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Luke_A_Somers00

Paragraph 1: Well, yes. We seem to agree that he derived it from the requirement to treat it probabilistically.

The rest: Decoherence sets you up to the point where all you need to do is say is 'These things act exactly like probability. Since we see probability experimentally, let's say they're the same thing.' Once you've seen it in action, it would take willful ignorance not to draw the connection.

That is a postulate, but it's the sort of postulate that you want to have in a theory - the kind where the theory points to it and says 'Hey! There is a connection you can draw to real life right here.'

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EHeller00

Decoherence sets you up to the point where all you need to do is say is 'These things act exactly like probability. Since we see probability experimentally, let's say they're the same thing.' Once you've seen it in action, it would take willful ignorance not to draw the connection.

Sure, but that is NOT the many worlds claim. The many worlds claim is that we can remove the measurement postulate all together. Maybe this is the case, but it has not been proved.

You seem to agree on that point, and are arguing that we can rescue the spirit of many world... (read more)

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See in context
by DataPacRat
1 min read
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11

There are a great many ideas which don't have enough carefully-measured evidence to be sufficiently confirmed as scientific fact and accepted as such by the scientific community (a recent joke was "While the Higgs Boson has not been discovered yet, its mass is 125 GeV"), but don't have enough carefully-measured evidence to be ruled out yet, either. Do any of the tools of the LW community help narrow down which ones are more worthy of consideration than others?

Eg:

* Cryonics as an arguably reasonable bet for its cost: proto-science

* Cryonics as a surefire way to achieve immortality: nigh-certainly pseudoscience (unless it's the method by which your Everett Immortality keeps you alive)

* Using math to demonstrate that taking classical physics and adding determinism results in MWI-style quantum physics: proto-science.

* Using math to demonstrate that quantum physics proves Christianity is true, from a certain point of view: pseudo-science

* Tubulin might self-organize into microtubules capable of computation on a sub-neuron scale: Possibly proto-science

* Tubulin architecture is 'quantum' in nature and that is what gives rise to consciousness: Probably pseudo-science

* 'Quantum consciousness' means anything is possible: Downright silly

* The E8 Lie group can provide a system for organizing the properties of subatomic particles: Proto-science, perhaps

* Heim theory is useful for predicting particle masses: Pseudo-science, probabilistically

* Using the Bullet Cluster to claim that dark matter is a better theory than Modified Newtonian Dynamics: proto-science

* Claiming that dark matter is made of 'anapoles': Proto-science, perchance

* Suggesting that dark matter is actually gravitational leakage from MWI 'parallel universes': You tell me. (But if it's true, then since I can't seem to find any previous serious discussion of this idea, I get to name part of it after myself, right? :)  )

 

These may not be the best examples, but they're the closest ones I can think of to the boundary. If you know of any better ones, feel free to comment with them.

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How do you tell proto-science from pseudo-science?
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[-]DanielLC150

Suggesting that dark matter is actually gravitational leakage from MWI 'parallel universes': You tell me.

How much do you know about the relevant physics? If you're not an expert, and you're just saying whatever comes to mind, it's pseudo-science. You need a lot of evidence to narrow down the set of hypotheses enough to find the correct one. Not just anybody knows enough to do that.

