Thank you for your thoughtful comments. I’ve tried to answer some where I could.
(Upvoted.) I have to say that I’m a lot more comfortable with the notion of elite common sense as a prior which can then be updated, a point of departure rather than an eternal edict; but it seems to me that much of the post is instead speaking of elite common sense as a non-defeasible posterior. (E.g. near the start, comparing it to philosophical majoritarianism.)
I agree that it would be helpful if I emphasized that as a difference more in the beginning. I do think the idea of “convincing” elite common sense of something is helpful. It isn’t great if you say, “Well, elite common sense has a prior of 1:100 in X, and I just had an observation which, by my personal standards, has a likelihood ratio of 100:1 in favor of X, so that my posterior in X is 50:50.” In this framework, you need to be able to say, “I had an observation which, by the standards of elite common sense, has a likelihood ratio of 100:1 in favor of X, so now my posterior in X is 50:50.” Since priors set the standards for what counts as evidence for what, elite common sense gets to set those standards in this framework. In whatever sense you’re “stuck” with a prior, you’re “stuck” with the prior of elite common sense in this framework.
It also seems to me that much of the text has the flavor of what we would in computer programming call the B&D-nature,
Sorry, but I have no background in programming. I tried to figure out what B&D was, but it wasn’t readily googled. Could you provide a link or explanation please?
an attempt to impose strict constraints that prevent bad programs from being written, when there is not and may never be a programming language in which it is the least bit difficult to write bad programs, and all you can do is offer tools to people that (switching back to epistemology) make it easier for them to find the truth if they wish to do so, and make it clearer to them when they are shooting off their own foot. I remark, inevitably, that when it comes to discussing the case of God, you very properly—as I deem it proper—list off a set of perfectly good reasons to violate the B&D-constraints of your system.
One important point is that I mainly see this as in tension with the guideline that you stress-test your views by seeing if you can get a broad coalition of trustworthy people to agree, rather the the more fundamental principle that you rely on elite common sense standards of reasoning. I’m not sure if I’m effectively responding because of my uncertainty about what B&D means.
And this would actually make a deal more sense if we were taking elite opinion about God as a mere point of departure, and still more sense if we were allowing ourselves to be more selective about ‘elites’ than you recommend.
I am pretty open about playing around with who we count as elites. Ability to have a grip on their thoughts and avoiding cherry picking are very important to me though.
(It rather begs the question to point to a statistic about what 93% of the National Academy of Sciences believe—who says that theirs is the most elite and informed opinion about God? Would the person the street say that, or point you to the prestigious academies of theologians, or perhaps the ancient Catholic Church?)
I think the group of people I explicitly recommended—the upper crust of people with Ivy League-equivalent educations—would put a reasonable amount of weight on the scientists’ opinions if they were really trying to have accurate views about this question, but would resist using only that group as their starting point. I’m not sure how much these people would really say that the theologians had tried really hard to have accurate beliefs about whether God exists. I think they might point to philosophers and converts and such.
But even that’s hard to tell because the discussion is also very abstract, and you seem to be much more relaxed when it comes to concrete cases then when you are writing in the abstract about what we ought not to do.
Would you care to elaborate on this?
I would be interested in what you think this philosophy says about (a) the probability that quantum mechanics resolves to a single-world theory, and (b) the probability that molecular nanotechnology is feasible.
I myself would be perfectly happy saying, “The elite common sense prior for quantum mechanics resolving to a single world is on the order of 40%, however the posterior—now taking into account such matters as the application of the quantitative Occam’s Razor as though they were evidence being applied to this prior—is less than 1%.” Which is what I initially thought you were saying, and I was nodding along to that.
