Wave function collapse demystified

What evidence is there that the wave-function collapses? Maybe it's still there even when you detect the particle? Has anyone ever detected that the wave function was there, and then went away? Or is the whole idea an artifact of language? Last I heard, wave functions are not even measurable. So how would you know if it had collapsed if you can't measure it?

sorry, I meant to say an appearance of wavefunction collapse.

SOME THOUGHTS ON THE SUPERPOSITION OF STATES AND THE COLLAPSE OF THE WAVE FUNCTION

One quantum theory which IMHO is total nonsense is the collapse of the wave-function or the superposition of state concept and the requirement for an observer to resolve the superposition of state by collapsing the wave-function. This is usually illustrated via Schrodinger's cat. The cat is placed in a box along with a vial of poison, a hammer that can break the vial, and a radioactive substance that has a 50-50 probability of emitting a particle within one hour that will, if so emitted, release the hammer and break the vial and kill the cat. The question is, after one hour, is the cat alive or dead? The answer, via the Copenhagen Interpretation of quantum mechanics, is that until such time as some observer opens the box to see, the cat is both dead and alive at the same time. The cat is in a superposition of (dead and alive) states and only the observer will collapse the wave-function to reveal either a dead cat or an alive cat. Bull!

I would like to substitute a thermonuclear bomb for the cat. Can a thermonuclear bomb be in a superposition of states, that is both exploded and unexploded at the same time, which is until such time as an observer opens the box that contains the bomb, the hammer than triggers the bomb and the radioactive substance that, if it decays, will release the hammer that sets off the bomb? I would maintain that if the radioactive substance emits a particle that triggers the hammer to hit the fuse of the bomb setting it off, it would go off right there and then - ka-boom! The ka-boom wouldn't wait all contained in the box awaiting the observer to check! No thermonuclear bomb is ever going to be in a superposition of exploded/not exploded state.

Problem number two, going back to the cat, is that an observer checks after one hour and finds the cat either alive or dead. However, someone else outside of the room doesn't yet know and so that person still has a superposition of state cat. But when that person finds out, a third person outside of the building doesn't yet know and thus still accepts the cat as both alive and dead at the same time. And when that person finds out a fourth person a block away doesn't yet know and then a fifth person in another part of town, hence a sixth person in another city and a seventh person in another state, country, etc. and on it goes. You can drag this chain out to the very ends of the cosmos and to someone out back of the cosmic beyond, the cat will still be in a superposition of states. The wave-function will not have been totally collapsed nor can it ever be if the cosmos is infinite.

Problem three is that once upon a time in the cosmos, there were no biological observers to collapse any superposition of state wave-function. However, the cosmos got on just splendidly without them there observers. Observers were not, and are not, necessary to collapse a superposition of state wave-function for the obvious reason that the entire concept is total bovine fertilizer!

There's another reason why the concept of superposition of state is impossible. One could argue that everything is observing everything else 24/7/52. Observation isn't confined to sight, sound, smell and taste. There's also touch and not just sensation given by the immediate proximity of two objects, or even at close range (feeling the heat from a stove inches away), but at a distance - a very long distance.

If everything has mass then everything has gravity and thus via the gravitational force everything is 'observing' everything else. You are 'observing' the Moon even when you are inside your home and sound asleep. And the Moon is 'observing' you since there is a mutual attraction between the two objects - you and the Moon.

An electron 'observes' the photon that slams into it and kicks it into a higher 'orbit' and thus into a energy state or level. The photon 'observes' the electron as well.

The north pole of a magnet 'observes' the north pole of another magnet and both back off. But if the north pole of a magnet 'observes' the south pole of another magnet, well it's love at first 'sight'.

An electron can 'observe' another electron to 'see' if it is in the same quantum state as it is before allowing it to share its 'orbit' if not or disallowing it if it is.

The trio of quarks inside every proton or neutron 'observe' each other and know and react (via the strong nuclear force) when they are being pulled apart or separated.

Examples of these sorts of 'observations' could be extended within both the macro and the micro realms.

The upshot is, if everything is 'observing' everything else, if no 'man' (or any kind) is an island, then no superposition of state can ever form without being collapsed within less than a micro nanosecond.

