Moving, plus evidence and truth-value

Very long time, no blog. The main reason is a cross-country move and a new job. For those who don't already know, I'm now at Hobart & William Smith Colleges, in upstate New York. But I also spent a very nice 2+ weeks in Australia, seeing old grad school friends as well as meeting new family members.

A discussion with a student today brought up an interesting question (which probably has been extensively explored in a literature of which I'm completely ignorant). We were talking about what sorts of linguistic expressions were truth-valued, and which were not. She suggested that there might be some sort of connection between being the kind of thing that has a truth-value, and being the kind of thing that can have evidence count for or against it. But what's the connection between these two conditions? Necessary? Sufficient? Neither? Both? -- and is there already a thorough treatment of this question in the literature?

Note: As I understand it, this is not a variant of verificationism, since one can imagine evidence that is unavailable to us weak, frail humans, with our very limited epistemic powers.

Note 2: If you take the position that the sentence 'Planet Vulcan is between Mercury and the Sun' is truth-valueless, instead of false, then that sentence is an example where we have evidence against a claim, but it nonetheless lacks a truth-value. But maybe the other direction of the connection would still hold?


P.D. said...

One thought: According to some views, claims about the future do not (yet) have truth values. Nevertheless, there can be evidence for or against such claims.

Greg Frost-Arnold said...

Thanks -- that's another species of the genus including the 'Vulcan' case I mentioned in the main post.

Now that I'm already writing about this again, I just wanted to record why I care about this question in the first place, mostly for my own sake.

The answer to this question could be used as an argument _against_ those who think that sentences about the future, or containing non-referring terms (e.g.), are truth-valueless. Whether members of those two classes of sentences have truth-values is a contentious matter, and it would be nice to have a general principle that ruled on them.

Kenny said...

I've sometimes thought about the other direction of the claim than the one you seem to be focusing on. As a weakened version of Popper's falsifiability, I've thought it at least seems reasonable that a claim isn't scientific if there isn't some evidence that could affect one's credence in it (and further, that this means that some evidence could increase one's credence and some evidence could decrease it). Of course, this is about some notion of scientific respectability rather than about being such as to have a truth value, but it seems related.

Also, where in Australia were you? I suppose if you were seeing Pitt people that probably means Sydney.

Anyway, I hope the move has been going well!

Greg Frost-Arnold said...

Hi Kenny -

Good to hear from you. I was in Sydney, but I only saw family members there. I met up with old grad school friends at a conference in Brisbane, ISHPSSB (basically, a biology-related conference).

And your thought does seem quite related (at least if scientific theories are considered to be truth-valued -- which is I think the overwhelming majority position today, though it hasn't always been throughout history). Does anyone object to your idea, when you've floated it in the past? For me at least, I would've thought that your condition is so weak, and so intuitive, that everyone would accept it.

And why haven't you put up any posts in forever? I miss Antimeta and your TAR postings. (Now, on your next post, you can say 'back by popular demand'.)

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Larry Franz said...

I just happened to be reading something from "Aspects of Scientific Explanation", in which Carl Hempel said "it is a basic principle of contemporary empiricism that a sentence makes a cognitively significant assertion, and thus can be said to be either true or false" IFF it's analytic or contradictory, or else "it is capable, at least potentially, of test by experiential evidence".

He might have added that evidence not even potentially available to human beings wouldn't count, since the empiricist (or the pragmatist) is trying to explain the meaning of human language in terms of potential human experience.