They are very different things, and I meant ‘bigger’. Still one universe, but more of it than the story you found comfortable as a child. There were other universe theories (the only reasonable alternative to the intelligent design argument) long before Everett came along, so having other worlds is hardly a painful step.Notice the quotes around 'bigger'. What I think you actually mean is, 'many'. They're very different things. — Wayfarer
He also held to locality, so I think he would have liked an interpretation that was both local and deterministic.Einstein didn't like the uncertainty principle or the 'quantum leap' because he was a determinist.
I suspect that decoherence calculations do just that.The observer problem is a problem because there’s nothing in the maths to indicate where the observer must come into the picture. — Wayfarer
That it does. I’ve discarded that principle, as do most of the interpretations. The science doesn’t care. Quantum theory is not concerned with what goes on in the absence of interaction between systems.This undermines the principle of objectivity
What if the ratio isn’t rational?Per your comment, "one also has to deal with how some of them are more probable than others", the basic idea (from Zurek - see the above post) is that paths that are not equally probable can be mathematically reduced to paths that are. For example, a beam splitter with a 2:1 transmission/reflection ratio is equivalent to a beam splitter with a 1:1:1 ratio once a 1:1 beam splitter is added to the transmission path. — Andrew M
There's an 'observer effect' in Einsteinian relativity which nobody objects to. That's not the problem. — Andrew M
There is? There are dependencies on frames (what velocity has object X?, a completely frame dependent question since Galileo), but I've not heard that observers have any effect at all. — noAxioms
That is a dependency on a choice of coordinate system. No actual observer need be present, or be stationary, in an arbitrary choice of coordinate system. The people on the platform and the train may (or may not) just happen to make different choices. You make different choices for yourself, such as using one frame to describe where your house is, and a completely different one to describe what Neptune is doing (which is moving faster than c in the frame you probably chose for your house).Yes, I'm referring to frame dependency. — Andrew M
That’s quite different than the interaction (measurement) actually changing the system being measured, which is what this topic is about.While the laws of physics are the same for all observers, they may describe things differently from their respective reference frames.
On the contrary, he brought light to be included in the principle of relativity, that it moving at c was such a law of physics that was unchanging, part of the principle of relativity. He freed light speed from being relative to a medium, or possible relative to that which emitted it, in both cases being different from one frame to the next. We each see the same things differently. I see it as bringing light into PoR, and you see it as being taken out.What Einstein does with "special relativity" is to give 'special' status to light, freeing it from the principles of relativity — Metaphysician Undercover
But it’s motion IS relative to material bodies, or rather relative to any inertial frame including the one in which the material body is stationary. The second premise says that directly.to allow that its motion is not relative to the motions of material bodies.
But those are all frame effects, not observer effect. For instance, a clock coming at you fast will tick slow in your inertial frame, but it will be observed to run fast. Observer effects and frame effects are not the same.This amplifies the 'observer effect' by greatly increasing the possibilities for subtle differences. Now there is a need for principles like time dilation, length contraction, relativistic mass, and things like that.
Shouldn’t the cat simply be dead or alive then? What’s the difference when the box hasn’t yet been opened, other than the epistemological one where the lab guy doesn’t know the state of the cat. That would be a classic state like a coin tossed and caught, but not yet revealed. What makes the cat different if the world has already split?Schrödinger's cat (call PETA asap) is both dead and alive (this is impossible in one world) — Agent Smith
I understand your point, however the specific contrast being made was between an observer qua reference frame and an observer qua rational agent. Only the latter can be understood as a user of quantum theory, and thus active in that sense.
Unfortunately, I was not able to easily follow the rest of your post. Perhaps you could concisely state your claim and quote specifically from SEP what you're arguing for (or against). — Andrew M
On the contrary, he brought light to be included in the principle of relativity, that it moving at c was such a law of physics that was unchanging, part of the principle of relativity. — noAxioms
I see it as bringing light into PoR, and you see it as being taken out. — noAxioms
But it’s motion IS relative to material bodies, or rather relative to any inertial frame including the one in which the material body is stationary. The second premise says that directly. — noAxioms
But those are all frame effects, not observer effect. For instance, a clock coming at you fast will tick slow in your inertial frame, but it will be observed to run fast. Observer effects and frame effects are not the same.
