And in that I would hope we can still use the concept of reference but in this context of fuzzyness, indeterminacy, vagueness. Reference isn't about look-up table or translation manual in your head. — Apustimelogist

I will say that Moliere and I are referring to the same thing with 'chair' or 'rabbit'. Someone else will come along and tell me that there is a 0.1% chance that we might disagree on what is a chair or a rabbit. And then we can argue about whether that 0.1% chance secures some particular thesis of "inscrutability of reference." To me it seems like this is really stretching the meaning of that word "inscrutability."

Perhaps the modern focus on quantity makes it hard to understand reference. If reference has to do with the extension of sets then there is nothing arbitrary about a 0.1% offset. If that is right then it's back to the old question of nominalist collections vs. universals and genera.

Perhaps your landlord? — Banno

Presumably we all agree that words signify by convention ("nomina significant ad placitum").

So then a token like J-o-h-n will be indeterminate if there is more than one person named John (or if our interlocutor knows more than one person named John).

If that is all that is meant by inscrutability of reference then it strikes me as trivial.

Islamaphobia is obviously made up. — AmadeusD

"Islamophobia" - "Homophobia" - "Transphobia"

Whenever someone tries to attach a term from psychiatric diagnostics ("phobia") to the person they disagree with, you can be sure they are full of crap and have no real argument to offer.

reference is a social act whereby we make a judgment call that could be wrong, some of the time — Moliere

"There are no fixed referents," vs, "We could be wrong some of the time." Do you see how the latter does not justify the former?

If you and I are sitting in an empty room with a dog, and I say, "The dog," there is a fixed referent. You know exactly what I am referring to. So it looks like there are fixed referents (i.e. referents that are fixed between at least two individuals).

I'm not convinced that <chair-concept> is the object being referred to in using 'chair' -- I'd say that it's the chair being referred to, rather than the <chair-concept> — Moliere

Well you just used the word 'chair'. What chair are you referring to? And do I know what you are referring to?

In fact there is no chair, and yet you used the word successfully. That is, I know what you are referring you despite the fact that there is no individual chair being referred to. That is what it means to say that we both have the same concept of a chair. Back to the original point, if we do not mean the same things by the words we use, then we cannot now be communicating.

But that there's a fact to the matter doesn't affix the reference, is what I'm contending. — Moliere

And I just showed how it does. You and I mean the same abstract thing by 'chair', therefore the reference is fixed.

It's just not a metaphysical or ontological connection -- only a collective effort, or social dance. — Moliere

Sure, but conventions are factual.

1. "Moliere understands 'chair' to signify <chair-concept>."
2. "Leontiskos understands 'chair' to signify <chair-concept>."
3. "Therefore, Moliere and Leontiskos understand 'chair' to refer to the same kind of object."

(1) and (2) are either true or false, and if they are true then on your definition they represent a fact. No one is saying that there are chair-concepts floating about in the Platonic ether. The point is that we both have an abstract notion of a chair such that the word signifies equivalently for each of us.

(Perhaps I should clarify that "same kind of object" != chair-concept. The idea was rather that a chair is a kind, namely a kind of object. The concept is what connects different chairs to that same kind. If you are a descendent of Frege then you can explicate this in terms of sets and extension. The point is only that "chair" is a reference common to us both, i.e. it is fixed between the two of us.)

I’m not sure he could do otherwise, could he? — Mww

I mean, for hundreds of years Christian theologians had been incorporating Aristotle into their work and refusing Occasionalism, which is pretty close to what Berkeley promoted. See, for example, Aquinas on secondary causality. To say that Berkeley is not representative of Christian theology up to that point would be an understatement. And isn't Berkeley reacting primarily to John Locke, who was himself religious? Berkeley may have been opposed to realism, but that doesn't mean religion is opposed to realism.

The reason for the fable is we are misled by being able to refer in our language into thinking that there is some fixed reference. — Moliere

Okay, so now you are saying that reference is inscrutable even to fellow language-speakers. Or more precisely, that there are no fixed referents amongst fellow language-speakers.

But that doesn't seem right. If you and I are sitting in a room together there will be any number of fixed referents available, e.g. "table," "chair," "dog," "television," "photograph," etc. So how does that work? Do you mean something very specialized by "fixed reference"?

