Change of Meaning, Change of Belief

This below is meant as comment to Jones's point in "I propose this as interesting stuff for Carnap-Grice interface", THIS BLOG.

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Good.

So, indeed, if we change our minds about meaning we change our linguistic frameworks. Even that bit may need some elucidation.

Let me rephrase the abstract bit by bit. Actually, I'm a bit familiar with H. Arlo Costa's theory on this. It seems quite a problem for formalists of the logic of belief. So I supposed that for Carno-Griceian studies it may do, too.

The authors of the essay cited above write in the abstract:

"One of the standard principles of rationality guiding traditional accounts of belief change is the principle of minimal change: a reasoner's belief corpus should be modified in a minimal fashion when assimilating new information."

I was thinking of Carno-Griceian ways out to Quine. Recall Grice's and Strawson's TWO examples. One as a reply to a synthetically false sentence, another to an analytically false sentence:

A: My neighbour's three-year old child understands Russell's theory of types.

B: That's almost unbelievable!

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versus:

A: My neighbour's three-year-old child is an adult.

B: I won't BELIEVE THAT.

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For Grice and Strawson, the second scenario is BEYOND belief, as it were. But of course, one may adopt the linguistic framework of one's interlocutor and DO COME to 'understand', and then perhaps 'believe'.

The authors continue:

"This rationality principle has stood belief change in good stead. However, it does not deal properly with all belief change scenarios."

Another case that I have considered in extenso elsewhere is what I called "Speranza": a machine unable to understand novel metaphors. Like, "Meaning is a dinosaur", or "My brother had an abortion". Or things like that. I should revise the cases. But the point is that there seems to be a LEAP at some point and that it's very bold of an interpreter to deal with a metaphor, because, when taken literally, metaphors are obviously FALSE.

The authors go on:

"We introduce a novel account of belief change motivated by one of Grice's maxims of conversational implicature: the reasoner's belief corpus is modified in a minimal fashion to assimilate exactly the new information."

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So, here we do need to formalise, to see what's going on if the 'change of 'our minds'' is about meaning or what.

First we should consider just synthetic change of belief.

"Is it raining?"
"No. It's not."
"Oh. I thought it was. Thanks for informing."

So here we have a change from

B(A, -p)

to

B(A, p)

Not tragic.

"Is it raining?"
"No. It's pouring!"

--- Here the case is impicatural. I take the answer as being FALSE. Pouring IS a kind of rain!

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"Is it raining?"
"Yes. Cats and dogs".
"Whoa?"
"It's raining cats and dogs".
"I hope you are being figurative".

---- This may be one silly case, but suppose that the utterer A refuses to use "to rain cats and dogs" even figuratively. So he may need to translate that silly idiom into something he will understand, "very hard".

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Finally we get to the cases of meaning postulates:

First the synthetic scenario:

B (A, - 'Tim understands Russell's theory of Types')
to
B (A, 'Tim understands Russell's theory of types')

In this, I'm not sure there is a change of belief involved, since U never actually DISBELIEVED that the 3-year-old child understood it.

So, we get to the 'trick' case:

B(A, -'A 3-year-old child is an adult')

to

B(A, 'A 3-year-old child is an adult')

Since one's interlocutor is actually saying that a 3-year-old child is an adult, and possibly believing it, how do we change our belief about meaning?

There must be more obvious cases. Another one would be the taste of twater for Putnan. I see that Barbara Abbott wrote about this for the Aristotelian Society.

Or consider Copernicus:

"I used to believe that the sun went around the earth, but I changed my mind."

---- No change of meaning involved. But surely there are such changes of meaning in the history of science. Indeed, that was Quine's point about Duhem, etc.

I can't think of one! Perhaps Einstein's ideas as 'changing the meaning' of 'time' and 'space' (notably space) as the idea was understood in Newtonian physics? Etc.