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Eliezer_Yudkowsky comments on Welcome to Less Wrong! (5th thread, March 2013) - Less Wrong
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Yep. I also tend to ignore nontechnical folks along the lines of RationalWiki getting offended by my thinking that I know something they don't about MWI. Carl often hears about, anonymizes, and warns me when technical folks outside the community are offended by something I do. I can't recall hearing any warnings from Carl about the QM sequence offending technical people.
Bluntly, if shminux can't grasp the technical argument for MWI then I wouldn't expect him to understand what really high-class technical people might think of the QM sequence. Mihaly said the rest of the Sequences seemed interesting but lacked sufficient visible I-wouldn't-have-thought-of-that nature. This is very plausible to me - after all, the Sequences do indeed seem to me like the sort of thing somebody might just think up. I'm just kind of surprised the QM part worked, and it's possible that might be due to Mihaly having already taken standard QM so that he could clearly see the contrast between the explanation he got in college and the explanation on LW. It's a pity I'll probably never have time to write up TDT.
I have a phd in physics (so I have at least some technical skill in this area) and find the QM sequence's argument for many worlds unconvincing. You lead the reader toward a false dichotomy (Copenhagen or many worlds) in order to suggest that the low probability of copenhagen implies many worlds. This ignores a vast array of other interpretations.
Its also the sort of argument that seems very likely to sway someone with an intro class in college (one or two semesters of a Copenhagen based shut-up-and-calculate approach), precisely because having seen Copenhagen and nothing else they 'know just enough to be dangerous', as it were.
For me personally, the quantum sequence threw me into some doubt about the previous sequences I had read. If I have issues with the area I know the most about, how much should I trust the rest? Other's mileage may vary.
Actually, attempting to steelman the QM Sequence made me realize that the objective collapse models are almost certainly wrong, due to the way they deal with the EPR correlations. So the sequence has been quite useful to me.
On the other hand, it also made me realize that the naive MWI is also almost certainly wrong, as it requires uncountable worlds created in any finite instance of time (unless I totally misunderstand the MWI version of radioactive decay, or any emission process for that matter). It has other issues, as well. Hence my current leanings toward some version of RQM, which EY seems to dislike almost as much as his straw Copenhagen, though for different reasons.
Right, I've had a similar experience, and I heard it voiced by others.
As a result of re-examining EY's take on epistemology of truth, I ended up drifting from the realist position (map vs territory) to an instrumentalist position (models vs inputs&outputs), but this is a topic for another thread. I am quite happy with the sequences related to cognitive science, where, admittedly, I have zero formal expertise. But they seem to match what the actual experts in the field say.
I am on the fence with the free-will "dissolution", precisely because I know that I am not qualified to spot an error and there is little else out there in terms of confirming evidence or testable predictions.
I am quite skeptical about the dangers of AGI x-risk, mainly because it seems to extrapolate too far beyond what is known into the fog of the unknown future, though do I appreciate quite a few points made in the relevant sequences. Again, I am not qualified to judge their validity.
How is that any more problematic than doing physics with real or complex numbers in the first place?
It means that EY's musings about the Eborians splitting into the world's of various thicknesses according to Born probabilities no longer make any sense. There is a continuum of worlds, all equally and infinitesimally thin, created every picosecond.
The way I understand it, it's not that “new” worlds are created that didn't previously exist (the total “thickness” (measure) stays constant). It's that two worlds that looked the same ten seconds ago look different now.
That's a common misconception. In the simplest case of the Schrodinger' cat, there are not just two worlds with cat is dead or cat is alive. When you open the box, you could find the cat in various stages of decomposition, which gives you uncountably many worlds right there. In a slightly more complicated version, where energy and the direction of the decay products are also measurable (and hence each possible value is measured in at least one world), your infinities keep piling up every which way, all equally probable or nearly so.
(By “two” I didn't mean to imply ‘the only two’.)
Which two out of the continuum of world then did you imply, and how did you select them? I don't see any way to select two specific worlds for which "relative thickness" would make sense. You can classify the worlds into "dead/not dead at a certain instance of time" groups whose measures you can then compare, of course. But how would you justify this aggregation with the statement that the worlds, once split, no longer interact? What mysterious process makes this aggregation meaningful? Even if you flinch away from this question, how do you select the time of the measurement? This time is slightly different in different worlds, even if it is predetermined "classically", so there is no clear "splitting begins now" moment.
It gets progressively worse and more hopeless as you dig deeper. How does this splitting propagate in spacetime? How do two spacelike-separated splits merge in just the right way to preserve only the spin-conserving worlds of the EPR experiment and not all possibilities? How do you account for the difference in the proper time between different worlds? Do different worlds share the same spacetime and for how long? Does it mean that they still interact gravitationally (spacetime curvature = gravity). What happens if the spacetime topology of some of the worlds changes, for example by collapsing a neutron star into a black hole? I can imagine that these questions can potentially be answered, but the naive MWI advocated by Eliezer does not deal with any of this.
coughmeasurecough
Is there actually any physicists that find QM sequence to be making such a strongly compelling case for MWI as EY says it does?
I know Mitchell Porter is likewise a physicist and he's not convinced at all either.
Mitchell Porter also advocates Quantum Monadology and various things about fundamental qualia. The difference in assumptions about how physics (and rational thought) works between Eliezer (and most of Eliezer's target audience) and Mitchell Porter is probably insurmountable.
Yeah, and EY [any of the unmentionable things].
For other point, scott aaronson doesn't seem convinced either. Robin Hanson, while himself (it seems) a MWI believer but doesn't appear to think that its so conclusively settled.