Finally, with respect to the facet of quantum physics known as the superposition of states, perhaps things aren't quite as mysterious as they first appear.

Superposition of states is just a mental concept that has no bearing on reality. It is a way of enabling us to come to terms with lack of certainty whether you're wondering about where that electron is or what the next card to be dealt is going to be or what the fate of Schrodinger's cat is. Since certainty is normally the bedrock of our existence, we deal with uncertainty uneasily by looking at all the variations that are equally possible. But what is that one possibility that will ultimately be - we'd better check. Meantime...

IMHO, the electron is somewhere with precise coordinates even if you can't pin it down. It's not in two or more places at the same time. The next card to be dealt is fixed even if you never peek. Schrodinger's cat is not both dead and alive but dead or alive even before you open the box.

If you really believe there is a real superposition of states, then substitute Schrodinger's cat for John's thermonuclear bomb and be willing to stand by the box that houses and conceals that bomb for the duration. I maintain you'd be foolish to do that since a thermonuclear bomb cannot be both in a state of explosion and non-explosion simultaneously.

But if you seriously believe that a thermonuclear bomb can be in a superposition of states, then after a reasonable time interval has elapsed, you can scurry off to the bunker and send in a robot with a video link to open the box and see if the bomb is intact or not. I feel that will prove to be an unnecessary step.

Just like the concept of the superposition of states is an abstraction, a mental concept, the associated collapse of the wave function is just the mental satisfaction gained in resolving an either/or dualism or situation into an either this or that reality (or acceptance that resolution is beyond your means through no fault of your own). But in neither case is there a really real superposition of states or a collapse of any wave function.

EXTERMINATE THE OBSERVERS: EXTERMINATE, EXTERMINATE!

Quantum physics is a world where we're told that probability and uncertainty rule and causality is thrown to the winds. However, I think it's the observer that's the real fly in the quantum physics ointment. Left to its own devices, the micro (quantum physics) would (certainly should) mirror the macro (classic physics) and thus causality rules both realms. Whatever applies to the micro must apply to the macro since the macro is made up of the micro (and thus I feel free to sometimes use more familiar macro examples in the following text). It's the observer who is interpreting, albeit through no fault of her own, things as being in a state of uncertainty or as just probability.

An electron has mass. An electron can collide with other particles. Electrons travel along your copper wires, impact the insides of your TV/computer monitors giving you your pictures, and of course are the backbone of your nervous system and brain activity. That makes an electron to my way of thinking a little billiard ball. Just like a real billiard ball can be bounced around by other objects, and end up predictably in another place (the side pocket?), so too can an electron be bounced around by interactions with other bits and pieces. It's those bits and pieces, the photons that our senses can detect, all bouncing off and thus bouncing around electrons, photons that ultimately bounce into our eyes, and thus tell us where the electron is and how it is moving. Alas, that same photon that conveys to us that information has also bounced the electron off on some other path at some other velocity, so we're still none the wiser about where the electron is. It's uncertain, but it's probably somewhere close by; and even more probably somewhere reasonably near by, but it could be far, far away. You just don't know. And a further observation will just repeat the process - Endlessly. The question really is, is our elusive electron only probably somewhere, or is it actually somewhere? At any given nanosecond, does it have coordinates in space and a specific velocity or is it fuzzy? If you are an observer, it is fuzzy. But, if there is no observer, then I suggest that electron is as fixed in space as our billiard ball heading towards the side pocket. The electron 'knows' where it is and where it is heading and how fast, even if you don't.

Okay, that's the electron as particle. When you wish to interpret an electron as a wave (all particles - for that matter all matter - has wave-particle duality), say doing the double slit experiment but with electrons instead of light photons, and thus getting classic wave interference patterns, then it is logical to consider the electron as more defuse or spread out - but not infinitely so. If the experiment is being carried out in New York, no part of the electron wave will appear in L.A., far less on Mars or at a distant star or galaxy. That's just common sense - a trait not to be dismissed out of hand or totally ignored even in the weirdness that is quantum physics. In fact, I doubt if there is really much probability of finding any part of the wave activity outside the lab walls!