There are objective demonstrations of say length contraction, contraction that is real regardless of observer or choice of frame. That makes length contraction part of ‘a true perspective’, if that phrase is to have any meaning. — noAxioms
It would be better to simply recognise there are things science is unable to ascertain and leave it at that. As a general rule, knowing you don’t know something is preferable to thinking you know something that you don’t. — Wayfarer
The irony in this statement is that it seems to be based on you thinking that you know what science can and cannot ascertain, rather than leaving it as an open question to be determined by further inquiry. — Janus
Schrödinger's cat (call PETA asap) is both dead and alive (this is impossible in one world)
— Agent Smith
Shouldn’t the cat simply be dead or alive then? What’s the difference when the box hasn’t yet been opened, other than the epistemological one where the lab guy doesn’t know the state of the cat. That would be a classic state like a coin tossed and caught, but not yet revealed. What makes the cat different if the world has already split? — noAxioms
I thought that superposition is a fact and not just a hole in our knowledge. In other words the coin is heads and tails and not that it's either heads or tails, only we don't know which. — Agent Smith
You thought correctly. And importantly this is a testable hypothesis that has been experimentally verified. — PhilosophyRunner
But it’s motion IS relative to material bodies, or rather relative to any inertial frame including the one in which the material body is stationary. The second premise says that directly. — noAxioms
I thought that superposition is a fact and not just a hole in our knowledge. In other words the coin is heads and tails and not that it's either heads or tails, only we don't know which. — Agent Smith
. . .Quantum superposition is a fundamental principle of quantum mechanics. It states that, much like waves in classical physics, any two (or more) quantum states can be added together ("superposed") and the result will be another valid quantum state; and conversely, that every quantum state can be represented as a sum of two or more other distinct states. Mathematically, it refers to a property of solutions to the Schrödinger equation; since the Schrödinger equation is linear, any linear combination of solutions will also be a solution(s)
In quantum physics, a quantum state is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system
↪jgill
Well then what explains all the Sturm und Drang mon ami?! Why the hullabaloo if the cat is simply dead OR alive? — Agent Smith
No one really knows exactly whats going on at the quantum level. If you simply follow the math and avoid all this metaphysical stuff, you do well at predicting. Apparently. Once the science popularizers get into the game, however, you see the Earth in basketball nets. Best to let the Q-physicists argue it out. My opinion. FWIW. Not much — jgill
No one really knows exactly whats going on at the quantum level. If you simply follow the math and avoid all this metaphysical stuff, you do well at predicting. Apparently. Once the science popularizers get into the game, however, you see the Earth in basketball nets. Best to let the Q-physicists argue it out. My opinion. FWIW. Not much. — jgill
Metaphysics consists of different principles which physicists have not been trained in. — Metaphysician Undercover
What if the ratio isn’t rational? — noAxioms
For any wave function with irrational squared-amplitudes there exist arbitrarily similar wave functions with rational squared-amplitudes (as the rationals are a dense subset of the reals). — Self-Locating Uncertainty and the Origin of Probability in Everettian Quantum Mechanics - Sebens and Carroll, 2015
"While the laws of physics are the same for all observers, they may describe things differently from their respective reference frames." - Andrew M
That’s quite different than the interaction (measurement) actually changing the system being measured, which is what this topic is about. — noAxioms
In a state-of-the-art 6-photon experiment, we realise this extended Wigner’s friend scenario, experimentally violating the associated Bell-type inequality by 5 standard deviations. If one holds fast to the assumptions of locality and free-choice, this result implies that quantum theory should be interpreted in an observer-dependent way. — Experimental test of local observer-independence - Proietti, et al., 2019
So I'll give you the gist in a more straight forward way. — Metaphysician Undercover
Not quite. All motion can be specifed relative to a frame, specifically an inertial frame. Light speed is specified relative to (and is fixed only relative to) any inertial frame, so it isn’t an exception.The principle of relativity makes all motions equally relative to each other. — Metaphysician Undercover
Never said that. You’re saying it, and it’s wrong since it would exempt it from the principle. Light has no special status in this regard.To stipulate that one movement, "c", is exempt from that principle
The principle of relativity is one of the postulates of special relativity. Being part of that theory doesn’t mean anything gets special status. The word ‘special’ means a special case of no gravity being involved. With gravity, there are no longer non-local inertial frames and fixed speed of light goes away.is to remove it from the application of that principle, "relativity", and give it special status, and we are left with "special relativity".