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1Ishaan
My impression is that MW vs. other theories are not a disagreement about the math, but about how the math should be interpreted. Doesn't that actually put the question out into philosophy? (specifically ontology in this case, I think)...because, without really knowing much about the physics, it seems to me that the whole disagreement stems from not defining the word "reality" rigorously enough. Essentially, I suspect that we should be able to make a simplified model that doesn't involve extremely complex math, which showcases the disagreement inherent in MW / copenhagen / etc so that non-physicists can think about the problem. ...And I might be completely wrong about that, because I don't know physics...I'm drawing my conclusions mostly from the pattern of disagreement that I see in discussions involving this issue. It's the sort of pattern that arises from a philosophical dispute rather than an empirical one.
4EHeller
Just sticking to the quantum interpretations discussed in the sequences, Everettian/MW quantum mechanics has 1 fewer postulate then Copenhagen quantum. The question as to whether they are empirically identical is still open- no one has derived the Born probabilities in many worlds. Until someone does, no one really knows what many worlds predicts. Most pop-science sweeps this under the rug- including the sequences. The inability to derive the Born probabilities is THE key area where many worlds fails, and its a technical problem with the physics/math.
-1Luke_A_Somers
Why oh WHY do people keep claiming this? Born didn't pull the Born rule out of nowhere. He derived it from the supposition that you'd want to treat the wavefunction probabilistically. Under MWI, the notion that you'd want to treat the wavefunction probabilistically is of course still motivated by experiment, but within-theory, it is specifically enabled by decoherence. It is something you find, much like, say, the atomic orbitals, or ferromagnetism... even though we made the theory with finding that in mind, we didn't need to put it in specially once we'd defined the system.
0EHeller
Born started by considering scattering, and discovered you got ridiculous answers if you thought of the wavefunction as charge-density. He solved this conundrum by treating the wavefunction probabilistically, but its not DERIVED, its a postulate grafted on. In MWI, you don't have the measurement postulate (which is the whole point). Decoherence gets you from off-diagonal to diagonal densities, but thats it. It won't tell you how to interpret a diagonal density matrix. There is a reason that Many World's supporters spend a lot of time trying to derive Born (Everett's original paper, Deustch and Wallace, etc)- they realize its an important open problem. Its also why that (and the preferred basis problem) are the most commonly cited reasons to oppose many worlds (see for instance the review papers Adrian Kent has written. The general consensus even among many worlds proponents (see Deutsch and Wallace for instance) is that decoherence solves the preferred basis problem, but it doesn't solve the probability issues.
0Luke_A_Somers
Paragraph 1: Well, yes. We seem to agree that he derived it from the requirement to treat it probabilistically. The rest: Decoherence sets you up to the point where all you need to do is say is 'These things act exactly like probability. Since we see probability experimentally, let's say they're the same thing.' Once you've seen it in action, it would take willful ignorance not to draw the connection. That is a postulate, but it's the sort of postulate that you want to have in a theory - the kind where the theory points to it and says 'Hey! There is a connection you can draw to real life right here.'
0EHeller
Sure, but that is NOT the many worlds claim. The many worlds claim is that we can remove the measurement postulate all together. Maybe this is the case, but it has not been proved. You seem to agree on that point, and are arguing that we can rescue the spirit of many worlds by putting in a slightly weaker measurement postulate. That is clearly true, but it leads to technical issues: what exactly do we take for our postulate? There are lots of ways to do this, for instance- consistent histories gives us a consistency operator, and we have a probability over histories (more or less, there are obviously technical details being smoothed over here, see Bob Griffith's book for more on this). "many minds" puts a probability over mind-sets, The ensemble interpretation tells us that our density matrix is JUST a probability distribution and that quantum mechanics only applies to ensembles of systems,etc (Ballentine is famous for championing this view). All of the interpretations that have an explicit postulate for measurement tend to go by a different name then 'many worlds'. And then the philosophical argument- no matter how you add your measurement postulate, your new many-worlds interpretation will have the same number of postulates as consistent histories or ensemble interpretations (which also have no collapse), BUT it also adds an uncountable number of (fundamentally) unmeasurable worlds- shouldn't occam throw it out?
-1Luke_A_Somers
p1: Many Worlds says that the only dynamical rule is Schrodinger's equation acting on a real wavefunction (not numerically 'real'). That's the end of it. If you hold that, you end up with many worlds whether you like it (or realize it) or not. People may feel unsatisfied with that and add more explanation, but when it comes down to it, that is what MWI is. See, there are (at least?) two kinds of postulates. I don't know of names for them so I'm going to call them types 1 and 2. Type 1 says what the system does. Type 2 is how you map the system onto our perceptions. Like, in Newtonian mechanics, Newton's 3rd law is a type 1 postulate. The mapping of the xyz coordinate parameters onto our 3-dimensional space is a type 2 postulate. Alternately, on a world map, the projection used is type 2 (or if you're using a globe then that fact is also of type 2). Copenhagen-style objective collapse treats the Born rule as a type 1 postulate. MWI treats the Born rule as a type 2. Anyone else who introduces the Born rule as a type 2 rule somehow and doesn't add any other dynamical rules, ends up with a flavor of MWI. Their arguments, reasoning, etc. are irrelevant. P2,3: Those sound like flavors of MWI. If they add dynamical rules then they're not. If they don't use the Born rule (unlikely) then they're not, except that in the many minds interpretation I suppose we could introduce a correction for differences in numbers of minds by way of anthropic reasoning, but that depends how you put the question. P4: Not all postulates are created equal. Euclid's 5th is far uglier than the 1st to 4th, for instance. If you take one tine of the fork in a Gödel sentence, that's going to be waaaay uglier still. And generally speaking, it's fair to weight type 1 and type 2 differently. In the globe analogy, the MWI family is the equivalent of using a globe to represent the Earth, while Copenhagen is the equivalent of flattening it by the two-point equidistant projection onto a billion-piece ji
0EHeller
Your p1: Thats simply not true. Consistent histories, for instance is definitely NOT many worlds, and yet it only has the one dynamical rule. Similarly, Ballentine's ensemble interpretation has only one world,but only the one dynamical rule (it denies the "reality" of the wavefunction to get there). Your p2: I'm not sure your two kinds of postulates are distinct categories. Consider the standard quantum postulate: All observables are associated with Hermitian operators. Is this type 1 or 2? It defines what we measure, but its also defining the system. Can you list a type 2 postulate for me that isn't the measurement postulate? Your p4: In my mind (and in most literature I'm familiar with) many worlds means specifically Everett's intepretation. In Everett's interpretation: you don't take measurement as EITHER a type 1 or a type 2 postulate, and people like Wallace insist that you can deduce the "type 2" of the theory from the dynamics. I'd be willing to extend the term "many worlds" to any interpretations that insist on the existence of multiple "worlds", but to suggest consistent histories or Ballentine's ensemble are many worlds variants is to weaken the term to the point of meaningless. Neither have any kind of multiple worlds! Consistent histories, for instance, is most often described (by Omnes, for instance) as Copenhagen made more precise. P penultimate:I haven't discussed copenhagen in the comments in this chain,or any objective collapse intepretations. This whole paragraph seems off point. Your choices aren't only between many worlds and Copenghagen (unless you continue with your definition of many worlds as 'anything not Copenhagen'). There are many other modern interpretations.
0Luke_A_Somers
I've seen variants of MWI that were explicitly MWI, so what you're calling MWI would be straight Everettian MWI. But really, here, I'm asking: "Does this theory have multiple worlds in it?" I care significantly less what it's called. For instance, Consistent Histories looks at things quite differently, but if you ask the critical questions of it, it looks like it has many worlds in it. It primes you to zero in on one of them, but if you're going to stick with the wavefunction being real then the histories you don't observe are going to be equally real, just less relevant. On the other hand if you say it's just a trick for finding the probabilities, well, then it's just a formalized ontological collapse and not MWI. I don't see any middle ground or ground off to the side here (aside from throwing your hands in the air and saying you don't know, which is perfectly legitimate but it isn't an interpretation). The associations of the hermitian operators corresponding to observable quantities are very type-2. We should feel about as justified using them as using the Born rule. The point of mentioning objective collapse in the last 2 paragraphs was as a reference point for the non-equality of type-2 postulates. I know it's terrible, and you know it's terrible - that's the point.
