Vladimir_Nesov comments on Philosophy Needs to Trust Your Rationality Even Though It Shouldn't - Less Wrong

27 Post author: lukeprog 29 November 2012 09:00PM

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Comment author: Vladimir_Nesov 29 November 2012 10:37:32PM *  7 points [-]

If you took a poll of physicists asking them to explain what their fundamental model — quantum mechanics — is actually asserting about the world (surely a simple enough question), there would be disagreement comparable to that regarding the philosophical questions you mentioned.

A major problem with modern physics is that there are almost no known phenomena that are known to work in a way that disagrees with how modern physics predicts they would work (in principle; there are lots of inferential/computational difficulties). What physics asserts about the world is, to the best of anyone's knowledge, coincides with what's known about most of the world in all detail. The physicists have to build billion dollar monstrosities like LHC just to get their hands on something they don't already thoroughly understand. This doesn't resemble the situation with philosophy in the slightest.

Comment author: RobbBB 29 November 2012 10:51:15PM 2 points [-]

You're speaking in very general terms, and you're not directly answering my question, which was 'what is quantum mechanics asserting about the world?' I take it that what you're asserting amounts to just "It all adds up to normality." But that doesn't answer questions concerning the correct interpretation of quantum mechanics. "x + y + z . . . = normality." That's a great sentiment, but I'm asking about what physics' "x" and "y" and "z" are, not questioning whether the equation itself holds.

Comment author: Vladimir_Nesov 29 November 2012 11:02:01PM *  2 points [-]

you're not directly answering my question, which was 'what is quantum mechanics asserting about the world?'

I'm pointing out that in particular it's asserting all those things that we know about the world. That's a lot, and the fact that there is consensus and not much arguing about this shouldn't make this achievement a trivial detail. This seems like a significant distinction from philosophy that makes simple analogies between these disciplines extremely suspect.

(I agree that I'm not engaging with the main points of your comment; I'm focusing only on this particular aside.)

Comment author: RobbBB 29 November 2012 11:07:26PM *  -2 points [-]

So your response to my pointing out that physicists too disagree about basic things, is to point out that physicists don't disagree about everything. In particular, they agree that the world around us exists.

Uh... good for them? Philosophers too have been known to harbor a strong suspicion that there is a world, and that it harbors things like chairs and egg timers and volcanoes. Physicists aren't special in that respect. (In particular, see the philosophical literature on Moorean facts.)

Comment author: Vladimir_Nesov 29 November 2012 11:11:43PM *  2 points [-]

physicists don't disagree about everything. In particular, they agree that the world around us exists. ... Philosophers too have been known to harbor a strong suspicion that there is a world

Physicists agree about almost everything. In particular, they agree about all specific details about how the world works relevant (in principle) to most things that have ever been observed (this is a lot more detail than "the world exists").

Comment author: RobbBB 29 November 2012 11:25:04PM *  1 point [-]

They agree about the most useful formalisms for modeling and predicting observations. But 'formalism' and 'observation' are not themselves concepts of physics; they are to be analyzed away in the endgame. My request is not for you to assert (or deny) that physicists have very detailed formalisms, or very useful ones; it is for you to consider how much agreement there is about the territory ultimately corresponding to these formalisms.

A simple example is the disagreement about which many-worlds-style interpretation is best; and about whether many-worlds-style interpretations are the best interpretations at all; and about whether, if they are the best, whether they're best enough to dominate the probability space. Since the final truth-conditions and referents of all our macro- and micro-physical discourse depends on this interpretation, one cannot duck the question 'what are chairs?' or 'what are electrons?' simply by noting 'chairs are something or other that's real and fits our model.' It's true, but it's not the question under dispute. I said physicists disagree about many things; I never said that physicists fail to agree about anything, so changing the topic to the latter risks confusing the issue.

Comment author: prase 30 November 2012 07:24:57PM 3 points [-]

You are basically saying that physicists disagree about philosophical questions.

Comment author: RobbBB 30 November 2012 07:38:10PM 1 point [-]

Is the truth of many-worlds theory, or of non-standard models, a purely 'philosophical' matter? If so, then sure. But that's just a matter of how we choose to use the word 'philosophy;' it doesn't change the fact that these are issues physicists, specifically, care and disagree about. To dismiss any foundational issue physicists disagree about as for that very reason 'philosophical' is merely to reaffirm my earlier point. Remember, my point was that we tend to befuddle ourselves by classifying issues as 'philosophical' because they seem intractable and general, then acting surprised when all the topics we've classified in this way are, well, intractable and general.

It's fine if you think that humanity should collectively and universally give up on every topic that has ever seemed intractable. But you can make that point much more clearly in those simple words than by bringing in definitions of 'philosophy.'