I realize you think that, and I’m trying to actually grok your opinion to the contrary. But as I say, mathematically it doesn’t work. Light obeys the same rules as everything else, just like PoR says it should.I think you are "seeing" it incorrectly then.
This statement also seems to contradict what you’re asserting. Anyway, post-Michelson–Morley at least, new rules were needed since Newton’s application of PoR wasn’t working. In particular, relative velocity addition needed modification.Prior to Einstein there appeared to be no way to make the motion of light compatible with the principle of relativity.
First of all, one-way SoL still cannot be measured by any means, hence the speed being fixed being an additional premise, not something derived or measured. Secondly, the assertion you make (that these two observers would have to measure different speeds) does not follow from PoR.It was a practical problem involving the difficulty in measuring the speed of light. If light was included within the application of the relativity principle, then the person on the embankment, and the person in the train car, would have to measure the light from the same source as having a different speed.
Again I agree that such an exception would constitute a fundamental flaw, but this seems to be exactly what you’re suggesting.The problem is that the whole idea that we can employ the relativity principle, and arbitrarily exempt something like light from it, for simplicity sake, is fundamentally flawed.
This has no meaning under relativity theory, or for that matter any of the alternatives.space and time from the theoretical framework of light
Not necessarily so. Velocity might be specified relative to a frame of reference, but it just might by chance be the same from one frame to the next. PoR does not demand otherwise.You are using "relative" ambiguously, and you need to be careful not to equivocate. In the relativity principle, the motion of bodies is "relative" in the sense that velocity varies according to the frame of reference.
It is exactly relative in that sense. For one thing, a given pulse of light might be heading north relative to one frame and east relative to another. But the magnitude of that velocity would be the same, yes, which is exactly what you’d compute if you performed a Lorentz transform from one frame to another You find this fixed speed to be a contradiction, but PoR does not forbid it. It just says the rules of physics are frame independent. You cannot locally detect your motion in an inertial frame. If you can show how that could be done, then I’d accept that some kind of exception was being made. It could be done under Newtonian physics, and M+M tried to measure just that: a detection of local motion as the understanding of the PoR suggested at the time.But the motion of light is constant, "an absolute" in relation to the motion of material bodies, not variable or relative in that sense.
When you say ‘relative to light’, it is you that is using the term incorrectly. ‘Light ‘does not specify a frame, and you know that (or at least I hope you at least know that much).Therefore it is not "relative" in the sense of the relativity principle. So when you say the motion of light is "relative to material bodies" you are using "relative" in a way other than it is used in relativity theory, because every body regardless of its relative motion (according to relativity principle) is essentially at rest "relative" to light.
OK, I choose a roller-coaster track in a circle, and the frame where that track is stationary. We pack it with cars with no space between them. Then we get them going around the track together, and due to length contraction, spaces form between the cars. Are you going to tell me that there is an observer somewhere that doesn’t measure these spaces between the cars? That’s what I mean by the effects (length contraction in this case) being real, not just coordinate effects.I'll try anyway. To put it simply, the observer chooses the frame, so "frame effects" are observer effects.
Not even then, but motion would admittedly be pretty meaningless in a universe where time itself is meaningless.By the principle of relativity no body can be truly at rest unless all bodies are at rest. — Metaphysician Undercover
Sounds like you’re now in denial of what an inertial frame is, perhaps suggesting that any inertial frame with something moving (or accelerating) in it isn’t a real oneSo "inertial frame" is a sort of arbitrary designation requiring only constancy, uniformity.
The principle does not define ‘rest’, and certainly does not suggest that there is but one rest frame, a direct violation of the principle.Motion which stays the same as time passes is the principle of relativity's "rest".
OK, this is pretty much rhetoric from the relativity denialist literature. You’re entitled to this opinion, but none of this is part of relativity theory.And as you say, the motion of light "c" is relative to any inertial frame. But "inertial frame" is a feature of the theory, it is a theoretical observational tool derived from the uniformity observed in the passage of time. What defines the "inertial frame" is the uniform, constant passage of time.