0EHeller
Right- in consistent histories there is 1 world. When you make a measurement, you get one answer. In ensemble quantum mechanics there is 1 world. Remember- the creators of consistent histories (Hartle, for instance) consider it a formalized and clarified copenhagen variant (though inspired by many worlds). Maybe think about it like Bohmian mechanics- the "world" that the Bohmian particle actually sits in is the 'real' one. Similarly, in consistent histories, the answer you get picks out a set of projection operators as "real." Side question- do you know a many worlds variant (in the sense of more than one world) that makes explicit what its "type 2" postulate is? The only variant I know of is many minds, which I find sort of abhorrent and disregard out of hand. The reason I insist that "many worlds" is incomplete is that the only formalized version I know is Everettian many worlds (which we both seem to agree IS incomplete). But also type 1, because it defines the system (hermitian operators on a Hilbert space). What would you consider the type 2 postulates of Newtonian mechanics? What would you consider the type 2 postulates of GR?
0Luke_A_Somers
In that case, Consistent Histories is both not WMI and I didn't say it was, because it doesn't consider the wavefunction fully real in its own right (there were two criteria, not just one, in that sentence)*. Just as Bohm isn't, on the same grounds. Type 1 vs type 2: Normally we don't even talk about these types - if it were a matter of discussion, we wouldn't be using these terms! With the observables, using them in the theory is type 1. Associating each one to a part of the world we experience is type 2. As for the incompleteness of Everett, I hold that you can deduce that the Born Rule is one possible way of finding sapience within wavefunctions. I am not at all sure that you can prove that there aren't others, so barring such a proof, a postulate is necessary to exclude them - "The way of getting to a perceivable world from this theory is... THIS one, not any others." * ETA: and in this case Consistent Histories deserves every bit of scorn that Eliezer heaped on Copenhagen in the 'what does it have to do, kill a puppy' rant.
1DanielLC
Eliezer came up with a good analogue in Where Physics Meets Experience and Where Experience Confuses Physicists. To summarize, the universe is a three-dimensional sheet in a four-dimensional universe. It's predicted that it occasionally splits into two thinner sheets. The probability of being in a sheet is measured to be proportional to the square of the predicted thickness. The Copenhagen interpretation claims that, once the sheets have separated beyond a certain distance, one of them completely vanishes for no adequately explained reason. It's not known how far apart they have to be, beyond that it's further than you can detect a parallel universe. The Many Worlds Interpretation claims that all the sheets continue to exist. No explanation is given for why you end up in the thicker one at that rate. It's just assumed that there's a better reason than that one universe ceases to exist.
4philh
"One universe ceases to exist" doesn't explain why the universes survive with that probability either. This was one of the points raised in the QP sequence. You can't say "MWI doesn't explain these probabilities" as evidence for Copenhagen, because Copenhagen doesn't explain them either. (I don't actually know the physics, I'm just repeating the teacher's password.)
1Ishaan
I've read those sequences - I was more asking about your reasons for believing that one must be a domain expert in QM and be familiar with the empirical evidence on the topic to have an opinion about this issue. My central point is that the two things you described are empirically identical, and the only difference between them is which parts of the math are defined as "existing". The underlying question here is What is Reality and What exists. My intuition is that you don't really need to be an expert on anything or really understand physics to have an opinion about this largely ontological question. From what I've heard of the two arguments so far, I don't actually see why you need a background in physics, or any empirical knowledge at all, to answer this question once it has been posed. Unless I haven't understood the question / something really important was lost in simplification.
3DanielLC
The original post wasn't talking about having an opinion on someone else's theory. It was making up a new theory. If two experts argue about something, and they explain it well to you, and you form an opinion on this, you will probably be right. There's still a pretty good chance you'll be wrong, so you shouldn't form a strong opinion, but you can get higher than 50%. If you make up your own theory, then you are distinguishing one out of a huge number of possibilities without anyone explaining anything to you. Your theory will probably be nonsense. If it isn't, it will probably be fundamentally flawed. If it isn't, it will probably be something that can be readily disproven. If it isn't, it will almost certainly not be the simplest explanation. You can easily make an accurate opinion in this situation, by assuming that your theory is wrong. They are identical to within measurable error. However, there is a difference. There are ways to detect entangled systems. It just gets exponentially harder as you increase the size of the configuration space by adding particles or letting them move more etc. In principle, no matter how much has to get entangled for a waveform to collapse, you could entangle more than that and check to see if it stays entangled. No it is not. The math shows how an entangled system of particles evolves. The Copenhagen interpretation does not say that after a certain number of particles get involved it stops being "real". It says that it collapses, in a manner that presumable could be precisely defined, but since there's neither theory nor empirical data behind the idea, they can't actually tell you what the definition would be. Of course you don't. You're not a domain expert. It's hard to see why you need the background knowledge, when you don't have the background knowledge and you can't see how it helps. There are times where the background knowledge doesn't help much. Like understanding the Born probabilities, for example. If the domain exp
-3DataPacRat
I'm not an expert. My reasoning process, such as it was, was, "MWI is not generally accepted by the scientific community, but is on LW. Are there any existing scientific mysteries which could potentially be solved by examining them from the perspective of assuming MWI is true, that wouldn't be thought of without that assumption?". Dark matter was at the top of the list, and gravity 'leakage' the simplest way to describe such a possible solution.
9AlexMennen
IIRC, less than half of physicists believe in the Copenhagen interpretation, and more than half of the rest believe in MWI. At any rate, actual physicists who ascribe to MWI are not rare, and if your conjecture had anything going for it, I'm sure one of them would have thought of it. I'm under the impression that we have good theoretical reasons to believe that such interactions cannot happen. Making up statements that sound plausible given a few other assertions you've heard, without first understanding the technical details behind those assertions, is a poor way to generate hypotheses.
5Mitchell_Porter
The main alternative paradigm to dark matter is modified gravity (above all, MOND, Modified Newtonian Dynamics). Modified gravity theories usually involve a change at the classical level, but it has been suggested that the galactic rotation curves, etc., might be due to some specifically quantum effect. In quantum field theory, a classical force field generated by an object is understood in terms of virtual particles emitted by that object, the quantum details can cause the field to exhibit properties different from the classical approximation, and maybe virtual gravitons do something funny when they are summed on galactic scales. If you could explain such quantum modifications to gravity on astronomical scales, as a result of interaction between Everett worlds, then you could have something like your MWI theory of dark matter. The real problem with that, is in finding a coherent causal account of inter-world interaction. ETA By the way, I suspect that your idea of how MWI gravitational leakage would work, uses paradigms from the wrong multiverse "level". In string theory there is the idea of membranes in hyperspace, each with its own matter attached, and with gravity being the one force that can cross hyperspace. So what we can see in space might be just one brane, and the dark matter could be matter on other nearby branes. I suspect that you're thinking of the MWI multiverse in similar terms - a stack of worlds, with some gravitational interaction between neighbors. But in QM, quantum interference involves whole configurations at once. Suppose you have two entangled particles x and y, that are far apart in space. Schematically, their combined wavefunction will be x1 y1 + x2 y2 + x3 y3 + ... where the x's and y's are different possible wavefronts for the individual particles, and xi yi is a formal product of two such individual wavefunctions. The point of nonlocality is that the combined wavefunction of the two particles is simultaneously susceptible to changes
0ChristianKl
The fact that MWI isn't generally accepted doesn't mean that there a sizable chunk of physicists who do accept it. I'm not even sure that you need to accept it to run the relevant equations.
0DataPacRat
Do you know anyone who would be willing to run through said equations?
[-]V_V150