A fact is a set of true sentences. — Moliere

"Moliere understands 'chair' to signify <chair-concept>."
"Leontiskos understands 'chair' to signify <chair-concept>."
"Therefore, Moliere and Leontiskos understand 'chair' to refer to the same kind of object."

Those are three propositions, and if they are a set of three true sentences then on your view they would be called a "fact." If this is a fact, then it looks like there are facts of the matter with respect to reference.

So when I say Truman is dead that is a true sentence about Truman. That Truman is dead, however, does not affix the reference of "Truman" -- nor do any other true sentences. — Moliere

Right: the (conventional) association between Truman and 'Truman' is already "affixed" before the true sentence is uttered. If it were not then the true sentence would not be true.

You ever read about feral and dramatically maltreated children? — Moliere

I've read some, and I agree that it seems to substantiate my thesis.

My solution is that if I check in with you and ask "Oh, do you mean this Truman or that Truman" we can refer in a given conversation, rather than that "Truman" always refers to Truman because of this or that theory of reference. — Moliere

I definitely agree that there is more than one person named "Truman."


I think what you and some others are trying to say is this: "Reference cannot be fully and exhaustively explained." I would say that it depends what tools we have to hand and what we mean by "fully and exhaustively explained."

- Thanks.

Science let it be known humans could have things, could do things, entirely on their own, or at least enough on their own to call into question isolated external causality of the Berkeley-ian “un-constructed” spirit type... — Mww

Yes, but is it just modern science? Because there is plenty of philosophy between Plato and Berkeley that manages to avoid Berkeley's idealism. I'm sure if I investigated the way that Berkeley was reacting to Locke I would have a better understanding of this issue.

---

- Okay, thanks. :up:

it's inscrutable from the perspective of a person without knowledge of the language — Moliere

But that's a mundane claim, isn't it? Almost tautologous? The stronger and more interesting claim is that something is inscrutable in that it cannot be fixed. I hope Quine is doing more than uttering a tautology.

My take-away here is that since there's no fact of the matter that affixes reference, but we are able to refer, there must be something other than the facts which makes us able to refer. — Moliere

From the early pages of this thread I have objected to this vague use of the word "fact." What is it supposed to mean? Does it mean anything to say there is no fact of the matter? If it did, then what would it look like if there were a fact of the matter?

It takes two to refer. — Moliere

Will someone raised apart from language and people be able to identify food, such as berries? And will this be a cognitive identification, such that they might find they are hungry for berries and decide to go out looking for them? Because if so, then it looks like they can refer to berries without two.

- In a general way, how do you see Kant relating to Berkeley?

- Very informative post. :up:

To me, thinking that such a premise is true, just demonstrates a lack of understanding of Berkeley, — Metaphysician Undercover

What you are accusing him of is ignoratio elenchus, not begging the question. — Leontiskos

I received a PM from someone essentially asking, "What's the fuss?" — Leontiskos

What is a way into the paper? In footnote 3 Klima points to Frege's Kantian criticism of Anselm's proof. Let's look at that source:

§ 53. By properties which are asserted of a concept I naturally do not mean the characteristics which make up the concept. These latter ate properties of the things which fall under the concept, not of the concept. Thus “rectangular” is not a property of the concept “rectangular triangle’; but the proposition that there exists no rectangular equilateral rectilinear triangle does state a property of the concept “rectangular equilateral rectilinear triangle”; it assigns to it the number nought.

In this respect existence is analogous to number. Affirmation of existence is in fact nothing but denial of the number nought. Because existence is a property of concepts the ontological argument for the existence of God breaks down. But oneness* is not a component characteristic of the concept “God” any more than existence is. Oneness cannot be used in the definition of this concept any more than the solidity of a house, or its commodiousness or desirability, can be used in building it along with the beams, bricks and mortar...

* [I.e. the character of being single or unique, called by theologians “unity”.] — Frege, The Foundations of Arithmetic, tr. Austin (1960)

Frege seems to be appealing to some notion of extensionality. He thinks that existence is a property of concepts insofar as number is assigned to concepts. For example, what number is assigned to the concept, "Moons orbiting Earth"? The answer for Frege is '1', and in virtue of this "denial of the number nought" there exists a moon orbiting Earth. Rather, that is what existence means for Frege. Similarly, if Frege wanted to tell us that there do not exist any motorcycles that are orbiting Earth, what he would say is that the concept, "Motorcycles orbiting Earth," is to be assigned the number '0'. Such is his account of existence.