My background on this question mainly consists of taking a couple of courses on quantum mechanics (one by Tim Maudlin in philosophy and one by Shelly Goldstein in applied math) in graduate school and reading your quantum physics sequence. I think that the first pass would be to ask, what do physicists think about the question? In the survey I’ve heard of, many worlds got 18% of the votes of 33 physicists at a quantum foundations meeting. I would take that as a starting point and then update based on (a) my overall sense that the arguments favor many worlds and (b) my sense that people impressive to me tend to go for the many worlds interpretation. Regarding (a), I think there is a very strong update against Copenhagen interpretation, a moderate update against Bohm, and I don’t really know what some of the other interpretations even are. (a) and (b) aren’t really independent because the people I am impressed by share my biases and blind spots. Together these points maybe give an update on the order of 5:1 to 30:1 in favor of many worlds, so that my posterior in many worlds is around 50-85%. This would be pretty open to changing on the basis of further considerations. [Edited to add: I’m not very sure what my framework implies about this case. I wouldn’t be that surprised if my framework said I shouldn’t change much from the physicists distribution of answers to this question, but I also would be surprised if I should change substantially.]
I have so little to go on regarding the feasibility of molecular nanotechnology that I’d prefer to avoid public embarrassment by making up numbers. It’s something I would like to look into in greater depth eventually. Most of my update on this comes from “a lot of smart people I know take it seriously.”
So far as distinguishing elites goes, I remark that in a case of recent practice, I said to someone, “Well, if it comes down to believing the systematic experiments done by academic scientists with publication in peer-reviewed journals, or believing in what a bunch of quantitative self people say they discovered by doing mostly individual experiments on just themselves with no peer review, we have no choice but to believe the latter.” And I was dead serious. (Now that I think about it, I’ve literally never heard of a conflict between the quantitative self people and academic science where academic science later turned out to be right, though I don’t strongly expect to have heard about such a case if it existed.)
It’s a tricky test case for me to check because I am not very familiar with the quantified self people. Depending on what kind of experiments the scientists did and what these people are like, I may agree with you. A really important test here is whether you think that if the “elite” people had access to your evidence and analysis on this issue, they would agree with your perspective.
I haven’t seen any of these interpretation polls with a good random sample, as opposed to niche meetings.
One of the commenters below the Carroll blog post you linked suggests that poll was from a meeting organized by a Copenhagen proponent:
I think that one of the main things I learned from this poll is that if you conduct a poll at a conference organized by Zeilinger then Copenhagen will come out top, whereas if you conduct a poll at a conference organized by Tegmark then many worlds will come out top. Is this a surprise to anyone?
The Tegmark “Everett@50” (even more obvious bias there, but this one allowed a “none of the above/undecided” option which was very popular) conference results are discussed in this paper:
Which interpretation of quantum mechanics is closest to
your own?
2 Copenhagen or consistent histories (including postulate
of explicit collapse)
5 Modified dynamics (Schrdinger equation modified to
give explicit collapse)
19 Many worlds/consistent histories (no collapse)
2 Bohm
1.5 Modal
22.5 None of the above/undecided
Do you feel comfortable saying that Everettian parallel uni-
verses are as real as our universe? (14 Yes/26 No/8 Undecided)
A 2005 poll of fewer than 40 students and researchers taken after a course on the Interpretation of Quantum Mechanics at the Institute for Quantum Computing University of Waterloo found “Many Worlds (and decoherence)” to be the least favored
And there is a strange one, for which I don’t yet have a link to the original, critiqued at Wikipedia and discussed here, that claimed majority support for MWI in a a sample of 72. The argument for it being compatible with other polls is that it includes a lot of cosmologists, who tend to support MWI (it makes it easier to explain the evolution of the universe as a whole, and perhaps they are more open to a vast universe extending beyond our vision), but something still seems fishy about it.
1) “Yes, I think MWI is true” 58%
2) “No, I don’t accept MWI” 18%
3) “Maybe it’s true but I’m not yet convinced” 13%
4) “I have no opinion one way or the other” 11%
Quick remarks (I may or may not be able to say more later).
If your system allows you to update to 85% in favor of Many-Worlds based on moderate familiarity with the arguments, then I think I’m essentially okay with what you’re actually doing. I’m not sure I’m okay with what the OP advocates doing, but I’m okay with what you just did there.
Thank you for your thoughtful comments. I’ve tried to answer some where I could.