MWI doesn't have different equations than "mainstream" quantum mechanics. It's just an epistemological interpretation.

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-1EHeller
This is a misconception. Many worlds has one fewer postulate then Copenhagen quantum, so there are operations you can do in Copenhagen that don't make sense in Everettian quantum (measurement as a projection operator). Most of the physicist I know who object to many worlds object that it doesn't have enough structure in the postulates to actually get predictions out. Most interpretations are similar- they remove or introduce other postulates. Consistent histories, for instance, has a consistency operator that you wouldn't use in another formulation.
0V_V
The complaint is that MWI is not complete enough to give a satisfactory interpretation for the Born rule. Nevertheless, those who support MWI do believe that Born rule is essentially accurate.
0EHeller
Sure, its obvious empirically. The question is- can you do without the measurement postulate and recover the Born rule. If you can't, then Everett's interpretation doesn't work, you still have an ugly measurement postulate grafted on to the unitary theory, and you gain no elegance.
0ChristianKl
I don't even know enough about the physics to know which equations you would have to run. However there are a lot of theoretical physics Phds. I know one who tries to writes her thesis on two dimensional time. It's my impression that theoretical physicists just try out various different methods of writing formula in the hope of discovery something "beautiful" or something that at least makes testable predictions.
0[anonymous]
MWI has no equations distinct from the standard approach.
[-]hyporational110