Of course a wave can be in two or more places at the same time, but there are limits, as suggested above. You could have an ocean wave hundreds even thousands of kilometres long, but what is the probability any of that wave activity is detectable in Kansas?

A seismic wave may rock the Earth and clang it like a bell, but it's a non-event to an inhabitant on an extra-solar planet. It won't feel a thing. No shake; no rattle; no roll.

You can scream your head off and be heard vast distances away (and all points in between), but on Mars no one can hear that scream (the vacuum of space sorts of cramps sound wave activity).

Wiggle a string - that's wave action, but it stops at the ends of the string.

Shine a flashlight at the ground. Does the light wave, wave its way through the planet and exit on the other side?

Waves, no matter what's waving, can ultimately be blocked, even those ghostly neutrinos which, as particles, can also be interpreted under the right conditions as wave phenomena. Anyway, once blocked, the probability of the wave being on the other side is zero. In other words, wave activity is confined and isn't infinite in scope.

An electron, as particle, can not be in two places at the same time, any more than you (as 'particle') can be (unless you allow for time travel of course). An electron could probably be in any one of a zillion locations for all the observer knows, but the operative word here is 'one'. An electron wave can be in two (or more) places at the same time, but, I suggest those locations are in pretty close proximity. Say your TV set emits an electron (as particle) and your TV screen receives that electron (as particle). However, one can imagine that in-between the electron is exhibiting wave properties. However, if that in-between wave waved all over creation, instead of following the shortest distance between two points - a straight line - your TV picture would be an unholy mess!

I suggest that this example makes nonsense of the idea that all things quantum revolves around uncertainty and probability. That's only the case from the point of view of the observer. Things are certain and fixed when the observer is removed from the picture as far as Mother Nature* is concerned.

Even if just one quantum phenomenon is based on probability without any underlying causality, even when no observer is present, then - well I'm not prepared for the world to end quite yet!

There is one very interesting quantum uncertainty/probability phenomenon we're all familiar with via watching television shows. We've all seen those half-way mirrors where you can be observed but you can't observe in return (so that the powers-that-be can monitor you from another adjacent room but all the while you can't see them). Another example is from your own home (or office) window where some of an internal light will go though the window but some will be reflected back at you. In either case, how does any individual photon 'know' whether to reflect or pass through since the entire surface of the one-way mirror or the window glass is identical? Actually in the case of the glass, it is actually surfaces - one on the inside; one on the outside. It should be a 100% either pass/or reflect situation. Tis a puzzlement! One would assume that eliminating the observer wouldn't alter the physics any.

I don't think there's a great mystery here. When a photon hits the surface, it actually will be interacting with the electrons in 'orbit' around the molecules of glass. The electrons will absorb the photon increasing their energy state and jumping up to a higher 'orbit'. That situation doesn't last, and in quick-smart time, the electron jumps back to a lower energy state and gives off a photon in the process. That photon may be then facing further on into the glass, or it might be facing away (i.e. - reflected back). That process is repeated again and again until some of the photons escape the glass to the outside (pass through the glass), or escape from the glass by 'reflecting 'back inside. No mystery. There's probability involved, but also causality.

Anyway, as suggested above, it's not entirely true that quantum physics is all about probability and uncertainty. Not everything quantum has or is measured as probability or uncertainty. In the world of the quantum, all things come in packets or quanta of discrete and individual units. An electron has a charge of negative one unit. An electron never has a charge of negative one-half unit, or at one and a half units. An electron can 'orbit' a nucleus at this energy level one, or that energy level two, or the next energy level three, but not just at any old energy level, like one corresponding to level 2.739. An electron can jump between energy levels like you can travel between floors in a building, but just like you can't occupy the 11 7/8ths floor, neither can an electron jump to the 11 7/8ths energy level. An electron might be spin-up or spin-down, but not somewhere in-between. In all things quantum, there is such a thing as a fundamental lowest possible unit of time, of length and of energy.

There are other ways all things quantum are 100% certain and predictable. An electron, as noted above, has a fixed rest mass. Unlike humans, that mass doesn't alter. Humans can be 50 kg or 100 kg, even more or even less, and of course in-between. An electron has a mass of one unit, not one half unit or ten units, just one and one only unit. Ditto the proton and the neutron. There's no probability here. It's fixed; absolute; quantified. Every fundamental particle is an absolute clone of every other fundamental particle of its kind (i.e. - all positrons are absolutely identical).

