical frame and asking something like, "But do they add anything as far as the logic is concerned?" But this raises the fraught question of where the logical ends and the metalogical begins, or else where the metalogical ends and the ontological begins, in any given system.

J could easily respond by restricting his sphere of discourse to the logical frame and asking something like, "But do they add anything as far as the logic is concerned?" But this raises the fraught question of where the logical ends and the metalogical begins, or else where the metalogical ends and the ontological begins, in any given system. — Leontiskos

Yeah. Theoreticians are still scratching their heads over the question of an inflection point linking metalogical with ontological.

What I'm trying to pin down is whether anyone has addressed specifically the apparent parallel between "Existence is not a predicate" and "Truth is not a predication." Does it ring any bells? — J

I agree that the following doesn't help in knowing which philosophers addressed the problem, but is just a couple of random thoughts.

"A hundred thalers exist"
In the expression "A hundred thalers are heavy", what is the predicate "are heavy" referring to?

The predicate "are heavy" cannot be referring to the expression in language "A hundred thalers", as an expression cannot be heavy. The predicate "are heavy" must be referring to a hundred thalers in the world.

"A hundred thalers are heavy" is true IFF a hundred thalers are heavy.

Similarly, in the expression in language "A hundred thalers exist", the predicate "exist" is not referring to the expression in language "A hundred thalers", which would be a redundancy, but is referring to a hundred thalers in the world.

"A hundred thalers exist" is true IFF a hundred thalers exist.

IE, the expression "a hundred thalers exist" is a valid statement.

"It is true that there are a hundred thalers on the table"
If I told someone that "there are a hundred thalers on the table", they may not believe me. This forces me to say "it is true that there are a hundred thalers on the table".

But in language as we don't normally use quotation marks, what I am actually saying is ""it is true that "there are a hundred thalers on the table""

IE, I am not saying "it is true that there are a hundred thalers on the table", but rather ""it is true that "there are a hundred thalers on the table"".

This is certainly relevant
https://en.wikipedia.org/wiki/Tarski%27s_undefinability_theorem
In scholastic metaphysics truth is convertible with being. Truth is jsut a property of a being and only derivatively it's a property of judgements (and even more remotely a property of sentences). Truth, just like being is undefinable, because there's nothing untrue to differentiate it. Wrt to predication of existence look up free logics and Abstract Object Theory of Zalta where existence is a predicate, look up Meinongianism, pluralism and neo-fregeanism in metaontology.

I think you’d get a lot out of Kimhi’s book – I certainly have. It’s the most interesting work of contemporary philosophy I’ve read since Ted Sider’s Writing the Book of the World. But it’s hard going, even if you have a taste for “metalogical” issues. This current OP is an attempt to start some sharing of Kimhi’s ideas, and I hope to continue in future threads.

Minor point: The passage you quote from p. 39 isn’t actually about Frege and Geach. Kimhi is talking here about what he later labels “Wittgenstein’s point,” which is contrasted with Frege and Geach’s (incorrect, according to Kimhi) understanding of what it means for a proposition to occur in a context. Shortly after the quoted passage, he writes “I shall call the conclusion Geach and Frege draw from [Wittgenstein’s point] – that assertoric force must be dissociated from a proposition’s semantical significance – Frege’s point. We shall see that Frege’s point is mistaken. It only seems necessary if we accept certain functionalist (and more generally, compositionalist) assumptions about logical complexity.” I don’t want to take us too far into the weeds on this, so I’ll stop, and anyway it doesn’t affect the point you’re making in your post.

Good insights, thanks. I could indeed try to limit the question to one about formal logic, and it may turn out that the isomorphism between existence and truth breaks down in formal logic. But as the QM example suggests, what's really interesting is that borderline between what is "strictly logical" and what is ontological. Stipulating something as ontologically neutral doesn't make it so; stipulating a "law of logic" doesn't show why it would obtain in the world of being. These deep borderline questions are exactly what Kimhi is chasing down, just as you'd expect from a book called Thinking and Being.

I am not saying "it is true that there are a hundred thalers on the table", but rather ""it is true that "there are a hundred thalers on the table"". — RussellA

Right, it's predicating truth of "there are a hundred thalers on the table." This doesn't have to come up only in cases of questioning or doubt. It's the difference between 'There are a hundred thalers on the table' understood as the occurrence of a proposition, supposedly without assertoric force, and the same statement given as an assertion (maybe using Frege's assertion symbol). That said, I think all sorts of questions remain about exactly what "is true" predicates.

