Mon Apr 28, 2008 3:19 pm by Spork
What Barry _wanted_ to maintain (Part 18 ) was: the sentence “Barry’s favourite flavour is not pistachio” is _false_.
But Hubbard’s theory of truth rules this option out. Truth and falsity are gone; all we have are truth-for-so-and-so and falsity-for-so-and-so. (Or if some more or less ordinary notion of truth remains in the language, it reduces to truth as relativized to persons.)
On Hubbard’s theory, the same sentence can be true for Barry but false for Spork. This unfortunately left Barry no ground on which to assert his favourite ice cream in a way which had any relevance to me.
Why did this occur? How was it even possible, assuming truth is person-relative?
The reason seems to be this. If the same sentence can simultaneously be true for one person and false for another, that sentence must _mean_ something different for each. This will emerge from the following.
Whatever we might think of Hubbard’s proposal to relativize truth to persons, one useful thing we can say about it is this: For any sentence S and person P,
S is true for P if and only if for P, S.
This principle gives the conditions under which a sentence S is true for P: namely just in case for P, S. (Quotation marks are omitted for simplicity.)
We’ve already seen this principle at work in Part 12. If Barry holds “The beer is warm” is true for him, he might as well have said that for him, the beer is warm. (He doesn’t like to say that, but that’s a problem for Hubbard’s idea that truth is person-relative, not for the principle above.)
(The significance of the principle is that it (or one like it) must lie at the heart of any theory which says that truth is person-relative. It specifies what it is for a sentence to be true for someone. Without some such principle there’s no theory of the person-relativity of truth. For people who want to believe that what’s true is what’s true for them, it isn’t really open to them to deny that something is true for them if and only if for them, the fact of that something obtains. Unless they want to deny that any facts obtain for them.)
So (to take a fresh example) if “It’s raining in Denver” is true for John, then for John, it’s raining in Denver. If “It’s raining in Denver” isn’t true for Mary, then for Mary, it isn’t raining in Denver.
Now suppose all this happens at the same time of the same day. There’s absolutely no provision in Hubbard’s theory to rule this out.
On such a day there’s only one conclusion to draw: John and Mary must each mean something different by “It’s raining in Denver.”
“It’s raining in Denver” has to mean something different in John’s world (or in his direct observation or personal reality or own special language) than it means in Mary’s, because in John’s world it’s true and in Mary’s it’s false.
On that day, if John and Mary engage in communication using the phrase “It’s raining in Denver”, they’re not likely to understand each other.
That’s apart from the question: What on earth is the weather like in Denver that day?