I continue to worry this technical bone, which is not a mere technicality, inasmuch as the topic of presupposition opens out upon some very Big Questions indeed. Anyway, back to work. I thank Ed Buckner for getting me going on this.
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It should be obvious that one does not assert everything that the content of one's assertion entails. If I assert that Venus is a planet, I do not thereby assert that either Venus is a planet or Putin is a former KGB agent, even though the content of my assertion entails the disjunctive proposition. The content of an assertion is a proposition, and for any proposition p, p entails p v q.
A more interesting, and more difficult, question is whether one asserts any proposition that the content of one's assertion entails (apart from the proposition that is the content of the assertion).
Suppose you ask who won the 10K Turkey Trot and I assert that Tony won the race. Do I thereby also assert that he competed in it? That he competed in it is entailed by the fact that he won. And it is entailed in a stronger sense that the sense in which Venus is a planet entails Venus is a planet or Putin is a former KGB agent. For there is a semantic connection between winning and competing, but no semantic connection in the Venus-Putin case. You could say that it is analytically impossible that Tony win without competing: what makes it true that there is no possible world in which Tony wins but does not compete is the semantic connection between winning and competing.
Still, I want to say that Tony's competing is presupposed but not asserted when I assert that he won the race. Necessarily, anything red is colored. But when I assert that Tom the tomato is red, I do not thereby assert that it is colored, although of course I presuppose that it is colored. Note the word 'thereby.' It is no doubt possible for me to assert that Tom is colored, a 'vegetable of color' if you will, but that is a different assertion.
Go back to Tony the runner. That Tony did not cheat by taking a short cut is analytically entailed by the fact that he won. (To win a foot race it does not suffice to be the first to cross the finish line. Remember Rosie Ruiz of Boston Marathon 1980 notoriety?) Will you say that when I assert that Tony won the race I also thereby assert that he did not cheat by taking a shortcut? I would say No. For that would be an unbearably counter-intuitive thing to say. I presuppose, but do not assert, that Tony did not cheat by taking a shortcut
You can see how this series of questions can be extended. One can cheat by getting a head start or by jumping in at mid-course, which is what Rosie Ruiz did at Boston. You can cheat by hiring a a world-class doppelgaenger, by wearing special shoes . . . .
Note also that if Tony won, it follows that he either won or didn't win. Will you say that when I assert that Tony won the race I am also thereby asserting that he either won it or didn't? When I assert that Tony won, I am not asserting the Law of Excluded Middle (LEM). At most, LEM is a presupposition of my assertion, and of every assertion.
If Tony won, then it was possible that he win. For everything actual is possible. But when I assert that Tony won, I presuppose, but do not assert, that it was possible at the time of the race that Tony win.
I am toying with a strong thesis:
When an agent A makes an assertion by uttering or otherwise tokening a sentence s (which is typically, but needn't be, in the indicative mood), the content of the assertion is exactly the (Fregean) proposition explicitly expressed by the tokening of s and no other proposition. Propositions other than the content proposition that are entailed by the content proposition are at most presuppositions of the assertion.
Why hold this view? Well, it seems to me that what I assert on any occasion is precisely what I intend to assert on that occasion and nothing else. When I make an assertion I translate into overt speech a belief that I have. The content/accusative of the belief is a Fregean proposition and there is nothing in that proposition that is not open to my mind at the time I express my belief.
Two purely technical points here.
1. According to Strawsonian presupposition, ‘One sentence presupposes another iff whenever the first is true or false, the second is true. On the ‘presupposition via negation’ definition, ‘One sentence presupposes another iff whenever the first sentence is true, the second is true, and whenever the negation of the first sentence is true, the second sentence is true. I prefer the first definition, but both are problematic for existential propositions.
2. In the medieval tradition, there was a lot of discussion of propositions like ‘Socrates begins to run’. According to many of the scholastics, such a proposition has two ‘exponents’. For example, ‘Socrates is now running, but immediately before this was not running’.
This is in haste, wife is shouting for me to go to lunch.
Posted by: The Bad Ostrich | Sunday, January 06, 2019 at 06:02 AM
ad 1) The two definitions appears to be logically equivalent if we assume Bivalence (exactly two truth values, T and F)
If Socrates stopped talking, then he was talking. If Socrates did not stop talking, then he was talking. The consequent survives the negation of the antecedent. So by the above criteria, *Socrates was talking* is a presupposition of both conditional sentences.
Note that neither assertion, nor any other speech act, comes into the above definitions.
This is semantic presupposition which is not the same as pragmatic presupposition. The first connects propositions; the second a person and a proposition.
Now which of these is your main concern?
Posted by: BV | Sunday, January 06, 2019 at 12:00 PM
To avoid all confusion, let’s focus on propositions, although I suspect there will still be confusion.
p = *Socrates stopped talking*
q = *Socrates was talking*
On the view you express above, (p v not-p) entails q. Presumably you hold excluded middle, i.e. necessarily (p v not-p). Then necessarily q.
So it is necessary that Socrates was talking. Why? What if he was a deaf mute, and never talked?
Posted by: The Bad Ostrich | Monday, January 07, 2019 at 01:45 AM
>> At most, LEM is a presupposition of my assertion, and of every assertion.
True, but you need to avoid consequences of contingent propositions turning into necessary ones. If (p v not-p) entails q, then q is necessarily true. But the proposition expressed by ‘Socrates was talking’ is not a necessary truth.
>> it seems to me that what I assert on any occasion is precisely what I intend to assert on that occasion and nothing else.
We have discussed this before, and we disagree. I utter ‘Jake is thin’, but I intend to assert that Jake is thick. The word came out all wrong. According to you, what I have asserted is that Jake is thick. According to me, what I have asserted depends on the conventional meaning of the word ‘thin’, which means thin not thick.
Generally I disagree with the possibility of telepathy. We aim to show what we intend by means of sounds or symbols which have a community-wide meaning. We are not mind readers.
Posted by: The Bad Ostrich | Monday, January 07, 2019 at 01:58 AM
Is an ontology presupposed by any proposition?
Tillich: "Every epistemological assertion is implicitly ontological".
"Tony Won the Race" v an ontology.
How is an 'implication' related to an 'assertion' or to a 'presupposition' when it is an ontology that in inferred?
Posted by: David Bagwill | Monday, January 14, 2019 at 03:01 PM
To be more clear:
Do all propositions imply an ontology?
Is "imply" strong enough to bear the weight of 'assertion"? Or is 'imply' basically an equivalent to 'presuppose'?
Posted by: David Bagwill | Monday, January 14, 2019 at 04:59 PM