I'm sitting at the dining room table eating lunch, when I get the feeling of being watched. I look around, and see the dog across the room, curled up on her pillows staring at me. She's quietly chanting to herself "I get stuff. I get stuff. I get stuff."
"You're not trying that hypnosis thing again, are you?" I ask. "You know it won't work."
"No. I'm manipulating the wavefunction of the universe to bring me good things. Such as, for example, that cheeseburger you're eating."
"Really. Manipulating the wavefunction of the universe?"
"Really. You see, all conscious beings are surrounded by an energy field that can be manipulated to attract good fortune. If you just focus your mind on good things, you can get good things, by collapsing the wavefunction through spooky action at a distance."
"That's ridiculous. No more late-night tv for you."
"But it's scientifically proven! Because of quantum." She pouts.
"That's not quantum mechanics, that's just gibberish."
"Are you denying that consciousness plays a role in quantum physics?"
That catches me a little off guard. "Well..."
"Ha!" she says, "I knew it!" She wags her tail smugly.
"I'm not admitting to anything. It's just that the relationship between consciousness and quantum physics is complicated."
"Everything in quantum physics is complicated."
"OK, sure, but consciousness is especially complicated. There are people who hold that our consciousness originates with quantum phenomena in the brain, and other people who would say that it's pretty much incidental to the whole thing. There's essentially no evidence either way, so it's a very fluid thing."
"It requires consciousness to collapse a wavefunction, though, right? I read that in one of your books."
"You're not going to win any debates by citing Greg Egan novels to support your position. And, anyway, the answer to that depends on who you ask. There are multiple interpretations of quantum mechanics that hold that there's no such thing as the collapse of the wavefunction."
"Oh, right. Many-Worlds and that stuff."
"Exactly. Now, consciousness still plays some role in that theory, in that our brains become entangled with the various measurement outcomes, and thus we perceive different results in different branches of the wavefunction. But the heavy lifting is really done by decoherence."
"The tricky part of any interpretation of quantum theory is coming up with an explanation for why we don't see quantum effects for macroscopic objects. In most modern theories, that's done through the process of decoherence, in which unmeasured interactions with the environment cause shifts between the different parts of the wavefunction so that we can't see macroscopic objects interfering with each other. They do interfere, but we can't build up an interference pattern through repeated measurements, because environmental interactions are always shifting things around, so there's no way to tell."
"Well, ok, but what if the collapse people are right?"
"Even in an interpretation with collapsing wavefunctions, decoherence takes care of most of the problem. Decoherence explains how you get a system from a superposition of being both here and there, to a mixture of either here or there. That's most of the work right there-- the problem of choosing which outcome we actually see is a small detail compared to that."
"Okay, I guess. But what about quantum causing consciousness? How do you explain that?"
"I don't, because it's not really a mainstream theory. There are people here and there who believe that what we perceive as consciousness is the result of quantum processes taking place in the brain. The most famous proponent of this is Sir Roger Penrose, a famous British mathematical physicist."
"Well, there you go. If he's famous, he must be right."
"He's famous for other stuff, not this. Really, the notice he gets for the brain stuff is probably closer to 'notoriety' than 'fame.'"
"What do you mean?"
"Well, my impression of his argument is that there's not much to it beyond saying 'We don't really understand quantum physics, and we don't really understand how consciousness works, therefore, the two must be related.'"
"That sounds convincing to me."
"Yeah, but you're a dog. You probably think cats have something to with it, because you don't understand cats."
"Cats are tricksy. We don't like cats."
"Yes, I know. The point is, that's not a very convincing argument. There's some stuff about small structures in the brain that might be on the right scale to have quantum processes, but that's awfully thin. I don't know anybody who takes it all that seriously."
"Oh." She looks disappointed. "So, what's left? How is consciousness related to quantum physics?"
"Beats me. I suspect it isn't, at least not in any grand, universe-changing way. My personal pet metaphysical theory is that quantum mechanics accounts for free will, by adding a tiny element of randomness to our brains and preventing us from being wholly deterministic biological automata. But then, I don't have any more evidence for that than Penrose has for his stuff. I just like the sound of it."
"Yeah, whatever. Very poetic."