Now while any particular radioactive atom has just a probable value of decaying and going poof in any given time frame (though I suspect there are hidden variables which we're as yet unawares and which will govern the decay process from one of probability to one of causality and predictable certainty), when that decay happens, it happens in a fixed and unalterable way, one step at a time (assuming several intermediary steps that do occur in some decay processes). Regardless, the upshot is that radioactive A always yields B which always yields C which in turn yields stable D. One uranium atom doesn't decay ultimately to lead, while another becomes gold, and a third mutates to oxygen. That doesn't happen - ever.

The vacuum energy (quantum fluctuations) will produce virtual particle matter - antimatter pairs, like an electron - positron. It will not produce a positron - proton pair or a neutron - neutrino pair. There's no probability here - well actually there is - it's zero percent.

Four hydrogen atoms (or two hydrogen molecules) can fuse together to form a helium atom plus neutrinos and energy. Not five hydrogen atoms or three - it's four all the time, every time. There are no quarks emitted instead of neutrinos, and not just any old energy amount is given off but a predetermined and fixed amount, every time, all the time, full stop.

Your compass doesn't statistically or probably point towards the magnetic north, it points towards magnetic north, yet the entirety of electromagnetic phenomena is quantum based.

To repeat, it is claimed by some that it is nonsense to talk about the existence and properties of anything in time and space until such time as an actual observation or measurement is made. (I assume here that previous observations/measurements recorded in some manner or other, by observers who no longer exist, is taken as valid.) Anyway, everything is just probability until that measurement/observation happens. The old quandary that revolves around that tree in a forest falling - if there is nobody around, is there any sound? Well, claimants of the no observation - no reality philosophy would have to conclude 'no' because the tree doesn't exist in the first place (neither does the forest) because nobody is observing it!

Okay, lets say that's true and say, as a thought experiment that nobody (human anyway) has even seen, measured, recorded, photographed, etc. the Moon (there was no Apollo program and no lunar landings). Some theorist speculating about a Moon could only say it existed with such and such probability. Mother Nature may, or may not have blessed us with a Moon. Since nobody has observed a Moon, the probability is probably close to zip and our theorist is headed towards a career meltdown!

What about indirect observations? Are they sufficient to prove the Moon exists and save the theorist's bacon? I mean observers have observed such things as how the Earth is highly stable in its revolving about its axis. Observers have noted that sometimes at midnight it's pretty bright outside (full Moon) yet two weeks later it's pretty dark at midnight (new Moon). Observers have noted that sometimes when it's very bright outside at midnight, for a few hours that brightness dims and turns a reddish colour (lunar eclipse). Observers have noted that sometimes it gets partially, sometimes totally dark during broad daylight (solar eclipse). Observers have noted lots of phenomena that have a 27 to 28 day cycle without any apparent reason(s). Observers have noted and measured the tides and tidal cycles. From all this indirect evidence, sceptics have concluded our theorist is right and that a Moon must be orbiting Earth with such and such properties. Those being the case, direct observations of the Moon are irrelevant in terms of proving its existence. The Moon exists without being stared at**.

In real life the existence of many unobserved objects has been proven to exist - indirectly - without any direct observation. Black Holes are a case in point. The nature of the Earth's core is another. Now if something can exist with just indirect observation, then things can exist without any observation at all. A planet hasn't just popped into existence around a distant star just because our technology has reached a certain degree of sophistication, sophistication now able to detect (observe/measure) it.

To take a more everyday example familiar to us all, throw a dice. Examine the five sides visible to you - you don't have to be a rocket scientist to deduce the value of the unobserved (face down) side!

There's another quantum category that suggests that observation is not always necessary. That's the phenomena of quantum entanglement. Okay, it's necessary to observe one thing, but in doing so you don't have to observe something else in order to know something about it. Its phenomena where by two things are entangled and knowing the state of one thing tells you the properties (some of them at least) of the other.