OK, so where should light be at the rate of one hour per hour (just guessing at the rate)? IOW, what the heck does that statement even mean? What if time passed at one second per day? How would that affect where goes or what we see?Therefore the speed of light is not grounded in, or relative to any material bodies, it is relative to the defining feature of the "inertial frame", which is the uniform passage of time.
Yes, so we either have two or more worlds in a box, or they’re not really worlds. Either way, it’s different than there being just one state and we just don’t know.I thought that superposition is a fact and not just a hole in our knowledge. — Agent Smith
Ouch. It would really such if nature allowed such approximations. I’d always envisioned pure mathematics behind the physics, not digital mathematics where all numbers are representable with finite states.Any irrational number can be approximated to an arbitrary degree of accuracy by a rational number. From the associated paper: — Andrew M
The discussion was about observer effect (the observer causing effects), not observed effects (effects merely noticed by the observer), Relativity effects seem to fall under the latter category, prompting my foul call.Yes, it is quite different. As is the effect you mention of a clock travelling fast towards you that appears to be ticking faster than it is. Perhaps we can call them (classical) perceptual effects, (relativistic) frame effects, and (quantum) measurement effects to disambiguate them for the purposes of this discussion.
Not sure what this is. Got a link for this one?A related test has been carried out at a microscopic level (using photons instead of AI's) where it was shown that physical collapse does not occur.
Ouch. It would really such if nature allowed such approximations. I’d always envisioned pure mathematics behind the physics, not digital mathematics where all numbers are representable with finite states. — noAxioms
Geometrically, the square root of 2 is the length of a diagonal across a square with sides of one unit of length; this follows from the Pythagorean theorem. — Square root of 2
The discussion was about observer effect (the observer causing effects), not observed effects (effects merely noticed by the observer), Relativity effects seem to fall under the latter category, prompting my foul call. — noAxioms
"A related test has been carried out at a microscopic level (using photons instead of AI's) where it was shown that physical collapse does not occur." - Andrew M
Not sure what this is. Got a link for this one? — noAxioms
In a state-of-the-art 6-photon experiment, we realise this extended Wigner’s friend scenario, experimentally violating the associated Bell-type inequality by 5 standard deviations. If one holds fast to the assumptions of locality and free-choice, this result implies that quantum theory should be interpreted in an observer-dependent way. — Experimental test of local observer-independence - Proietti, et al., 2019
Yes, so we either have two or more worlds in a box, or they’re not really worlds. Either way, it’s different than there being just one state and we just don’t know.
OK, they’re not actually going to do it with a cat because there’s no way they’re going to get a live cat state to interfere with a dead cat state. The cat may be both dead and alive in the box, but superposition is more than that, requiring some sort of interaction (interference) between the two states. — noAxioms
Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics.
Please elucidate the training program in metaphysics I would need to complete to be considered competent in metaphysics. Be specific as possible. — jgill
Suppose I am a typical Q-physicist, following the mathematics but paying little attention to authorities in my subject babbling woo about interpretations. Please elucidate the training program in metaphysics I would need to complete to be considered competent in metaphysics. Be specific as possible.
Would I need to attend the University of Metaphysics? Would a bachelor's degree be sufficient? — jgill
Not quite. All motion can be specifed relative to a frame, specifically an inertial frame. Light speed is specified relative to (and is fixed only relative to) any inertial frame, so it isn’t an exception. — noAxioms
You seem to see an exception when I don’t. Mathematically, how does this work? — noAxioms
You seem to see an exception when I don’t. — noAxioms
It is exactly relative in that sense. — noAxioms
Sounds like you’re now in denial of what an inertial frame is, perhaps suggesting that any inertial frame with something moving (or accelerating) in it isn’t a real one — noAxioms
OK, this is pretty much rhetoric from the relativity denialist literature. You’re entitled to this opinion, but none of this is part of relativity theory. — noAxioms
OK, so where should light be at the rate of one hour per hour (just guessing at the rate)? IOW, what the heck does that statement even mean? What if time passed at one second per day? How would that affect where goes or what we see? — noAxioms
I would say any university with a good philosophy program, and adequate courses in metaphysics. — Metaphysician Undercover
Introduction: what is metaphysics? An introduction to the distinctive character of metaphysical questions: the history of the idea of metaphysics, understood as the most general and abstract inquiry into the nature of reality.
