Maverick Philosopher

Footnotes to Plato from the foothills of the Superstition Mountains

Battling the Bad Ostrich over Assertion

BV said:

I will now pose a problem for the view that assertion = proposition.  Suppose I give the following valid argument, an instance of modus ponens.  By 'give an argument,' I mean that I assert its premises, and I assert  its conclusion as following from the premises, and this  in the presence of one or more interlocutors.  Thus the argument is to be taken in concreto, not in abstracto.

If Tom is drunk, then Tom ought not drive
Tom is drunk
—–
Tom ought not drive.

If the argument is valid, as it plainly is, then, in both of its occurrences,  the sentence 'Tom is drunk' must express the same proposition.  But this cannot be the case if  a proposition is identical to an assertion. For the proposition Tom is drunk occurs unasserted in the major, but asserted in the minor.  (To assert a conditional is not thereby to assert either its antecedent or its consequent.) Since one and the same proposition can occur unasserted in one context and asserted in another, we must distinguish between a proposition and an assertion.

The Ostrich responds:

I deny that the sentence ‘Tom is drunk’ in the major expresses a proposition at all. It expresses a proposition in the minor, I agree. I also claim that both sentences must have the same content in major and minor. But having the same content is not the same as expressing the same proposition. Perhaps we should rewrite the major as follows:

That Tom is drunk implies that Tom ought not drive.

We connect a name for contents, using a that-clause, with the connector ‘entails’. Thus we express the whole argument as follows

It is the case (that Tom is drunk implies that Tom ought not drive)
It is the case that Tom is drunk
It is the case that Tom ought not drive.

BV counter-responds:

The Ostrich carelessly leaves out the parentheses in the minor and in the conclusion of his re-write of the original argument.  His re-write should look like this:

It is the case (that Tom is drunk implies that Tom ought not drive)
It is the case (that Tom is drunk)
It is the case (that Tom ought not drive).

'That Tom is drunk' is not a sentence but a nominal phrase.  In the major, it names a proposition, the proposition expressed in English by a tokening of 'Tom is drunk.'  It has to name a proposition because the implication relation connects propositions to propositions. In the minor 'that Tom is drunk' also expresses a proposition. It has to if the argument is to be valid.

So one and the same proposition — the one named by 'that Tom is drunk' — occurs in both the major and the minor.  It is just that in the major it is not asserted, whereas in the minor it is.  Therefore, a proposition is not the same as an assertion — which was my claim all along.  (Not original with me, of course.  From Frege via Peter Geach.)

So the Ostrich re-write is useless rigmarole.  Consider the following re-write:

That Tom is drunk implies that Tom ought not drive
Tom is drunk
Tom ought not drive.

This is valid. In the major, 'That Tom is drunk' names but does not assert a proposition. In the minor 'Tom is drunk' asserts the very same proposition.  So one and the same proposition can be both asserted and left unasserted. Therefore, a proposition is not the same as an assertion.

The Ostrich tells us, "But having the same content is not the same as expressing the same proposition." I don't understand that.  A content in this context just is a proposition.

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7 responses to “Battling the Bad Ostrich over Assertion”

  1. The Bad Ostrich Avatar
    The Bad Ostrich

    Up to a point I don’t see that we have any fundamental disagreement, although there is the usual confusion about the meanings of key terms. By ‘proposition’, you clearly mean what I am calling ‘propositional content’. Thus

    ME: ‘that Tom is drunk’ refers to a propositional content
    BILL: ‘that Tom is drunk’ refers to a proposition

    Now I wrote

    So I must rewrite my claim ‘I deny that the sentence ‘Tom is drunk’ in the major expresses a proposition at all. It expresses a proposition in the minor, I agree.’

    You will object that ‘Tom is drunk’ in the major does express a proposition, because you mean by ‘proposition’ what I mean by propositional content.
    So this is partly a disagreement about what we mean. I shall graciously agree to go along with your definition of ‘proposition’, i.e meaning propositional content. But I disagree that in the sentence ‘Tom is drunk’ expresses a proposition in the major, although I agree it does express a proposition in the minor.
    We have the relation of naming (or referring) and expressing. Whole sentences (not sentence-clauses) express propositions, they do not name them. That-clauses name propositions, without expressing them.
    Now your write
    >> So one and the same proposition — the one named by ‘that Tom is drunk’ — occurs in both the major and the minor. It is just that in the major it is not asserted, whereas in the minor it is.
    Agree with this (understanding ‘proposition’ to mean what I call ‘propositional content’). I would say that in the major it is not expressed, whereas in the minor it is expressed.
    >> Therefore, a proposition is not the same as an assertion
    Right: a proposition in your sense (me: a propositional content) is not the same as a proposition-expressing sentence.
    >> In the major, ‘That Tom is drunk’ names but does not assert a proposition.
    Correct. A noun-phrase cannot express a proposition, although it can specify or name it.
    >> In the minor ‘Tom is drunk’ asserts the very same proposition.
    Agree. In the minor ‘Tom is drunk’ expresses the same proposition.
    >>So one and the same proposition can be both asserted and left unasserted.
    I.e. one and the same propositional content can be expressed, or not expressed, by the very same sentence. On my view, this is possible because the word ‘that’ extracts the expressional part from a meaningful sentence. E.g. suppose I say