So when considering Anselm's proof Frege tells us that 'oneness' (namely, the variety of non-noughtness traditionally accorded to God), "is not a component characteristic of the concept 'God'..." That is, the concept "God" does not have an intrinsic property '1'. In Kleine Schriften he will talk about a concept being "not empty." Klima follows Haaparanta in tracing some of this back to Kant, who was a strong influence on Frege and who Frege agrees with vis-a-vis Anselm's proof.

So on Frege's proto-extensional understanding, Anselm is saying that the concept 'God' has a component characteristic of oneness (which entails that the concept is not nought or not empty, ergo, that it exists). Frege claims that this is false and that the proof therefore fails. He says, "No, Anselm, the concept 'God' is not non-empty qua concept."

Like I said, I haven't read beyond section 1, and I don't want to go too fast, but this is at least the foil that Klima is using in setting out a medieval approach—in setting out a more accurate way to interpret Anselm's proof.

"All that is can be thought," does not imply "all that is thought is." — Count Timothy von Icarus

Yes, and I think the quotes you highlight are important:

At this point, however, anyone having qualms about “multiplying entities”, indeed, “obscure entities”, should be reminded that the distinction between objects, or beings (entia) simpliciter, and objects of thought, or beings of reason (entia rationis) is not a division of a given class (say the class of objects, or beings, or entities) into two mutually exclusive subclasses. — Gyula Klima, St. Anselm's Proof: A Problem of Reference, Intentional Identity and Mutual Understanding - Section 1

So what is going on here? On the modern scene it is well accepted that a term can refer to beings (entia), such as deer, socks, trees, etc. But then when it is proposed that a term can also refer to beings of reason or objects of thought (entia rationis), the common objection is that this will "multiply entities" and thus transgress Occam's Razor. Specifically there is the idea that it will require two mutually exclusive ontological subclasses, one subclass for beings simpliciter and one subclass for beings of reason.

We actually saw this play out two days ago in the midst of a discussion on Mario Bunge, who admits of conceptual existence and who treats existence as a first-order predicate. A response was as follows:

A few notes on treating existence as a predicate. We can of course do this, with some cost. The result is a logic that ranges over things that exist and things that do not exist. That is, it in effect has two domains, one of things that exist and one of things that... do not exist. — A Response to Mario Bunge

(Consider also footnotes 7 and 12. The assumption here derives from Quine's opposition to Alexius Meinong, who posited two ontological subclasses of a sort.)

That is, the assumption is that Bunge must be working with two mutually exclusive subclasses, at least "in effect." This is the sort of objection that Klima has in his sights. How does he address this objection?

...Mere beings of reason, therefore, are not beings, and mere objects of thought are not a kind of objects, indeed, not any more than fictitious detectives are a kind of detectives, or fake diamonds are a kind of diamonds.

Qualifications of this kind are what medieval logicians called determinatio diminuens, which cannot be removed from their determinabile on pain of fallacia secundum quid et simpliciter.[11] Accordingly, admitting objects of thought, or beings of reason, as possible objects of reference, does not imply admitting any new objects, or any new kind of beings, so this does not enlarge our ontology. — Gyula Klima, St. Anselm's Proof: A Problem of Reference, Intentional Identity and Mutual Understanding - Section 1

First, there are not two ontological subclasses. In an ontological sense there are only beings (entia). But then how do beings of reason (entia rationis) fit in? According to Klima, beings of reason are not beings, but they can still be objects of reference.

For example, suppose Fido is a dog but Jordan thinks Fido is a cat. Jordan's thought or understanding of Fido as a cat does not refer to any being, given that Jordan is mistaken. Nevertheless, we can still refer to Jordan's cat-Fido thought because it is a being of reason and we can refer to beings of reason. Referring to Jordan's thought, we might tell him, "The way you are thinking about Fido is not correct." We refer to Jordan's thought without granting it ontological status as something that enlarges our ontology (and this is a generic move that can accommodate many different sub-theories).

Klima's point about "fallacia secundum quid et simpliciter" is effectively that there are rules against reifying beings of reason and shifting them into beings (simpliciter). If you fail to keep track of what is a being and what is a being of reason, or try to "pull a fast one" by swapping out a being of reason and swapping in a being (simpliciter) when no one is looking, then you're committing a fallacy. When beings of reason are allowed as referents new rules are added to make sure we don't mix up the two.