"Look, I'm sorry to burst your bubble, but all that 'Law of Attraction' stuff is a bunch of crap. There's no mystical quantum energy field permeating the universe that you can manipulate through the power of positive thinking. You can't cause the universe to bring you cheeseburgers just by wanting them badly enough. Anyone who says differently is a scam artist."
"And we shouldn't give money to scam artists." She perks up a little, God knows why.
"That's right. You're a very good dog." I turn back to my burger, which is starting to get cold.
"It's good that I didn't give them money, then."
"Pardon?" I say, with my mouth full.
"The people from The Secret. I didn't give them money."
"OK," I say, still chewing. And then, just as I start to swallow...
"I used your credit card," she says. "It's free for a month!" I choke on the burger. As I reach, coughing, for a glass of water, I fumble the half of the burger still in my hand, and it falls on the floor. Like a flash, she pounces on it.
"I get stuff!" she announces, happily chewing.
This post is a much-delayed pay-off for a DonorsChoose donation back in October. Thanks again, Ewan. I hope this was worth the wait.
Do you want a real burger? You can't handle a real burger! Carl's Jr. Six Dollar JalapeÃ±o Burger. You can swim in it. Rivers of steaming saliva will casacade down your chest.
The New York deli-esque greasy fries are a perfect accompanyment. Capsaicin is lipophilic.
Aw I love these posts! <3
I loooooooove these posts!
But you were not nearly hard enough on Penrose. What you said was correct, and you did not give him any ground, but he really deserves a swat on the nose with a rolled-up newspaper. Microtubules : Penrose :: Pineal Gland : Descartes.
The time scale is off by a factor of billions, and unless quantum effects are meaningful at the level of synaptic vesicles, the size scale is off by many orders of magnitude as well (how many, I am not knowledgeable enough to know. I know the neurobiology, but not the qm)
I would love to see a debate on consciousness and qm between Penrose and the Queen of Niskayuna. My money is on Her Majesty.
As corrective to previous practice, I will remain respectful, more or less humble, and impersonal in this critique of decoherence as a putative explanation (or close to one) of "collapse of the wave function." First: I take it that the object is to avoid the oddity of a special break in ordinary SchrÃ¶dinger evolution, by saying the waves continue to evolve and there is no special, inexplicable intrusion of "R" the reductive physics involving statistics of hit from privileged "detectors", cats either living or dying (but not "living and dying" etc.) I note that my misgivings are shared by Roger Penrose, and for basically the same reasons - see his Shadows of The Mind at relevant places. Also, his critique of decoherence is not to be confused with his ideas about mind and QM.
So, we are starting with "waves" and trying to get from being spread out to being "somewhere." But muddying up the phases of waves doesn't makes them any less waves, any less spread out etc. at any time. The rather abrupt localization at a particular place is the whole point and problem. It is "detector behavior" which does not come naturally out of anything about waves, coherent or incoherent, and which violates the principle of sufficient reason (why A and not B, etc.) Consider classical wave evolution, as e.g. Maxwell's equations and supposedly retained in the SchrÃ¶dinger evolution for collapse-avoidance schemes. The wave amplitude is a given value at each point in space and changes according to rules. There are no "statistics" for EM waves per se, regardless of whether they are mutually coherent enough to clearly interfere or not. Why would there be? Charges will be jiggled here and jiggled there, but none of them has the classical power to "grab" the energy of a wave and suck it into themselves.
I see no rational, "coherent" (in the general logical sense) way to even explain what it means for a wave to be "here or there" instead of "here and there." Sure, once something that was originally spread out as a wave does collapse/localize (the abrupt capture of a spread out particle or quantum of energy by a detector.) The wave cum particle is no longer in both places, but that's what we are trying to "get to from below." It is a circular argument to slip that sort of thing in the back door to start. We need to explain collapse to start with, not use collapse to pretend to explain itself. Waves just don't have "or" and localization built into their math directly. It seems like they do, only because we are already used to collapse happening and taking the other location off the table. It's not a property of the waves themselves, and can't be. I see no other way out than either "objective collapse" or the much maligned "consciousness" notions, or maybe our world isn't "real" anyway and this Matrix-like "simulation" just has weird rules. Whatever, but I won't take a false IMHO way out.