Actually I quite love this idea of entanglement and to know the properties of something without ever having to actually observe or measure it. Let's return to my favourite imaginary couple, Jane and Clive, who, as we all know, are a bit weird. So, I can imagine this hypothetical macro example from the Jane and Clive archives, where Jane and Clive agree that on any given day, whatever colours Clive wears, Jane won't (or vice versa). So, if Clive is dressed in a blue suit, with white shirt and red tie, grey socks and hat, with black shoes, I can be sure, without observing, that Jane's outfit will consist of nothing that is black, white, blue, red or grey. So, I know something about Jane's properties without any observation because in this case Jane and Clive were entangled! In actual fact it is way weirder than that. If this were a real quantum entanglement example, then if Clive and Jane were on opposite sides of the Universe, and Jane had on a green outfit and Clive had on a red outfit, and Clive changed outfits to one of green, then Jane would have to also change - instantaneously. Now that's really spooky!

Or, say Jane and Clive are expecting company, but don't know when that company will arrive. Therefore, one or the other of them has to be home at all times - in case. So, if I see Jane shopping, I know, without observation, that Clive is home. Now let's take a micro example. The vacuum energy spits out a matter-antimatter particle pair, but they separate and escape and head off in opposite directions. Jane captures one in her particle trap (box); Clive gets the other one in his particle trap (box). Jane peeks into the box and sees a positron. That alone spoils the surprise for Clive, for without any need to look; he now knows his box contains an electron.

So classical (macro) reality, as well as quantum (micro) reality (IMHO), is the same reality whether or not there is an observer around, so I repeat, it's nonsense to say that they - observers - are the be all and end all of what's real.

Still, when it comes to the nitty-gritty of trying to pin down the specifics of quantum activities, all is probability, and things can both be and not be (the technical phrase is superposition of state) at the same time with equal probability, only becoming either/or when the observer struts her stuff and observes. [The observer can be an instrument, but ultimately that instrument transmits the observation to the human that operates the instrument.] The case of Schrodinger's Cat is the best known example. A Rube Goldberg device is constructed and operated by a probabilistic quantum process that will subject a cat to a life or death fate with a 50/50 probability of either life/or death after a fixed interval of time has passed (then the device turns off). The idea is that all remains probability until such time, and only until such time, as an observer actually looks and sees an animated cat, or a dead cat. Until that observation, the cat is in a limbo state of being both alive and dead simultaneously. But what if there is no observer? Would the cat remain in a limbo state for all eternity? Clearly that's not, and can not be, the case. The cat is either alive, or it is dead, and the observer be damned! The observer is irrelevant.

When an electron is emitted (A) we know the details. When the electron hits its target (B), we know the details. Where is the electron in-between? Who knows? It's all probability. But, does that mean that the electron has actually taken all possible pathways between A and B, or just one? The observer is hapless in such an experiment because observing the electron in mid-path not only changes that path, but says nothing about what path the electron took between A and the in-between observation.

This is weird. In one case, trying to observe an electron (which I'm certain had a precise set of coordinates at the time the observation was made) results in the observer only being able to conclude that the electron's location is only just an observation of probability; while observing the cat changes probability to certainty.

Smite the observer! Off with her head! In Dalek-speak, "Exterminate!" At all times the electron is at certain fixed place and moving at a certain velocity and interacting with other things, like the little billiard ball it is, much like a real billiard ball that's at a fixed set of coordinates, moving at a certain velocity as a result of interacting with other things, like the cue ball. From the electron's point of view, there's no probability or uncertainty. Screw the observer - she's an uninteresting and unnecessary complication that has no bearing on reality, even at the quantum level. Ditto the cat. The cat is alive, or the cat is dead, and the cat 'knows' what state it is in even if the observer hasn't a clue because she hasn't yet made the relevant observation.

It is also claimed that the very act of observing or measuring alters the properties or values of what you are observing or measuring. Well, yes and no. Let's take the 'yes' case first. If you put a photon detector between the photon emitter and its target (say at the point of the double slit to try and pin down which slit the photon is going through, then of course the act of doing that, the act of measuring or observing in midstream disrupts the otherwise natural state of affairs.

A biologist monitoring wildlife populations, movements and interactions may, if not very careful, influence those very parameters by her presence, just like human behaviour is altered if you know you're in the spotlight.