    Bill says that Tom is drunk

    That’s a 6-word sentence that contains a 3-word sentence. The 6-word sentence expresses a propositional content (you: ‘proposition’), namely the content specified by the clause ‘that Bill says that Tom is drunk’. The 3-word sentence doesn’t express the propositional content that it would express were it grammatically the main clause (‘a clause that can form a complete sentence standing alone’, although that same propositional content is named or specified by the 4-word clause ‘that Tom is drunk’.
    I am not sure we deeply disagree so far, except for one part. I say that the difference in meaning of the sentence-tokens of ‘Tom is drunk’ is the result of syntax and semantics only. I believe that we could devise an algorithm to detect when a meaningful sentence was expressing a proposition (in your sense) or not. One simple rule is whether the sentence is wrapped in a ‘that’ clause.
    Your fundamental claim, on the other hand, seems to be that there could be no such algorithm. Propositions, on your view, are only expressed via a speech act. This leads to the absurdity, in my view, that the whole of Deuteronomy expresses not a single proposition, and so cannot be evaluated for truth and falsity. Yet the question of whether Moses died in Moab is an important historical question.
    Your view also leads to the absurdity that whether a sentence expresses a proposition is at the whim of the utterer of the sentence. Thus it should be possible, in your view, to utter ‘If Tom is drunk, then Tom ought not drive’, in such an assertive way that you have asserted that ‘Tom is drunk’. Clearly that is ludicrous. Anyone who understand the rules of English grammar knows that this is impossible. It’s all down to syntax and semantics.

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  2. BV Avatar
    BV

    Ostrich,
    Excellent comments, far better than your usual comments. You are actually engaging what I said. We agree that a sentence is not a name, and that we must distinguish between expressing and naming. ‘Tom is drunk’ expresses, but does not name, a proposition. ‘That Tom is drunk,’ on the other hand, names, but does not express a proposition.
    I agree that there is a computer-implementable algorithm that detects sentences. But it can’t just look for embedment in that-clauses because of sentences like this: “Whether Tom is drunk depends on how you define ‘drunk.’” And this: ‘Molly is angry because Tom is drunk.’
    Do I deny that there could be an algorithm for the detection of declarative sentences? No. If a machine implementing an algorithm detects a sentence, it does this by recognizing the geometrical properties of strings of marks, for example, the absence of marks having the shape of ‘that.’ You input a bunch of strings and the machine sorts them into sentential and non-sentential strings, and then sorts the sentential strings into declarative and non-declarative. It detects the difference between ‘The door is open’ and ‘Is the door open?’ by noting word order and the presence or absence of the mark ‘?’
    My point, however, is that a declaratively sentential string of marks does not by itself express a proposition. The string ‘Tom is drunk,’ qua string, expresses no proposition. It does so only when used by a person to express a proposition. So while there can be mechanical sentence detectors, there cannot be mechanical proposition detectors. There is no meaning without mind.
    As you know, one and the same sentence can be used to express both a proposition and its negation. ‘The weather is just wonderful’ can be used to express the thought that the weather is inclement.
    I’ll reply to the Biblical example later.

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  3. The Bad Ostrich Avatar
    The Bad Ostrich

    My comments are always excellent but you can’t always see this. Never mind.
    >>My point, however, is that a declaratively sentential string of marks does not by itself express a proposition.
    Right so the original Geach objection, which you have posted a few times, is irrelevant, no?
    >>As you know, one and the same sentence can be used to express both a proposition and its negation. ‘The weather is just wonderful’ can be used to express the thought that the weather is inclement.
    This is why the scholastics used the phrase ‘de virtute sermonis’, to mean something like ‘literally speaking’. What you utter has a meaning by itself which we cannot change, because it is determined by imposition or convention, ‘in virtue of the words themselves’.
    Now I don’t disagree that we can pragmatically express propositions that are not a part of, or are opposite too, the original meaning. “Tom’s wife is such a treasure”.
    >>a machine implementing an algorithm detects a sentence, it does this by recognizing the geometrical properties of strings of marks, for example, the absence of marks having the shape of ‘that.
    Let’s assume it’s something like that. But do humans not use some such kind of algorithm? If not, how do they do this, unless there is some kind of telepathy – which I deny.
    >>There is no meaning without mind.
    OK let’s go along with that. My point remains that ‘Tom is drunk’ and ‘that Tom is drunk’ have a different meaning, and that difference is precisely between assertion and naming of propositions, and that the difference is signalled (you don’t like ‘signify’) by the text, de virtute sermonis. Now, we are condemned never to be able to name the assertoric meaning, because if we did, we would have to use a noun phrase to do so, and a noun phrase is not a sentence. But it exists.
    >> The string ‘Tom is drunk,’ qua string, expresses no proposition. It does so only when used by a person to express a proposition.
    Back to my Biblical example. No one exists to express the proposition if the corresponding sentence was written more than 2,000 years ago. Perhaps we need a reader to understand the sentence, I will concede that much. But there is no ‘speech act’. Rather, an ‘understanding act’.