Yes mixtures have a different statistics than superpositions. But again, that's only because there's an outside imposition to "break the symmetry" and force "statistics" that are "put in by hand" as patterns of hits here and there - a statistics that otherwise wouldn't appear, as I said. (Note: statistics is not in the math of amplitudes etc. themselves. That feature refers to "probabilities" PIBH from the squared amplitudes, a feature that again isn't a rational part of SE, but is contrived after the fact from what collapse forces us to find.
Now if we muddy things up in a density matrix (only because we don't know just exactly what composed that WF, that does not necessarily describe a new kind of "object in nature"), we simply have substituted vague values (maybe just because mere people don't know any better) for a range of possible values of amplitudes. In such a case, the resultant amplitudes from superposition would be similarly vague. (Amplitudes superpose, period, true? If we don't know just what were added, so what? The principle of the thing is the same, and they are still waves.)
Just think of classical E&M antennas radiating without well-defined phase - that doesn't make a particulate character for the waves, there's nothing about "waves" that would be more particulate or localized than if the antennas were in perfect phase. What is called a "mixture" only has different "statistics" because collapse leads to a different pattern, but again: without collapse PIBH there wouldn't be any statistics anyway.
Here's an "intuition pump": consider the light coming from an "incoherent" source, such that genuine interference isn't possible. Do you really want to say, that "particles" and not waves are coming from that emitter? Some are tempted to say that question isn't "real" because we're just talking "observations." (But I thought that WFs *were* supposed to be real in deco, they just didn't ever "really collapse"? - Deco isn't supposed to be a form of "shut up and calculate" is it?) But in any case this "incoherent radiation" of a filament still acts like waves: we can focus it with lenses and the image outline will still be "diffraction limited" in detail, there will still be diffraction around edges of shadows, etc - they just won't be as nicely "fringed" as from a coherent source.
Yes, entanglement comes in somewhere but there seems to be two sorts, which mean different things. One is the weird "Bell" kind in which there really isn't a definite state of polarization for either of two or more entangled photons - until a "measurement" picks out a state for one of them, and the other has to correlate in the special strong way. But I hear in decoherence discussions, a more "banal" sort which seems simply the unsurprising (and not "strong" I suppose?) correlation that "being there and being detected there" is "entangled" with "being here and being detected here" but not in a way which violates local realism, etc per having a *definite local state* of the WF. This is the part I'm least clear on, so I may well have not hit the spot on that.
I'll pass on long critique of MW, but leave the simple point that how could a "split" provide for say, 70/30 break in chance for two outcomes? How many "worlds" to get proper statistics? Finally, if I misunderstood the point of decoherence - to whatever degree - well then, what is that point - in any sense I didn't already cover? Tx.
Sorry, I should just say "range of values" for a DM. "Vague" isn't really a good way to put it (implying use of "sort of" language etc.), even if that is a good slang way to refer to it not being a definite amplitude. It is of course an actual distribution, in the math, regardless of what "nature really is".
You're talking about the mathematics of waves in the far field. The infinite plane wave is the archetype, and you're right about that not being local. However, make a superposition of lots and lots of frequencies, and you get something localized in time and space. Physicists call them wave packets. Geophysicists call them wavelets. The mathematicians call them linear combinations on a basis of sinces and cosines (or other bases, such as the wavelets made famous over the last 10-15 years, which isn't the same thing the geo people refer to as a wavelet.) I don't know what the electrical engineers call it, but as a group they seem to be the highest masters of Fourier in practice: Green's functions and convolutions and signal processing for fun and profit. All this,entirely classical, well before quantum mechanics ever shows up to the departmental christmas party.
Chad, the ending felt predictable, and yet you worked in an entertaining surprise twist. Bravo!
Right on! The ridiculous notion that consciousness is a quantum effect, even though QM is not needed for ANY neurological model to work, gets my blood boiling every time.
Then there's this other thing where the perception of an event by a consciousness is supposed to be the reason for decoherence - a line of thought that's even supported by some otherwise intelligent physicists who seemingly don't get that the collapse happens at the moment of interaction, whether there is a conscious observer present ot not.