I agree that it would be helpful if I emphasized that as a difference more in the beginning. I do think the idea of “convincing” elite common sense of something is helpful. It isn’t great if you say, “Well, elite common sense has a prior of 1:100 in X, and I just had an observation which, by my personal standards, has a likelihood ratio of 100:1 in favor of X, so that my posterior in X is 50:50.” In this framework, you need to be able to say, “I had an observation which, by the standards of elite common sense, has a likelihood ratio of 100:1 in favor of X, so now my posterior in X is 50:50.” Since priors set the standards for what counts as evidence for what, elite common sense gets to set those standards in this framework. In whatever sense you’re “stuck” with a prior, you’re “stuck” with the prior of elite common sense in this framework.
Sorry, but I have no background in programming. I tried to figure out what B&D was, but it wasn’t readily googled. Could you provide a link or explanation please?
One important point is that I mainly see this as in tension with the guideline that you stress-test your views by seeing if you can get a broad coalition of trustworthy people to agree, rather the the more fundamental principle that you rely on elite common sense standards of reasoning. I’m not sure if I’m effectively responding because of my uncertainty about what B&D means.
I am pretty open about playing around with who we count as elites. Ability to have a grip on their thoughts and avoiding cherry picking are very important to me though.
I think the group of people I explicitly recommended—the upper crust of people with Ivy League-equivalent educations—would put a reasonable amount of weight on the scientists’ opinions if they were really trying to have accurate views about this question, but would resist using only that group as their starting point. I’m not sure how much these people would really say that the theologians had tried really hard to have accurate beliefs about whether God exists. I think they might point to philosophers and converts and such.
Would you care to elaborate on this?
My background on this question mainly consists of taking a couple of courses on quantum mechanics (one by Tim Maudlin in philosophy and one by Shelly Goldstein in applied math) in graduate school and reading your quantum physics sequence. I think that the first pass would be to ask, what do physicists think about the question? In the survey I’ve heard of, many worlds got 18% of the votes of 33 physicists at a quantum foundations meeting. I would take that as a starting point and then update based on (a) my overall sense that the arguments favor many worlds and (b) my sense that people impressive to me tend to go for the many worlds interpretation. Regarding (a), I think there is a very strong update against Copenhagen interpretation, a moderate update against Bohm, and I don’t really know what some of the other interpretations even are. (a) and (b) aren’t really independent because the people I am impressed by share my biases and blind spots. Together these points maybe give an update on the order of 5:1 to 30:1 in favor of many worlds, so that my posterior in many worlds is around 50-85%. This would be pretty open to changing on the basis of further considerations. [Edited to add: I’m not very sure what my framework implies about this case. I wouldn’t be that surprised if my framework said I shouldn’t change much from the physicists distribution of answers to this question, but I also would be surprised if I should change substantially.]
I have so little to go on regarding the feasibility of molecular nanotechnology that I’d prefer to avoid public embarrassment by making up numbers. It’s something I would like to look into in greater depth eventually. Most of my update on this comes from “a lot of smart people I know take it seriously.”
It’s a tricky test case for me to check because I am not very familiar with the quantified self people. Depending on what kind of experiments the scientists did and what these people are like, I may agree with you. A really important test here is whether you think that if the “elite” people had access to your evidence and analysis on this issue, they would agree with your perspective.
I haven’t seen any of these interpretation polls with a good random sample, as opposed to niche meetings.
One of the commenters below the Carroll blog post you linked suggests that poll was from a meeting organized by a Copenhagen proponent:
The Tegmark “Everett@50” (even more obvious bias there, but this one allowed a “none of the above/undecided” option which was very popular) conference results are discussed in this paper:
A 1997 workshop:
More polls are cited at Wikipedia.
And there is a strange one, for which I don’t yet have a link to the original, critiqued at Wikipedia and discussed here, that claimed majority support for MWI in a a sample of 72. The argument for it being compatible with other polls is that it includes a lot of cosmologists, who tend to support MWI (it makes it easier to explain the evolution of the universe as a whole, and perhaps they are more open to a vast universe extending beyond our vision), but something still seems fishy about it.
Quick remarks (I may or may not be able to say more later).
If your system allows you to update to 85% in favor of Many-Worlds based on moderate familiarity with the arguments, then I think I’m essentially okay with what you’re actually doing. I’m not sure I’m okay with what the OP advocates doing, but I’m okay with what you just did there.
B&D-nature.