4/13/2007

APA wrap-up: Kyle Stanford's "New Induction"

My time at the APA last weekend was pretty good: I learned a few new things, met some new people I've been wanting to meet, and got to catch up with a couple old friends. Particularly helpful/ enlightening presentations included Angela Potochnick on how the context of inquiry shapes explanation, Ken Waters (plus commenters Jay Odenbaugh and Michael Strevens) on causes that make a difference (not, I learned, to be confused with the conception of causes as 'difference-makers'), and the Author-Meets-Critics session on Kyle Stanford's Exceeding Our Grasp.

Stanford's basic claim is that current scientific theories are underdetermined -- not because we can generate empircially equivalent rivals to our currently accepted theories, but rather because at many, many times in the past, the scientific community has been unable to conceive of good alternatives to the then-current theory. The evidence that such alternatives exist is the fact that they are proposed and accepted centuries later: thus, Newton's mechanics did not consider special relativity as an alternative hypothesis; Newton's, when he proposed his gravitation theory, did not consider the general theory of relativity as an alternative; no classical physicists before 1900 considered quantum mechanics as an alternative explanation of the data, and so on. This is what Stanford calls the "New Induction" over the history of science.

The idea, as just presented, strikes me as a promising line to take. But there is one aspect of Stanford's presentation of the problem that I don't understand. Fiona Cowie asked (in part) about this in the question and answer session, but I still didn't follow the answer. Stanford says that (e.g.) in 1700, the special theory of relativity and Newtonian mechanics were "(roughly) equally well-confirmed". Similarly for the other cases: the future theory is supposedly just as confirmed as the old one -- even in the past.

I don't understand why Stanford says this for two reasons: (1) He doesn't need the theories to be equally well-confirmed for his point to hold (viz., scientists aren't even conceiving of a hypothesis that will later be accepted as superior), and (2) it seems false to me, on any reasonable (i.e., not hardcore hypothetico-deductive)notion of confirmation. In 1700, it is true that special relativity and Newtonian mechanics agreed on all the consequences that could then be observed. But someone who, in 1700, said "Newton is approximately right, yet when something goes really, really fast its length will contract and its local time will dilate from the point of view of slower-moving observers" -- there is NO evidence at all for postulating that further bit of theory. And it's the same with GTR (what evidence would there've been for gravitation being a 10-component tensor instead of a scalar?) and especially QM (what evidence was there for thinking a body cannot have a determinate position and momentum simultaneously?). In 1700, these now-accepted alternatives were consistent with the data, but they were not equally well-confirmed.

Note: a very similar line of objection is pushed at the end of P.D. Magnus's "What's New about the New Induction?" (Synthese, 2006), though he develops it slightly differently, I think. (As I understand him, P.D. claims that in 1700, STR, GTR and QM would look like 'gruesome' hypotheses.)

5 comments:

Kenny said...

Sorry we didn't meet up. I'll let you know next time I'm planning to be in Vegas!

Anonymous said...

Sounds like an interesting session. I wish I'd been there.

My view is this: If Kyle is correct that STR, GTR, and QM were just as well confirmed as Newtonian mechanics in 1700, then grue hypotheses are just as well confirmed as green hypotheses. (Is this the same as saying that STR et al. were gruesome in 1700? Maybe.)

Greg Frost-Arnold said...

Hey P.D. --

I'm curious: do you think Kyle's argument is any worse if he dropped the '(roughly) equally well-confirmed' bit and replaced it with mere consistency with the known phenomena? (... which he sometimes does in the "Devil's Bargain" paper.) This is just the point I labelled "(1)" in the original post.

Anonymous said...

Greg,

If it is mere consistency with phenomena that worries us, how is the argument any different than usual woes about empirical equivalence? (Merely switching from timeless to transient equivalence doesn't seem like enough of a difference. The Matrix, after all, is an evil demon deception that you can escape-- but it is still prima facie just an evil demon scenario.)

--P.D.

Greg Frost-Arnold said...

Hey P.D. --

right, but I think here Kyle's "problem of unconceived alternatives" may cut some ice: in 1700, some of the 'merely consistent' theories in 1700 are crazy like the Matrix, but some of them (GTR, QM) are eventually accepted -- so they _can't_ be dismissed as crazy fantasies, in the same boat with Cartesian demons.