One admittedly problematic heuristic I immediately thought of is that proto-scientists are significantly less certain about their claims than pseudoscientists are.

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1ikrase
Also, pseudoscientists very, very often seem to have either an agenda, or a desperate desire to escape epicureanism.
1hyporational
The problem with using agenda as a heuristic is that it could be claimed most scientists have one. Perhaps if you divided agenda into subcategories, some of those could be useful, like political or religious agenda.
0ikrase
I guess that's right.
[-]Shmi90

The difference between a pseudoscience and a far-fetched hypothesis is the attitude toward the scientific method. Wikipedia:

Pseudoscience is a claim, belief, or practice which is presented as scientific, but does not adhere to a valid scientific method, lacks supporting evidence or plausibility, cannot be reliably tested, or otherwise lacks scientific status.[1] Pseudoscience is often characterized by the use of vague, contradictory, exaggerated or unprovable claims, an over-reliance on confirmation rather than rigorous attempts at refutation, a lack of

... (read more)
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[-]V_V60

Cryonics as an arguably reasonable bet for its cost: proto-science

Is it?

Using math to demonstrate that taking classical physics and adding determinism results in MWI-style quantum physics: proto-science.

I'm not an expert, but isn't Tipler considered largely a pseudo-scientist?

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2passive_fist
The E8 theory of particle physics is also largely considered to be pseudoscience.
2DataPacRat
How do you tell whether those who claim it's pseudoscience are more reliable than those who claim it's not?
3Mitchell_Porter
It's not a theory that makes quantitative predictions, it's more a blueprint for a future theory, and the critics would say that the blueprint is hopelessly flawed - that no such theory is mathematically possible. The larger theoretical context of Lisi's work is the attempt to describe 4D gravity as a gauge theory, the viability of which is the central dispute between string and loop theories of quantum gravity. Lisi's theory is a "GraviGUT" theory which then adds to this problematic foundation, even wilder hopes about getting fermions from "BRST ghosts", and about finding loopholes in theorems which say that even then, you couldn't get the necessary three generations of them, out of a single E8 gauge field. Incidentally, there are various ways to get three generations of particles "from E8" in string theory, so perhaps those should be regarded as the real "E8 theories".
0[anonymous]
I never understood how Lisi's E8 got around the Weinberg-Witten no-go. Was there some reason it didn't apply?
2passive_fist
I've looked at the theory myself, if that's what you mean (I have a background in mathematical physics). If you like, I can give more explanation about the severe drawbacks of the theory and why it's considered to be pseudoscience and probably not worthy of further investigation.
2DataPacRat
Those last six words are what I'd like to find out, as soon as possible, if it's possible to do so; and I would appreciate any assistance on that score. (I regularly read 'Not Even Wrong', whose author puts forward a strong case that string theory is also worth skipping; which doesn't leave too many possibilities on the ground to pick from, these days.)
[-]passive_fist100

As Mitchell pointed out below, there are severe theoretical issues. The theory predicts 22 new particles (and doesn't even specify their masses thus making detection difficult) and fails to account for the properties of many existing ones. Most importantly, the theory has no chirality, and chirality is extremely important for fundamental particles. This error is severe and no way to avoid it has been found. E8 does crop up in string theory in other settings but it's unrelated to Lisi's work.