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  4. BV Avatar
    BV

    >>Propositions, on your view, are only expressed via a speech act. This leads to the absurdity, in my view, that the whole of Deuteronomy expresses not a single proposition, and so cannot be evaluated for truth and falsity.<< My Bible is on the shelf, closed. Not one sentence in it expresses a proposition. If 'Moses died in Moab' is a sentence in Deuteronomy, then that particular sentence token in my particular copy of the Bible expresses no proposition. If I open the book and read that sentence, then it expresses-- wait for it -- that Moses died in Moab! No linguistic tokens in any medium have their meaning intrinsically. In fact, a string of marks on a page is a LINGUISTIC token only if it is intended by someone or interpreted by someone as belonging to a language. The string 'hat' is a word of German and a word of English. Same string, but different words with different meanings. It follows that the meaning is not intrinsic to the string. The meaning depends on how the string is used by language-users who are persons. Could an Englishman say, 'I've misplaced my torch'? If I said that it would sound like a joke. It is not only the same string, it is the same English word, but the meaning varies depending on the users. So the meaning of 'torch' is not intrinsic to it. If all language users ceased to exist, then all the sentences out there whether carved in stone or written in books would at best be potential bearers of meaning. A potential F is not an actual F. So a sentence after all minds have been annihilated is not a bearer of meaning and does not express a proposition. In fact, it is only potentially a linguistic item. Does Deuteronomy express any propositions even though the authors are all dead? Yes, of course. There are readers and speakers of Hebrew. By looking at those strings of mark they are able to attach a meaning to them. They are able to do this without getting into the heads of dead men. This is because Hebrew readers and speakers have existed since those early days and those people have kept alive the meanings of those strings of squiggles. By the way, I never said that propositions are expressed only by speech acts.

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  5. The Bad Ostrich Avatar
    The Bad Ostrich

    So, er, the word ‘grass’, which is lying in my dictionary on the shelf, closed, does not mean grass?
    Perhaps you have some special sense of words like ‘mean’ and ‘express’? I say that ‘grass’ means grass, and that the English sentence ‘Moses died in Moab’, expresses the proposition that Moses died in Moab. Do you disagree? Or are you claiming some kind of dispositionality. ‘Grass’ means grass in the sense that drunk driving kills people, even though perhaps no one is now being killed by a drunk driver.
    You haven’t addressed my point about literal meaning, or do you now accept this?
    >>Does Deuteronomy express any propositions even though the authors are all dead? Yes, of course.
    This appears to contradict your earlier claim that not one sentence in the Bible expresses a proposition.
    >>By the way, I never said that propositions are expressed only by speech acts.
    So propositions can be expressed through reading? But what is the subject of the verb ‘express’? Clearly the reader isn’t expressing anything, but rather understanding what the text says. Is the text expressing something?

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  6. The Bad Ostrich Avatar
    The Bad Ostrich

    We should also get back to the original question, raised in your post here. You wrote

    I have no objection to the above as a setting forth of one sense of ‘assertion.’ In this sense, an assertion is the content or proposition asserted. But I must quibble with the last sentence: “All of these [sentences/propositions] assert that the existence of some . . . .” That is a loose way of talking, allowable in some contexts, but not in the present one in which we are discussing assertion, presupposition, Excluded Middle, and cognate topics. A proposition doesn’t assert anything, and neither does a sentence. People assert, and when they do, what they assert is a proposition.

    That suggests you are comfortable with saying e.g. the ‘grass’ means grass, with the subject of ‘means’ being the term ‘“grass”’ (note the double quotes, as I am referring not to the word ‘grass’, but the name of that word). But this is a ‘loose way of talking’, correct?
    How does our long debate about assertion engage with presupposition and excluded middle?

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  7. The Bad Ostrich Avatar
    The Bad Ostrich

    The dispositional talk reminds me of my undergraduate project on Locke on secondary qualities. On a naïve interpretation we shouldn’t say that bananas are yellow, because bananas are really a collection of colourless atoms, which light strikes, the light reaches the eye and thus causes a yellow sensation in the mind. So it is the sensation which is yellow, not the banana.
    That’s completely wrong of course. It’s not wrong to say bananas are yellow, nor is it ‘loose talk’. Bananas have a disposition to cause sensations of a certain sort in the human (and animal) mind, and it is having that disposition which consists in being yellow. Bananas would be yellow even if all human life were extinguished. Likewise, the tree falling in the forest does make a sound.
    Likewise, I claim, the type ‘grass’ means grass even if there were no humans around.

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