Appreciate the references, many thanks.

Truth is just a property of a being and only derivatively it's a property of judgements — Johnnie

Not to turn this into a Kimhi seminar, but he devotes an entire chapter of his book to this point. The chapter is called "The Dominant Sense of Being," and takes off from Aristotle's claim [Metaphysics Theta 10] that being-true exists in things, and that this sense of "being" is kuriotata, which evidently can be translated as "proper, dominant, or governing."

I guess there's a sense of truth where it's a matter of apprehending the existence of something or some situation (state of affairs). Sometimes "true" is synonymous with "real."

There are other senses, like Heidegger's phenomenology of truth: that it's about revelation, like something was hidden or obscured, and now it's uncovered.

The analytical approach is to see it as a predicate, even in the case of truth skepticism, where truth is just a facet of speech.

I think you’d get a lot out of Kimhi’s book – I certainly have. — J

Okay, thanks for the recommendation. I will consider it.

Minor point: The passage you quote from p. 39 isn’t actually about Frege and Geach. — J

Thanks for the correction. It resolves the question I had after skimming that passage, as I had added "[Frege and Geach]" in an edit.

These deep borderline questions are exactly what Kimhi is chasing down, just as you'd expect from a book called Thinking and Being. — J

:up:

↪Johnnie Appreciate the references — J

I would say that Scholasticism does not make truth a property of being when it calls them convertible. "Truth is convertible with being," does not mean, "Truth is a property of being." It means that everything which has being has truth qua intellect. Truth is being under the aspect of being-known (Aquinas). The trick is that this is not limited to the discursive intellect, and for theists all being simultaneously has truth through being known by God (or thought by God). Modern philosophers would see this as substantial insofar as it commits itself to the position that all being is knowable.

The corollary is that all truth has being. All knowledge and acts of knowing also have being. I.e. thought is not ontologically neutral. Further, to know a proposition and to know that proposition is true are two different acts of knowledge, two different truths with two different kinds of being.

wow I didn't know this guy will certainly check out because arguing this point is hard (which is why I limited myself to stating what scholastics thought)

“Putatively existing” is indeed awkward, but – as you and Frodo explicated – it’s hard to find the right language in these situations. I meant what you mean: We’re talking about something in a given domain, and whether it “exists” depends on other linguistic and metaphysical commitments.

So, granted all that, here’s the concern I want to raise. We agree that in the case of ‛p is true’, we’re ascribing a property to p; we’re predicating something of p, namely its truth. But in the case of E(x)f(x), we are not ascribing a property to f. This would seem to show that “truth” and “existence” don’t share an isomorphism at this level.

And yet . . . I’m going to “tell a story” using the simplest language I can, which means I have to ignore a dozen subtleties and exceptions. But I want to capture what seems wrong with this picture. Here’s the story: Both “truth” and “existence” – especially when used in more or less ordinary discourse, about the most common topics – have the characteristic of “promoting” or “ratifying” something otherwise hypothetical. If I say of p that it is true, I’ve inducted it into the Hall of Fame of propositions that state what is the case, which is precisely what we want our propositions to do. In the same way, if I say of X that it exists, I’ve raised it out of the limbo of possibility and awarded it actuality, or being. I’m being deliberately gaudy with my terms here because I want to capture the flavor of improvement, even teleology, that is part of the story I’m telling.

So this seems like quite a parallel between “truth” and “existence,” but there’s more. We can also say (as Peter Geach does, I believe, concerning the “is” of predication) that the same state of affairs makes X exist and p true. If I discover that there is something that is a ball, whatever reasons I give to support that discovery will be the same reasons needed to show that ‛There is a ball’ is true. There is no further fact I need to learn in order to affirm the truth of the proposition about the ball’s existence. This takes “parallel” extremely close to “identity,” and at this point I could import Kimhi’s jargon for all this but I won’t. Suffice it to say that he is indeed a monist on this issue, in a way that I find confusing, annoying, but impossible to dismiss out of hand.

What’s going on here? Again, this is a very rough-grained account, especially in its cavalier separation of “truth” from any language. But still. Is this a pseudo-problem, or do we need a deeper understanding of predication from the get-go?