A deeper problem is that the theory doesn't actually solve a lot of problems, even if it were true. You mentioned Not Even Wrong; here is an excerpt from Peter Woit on the E8 theory:

One idea Garrett is fond of that has generally left me cold is the idea of unification via a large simple Lie algebra like E8. While there may be some sort of ultimate truth to this, the problem is that, just as for GUTs and for superstring models, all you’re doing when you do this is changing the unification problem into the problem of what breaks the large symmetry. This change in the problem adds some new structure to it, but just doesn’t seem to help very much, with the bottom line being that you get few if any

... (read more)
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0DataPacRat
Fair enough. Do you have any suggestions of other theories that would be better worth the time to read up on?
6passive_fist
As others have said, it really depends what level you're on and what you're interested in. At the very least I recommend familiarity with quantum field theories before even attempting to touch more speculative physics. This includes general Yang-Mills theories and their algebraic underpinnings.
0DataPacRat
It's not accepted by the majority of the scientific establishment, so it's not "science". However, it's claims don't violate known physical law. If someone says that it has a 5% chance of working, and they'd be willing to pay 20x the cost of cryonics to cure themselves of a disease, that seems to fall within "arguably reasonable". I listed the next item, which was a link to an interview with Tipler, as pseudo-science. Victor Stenger, who authored the other PDF in the line you quoted, seems to have his head on reasonably straight. And even if Tipler's beliefs are pseudo-scientific, the math involved in the two PDFs seems to check out, as best I can tell, without any reliance on anything on the pseudo-scientific side.
3ChristianKl
Whether something is a science has nothing to do with whether it violates physical law for which a consensus exists within the scientific community. Paranormal is a much better word to describe those claims. When Feynman made up the term cargo-cult science one of is prime examples was rat psychology research. Those researchers where doing experiment but the didn't do them in a way that really tested the claims they were investigating. Pseudoscience is when you claim that there scientific evidence for a claim when there isn't. You aren't a pseudoscientist for investigating a hypothesis.
0V_V
As ChristianKI already said, whether something strictly violates known physical laws is a poor criterion for telling science from pseudoscience. According to that criterion, paradigm-breaking physical theories such as Einstenian relativity and quantum mechanics would have been pseudoscience when they were presented, while lots of medical snake oil (including literal snake oil) would be not. But it hasn't been established that cryonics has a 5% chance of working, or even a 0.25% chance. I haven't had the time to read it yet, and this is not my field of expertise, but AFAIK attempts to reduce quantum physics to classical physics have been around since quantum physics exists, and they have always turned out to be unsuccessful. Even Einstein dedicated a large part of his research to that goal, to no avail. Thus I don't expect any of them to succeed anytime soon. Past a certain point it stops being proto- and it starts to become largely pseudo-.
-1DataPacRat
Since E8's predictions about a few new particles also violate currently known physical laws, that interpretation of 'pseudoscience' would include E8 - but in my rough definitions above, I've included E8 as coming closer to proto-science than pseudo-science; so I'm going to have to disagree with you about your described criterion matching the dividing line I'm trying to draw. On the other paw, it hasn't been established that cryonics has a 5% chance of failure, or even a 0.25% chance. It seems worthwhile to determine what the relevant null hypothesis /is/, before determining in which direction the burden of proof lies. (Either that, or one could try a Feynman estimate. A 0.5% chance of success seems too low; and a 10% chance seems too high; so somewhere around 3% seems within the right order of magnitude.) They're both quite short; I even managed to describe the ideas involved to a complete non-physicist: [You are] probably familiar with Newtonian physics: force, mass, action and reaction, conservation of momentum, etc. The equations involved in all of that can be written out in different ways, which all add up to the same things, like x=y is the same as x-y=0. One if those ways is called the Hamilton-Jacobi Equation, which is one of the more powerful and general versions, but with a flaw - it's "non-deterministic", meaning it's rubbish at telling you what actually would happen when particles interact. Fortunately, it's possible to add a term to H-J, which arises from adding the premise that "God does not play dice with the universe" (aka 'determinism', something which physicists prize in such equations), which fixes that flaw. A surprising consequence of doing so is that the H-J equation can then be rearranged into another equation: the Schrodinger Equation, which is the foundation of quantum mechanics. Which means that all that quantum mechanics really is nothing more or less than classical physics, where all the different possible sequences of events happen in
5V_V
So why did you mention not violating known physical laws as a criterion for cryonics not being pseudoscience? Seriously? Somebody claims they have invented a method to achieve nigh-immortality, except they can't demonstrate that it works right now, and it's success conjunctively depends on a large number of highly questionable assumptions, and people with relevant domain expertise either ignore it or actively distance themselves from it. I wonder what the relevant null hypothesis might be... You mean Fermi estimates, and they don't work by pulling numbers out of your hat as you seem to be doing here. I've read the introduction of the first one. It seems that the author is taking the Hamilton-Jacobi equation, adding a special extra term (the "quantum potential") and massaging it to get the Schrödinger equation. That's doesn't strike me as particularly surprising, since it is well known that the Schrödinger equation is mathematically similar to the Hamilton-Jacobi equation. The "Hamiltonian operator" in the Schrödinger equation is called that way for a reason, and the Schrödinger equation converges to the Hamilton-Jacobi equation in the classical limit.
1CronoDAS
Huh, I've seen something vaguely similar in a physics textbook: the authors "derive" the Schrodinger equation by describing the properties that an equation has to have in order to describe an object (such as a single photon) that "interferes with itself" in the double slit experiment. Another textbook I've read simply says that "derivations" of the Schrodinger equation are basically bogus; the Schrodinger equation is an empirical formula that is chosen because it matches observations, and doesn't actually have any more justification than that.
0EHeller
The best discussion you are likely to find is in Ballentine. If you accept (empirically) Galilean invariance, the STRUCTURE of the Schroedinger equation falls out of group representation theory quite naturally. The actual specifics of a problem involved picking a potential to use in the problem, and this is empirical. So if you ask the question: What equation does an electron in an atom obey? That is empirical. If you ask: Given Galilean invariance and a 1/r potential, what equation does an electron in an atom obey? This doesn't need any more empirics.
0CronoDAS
And assuming Lorentz invariance gives you the Dirac equation, right?
1EHeller
Sadly, with lorentz invariance things get quite a bit more complicated. Adding in Lorentz invariance forces you to deal more directly with spin (and lets you prove spin-statisics), so you end up with the Klein-Gordon equation for spin 0, the Dirac equation for spin 1/2, and variants of the Maxwell equations for spin 1. But you also get weird "paradoxical" effects trying to interpret the results of those equations along the lines of non-relativistic quantum, so you are forced to push towards full field theory.
[-]advancedatheist50
  • Cryonics as an arguably reasonable bet for its cost: proto-science