Somehow, in this day and age, there are still "scientists" who believe a falling tree doesn't make a sound when there's no human in the forest to perceive it. How come we let people still get away with this?!?
On a personal note, I'm one of the "the universe is basically just information" people. I think it's reasonable that object properties are defined just-in-time, at the moment when the object is used, meaning when it participates in an interaction where that property is needed. Mystery solved.
OK, I'm a computer scientist, but if was to implement a universe, that's one way to do it and it's exactly the way those superstates seem work in reality as well. The idea that consciousness is required at any point for this to work is just insane.
Agm, you're missing the whole point. Of course there's a "wave packet" in the case of particles with mass, but that's still a superposition of different waves and does not directly exemplify or explain a "statistics". That's the "SchrÃ¶dinger wave" that evolves according to a deterministic formula. Note that is *spreads out over time* because different momenta correspond to different velocities, so it gets less "particle like" over time, not more. A photon keeps it's longitudinal extent (all going at c) but still spreads out over space, like an expanding shell or beam.
The still unexplained problem is, the "collapse" of that sort of thing when it reaches say, two widely-separated detectors. Then "bang" there's a click in one detector, and can't be in the other one anymore. Then it can start over again as a small "packet." (So indeed, ironically, the "wave packet" is only small from it being either genuinely measured/collapsed or created just recently.)
Mixing waves can alter the distribution, yes. But that doesn't explain the detector behavior, response to measurement, thus "statistics" etc. that is the problem of "collapse." When I said "localize" I meant in that special and extreme sense, as of a single atom plucking the energy of a wave out of space to suddenly in that atom. By (just before) then, the wave packet could have spread out to being light-years across.
To make it simple: whether waves are mixed together coherently or incoherently, so they can interference or not, no "statistics" comes out of that unless imposed in the mysterious "collapse" way. There is no statistics intrinsic to wave evolution, for momentarily localized packets, or big messed up jumbles of many waves, or nice very long monochromatic coherent waves. It just doesn't get you to statistics. Collapse makes for statistics, not statistics for collapse. The statistics can't be used in a backwards pseudo-explanation of themselves.
Also, consider the decay of supposedly "structureless" muons at an unpredictable moment. There is nothing in there to interact or be in or out of phase with anything else, so I don't see a role for "decoherence" in the decay itself. Indeed, it is logically absurd for a structureless entity to do anything at all without outside stimulus - there is no "clock" or even an unpredictable type of clock to count time or evoke causal outcomes. But it does happen, because our world is just "absurd." That's the way it is, there's no point in our trying to evade it with comfortable stories that don't really work IMHO.
Udo, I'm not sure what you mean by "the collapse happens at the moment of interaction, ..." Are you aware of what the collapse problem is all about? Have you read about "SchrÃ¶dinger's cat" etc? The whole reason is that "interaction" is absolutely not supposed to collapse wave functions, they are supposed to continue to evolve with their original superpositions intact. As I explained, jumbling up phases does nothing to pull the WF together, wipe out the "lost possible outcomes/states" - it doesn't accomplish anything at all except just spread waves around in different distributions than before.
The early thinkers who appealed to consciousness (great and candid thinkers like von Neumann) were doing the best they could to find a way out of something that just didn't make sense (and really, still doesn't.) They didn't appeal to "detectors" directly because what makes a "detector" special?
As for the reverse idea, that QM affects/generates consciousness, that is not so silly. The brain is full of fairly free electrons etc and their uncertainties might well be a factor in just when a brain cell fires. Given the delicate "butterfly" type way in which a tiny variation could effect outcomes of such a complex, chaotic system, QM is a credible factor. Complaining on the basis of whether whole nerve cells, tubules etc, are proper "quantum objects" is as silly as thinking there's no QM about superconductivity (or indeed, plain old magnetism) because the whole piece of metal is too big.
I probably should not have left the basis of my reply implicit.
Quantum mechanical objects. Are. Not. Waves. Neither are they particles, but we see them as one or the other depending on what we do to them to investigate them. Schrodinger's equation is not the wave equation. Their solutions are quite similar in many ways, but they are also different in fundamental ways, containing different physical meaning on various levels.