Is a grain of salt that goes untasted salty? Presumably the act of tasting (an observation or measurement) alters the properties of what is being tasted - in the case of table salt, it dissolves when tasted.

Sticking some sort of device into flowing water to measure its rate of velocity, force, etc. will subtly change that flow and its properties. Stick a thermometer into a bowl of soup to measure its temperature - well that very act will of course change the temperature of the soup!

Now examples from the 'no' side: observing a star through a telescope doesn't change the properties of the star. Placing a seismometer on the ground to measure earthquake activity and intensity isn't going to cause any change in seismic activity. Hearing the thunder doesn't alter the properties of the lightning bolt.

Of course it could also be a 'yes' or a 'no' depending. You'd think that observing an electron because the photon has to bounce off it in order for you to measure it, must thus alter its course, and thus has affected the direction-of-motion property of that electron. But, it depends - would it have happened anyway or did you deliberately introduce the photon. If the former, your observation didn't affect the electron; if the latter, it did.

Upgrading the issue to the broadest of scales, if something is only known or has reality or is created by observation, then which came first, the observer, or the Universe? Since observers, of the flesh and blood kind, could not survive the reality of the Big Bang event (whether or not they created that reality) and conditions that existed shortly after the Big Bang - even long after the Big Bang in fact until the heavier elements like carbon, nitrogen, oxygen, etc. were manufactured inside stars - and since one can explain how an observer-less Universe can evolve observers, it seems the simplest explanation (simplicity, all else being equal, being one of the core philosophies in science) is that the Universe created the observer and not the other way around. I suspect that if all observers were to become extinct, the Universe would go on its merry way, caring not one bit.

Now if one has an observer as creator of the universe and its reality, that seems to be just a sleight-of-hand way of replacing the term 'God' with the term 'observer', and as physicist Victor Stenger and biologist Richard Dawkins (among others) have recently argued, there is no scientific evidence for a 'God' existing far less creating anything.

However, I can think of (not as my original thoughts I must add) two scenarios where our Universe and its reality were created by 'observers'. The first is a variation on physicist Lee Smolin's idea that a universe can 'reproduce' via black holes. Black holes can create or spawn baby universes, and so a universe that has physics that maximise the production of black holes maximises its own reproductive fitness. My variation is that an ultra advanced extraterrestrial civilization/technology could in fact have the ability to manipulate matter/energy into forming a black hole and thus creating a new universe - like our Universe!

The second scenario is again of an extraterrestrial intelligence nature. I can imagine some alien Ph.D. student doing a thesis along the lines of "Planet Earth and Associated Universe: A Simulated Construction". In other words, we are all, and our reality is all, just a simulation - a software package. But that's not so strange an idea. By analogy, there are multi-thousands of software simulation packages right here available for our scientific use, as a training tool (say for pilots, astronauts, medical doctors), and just for fun (video games). I actually find this quite plausible. Simulated universes can greatly outnumber a real universe, so what odds that we're in a real universe instead of a simulated one? I find one piece of evidence suggestive. That is, there are apparently two independent sets of software that together, but apart, run the cosmos - classical physics and quantum physics. I have sometimes wondered whether the quest for a Theory of Everything, for quantum gravity, is a futile exercise. See, our extraterrestrial Ph.D. student is a computer geek, not a physics geek!

If either of these above scenarios are correct, one can readily equate a supernatural God with a flesh-and-blood extraterrestrial whose technology is, from our point of view, indistinguishable from magic (i.e. - supernatural happenings), as Arthur C. Clarke would postulate.

What's at stake here? The macro universe, which is made up of by the micro (quantum) universe, at the level of billiard balls and pussy cats is anything but a universe measured in probabilities and degrees of uncertainty. The micro universe, from the point of view of observers, is everything probability and uncertainty. But, is the micro universe really that way or does it only give an illusion of that? If there were no observers (which would unfortunately mean we wouldn't have any ways and means of discussing the issue) I would maintain that the micro would mirror the macro. In short, causality rules at the most fundamental of levels.

