IANAPhysicist. So I may not fully understand quantum physics. But as I understand it, according to QP, the world exists in multiple realities, until a human observes or “measures” it. That in fact is what that experiment involving Schroedinger’s cat all about.
Anyway, I find that very hard to believe. But again, IANAPhysicist.
There’s a couple of reasons, though, why I doubt it still. I know when I leave a room, and come back, everything is exactly where I left it. OK that’s not much. But there’s more.
It seems to me, there are certain times when I am not using my conscious thought as such. Like when I am asleep, for example. And that doesn’t seem to affect anything.
And then there is this experiment I do. I am next to a wall. And I close my eyes, deliberately making sure I don’t know where the wall is. Then I slowly extend my hand, deliberately not expecting to find anything. My hand still eventually bumps into the wall.
What am I missing here? And what is wrong with the experiment? And while we are at it, could there be a better way to carry out an experiment like this (and preferably without killing a cat;))?
I await your replies and (constructive) criticisms:).
In the absence of measurement the wave functions of all the particles that make up your wall have a very very small non zero value everywhere in the universe, including the point 6 inches closer to your hand.
Your measurement collapsed them, and now they have (or had) a zero value at all the points you are not touching.
So did Erwin Schrödinger. He proposed this “thought experiement” to illustrate the absurdity of the Copenhagen interpretation and the presumed reality of collapse of the wave function as precipitated by the observer. For what it is worth, Neils Bohr did not strongly hold the opinion that observed wave function collapse was a real thing, and while it is often not stated explicitly in introductory modern physics courses when covering quantum mechanics, the collapse of the wave function is really just a starting place for calculating the effects of quantum mechanics. No one has ever observed a fundamental quantum particle in superposition and the resulting collapse because it is literally in contradiction to the interpretation, and many physicists expect that the actual rules of quantum mechanics involve principles we have yet to fully understand.
My personal preference is for the Bohmian interpretation which is entirely self-constent in having a deterministic reality but requires having non-local connections or non-local hidden variables which makes a lot of people very angry despite matching predictions and experiement observations of quantum entanglement.
Nitpick: There’s no requirement that the observer be human, or even conscious. Anything, such as a particle detector, that observes in the macro world will do.
One thing you aren’t understanding is that “observation” as used in QM does not mean “observation by a conscious being”. What it really means, more or less, is “interaction with another particle”. This is one of those times when scientific terminology is misunderstood by many non-scientists. It leads to a lot of strange woo.
Yeah, but who detects the detector? If they’re all just collections of quantum particles then who is to say taht they aren’t in a state of quantum superposition until I come along and observe it? Maybe I’m the Universal Privileged Observer and the rest of you are just results of the wave function I just collapsed right now! Prove me wrong!
And judging by the effect that Feynman videos usually have on people, now you still don’t understand it, but you realize that you don’t understand it, and know what exactly it is that you don’t understand, and have come to an uneasy peace with that lack of understanding.
I have a claim. I want to check whether I’m on the right track in playing “Spot the Woo”".
My claim: A real-world application of quantum theory - that is, one in which quantum effects are used or harnessed or taken into account, to change something about me or my environment - is a contradiction in terms and can’t exist.
Am I just creating my own woo, by saying that? Or is there something to it?
Just plain meaningless. QM isn’t some curiosity that is only observed in the laboratory. The entire known universe as you see it depends upon QM to work the way it does. All of known chemistry is an application of QED. No QM, no nuclear physics, no burning sun. No QM, no atoms. And so on. Making an application that changes something about you or your environment that doesn’t depend on QM would be essentially impossible.
The only real difficulties lie in how to make locality and causality fit with our understanding (or preconceptions) about how the universe works.
At the macroscopic scale the direct effects of quantum mechanics are not generally observable at an individual level, but as Francis Vaughan notes, quantum mechanics is required to explain the dual slit experiment or any number of phenomena we can observe in real world experiments such as stimulated emission and the corresponding coherence in light produced by a laser. There are other phenomena, such as cryogenic superfluidity in liquid helium or the behavior of a Bose-Einstein condensate which are distinctly quantized, and general electrochemical behavior is a result of the quantization of electron orbitals and energy levels, although at the level of practical chemistry with molar quantities (1 mole = 6.022x10[SUP]23[/SUP] particles) statistical mechanics and thermodynamics tend to average out individual interactions sufficient that individual quantum interactions can be ignored for convenience.
Local realism (locality) and causality are assumptions which we’ve developed from our everyday experience and underly the Einstein theory of gravity (general relativity) but there is no particular reason or evidence that they operate at the quantum level, and in fact there is pretty clear evidence from observation of quantum phenomena that one or both have to be dispensed with to make sense of phenomena at the level of fundamental particles. The overall behavior tends to mush out due to decoherence such that the everyday world looks causally connected and locally real, but then, water looks continuous and wood looks solid, and yet both are nothing but a cloud of closely interacting electromagnetic fields produced by electrons bound to a nucleus of baryons the configuration of which determines the resulting behavior of the fields, and everything we see are just photons flung away from these collections of particles. So…nothing is real in any sense that imagine it to be.
Firstly your understanding of quantum physics resembles a mix and match of a couple of different interpretations of quantum mechanics. It may be possible to, broadly speaking, interpret quantum mechanics that way, but it would need to be related to the mathematical machinery of QM.
Secondly it is not clear what you expect might be observed and the why behind such expectations. Without this it isn’t really of any value to comment on the specifics of the situation you have described.
Yeah, the frustrating thing about woo like “What the Bleep Do We Know” is that they attempt to show what a quantum world would look like, when we already know what a quantum world looks like: Just look around.
I read Wholeness and the Implicate Order perhaps two decades ago, and to be honest I couldn’t make heads or tales if he was just noodling around with metaphysics or had some deeper underlying point that I just wasn’t getting. More recently–well, within the last ten years–I’ve picked up The Essential David Bohm which is a collection of essays by Bohm largely about his notion of implicate and explicate orders, and I’ve gotten a bit more out of it but it is still a lot of philosophical meandering without defining any clearly objective phenomenon or test that could validate his notion of a larger interconnected universe in which thought and creativity are manifestations of quantum interconnectedness and some kind of universal subconsciousness.
Bohm always had a bit of a mystical streak about him (was also an advocate of Marxism which severely hindered his career and resulted in him going to the University of Sao Paulo) and became very interested in Buddhist philosophy and met several times with the Dalai Lama, and seems to be at least one of the roots of the frequent pop physics comparisons between Vajrayana Buddhism and quantum mechanics, but it hasn’t made much of a practical impact upon actual physics research because it hasn’t produced anything in the way of discriminative hypotheses between the Bohmian/pilot wave interpretation and other interpretations of quantum mechanics.
Even if it were somehow true that everything is part of an interconnected system with some kind of fundamental coherence and order, I’m not sure it really changes anything in a practical sense about physics or reality. We behave as if we are independent consciousnesses that have free will (even though cognitive neuroscience has pretty clearly demonstrated that our actual degree of deliberate decision making is far less than we generally believe), and any sufficiently complex system will look like ‘free will’ or ‘randomness’ even if it is based upon strictly deterministic principles.
“They may be pink, but their money’s still green!” –J. R. ‘Bob’ Dobbs, Figurehead of the Church of the Subgenius
I don’t know anything about that movie other than that it’s a bunch of nonsense, but this isn’t a completely unreasonable effort. We also live in a relativistic world, but we mostly don’t notice since the effects are small. One can make the effects more obvious by reducing the speed of light and seeing what happens. Likewise, one could play with physical constants to make QM effects more obvious.