Existence: what is existence? What is it to exist? People disagree about what exists; but how can we understand this disagreement? Are there things which do not exist?
Universals and particulars: in addition to particular objects and events, our world seems to contain general or universal features of things, like their colours and their shapes. Is this an illusion or does the world really contain such features, known as 'universals'?
Realism and idealism: does the world exist independently of our minds? Realism is the view that it does; idealism is the view that reality is mind-dependent. Are any features of the world mind-dependent?
The freedom of the will: we think our actions and decisions are free, or up to us, but this idea seems to be in conflict with the apparent fact that everything which happens is determined by what happens before it (this is known as 'determinism'). Does determinism imply that free will is an illusion, or are free will and determinism really compatible after all?
Cause and effect: what is it for one thing to cause another, or to make something happen? Is there more to cause and effect than the mere regularity of things happening after one another? If so, is causation a physical process, or is mental causation also possible?
The nature of time and space: what are time and space? Is there no more to them than the temporal and spatial relations which hold between events and objects? Or should they rather be conceived as the 'containers' in which things exist and events occur? Are the past, present and future genuine aspects of reality, or are they merely 'subjective' features of our experience of time?
We strongly recommend that you try to find a little time each week to engage in the online conversations (at times that are convenient to you) as the forums are an integral, and very rewarding, part of the course and the online learning experience.
I encourage any Q-physicist reading this post to consider enrolling in this course. — jgill
I encourage any Q-physicist reading this post to consider enrolling in this course — jgill
... where all numbers are representable with finite states. — noAxioms
We may still be able to have a precise geometrical representation. — Andrew M
I can still express the length √2 with two characters, a very finite state. Humans deal only with such representable numbers, and they’re countable. Actual numbers in nature (such as the ratio of the half lives of two specific isotopes) are not in this countable set. I have a hard time with a model of the universe that requires only the former sort of number, such as one would get in a simulation. Actual numbers are more analog, like ‘so big’ with your hands held apart.
Maybe it does, such as if our universe is digitally simulated. In this case, the amplitudes of the split beam would not be √2, but close.Nature doesn't encode a digital representation of that number
Going to get back to you on this one. Interesting read, but the introduction is already full of interpretation dependent assumptions, such as counterfactual statements. I will look at it from my relational perspective which doesn’t make those assumptions, but thus far I’ve not read enough to really comment on it.In a state-of-the-art 6-photon experiment, we realise this extended Wigner’s friend scenario, experimentally violating the associated Bell-type inequality by 5 standard deviations. If one holds fast to the assumptions of locality and free-choice, this result implies that quantum theory should be interpreted in an observer-dependent way.
— Experimental test of local observer-independence - Proietti, et al., 2019
There’s actually no empirical difference between those two cases. There is if there was a true superposition, but there isn’t in the cat case. It’s been demonstrated with macroscopic objects, but under conditions which would kill any cat (such as being in a vacuum and almost 0°K).I'm just surprised that the statement that describes the Schrödinger =n isn't that of ignorance (The cat may be dead or the cat may be alive, we don't know) but of knowledge (the cat is both dead and alive, we know). — Agent Smith
I guess so. I would have said it is an abstraction, an assignment of coordinates to events.An "inertial frame" is a theoretical derivative. — Metaphysician Undercover
This is nonsense. You have a reference to such a crazy definition from a consensus physics reference from the last century? What even is uniform existence? That a body must be the same everywhere? A carrot cannot taper? I presume you to be an absolutist and maybe get your definitions from the sites supporting such, but this is not the consensus definition as used by physicists.It is derived from any situation with a body assumed to have uniform existence.
perhaps suggesting that any inertial frame with something moving (or accelerating) in it isn’t a real one — noAxioms
Case in point.To speak of an inertial frame with something accelerating "in it" is just deception.
No, not at all. I can for example reference the inertial frame of Earth when referencing the twins scenario. No duration is specified or necessary when identifying that frame.Do you agree that the passage of time is an essential aspect of the concept "inertial frame", a duration of time is necessarily implied by "inertial frame"?
There were lots of basic topics covered, down to interpretations of time near the bottom, but I didn’t see quantum interpretations mentioned at all, which requires probably a whole separate course.I encourage any Q-physicist reading this post to consider enrolling in this course. :cool: — jgill
Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.