Modern thought sometimes has more difficulty with this to the extent that it has eliminated a solid understanding of, or ground for, the distinction between act and potency... — Count Timothy von Icarus

I agree. Good point.

- Good stuff. :up:

I'll just stick to the opening section for now. — Count Timothy von Icarus

Sounds good. I haven't even read section 2 yet. :cool:

I think it's probably a good idea to stick to section 1 before moving on to section 2; section 2 before moving on to section 3, etc. It looks like each section will have enough content to sustain its own discussion, questions, confusion, etc. Bite-sized pieces will also make participation easier, for myself included.

First, I will point out that the distinction... — Count Timothy von Icarus

Great thoughts. I've been on the road all day and need a nap, but I will come back to this. :smile:

You are neglecting a key point, the need to have truthful premises, in order for the conclusion to be sound. — Metaphysician Undercover

And Johnson thinks it is true, as does Tallis. If you think it is false then what you need to do is argue against it, not cry "fallacy!" Note that you haven't managed to address Tallis' argument at all, and Tallis is defending (1).

Designing your premise for the purpose of producing a specific conclusion with disregard for the truth or falsity — Metaphysician Undercover

Again, you are just imputing specious motives to Johnson. I see no reason to impute such motives, and that sort of psychologism/mind reading is bad philosophy. If you have an argument, offer it. If all you are going to do is say, "I did some mind-reading and found a bad motive," then you're not doing philosophy.

- Thanks. :up:
A mod is welcome to delete the whole mixup.

(My edit <here> is somewhat explanatory of what was going on.)

- I would prefer to delete but it's up to you.

@tim wood, @Banno

Oops. This was a PM. I wrote it out so that I could preview it, and I accidentally posted it here instead of in the PM. I've deleted it, but I will leave the part about Banno if he wants to dispute it.

- Okay, thanks.

-erroneous post-

clearly designed for the purpose of that refutation — Metaphysician Undercover

Every premise is designed for the purpose of the conclusion, and every premise of a refutation is designed for the purpose of the refutation. Perhaps you are the one begging the question, here.

The conclusion "this act refutes Berkeley" is only derived if the very dubious premise (this act will refute Berkeley), which is designed specifically for that purpose, of refuting Berkeley, is accepted. — Metaphysician Undercover

That's how arguments work. You design premises to reach a conclusion. This whole thread is a testament to the fact that it is not dubious, for the precise point of Tallis' paper is to show that it is not even an ignoratio elenchus, much less a begging of the question. "In what follows, I want to persuade you that the stone-kicking may deliver more than may be apparent at first sight."

Part 1. The Modern vs. the Medieval Conception of Reference

Russell and reference via quantification -- Quine's slogan -- misinterpretations of Anselm -- intention, medieval reference, and ampliation -- entia rationis -- ontological commitments -- correctly interpreting Anselm

Here are the first few sentences of the paper:

Saint Anselm’s proof for God’s existence in his Proslogion, as the label “ontological” retrospectively hung on it indicates, is usually treated as involving some sophisticated problem of, or a much less sophisticated tampering with, the concept of existence. In this paper I intend to approach Saint Anselm’s reasoning from a somewhat different angle.

First, I will point out that what makes many of our contemporaries think it involves a problem with the concept of existence is our modern conception of reference, intimately tied up with the concept of existence. On the other hand, I also wish to show that the conception of reference that is at work in Saint Anselm’s argument, indeed, that is generally at work in medieval thought, is radically different, not so tied up with the concept of existence, while it is at least as justifiable as the modern conception. — Gyula Klima, St. Anselm's Proof: A Problem of Reference, Intentional Identity and Mutual Understanding, 69

---

Edit: I received a PM from someone essentially asking, "What's the fuss?" If you are not familiar with the modern conception of reference stemming largely from Bertrand Russell, and also the way that quantificational logic understands existence via figures like Frege and Quine, then the paper may be somewhat opaque to you. Certainly the first section will be opaque. Nevertheless, the latter sections of the paper might be more accessible even to those who are not familiar with the modern tradition.

I think you've noted before that we need to do some tinkering within Fregean logic to accommodate the 1st person. Would you agree with Rodl that, without such tinkering, there is indeed a difficulty presented for the "doctrine of propositions"? — J

Think about it this way: if we zoom out then force represents subject/subjectivity and content represents object/objectivity. Now with Kimhi you were searching for "Monism," and I assume that the same sort of thing is at play with Rodl?