Comment author: Desrtopa 01 December 2012 04:41:38PM 3 points [-]

It seems that the matters you're arguing that scientists disagree on are all ones where we cannot, at least by means anyone's come up with yet, discriminate between options by use of empiricism.

The questions they disagree on may or may not be "philosophical," depending on how you define your terms, but they're questions that scientists are not currently able to resolve by doing science to them.

The observation that scientists disagree on matters that they cannot resolve with science doesn't detract from the argument that the process of science is useful for building consensuses. If anything it supports it, since we can see that scientists do not tend to converge on consensuses on questions they aren't able to address with science.

Comment author: RobbBB 01 December 2012 07:38:58PM *  0 points [-]

The observation that scientists disagree on matters that they cannot resolve with science doesn't detract from the argument that the process of science is useful for building consensuses.

Agreed. It's not that scientists universally distrust human rationality, while philosophers universally trust it. Both groups regularly subject their own reasoning faculties to tests and to distrust. (And both also need to rely at least somewhat on human reasoning, since one can only fairly conclude that a kind of reasoning is flawed by reasoning one's way toward that conclusion. Even purely 'empirical' or 'factual' questions require some amount of interpretive work.)

The reason philosophers seem to disagree more than scientists is very simple, and it's the same reason physicists trying to expand the Standard Model disagree more than physicists working within the Standard Model: Because there's a lack of intersubjectively accessible data. Without such data for calibration, different theoretical physicists' inferences, intuitions, and pattern-matching faculties in general will get relatively diverse results, even if their methodologies are quite commendable.

Comment author: prase 01 December 2012 06:25:07PM *  0 points [-]

I think you are reading too much into my comment. It totally wasn't about what humanity should collectively give up on, or even what anybody should. And I agree that philosophy is effectively defined as a collection of problems which are not yet understood enough to be even investigated by standard scientific methods.

I was only pointing out (perhaps not much clearly, but I hadn't time for a lengthier comment) that the core of physics is formalisms and modelling and predictions (and perhaps engineering issues since experimental apparatuses today are often more complex than the phenomena they are used to observe). That is, almost all knowledge needed to be a physicist is the ordinary "non-philosophical" knowledge that everybody agrees upon, and almost all talks at physics conferences are about formalism and observations, while the questions you label "foundational" are given relatively small amount of attention. It may seem that asking "what is the true nature of electron" is a question of physics, since it is about electrons, but actually most physicists would find the question uninteresting and/or confused while the question might sound truly interesting to a philosopher. (And it isn't due to lack of agreement on the correct answer, but more likely because physicists like more specific / less vague questions as compared to philosophers).

One can get false impression about that since the most famous physicists tend to talk significantly more about philosophical questions than the average, but if Feynman speaks about interpretation of quantum mechanics, it's not a proof that interpretation of quantum mechanics is extremely important question of physics (because else a Nobel laureate wouldn't talk about it), it's rather proof that Feynman has really high status and he can get away with giving a talk on a less-than-usually rigorous topic (and it is much easier to make an interesting lecture from philosophical stuff than from more technical stuff).

Of course, my point is partly about definitions - not so much the definition of philosophy but rather the definition of physics - but once we are comparing two disciplines having common definitions of those disciplines is unavoidable.

Comment author: RobbBB 01 December 2012 08:47:42PM *  1 point [-]

I don't think we disagree all that much; and I meant 'you' to be a hypothetical interlocuter, not prase. All I want to reiterate is that the line between physics and philosophy-of-physics can be quite fuzzy. The 'measurement problem' is perhaps the pre-eminent problem in 'philosophy of physics,' but it's not some neoscholastic mumbo-jumbo of the form "what is the true nature of electron?". Rather, it's a straightforward physics problem that happens to have turned out to be especially intractable. Specifically, it is the problem that these three propositions form an inconsistent triad given our Born-probabilistic observations:

  • (1) Wave-function descriptions specify all the properties of physical systems.
  • (2) The wave function evolves solely in accord with the Schrödinger equation.
  • (3) Measurements have definite outcomes.

De-Broglie-style interpretations ('hidden variables') reject (1), von-Neumann-style interpretations ('objective collapse') reject (2), and Everett-style interpretations ('many worlds') reject (3). So far. there doesn't seem to be anything 'unphysical' or 'unphysicsy' about any of these views. What's made them 'philosophical' is simply that the problem is especially difficult, and the prospects for solving it to everyone's satisfaction, by ordinary physicsy methods, seem especially dim. So, if that makes it philosophy, OK. But problems of this sort divide philosophers because they're hard, not because philosophers 'trust their own rationality' more than physicists do.