The view you put forth, and especially your reply, treats quanta as if they are exactly the same as waves (i.e., solutions to Schrodinger's eq and the wave equation are the same), but that at best only approximately correct physically and mathematically. The world is more than harmonic oscillations done up in newer, prettier clothes.
A wave packet can be small because the superposition for a reason other than you cite -- adding up lots of waves that only constructively interfere in a small region of space, and the integrals extend over infinite sets of frequencies, and energy conservation would be violated if wave packets weren't small in time, and this is true in both classical and quantum physics. You can then introduce probabilistic behavior to the description by randomly varying the phase due to interactions over the path length, or recognizing that a source will behave randomly as well when emitting a quantum in time, and in other ways. Individual solutions to Schrodinger's equation (or the Dirac equation, etc) are deterministic, but they can vary randomly then in space and time.
En masse the objects represented by these solutions obey probability distributions based on the physical properties of what the solutions represent, and this is a different type of probability altogether than just varying phase.
"Cats are tricksy. We don't like cats."
I didn't know Emmy channels Gollum ...
My personal pet metaphysical theory is that quantum mechanics accounts for free will, by adding a tiny element of randomness to our brains and preventing us from being wholly deterministic biological automata.
How does the randomness make room for free will?
A familiar example of a situation in which there is no free will is a 'forced move' in Chess: the move can be determined from the board position and the rules of the game. But it seems strange to say that a move in 'Snakes and Ladders' has anything more to do with free will just because it also involves the number rolled on a die.
Now, confessing my ignorance: I understand that events at a quantum level are random in a different way to the roll of a die. But I don't understand enough about this kind of difference to see how it helps the cause of free will.
No matter how much you dress it up with science, 'The Secret' stll doesn't work.
Agm, you (anyone welcome to step in) have a point about QM objects, although the fact that they aren't "just waves" is closely tied to what "collapse" does to the waves. BTW, I heard "there is no collapse, the SE just keeps on evolving" from Deco/MW supporters, so I'm taking their word for it - pls. REM the "self-consistency line of attack." Also, it doesn't simply depend on what we do to examine QMOs at the final stage of detection. If you are any kind of "realist" not SUAC, then they "must have been waves" meanwhile in order to produce the results they do when finally detected, and you must wonder "what happens to that wave, why and how" etc. Note the issue includes things like being focused by lenses, not just diffraction and interference. I accept that they "are both particles and waves", but not an IMHO deco' circular argument that introduces the very "statistics" in the back door it is supposed to explain - IOW, how do you get the waves to become the "particles" we do observe that way? And how does the cosmic Buridan's Ass (look that up) pick detector A over detector B, maybe millions of km apart? What was "out there" before the hit, what is "out there" afterwards? And we have the same picking and localization problem for coherent waves in an MZ etc. - what "collapses" them? (See also "Renninger measurement" for another twist!)
Like I said, waves only lead to "statistics" because collapse makes them appear in that granulated way - the collapse itself remains mysterious. (BTW I didn't make it clear earlier, that problem applies to the issue of superposed states of the detectors themselves. The environmental effects are supposed to enable decoherence to cause "the appearance of collapse" but it's still really the same basic problem as for the QMO waves to begin with, as earlier "Cat" puzzlers realized. Entanglement may be an issue, but you still need imposed collapse to force which possibility "manifests" - whether independently, or correlated across space.)
As for "randomness" in the wave itself: I'm not sure what either you mean or Nature Herself is doing with that. That gets to the heart of what a density matrix is. First, I well appreciate that the wave could be subject to various influences, like a charged particle's wave in an E field (yeah, I forgot to say that "classical waves" are non-interacting: they have rules about how dE/dt leads to Curl B etc., but they don't affect "each other" as such. But added interaction doesn't furl their "waviness" unless some weird business comes in to do it for them.)