Because if the critique of the force/content distinction is ultimately that it is dualistic, then I'm not sure where else there is to go. "Monism"? I would have to know what that means, but if there is more than one thinking subject in the world, and there is at least one common object of thought, then the dualism of subject and object is both inevitable and true.

That is, if we don't know what it is about the force/content distinction that is disagreeable but we just keep shooting at it anyway, then what is it we are aiming at? The duality of subject and object? Because as long as that duality exists I don't see how force/content will go away.

I do see the problem Rodl (and Kimhi) see. How can there be objective content that is also thought? — J

Is it any less pressing to ask, "How can there be non-objective content that is also thought?"

it's an ancient epistemological puzzle — J

Where do you find it before Descartes?

Either way, what is the teaser for how self-consciousness solves the problem of the objectivity of thought?

@Paine, how would you characterize the "big picture" here, especially with respect to the OP? Rödl says that the I think accompanies all my thoughts, or at the very least he wants to place a very strong emphasis on self-consciousness in thinking and judging. It seems overboard. What is the context that would account for this sort of emphasis? Thanks.

Judging from Rödl's work as it is presented here by those who are reading him, he seems seriously confused. — Janus

Yeh. A thread like this really needs to provide a clear account of the motivations behind the strange thesis.

"Why in the world would he do/say that!?"
"Because he was being chased by killer bees."
"Oh, okay. I get it now. Thanks for explaining."

Well for Aristotle the soul is the principle of life, so if Truman's body still has a principle of life, then he is not fully dead. But of course if we hold to a view where the soul perdures apart from the body after death then there arises the tendency to identify Truman with his perduring, separated soul.

Some contemporary Aristotelians suggest that Aristotle didn't think that artifacts had forms, because they think that an Aristotelian form has something to do with life. — Arcane Sandwich

Yes. For my teachers an artifact has a form, but not a substantial form. Yet a substantial form would not need to be soul/life, for there are inorganic compounds with a substantial form. Nevertheless, I agree that this last part is more controversial.

We would not say that Truman himself is identical to his life, rather we would say that Truman is alive. He has the property of being alive. It's an open question what happens when Truman dies. Is he still Truman, but dead? If so, then his form wasn't his life, after all. Or, one would instead say that it was, and that when Truman dies, what remains is no longer Truman. Instead, what remains is merely Truman's body. For someone like me, who claims that every human is identical to a living brain in a body, this is problematic. — Arcane Sandwich

Right, so the question has to do with how the "property" of life relates to Truman, namely whether it is something he needs in order to be himself. Or put differently, whether it is nonsensical to talk about Truman apart from his life.

Sure thing. But it will work better for substances than for artifacts a la material constitution. Granted, a similar problem would occur if the real Athena were flattened (as least if she were mortal). You would have a clump of matter that was Athena a moment ago, but no longer is (i.e. you would have substantial change).

Truman's formal cause, on the other hand, is not his two parents, it is instead his form. When I say that Truman exists because someone is Truman, I am not referring to Truman's parents, I am referring to Truman's form. — Arcane Sandwich

Perhaps what is happening here is that you want the referent for 'Truman' to be more than the bare particular of predicate logic, i.e. you want for Truman what is for species an essence. That is, you want to reference a primary substance rather than a bare particular.

If that is right, you may be interested in Gyula Klima's "Contemporary 'Essentialism' vs. Aristotelian Essentialism," where he compares a Kripkean formulation of essentialism to an Aristotelian formulation of essentialism, and includes formal semantics for signification and supposition, which involves the notion of inherence. Paul Vincent Spade also has an informal piece digging into the metaphysical differences between the two conceptions, "The Warp and Woof of Metaphysics: How to Get Started on Some Big Themes."

Note that Banno's whole logical horizon is bound up with the bare particulars of predicate logic, so I'm not sure it is possible to easily convey an alternative semantics to someone who who has never been exposed to an alternative paradigm.

- Then continue to go on contradicting SEP as you bristle, by all means. :up:

If you want to talk about empty domains, go ahead. — Banno

Why did it come up? Because we were talking about ontological commitment and SEP utilizes the empty domain as a useful way to talk about ontological commitment. See my post <here> for the genesis.

That the domain is not empty is a presumption for first order logic anyway — Banno

A convention. This happens to be a conversation about challenging conventions.