I got to meet Aubrey de Grey for the first time at the Venturists' cryonics convention in Laughlin, Nevada, last month, which I helped to organize. In his talk, Aubrey asks why people who accept in principle the idea that we could learn to cryopreserve viable organs like the human kidney think that the human brain has some spooky ability to defy this process and perversely die regardless.

  • Cryonics as a surefire way to achieve immortality: nigh-certainly pseudoscience (unless it's the
... (read more)
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[-]NancyLebovitz150

We want a lot more precision restoring brains than from restoring kidneys-- it's conceivable that there's a limit which makes good enough restoration for kidneys possible, but not for brains, though I don't think that's the way to bet. It's plausible to me that restoring brains adequately is much harder.

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3passive_fist
This seems like a non-obvious statement to me. Kidney function is dependent on fine microstructure: http://en.wikipedia.org/wiki/Renal_corpuscle The size of each corpuscle is about the same as the size of a neuron.
2V_V
Moreover, human kidneys can't be reversibly cryopreserved by current methods.
1TheOtherDave
Yes. It's also true, though perhaps irrelevant, that we don't actually care whether kidneys are restored. If my kidneys are damaged and a surgeon successfully transplants Sam's kidneys into my body, I'm basically OK with that... I don't especially want my kidneys, I just want kidneys. I suspect that's true of most people. If my brain is damaged and a surgeon transplants Sam's brain into my body, the corresponding thing is much less true. That being said, I expect that >99% of my cognitive function, memories, etc could be replaced by Sam's and I would be OK with that as well, even if I make the OKness evaluation with my current brain. Identifying the <1% for which that isn't true is a tricky project, though. That being said, I expect I'm very atypical in this respect.
2ChristianKl
I don't think that being open to testing a claim empirically in no way implies that you support the claim. Randi 1,000,000$ prize for psychics is also no endorsement of paranormal claims.
0advancedatheist
Sorry, you've made a bad comparison. Randi hasn't raised that money for a Paranormal X-Prize. The Brain Preservationists, by contrast, have strictly empiricist criteria for deciding who wins the incentive prizes. Reference: http://www.brainpreservation.org/content/competitors
0ChristianKl
Randi runs a paranormal X-Prize. Are you saying that Randi hasn't strictly empirical criteria for deciding who wins his price?
[-]passive_fist50

The definition of 'protoscience' given by different people seems to vary a lot. You seem to be defining it as "An idea that has not yet been rigorously tested but is worth pursuing." This definition is something most people would just call "science". The wiki article on protoscience has several more definitions for it http://en.wikipedia.org/wiki/Protoscience

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0DataPacRat
You are quite right about the definition I'm using for this post/thread. If I knew of a better word, I'd have used that, instead.
[-]Peter Wildeford40

I'm not sure you're suggesting this, but this essay makes it appear that one should distinguish protoscience from psuedoscience by checking to see whether the topic is approved by the LW community or not.

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5DataPacRat
That's not what I'd intended to intend. ... it's an interesting idea, though. So - what does the LW community think about vetting ideas by their level of approval in the LW community? :)
3Mestroyer
As availability heuristic-appointed representative of the LW community, I also disapprove.
3kalium
I disapprove.
2TheOtherDave
I see what you did there.
0Ishaan
I'd say It's similar to vetting ideas by their level of approval among the general public, except, I think, rather better. However, if you're not going to solve it for yourself anyway and going to be on the internet anyway, you might well figure out what the domain expert consensus is in roughly the same amount of time and that would be better still.
3dougclow
Isn't it the aspiration of the LW community for the causation to run the other way? That is, the LW community aspires to approve of protoscience but disapprove of pseudoscience.
[-]Daniel_Burfoot30

Proto-scientists will say: I have an idea A. Events of category Y will increase our confidence in A, while events of category X will make A less likely. Pseudo-scientists leave out the last clause.