Second: there are basically two ways to look at "uncertainty in the wave itself", and neither derive "statistics" or "collapses" per se unless that's "PIBH." One way is that we don't know just what the real amplitudes are (if we believe there's an "are" out there at all.) So we might have a range of possible values, and it doesn't have to mix orthogonal states, true? But let's say, the definite polarization angle (amount of |x> versus amount of |y> in the wave is unknown to us. Maybe I ran an unknown photon through a sloppy filter that passes "100"% of |x> and 25% of |y>, so now I'm not sure it will pass a second |x> filter. Hence I can refer to a mixture of |x> and |y> states. It's sort of like "tolerance" for manufactured items, here with theta = 0 +/- 14 degrees.
Now, I can imagine either that the wave "really is" in an orientation that I can't find, or I can imagine it is literally spread "along a range of values." But in neither case do I detract from the wave nature, the active standing of the basis states, nor do I add some sort of "granularity" that wouldn't still have to be popped in there the same as for "coherent waves." If the latter, one can imagine a sort of "range number" that can add to other "range numbers": such as 2~3 + 6~9 = 8~12 etc. Per the latter idea, I still can't imagine what a literal "range" in WF amplitudes is supposed to be, but if the universe is that weird so be it. But nothing is made any more intrinsically "statistical" out of that as such. That's why "R" represents a mysterious break in the description.
Maybe it's a semantic undermining of people's thinking. The idea of "It could be state s1 or state s2" gets imagined as an actual concurrent "or" of the thing: it's somehow both but they aren't "together" in space. But that doesn't equate to either logical way to imagine indistinct WF properties. Whether coherent or incoherent, definitive or over a range; what starts as a bunch of waves stays just a bunch of waves. You still don't get "statistics" unless you force them in there. (I said "starts as" to again cover your complaint of QMOs being both - sure, but it's getting from one to the other that's the problem.) Collapse leads to one type of statistics for coherent, another type for incoherent etc. however you string along the original object, the detectors, the environment, etc - but only once you have collapse to begin with. The explanation doesn't work the other way around. The original geniuses of QM realized that, why should I believe they were dumb?
SchrÃ¶dinger's Cat sez: Can I haz cheeseburger and eat it too? We still don't know why he can't!
I am declaring the argument in this thread over. If you would like to continue to discuss quantum measurement issues, I have a new post and comment thread set up for that purpose.
Further comments on this subject in this thread will be disemvowelled. If you want to talk about the dog, or consciousness, or some other aspect of quantum theory, that's great, but the quantum measurement stuff stops now.
Correction: the DM for the 100/25 filter is not like dimensional tolerance, since we could indeed get a y-axis value if that's what entered the filter to begin with. Rather, the chance of |y> is only 1/4 of that for |x>, etc. That doesn't detract from the essential point about DM and statistics.
As for free will, and here I do agree with the OP: The attraction of QM for real "free will" is that its probability is not "classical". Like I said, it is logically absurd for a structureless entity to "break up" with no internal clock to generate this behavior- yet that's what Nature does. (Or maybe there is a "string" in there, but still- if the string were deterministic, then we could in principle create or segregate inherently shorter or longer lasting muons, which is not supposed to be possible. Even natural processes could hardly create the right "mix" to simulate "real randomness" for such entities.)
Now, we don't consider the single particle to have "chosen" but since our brains are made of "uncertain things" their coordination may somehow partake of that special character, such that we face doing or not doing, and nothing can explain or even describe even in principle the way in which we "pick" what we pick. That can even be part of the "responsibility" issue, since the coordination yet unpredictability literally "is" me, I am not "made to" by it. (The latter I call the "fallacy of the passenger homunculus.") Note my counter to complaints "No QM effects for the brain" - they're as silly as saying QM isn't a factor in superconductivity just because entire coils aren't like QM objects as a whole.
By some chance, have you ever seen the movie "What the Bleep Do We Know?" The movie speaks mostly about the relationship between consciousness and quantum mechanics, mostly through what seem to be shoddy and unscientific experiments, and then somehow connecting this whole thing to religion. My high school physics teacher absolutely loved it. I, on the other hand, thought it was total garbage. Maybe I should send this post to him.
Regnirrab, most physicists don't like WTBDWK AFAICT. They think it's too psychobabbly "woo-ish", but I haven't seen it so I don't have an opinion. BTW if you don't mind, if that's your real name may I ask what national origin?