Showing posts with label colloquium. Show all posts
Showing posts with label colloquium. Show all posts
February 4, 2015
March 10, 2008
Colloquium Review of Brian Woodcock's "Quantum State Collapse Along a Light Cone: History and Objections"
This past Friday Brian Woodcock, a visiting professor at Carleton College in Northfield, presented his latest work "Quantum State Collapse Along a Light Cone: History and Objections." Needless to say, if you are an avid philosopher of 20th Century Physics, you missed a good one. Now, as someone whose knowledge of quantum physics probably hurt his cause more than helped it, I found Dr. Woodcock's talk to be very engaging. First of all, there were many pretty, geometrical pictures to keep my mind stimulated. Secondly, Brian also did a very nice job of giving a "prep-talk" to the quantumly-challenged in the audience that went over - pictorially even - the general ideas presented in a space-time diagram; a diagram he used extensively in the rest of his talk. This pre-lecture was very informative and it certainly set the stage for the rest of his talk. I won't go into specifics because it would basically be just restating his abstract, but I do want to talk briefly about his conclusions, particularly the type of conclusions that he, and other philosophers make in general.
Overall, Woodcock's talk did include some good historical segments, though it was primarily philosophical. He discussed 3 main attempts to understand the quantum collapse over the years, dating back to the early 1960s. For the historians in the audience, these types of descriptions and analyses are familiar. However, like many of the philosophy of science talks that occur during colloquium (including last week's talk on philosophy of race and the use of it in statistical work), the speaker's conclusions tended to be prescriptive rather than descriptive. I think this is where philosophers and historians of science really differ. There are many approaches in the history of science that utilize conceptual and intellectual approaches that touch on many of the issues that philosophers attempt to deal with. Historians, however, do not make any conclusions about how science should work now. Though I have been spending a lot of time over in the Minnesota Center for the Philosophy of Science lately, and have been thinking much more about the philosophical aspects of biology, I realize that this descriptive/prescriptive distinction is one that will always keep me registering for HSS rather than PSA when they are having their joint meeting.
Overall, Woodcock's talk did include some good historical segments, though it was primarily philosophical. He discussed 3 main attempts to understand the quantum collapse over the years, dating back to the early 1960s. For the historians in the audience, these types of descriptions and analyses are familiar. However, like many of the philosophy of science talks that occur during colloquium (including last week's talk on philosophy of race and the use of it in statistical work), the speaker's conclusions tended to be prescriptive rather than descriptive. I think this is where philosophers and historians of science really differ. There are many approaches in the history of science that utilize conceptual and intellectual approaches that touch on many of the issues that philosophers attempt to deal with. Historians, however, do not make any conclusions about how science should work now. Though I have been spending a lot of time over in the Minnesota Center for the Philosophy of Science lately, and have been thinking much more about the philosophical aspects of biology, I realize that this descriptive/prescriptive distinction is one that will always keep me registering for HSS rather than PSA when they are having their joint meeting.
January 26, 2008
The Strevens talk - a Michel reaction
Though I had volunteered to write up a quick review/reaction to the Strevens talk yesterday, Michel has beaten me to it (to my delight I must say). Michel has not entered the blog world as of yet, so I have posted his review below. Enjoy.
-Nathan
I thought I'd type up my reaction to yesterday's talk, focusing unsurprisingly on the exchange Antigone and I had with the speaker in Q&A. Here is a handout I have used in my COI class to deep-six instance confirmation. That may be helpful to those who weren't familiar already with the ravens. In what follows I assume everybody is.
So Strevens avoids some of Hempel's problems by recasting all ravens are black as a causal claim. That's a steep price to get out of trouble. As John Norton never tires of pointing out, it's not much help to cast your account of confirmation in terms of concepts that are even more poorly understood such as explanation or causation. But since IBE (inference to the best explanation) is my favorite account of confirmation, that objection doesn't carry too much weight with me (though bringing in causation would presumably set Hempel spinning in his grave).
The main problem with the account, it seems to me, is that the sliver of confirmation that he's looking at is just not where the action is in real science. Antigone put it very nicely in Q&A. In real science, you're not interested in confirming that all ravens are black, but in confirming some causal story about how raven-ness causes black-ness. And that claim is only indirectly confirmed on Strevens' account. He conceded when I asked him that that's not instance confirmation but something like IBE. In that case, IBE does all the interesting work. I think, however, that he was too quick conceding that point and later in discussion he actually had a better line of defense. Suppose you have two competing causal accounts of how raven-ness causes blackness. As long as they both entail that all ravens are black, the observation of yet another black raven indirectly confirms both of these accounts equally well. Other confirmation mechanisms (Bayes, IBE), it seems, need to be brought to distinguish between them. But, as Strevens pointed out, that's not necessarily true. These causal accounts correspond in real science to high-level theories which entail other laws subject to instance confirmation besides the one about ravens. So even though it may be a draw as far as the ravens are concerned, one may beat the other on some other entailed law that is subject to instance confirmation. So instance confirmation plus the indirect confirmation of higher level theories can capture more than one would think just focusing on the ravens. Still, the typical situation in science is probably NOT the one where you have two perfectly good competing accounts, but one in which you barely have the beginnings of one reasonable account. In that situation, the real work is done by IBE.