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[-]DuncanS30

My own definition - proto-science is something put forward by someone who knows the scientific orthodoxy in the field, suggesting that some idea might be true. Pseudo-science is something put forward by someone who doesn't know the scientific orthodoxy, asserting that something is true.

Testing which category any particular claim falls into is in my experience relatively straightforward if you know the scientific orthodoxy already - as a pseudoscientist's idea will normally be considered absolutely false in certain aspects by those who know the orthodoxy. A... (read more)

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0redlizard
This seems like an excellent heuristic to me (and probably one of the key heuristics people actually use for making the distinction), not not valid as an actual definition. For example, Sir Roger Penrose's quantum consciousness is something I would classify as pseudoscience without a second thought, despite the fact that Penrose as a physicist should know and understand the orthodoxy of physics perfectly well.
0Brillyant
I don't like the word 'orthodoxy'. From my understanding, it means 'correct belief'. Correct is constant, whereas belief is changing. The perception of which beliefs are correct keeps moving. So, unorthodox beliefs can be correct. In this sense, orthodox is meaningless as a defining characteristic of what is good belief.
2Douglas_Knight
That's not what it means.
0Brillyant
What does it mean? I'm sincerely very curious. In regard to religion, I hear this term often...
3Luke_A_Somers
It means that literally, but since no one gets to know what's correct, it means 'believing the same thing as the authorities'.
[-]ialdabaoth20

Suggesting that dark matter is actually gravitational leakage from MWI 'parallel universes': You tell me. (But if it's true, then since I can't seem to find any previous serious discussion of this idea, I get to name part of it after myself, right? :) )

I have conceived of exactly this idea - so it can't be just the two of us. Surely some people versed in cosmology can explain why the math doesn't work out?

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0[anonymous]
It doesn't work out because then you would expect the radial mass distribution of a galaxy to be just a multiple of its observed baryonic mass distribution, rather than almost exactly what you would expect from the gravitational collapse of a thin 'gas' of particles that cannot self-collide.
[-][anonymous]20

taking classical physics and adding determinism

I guess you meant to say something else: classical physics is already deterministic.

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[-]Vladimir_Nesov20

Whatever decisions or factual judgments about such claims you need to make, it seems better to formulate them more precisely, without using these categories. The examples in the post seem mostly useless (as in waste of cognition, low value of information).

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0DataPacRat
Could you offer an example of what you would feel is an example that's useful?
0passive_fist
I think Vladimir is making the point that the categories you're using don't give much useful information when applied to your examples. It would be better to narrow down and make precise various different criteria for judging whether an idea is worth pursuing or not.
-2DataPacRat
Hm... As an alternative category, how about "worth the effort of spending a few hours reading up on the details and implications" as opposed to "sufficiently unlikely that my time would be better spent looking for new rationalist (fan)fiction"?
1Vladimir_Nesov
Worth the effort to what end? For example, educational value of settled science is greater than that of almost any topic for which the question of being pseudoscience or "protoscience" even comes up (judged at the level where you are ready to study the topic).
-3DataPacRat
I'm familiar with any given popularization of a scientific topic, and have read through and assimilated enough of the Sequences to start really understanding that there is always going to be a higher level of rationalism to aspire to. I also only have so many hours per day to devote to any given reading topic, and can only focus on any particular topic for so many months at a time before my concentration will flag. Thus, I'm hoping to get a head start now on what's most likely to become settled physics in the future - which will, of course, bring advantages of its own.
4Kaj_Sotala
Really?
[-]Ishaan10

So we're assuming that it's easy to classify something in the "proto-or-pseudo-science" box...all statements about which you aught to have low certainty go into that box.

Then, the way to distinguish between the two is the level of certainty that the person making the claim projects. If they are projecting high certainty for a claim for which they aught to have low certainty, then it's likely to be pseudo-science.

Creating an explanation with a conclusion already in mind (the Christianity example) is a subset of high certainty - since they started... (read more)

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[-]lmm10

For people who find explicit Bayesian calculations about their own uncertainty useful (I don't) this is a pretty ideal case; you calculate how much weight to assign to facts like "is professor at a respected university"; "was published in journal X", "was paid by institute Y". (See Gwern's[?] example with the Death Note script)

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[-][anonymous]10

Sir Karl Popper suggested if a theory includes a description of how it can be observed to fail by outsiders, it is science. And that science is not about accepted or unaccepted ideas, professional or amateur research, but only falsifiability. He suggested science is one kind of explanation that has utility but expressly said it was not the only or best explanation.

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1ChristianKl
Pseudoscience is making claims that are falsifiable. If you don't make falsifiable claims you aren't engaging in pseudoscience but you are engaging in philosophy.
[-]CronoDAS00

Maybe we should build a Bayes net! ;)

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