The very that that it is possible to "talk past one another" relies on it not being the case that we always, or even mostly, talk past one another. — Janus

If the quote <here> were true then we would talk past one another much more often than we do.

You should know better than to confuse the metaphysical with the empirical. The point of the principle of falsifiability was to be able to distinguish metaphysical from empirical claims, but it does not aim to falsify metaphysics. In other words, a metaphysical posit is not challenged by its not being falsifiable. — Wayfarer

No, I don't think that's right at all. The same principle holds in metaphysics, or more generally, in argument of any kind. It's called the principle of sufficient reason. If there is no possibility of refuting Berkeley's claim, then it transgresses the principle of sufficient reason (for in that case Berkeley has no reason to assert it). Falsifiability is not limited to empirical matters; it's just that in non-empirical matters the falsification takes a non-empirical form.

You’re right that much of our own minds and bodies remains unperceived from our subjective perspective. But when we turn our attention to these unperceived attributes—whether mental or physical—they are thereby brought into the realm of perception and cognition. — Wayfarer

Sure, but Tallis' point stands. The lymphatic system continues to sustain us, perceived or unperceived. Tallis would not disagree that perceptible objects can be perceived at one time and unperceived at another.

The reason Johnson's argument is curious at all is because Berkeley's claim that matter does not exist is so implausible. Or in other words: Berkeley has the burden of proof. If he didn't, then Johnson's action would not attract as much attention as it has.

I really don't know Berkeley well enough to say how he would interact with Tallis, but Tallis' paper is somewhat interesting.

So I think the target is more various philosophical notions of reference rather than the whole ability to communicate. — Moliere

What I'd commit to is the idea that though reference is inscrutable we can still communicate. — Moliere

"How we manage to refer is mysterious, but what is being referred to is not indeterminate."

Yes?

Or:

"How we manage to refer is inscrutable, but what is being referred to is not inscrutable."

- A very useful post. :up:

and obviously just intentionally designed to produce the conclusion desired — Metaphysician Undercover

I don't grant your imputation of specious motive.

So does Tallis’ argument effectively challenge Berkeley’s idealism — Wayfarer

I think it's at least reasonable. He seems to be saying that we know matter exists in the first place because of our experience of our body, and it is the interaction of Johnson's material body with the object of the rock that secures the conclusion that the rock is material. I said something similar to Tallis' premise recently:

I think the question is whether sense of self is direct or indirect. If it were direct, then it would seem that there is nothing I would not know about myself. I would be fully transparent to myself. If it is indirect, then self-consciousness is not always present. — Leontiskos

Experience of our bodies shows us that there are existing things which are important and yet are not perceived:

My own body, however, delivers more to justify the intuition that it has a being that goes beyond perception.

For a start, the extent to which I experientially access my own body is very limited, and variable. Many of my organs, and most of the processes that take place in them, are hidden from me; and yet they are the continuous necessary conditions of my being alive and perceiving anything. I don’t know about you, but my lymphatic system has given me no notice of its essential existence over the many years of my life, but I wouldn’t be without it. More to the point, there is the necessary, if implicit, role of parts of my body of which I am unaware, or only patchily aware, when I perform ordinary actions. — Tallis

• If my lymphatic system did not exist, then I would not exist.
• But I do exist.
• Therefore, my lymphatic system exists.
• But my lymphatic system is not generally perceived.
• Therefore, unperceived things exist (i.e. matter).

And if Berkeley says that God constantly perceives Tallis' lymphatic system, Tallis might ask whether that sort of reliance on God constitutes a falsifiable claim.

Most of this seems to depend on just what definition of 'matter' we place in Berkeley's mouth.

There would be no reason to say they are talking past each other in any radical sense because their verbal dispositions are the same so they communicate perfectly. — Apustimelogist

Except Quine literally says, "the meanings or ideas expressed in their identically triggered and identically sounded utterances could diverge radically." If the meanings and ideas expressed by our identical utterances diverge radically, then I would say we are talking past each other by definition.

This is what I think it comes down to:

Are you saying that even if they do talk past each other, they won't tend to register each other's speech as inscrutable? — Leontiskos

The thesis you offer is that they would be objectively talking past each other without even knowing it. But that becomes more implausible the longer we draw out their conversation (say, from 15 seconds to 2 minutes to 5 minutes to 30 minutes...). The longer we talk the more likely we will realize that we are using words in radically different ways.