It was a strange experience listening to this talk about instance confirmation. It was a bit like someone telling me, after I thought I'd decisively overcome it at the age of 15, that there's something to Catholicism after all. So, I was very focused on what Strevens would say about the problems that killed instance confirmation for me. To me the white shoe is really indicative of two much more general problems with Hempel's account. The first is that it shows that it's hopeless to have a purely syntactic criterion of confirmation (of course, the grue paradox drives that point home even more forcefully). Strevens avoids that one by bringing in causation. But there's another problem that Strevens doesn't address. He's still assuming that the empirical domain of the theory can be carved up into instances independently of the high-level theory that is being tested. The white shoe illustrates that problem very nicely. The mechanism through which the white shoe seems to confirm that all ravens are black is what at Pitt back in the days we called "content cutting." If you spell out the set of instances in advance, the white shoe confirms because it eliminates a potential falsifier (an instance that could have been the dreaded non-black raven turns out to be another innocuous non-raven). Strevens' response to that one was that the hypothesis subjected to instance confirmation does the individuating of the instances. I don't believe that. It's the high-level theory that does that. That seems obvious in physics (but maybe that's because I'm a diehard Kantian), so I asked Ken Waters whether he could give me an example from the biological sciences. He mentioned ecology, which sounds like a great example to me. For these reasons I remain skeptical about instance confirmation.
Respectfully submitted,
Michel
-Nathan
I thought I'd type up my reaction to yesterday's talk, focusing unsurprisingly on the exchange Antigone and I had with the speaker in Q&A. Here is a handout I have used in my COI class to deep-six instance confirmation. That may be helpful to those who weren't familiar already with the ravens. In what follows I assume everybody is.
So Strevens avoids some of Hempel's problems by recasting all ravens are black as a causal claim. That's a steep price to get out of trouble. As John Norton never tires of pointing out, it's not much help to cast your account of confirmation in terms of concepts that are even more poorly understood such as explanation or causation. But since IBE (inference to the best explanation) is my favorite account of confirmation, that objection doesn't carry too much weight with me (though bringing in causation would presumably set Hempel spinning in his grave).
The main problem with the account, it seems to me, is that the sliver of confirmation that he's looking at is just not where the action is in real science. Antigone put it very nicely in Q&A. In real science, you're not interested in confirming that all ravens are black, but in confirming some causal story about how raven-ness causes black-ness. And that claim is only indirectly confirmed on Strevens' account. He conceded when I asked him that that's not instance confirmation but something like IBE. In that case, IBE does all the interesting work. I think, however, that he was too quick conceding that point and later in discussion he actually had a better line of defense. Suppose you have two competing causal accounts of how raven-ness causes blackness. As long as they both entail that all ravens are black, the observation of yet another black raven indirectly confirms both of these accounts equally well. Other confirmation mechanisms (Bayes, IBE), it seems, need to be brought to distinguish between them. But, as Strevens pointed out, that's not necessarily true. These causal accounts correspond in real science to high-level theories which entail other laws subject to instance confirmation besides the one about ravens. So even though it may be a draw as far as the ravens are concerned, one may beat the other on some other entailed law that is subject to instance confirmation. So instance confirmation plus the indirect confirmation of higher level theories can capture more than one would think just focusing on the ravens. Still, the typical situation in science is probably NOT the one where you have two perfectly good competing accounts, but one in which you barely have the beginnings of one reasonable account. In that situation, the real work is done by IBE.
It was a strange experience listening to this talk about instance confirmation. It was a bit like someone telling me, after I thought I'd decisively overcome it at the age of 15, that there's something to Catholicism after all. So, I was very focused on what Strevens would say about the problems that killed instance confirmation for me. To me the white shoe is really indicative of two much more general problems with Hempel's account. The first is that it shows that it's hopeless to have a purely syntactic criterion of confirmation (of course, the grue paradox drives that point home even more forcefully). Strevens avoids that one by bringing in causation. But there's another problem that Strevens doesn't address. He's still assuming that the empirical domain of the theory can be carved up into instances independently of the high-level theory that is being tested. The white shoe illustrates that problem very nicely. The mechanism through which the white shoe seems to confirm that all ravens are black is what at Pitt back in the days we called "content cutting." If you spell out the set of instances in advance, the white shoe confirms because it eliminates a potential falsifier (an instance that could have been the dreaded non-black raven turns out to be another innocuous non-raven). Strevens' response to that one was that the hypothesis subjected to instance confirmation does the individuating of the instances. I don't believe that. It's the high-level theory that does that. That seems obvious in physics (but maybe that's because I'm a diehard Kantian), so I asked Ken Waters whether he could give me an example from the biological sciences. He mentioned ecology, which sounds like a great example to me. For these reasons I remain skeptical about instance confirmation.
Respectfully submitted,
Michel
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