If I discover that there is something that is a ball, whatever reasons I give to support that discovery will be the same reasons needed to show that ‛There is a ball’ is true. There is no further fact I need to learn in order to affirm the truth of the proposition about the ball’s existence. This takes “parallel” extremely close to “identity,”... — J

Bringing in Aquinas:

Truth is being under the aspect of being-known (Aquinas). — Leontiskos

Objection 3. Further, things which stand to each other in order of priority and posteriority seem not to be convertible. But the true appears to be prior to being; for being is not understood except under the aspect of the true. Therefore it seems they are not convertible.

Reply to Objection 3. When it is said that being cannot be apprehended except under the notion of the true, this can be understood in two ways. In the one way so as to mean that being is not apprehended, unless the idea of the true follows apprehension of being; and this is true. In the other way, so as to mean that being cannot be apprehended unless the idea of the true be apprehended also; and this is false. But the true cannot be apprehended unless the idea of being be apprehended also; since being is included in the idea of the true. The case is the same if we compare the intelligible object with being. For being cannot be understood, unless being is intelligible. Yet being can be understood while its intelligibility is not understood. Similarly, being when understood is true, yet the true is not understood by understanding being. — Aquinas, ST Ia.16.3.ad3 - Whether the true and being are convertible terms?

Freddoso's alternative translation:

Objection 3: Things that are related as prior and posterior do not seem to be convertible. But true
seems to be prior to being, since a being is understood only under the notion of the true (sub ratione
veri). Therefore, it seems that they are not convertible.

Reply to objection 3: There are two ways to interpret the claim that a being cannot be
apprehended without the notion of the true (sine ratione veri).
In the first way, it has this sense: ‘A being is not apprehended unless the notion of the true follows
upon the apprehension of the being’. So interpreted, the claim is true.
In the second way, it can be interpreted as follows: ‘A being could not be apprehended unless the
notion of the true were apprehended’. And this is false.
It is the case, however, that something true cannot be apprehended unless the notion of being is
apprehended. For being enters into the definition of true.
It is the same as comparing intelligible to being. For a being cannot be understood unless that
being is intelligible, and yet a being can be understood without its intelligibility being understood.
Similarly, a being as understood is true, but it is not the case that in understanding being, one understands true. — Aquinas, ST Ia.16.3.ad3 - Is 'true' convertible with 'being'?

Perhaps Kimhi recognizes this, but the idea is that to recognize the notion of the true requires a second act of the intellect, a kind of back-folding of the intellect, or the trough and the crest of the selfsame wave of apprehension. This second act is what I was pointing to above dialogically with the interaction between Plato and Aristotle. Aquinas would presumably say that the apprehension of being is in some sense prior to the apprehension of the notion of (its) truth.

it’s hard to find the right language in these situations. — J

Indeed, and I think that making use of the grammar of first order logic helps here, in obliging us to take care as to what we mean by "exists". So "∃(x)f(x)" is understood as something like "Of the things we are discussing, some of them satisfy f". "∃(x)f(x)" will be true only in the case that something is f. The ontological commitments here are pretty minimal.

"∃(x)f(x)" will be true only in the case that something is f. So indeed, it may well be in the same "state of affairs" that x is something about which we can talk and that for some f, makes "∃(x)f(x)" true.

I am of the opinion that Banno at least somewhat derailed your thread on QV by immediately shifting it away from Sider's ontological realism and towards pure logical formalisms which intentionally avoid questions of ontology. I hope that does not happen again, as it would apparently be completely against the spirit of this thread to bracket all questions about being and ontology.

With that said, a bridge from Banno's concerns could be formed by considering the opinions of the inventors of the formalisms. What did Frege and Peirce, or older logicians like Kant, Abelard, or Aristotle think about the questions of the OP and the way that their systems interacted with it? Probably I am just repeating the prompt of the OP, but maybe that's okay.

So this seems like quite a parallel between “truth” and “existence, — J

As I see it, truth is about the relation between different things, and these different things exist.

The expression "p is true" says no more than "p"
We can't meaningfully say "p" is true, because there is no relation, but we can say "p" is true IFF p

We can't meaningfully say "x", but we can say "x exists"

For example, "there are a hundred thalers on the table" is true IFF there are a hundred thalers on the table.

Where "there are a hundred thalers on the table" exists in language and a hundred thalers on the table exists in the world.