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RobbBB comments on Philosophy Needs to Trust Your Rationality Even Though It Shouldn't - Less Wrong
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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.)
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").
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.
You are basically saying that physicists disagree about philosophical questions.
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.'
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.
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.
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.
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:
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.
I find it a bit tricky to formulate problems in propositions like yours (1) - (3) and insist that at least one must be rejected because of mutual inconsistency. The problem is that the meaning of the propositions is not precise. What exactly does "all properties of physical systems" denote? Is it "maximum information about the system that can be obtained in principle" (subproblem: what does "in principle" mean), or is it "information sufficient to predict all events in which the system is involved, if there is no uncertainty external to the system involved", or is it something else?
We know that the conditions under which we prepare the system can be summarised in a wave function and we know how to calculate the frequencies of measurement outcomes, given a specific wave function. We know that the knowledge of wave function doesn't let us predict the measurements with certainty. We even know, due to Bell's inequalities and the experimental results, that if there is some unknown property of the system which determines the measurement outcome prior to actual measurement, then this property must be non-local. We know that the evolution of systems under observation isn't described by Schrödinger equation only. All this is pretty uncontroversial.
Now the interpretations tend to use different words to describe the same amount of knowledge. Instead of saying that we can get unpredictably different outcomes from a measurement on a system with some given wave function, one may say that the outcome is always the same but our consciousness splits and each part is aligned only with a portion of the outcome, or one may say that the outcome is not "definite" (whatever it means). This verbal play is the unphysicsy thing with the given propositions.
You seem to be trying to explain something rather clear with something less clear. The sentence in question is simply affirming that the wave function captures everything that is true of the system; thus (if you accept this view) there are no hidden variables determining the seemingly probabilistic outcomes of trying to measure non-observables. There's nothing mysterious about asserting that there's a hidden cause in this case, any more than science in general is going Mystical when it hypothesizes unobserved causes for patterns in our data.
To say that the outcome is not "definite" is to say that it is false that a particular measurement outcome (like 'spin up'), and not an alternative outcome (like 'spin down'), obtains. "Definite" sounds vague here because the very idea of "many worlds" is extremely vague and hard to pin down. One way to think of it is that the statistical properties of quantum mechanics are an epiphenomenon of a vastly larger, unobserved reality (the wave function itself) that continues merrily on its way after the observation.
Where's the 'verbal play'?
Say there are no hidden variables and the evolution is probabilistic. Does then the wave function capture everything that is true of the system? It seems to me that it doesn't: it is true that the system will be measured spin up in the next measurement, but the wave function is as well compatible with spin down. But you seem to assert that if I don't believe in hidden variables then the wave function does capture everything that is true of the system. Thus I don't find it rather clear. Neither does "epiphenomenon of a vastly larger reality" seem clarifying to me even a little bit.