The relevance of Porter's physics beliefs is that any reader who disagrees with Porter's premises but agrees with the premises used in an article can gain little additional information about the quality of the article by learning that Porter is not convinced by it. ie. Whatever degree of authority Mitchell Porter's status grants goes (approximately) in the direction of persuading the reader to adopt those different premises.
In this way mentioning Porter's beliefs is distinctly different from mentioning the people that you now bring up:
What one can learn is that the allegedly 'settled' and 'solved' is far from settled and solved and is a matter of opinion as of now. This also goes for qualia and the like; we haven't reduced them to anything, merely asserted.
It extends all the way up, competence wise - see Roger Penrose.
It's fine to believe in MWI if that's where your philosophy falls, its another thing entirely to argue that belief in MWI is independent of priors and a philosophical stance, and yet another to argue that people fail to be swayed by a very biased presentation of the issue which omits every single point that goes in favour of e.g. non-realism, because they are too irrational or too stupid.
No, that set of posts goes on at some length about how MWI has not yet provided a good derivation of the Born probabilities.
But I think it does not do justice to what a huge deal the Born probabilities are. The Born probabilities are the way we use quantum mechanics to make predictions, so saying "MWI has not yet provided a good derivation of the Born probabilities" is equivalent to "MWI does not yet make accurate predictions," I'm not sure thats clear to people who read the sequences but don't use quantum mechanics regularly.
Also, by omitting the wide variety of non-Copenhagen interpretations (consistent histories, transactional, Bohm, stochastic-modifications to Schroedinger,etc) the reader is lead to believe that the alternative to Copenhagen-collapse is many worlds, so they won't use the absence of Born probabilities in many worlds to update towards one of the many non-Copenhagen alternatives.
And yet it proclaims the issue settled in favour of MWI and argues of how wrong science is for not settling on MWI and so on. The connection - that this deficiency is why MWI can't be settled on, sure does not come up here. Speaking of which, under any formal metric that he loves to allude to (e.g. Kolmogorov complexity), MWI as it is, is not even a valid code for among other things this reason.
It doesn't matter how much simpler MWI is if we don't even know that it isn't too simple, merely guess that it might not be too simple.
edit: ohh, and lack of derivation of Born's rules is not the kind of thing I meant by argument in favour of non-realism. You can be non-realist with or without having derived Born's rules. How QFT deals with relativistic issues, as outlined by e.g. Mitchell Porter , is a quite good reason to doubt reality of what goes on mathematically in-between input and output. There's a view that (current QM) internals are an artefact of the set of mathematical tricks which we like / can use effectively. The view that internal mathematics is to the world as rods and cogs and gears inside a WW2 aiming computer are to a projectile flying through the air.
Are they, though? Irrational or stupid?
I defected from physics during my Master's, but this is basically the impression I had of the QM sequence as well.
That sounds like reasonable evidence against the selection effect.
I strongly recommend against both the "advises newcomers to skip the QM sequence -> can't grasp technical argument for MWI" and "disagrees with MWI argument -> poor technical skill" inferences.
That inference isn't made. Eliezer has other information from which to reach that conclusion. In particular, he has several years worth of ranting and sniping from Shminux about his particular pet peeve. Even if you disagree with Eliezer's conclusion it is not correct to claim that Eliezer is making this particular inference.
Again, Eliezer has a large body of comments from which to reach the conclusion that Shminux has poor technical skill in the areas necessary for reasoning on that subject. The specific nature of the disagreement would be relevant, for example.
That very well could be, in which case my recommendation about that inference does not apply to Eliezer.
I will note that this comment suggests that Eliezer's model of shminux may be underdeveloped, and that caution in ascribing motives or beliefs to others is often wise.
It really doesn't. At best it suggests Eliezer could have been more careful in word selection regarding Shminux's particular agenda. 'About' rather than 'with' would be sufficient.
Shminux's and Eliezer?
Don't do that. I think the rest of your post is fine, but this is not a debate-for-debate's-sake kind of place (and even if it were, that's not a winning move).
Please change your posting style or leave lesswrong. Not only is disingenuous rhetoric not welcome, your use thereof doesn't even seem particularly competent.
ie. What the heck? You think that the relevance of authority isn't obvious to everyone here and is a notion sufficiently clever to merit 'traps'? You think that forcing someone to repeat what is already clear and already something they plainly endorse even qualifies as entrapment? (It's like an undercover Vice cop having already been paid for a forthcoming sexual favor demanding "Say it again! Then I'll really have you!")
Did you not notice that even if you proved Eliezer's judgement were a blatant logical fallacy it still wouldn't invalidate the point in the comment you are directing your 'trap' games at? The comment even explained that explicitly.
If I ever have cause to send Shminux a letter I will be sure to play proper deference to his status by including "Dr." as the title. Alas, Shminux's arguments have screened off his authority, and then some.
"No rational grounds" means a different thing than "the particular evidence I mention points in the other direction". That difference matters rather a lot.
"Rational grounds" includes all Bayesian evidence... such things as costly affiliation signals (PhDs) and also other forms of evidence---including everything the PhD in question has said. Ignoring the other evidence would be crazy and lead to poor conclusions.
That isn't a fact. I don't see anything going on here except the same blind side-taking as before.
Please consider whether this exchange is worth your while. Certainly wasn't worth mine.
I affirm wedrifid's instruction to change your posting style or leave LW.
I'm no IMO gold medalist (which really just means I'm giving you explicit permission to ignore the rest of my comment) but it seems to me that a standard understanding of QM is necessary to get anything out of the QM sequence.
Revealed preferences are rarely attractive.
Adds to "Things I won't actually get put on a T-shirt but sort of feel I ought to" list.