Einstein fought this battle and lost. There's currently experimental evidence that quantum physics is at the heart an uncertain world and a measure of all things that are just probability. That's the sort of environment that allows for free will - you just can't predict in advance which way you're brain is going to jump, brain activity being chemical, thus physical, thus ultimately quantum. But perhaps there's yet an undiscovered level of reality that governs al things quantum and eliminates probability and uncertainty, even though to us, as observers, that's what things look like - now. But even if some deeper level of reality within the quantum world exhibits real causality, if electrons have coordinates; if cats are alive or dead and not in-between, then there can't be free will. Perhaps that's what's ultimately at stake.

CONCLUSION: Things are only in-deterministic or uncertain (as in Heisenberg's Uncertainty Principal) or have probability (as in the cat is probably dead but equally probably alive) to the observer - or to use a layman's term, all things (well, some things) quantum are 'fuzzy'. However, from the point of view of Mother Nature, all things are deterministic, certain, and absolute. She knows where the electron is; and She knows all about that cat's state of animation. My bottom line is that if there were no observers, no life of any kind, no measuring devices like photographic film or Geiger counters or rulers or thermometers, the Universe would still exist. It would have an absolute physical reality. It would have to have that in order to bring forth into being observers who could and would observe and construct measuring devices to measure.

And with that statement, I've been expelled from Quantum Physics 101 - again.

* No, I'm not equating natural Mother Nature with a supernatural God or gods. They are two entirely different concepts.

** In another way, quite a valid way I might add, you do constantly observe the Moon - just not with your eyes (or ears that hear, or a nose that smells, or mouth that tastes for that matter). You 'feel' the Moon (and the Moon 'feels' you too). You have mass and therefore gravity - ditto the Moon. So, you and the Moon are attracted gravitationally to each other, albeit it's a very tiny attraction, but it is not zero, and tiny doesn't negate the reality of that dual attraction. You have directly observed the Moon! Therefore the Moon exists. It's observation via gravitations instead of photons. Since everything with mass has gravity and since gravity extends its influence out to infinity in theory (in theory because it travels at a finite velocity - the speed of light) and since gravity acts on all other masses, all objects with mass 'observe' all other masses. Now electrons, protons, neutrons, in fact all fundamental particles have mass, therefore gravity, and therefore participate in this universal 'observation' process because gravitational attraction is a universal 'observer'! Therefore, to exterminate all observers means exterminating the entire Universe! Of course this use of the word 'observer' is probably somewhat outside the usual and traditional meaning of the word 'observer' and that's why I've consigned it to this footnote. But, I suggest the argument isn't trivial and is a valid one.

EVEN IN COPENHAGEN, THE MOON SHINES

Quantum physics is schizophrenic to say the least. On the one hand, it's been experimentally verified to incredible precision and much of our modern technology and the economic benefits of that technology have roots in quantum physics. On the other hand, it makes little if any philosophical sense and it can not be reconciled with classical physics. Physicists don't understand quantum physics; they just tend to shut up and calculate and don't worry about deeper meanings. The Copenhagen Interpretation revolves around some of those deeper philosophical meanings.

The Copenhagen Interpretation of quantum physics is so named because the main centre where it was developed in the 1920's under the leadership of Neils Bohr was based in the city of Copenhagen.

The Copenhagen Interpretation of all things quantum states that's it is inappropriate to speculate on the existence and properties of any object until such time as the object in question (it's wave function) is actually observed and measured. Then, and only then, has the probability of such-and-such existing and what properties it possesses become certainty. That's termed the collapse of the wave function. The classic example is that an electron might be here, it might be there, it might be anywhere. The electron might be in a spin-up state, or maybe a spin-down state. Only a measurement or observation will resolve the issues. Ultimately, in the Copenhagen Interpretation, the observer (taken as evident to be human) is the be-all-and-end-all; the supreme umpire, judge, jury and executioner.

The counter classic example, proposed by physicist Erwin Schrodinger as a put-down to the Copenhagen Interpretation, illustrating the absurdity of it all, was Schrodinger's cat. The gist of this thought experiment (no animal was ever actually involved, so animal lovers can breathe easy) was that there would be some sort of quantum event (like a radioactive decay event) that had a 50-50 chance of happening in one hour. If the event happened, it would trigger off a chain of events that would cause the demise of a cat trapped inside an opaque sealed box. If the quantum event didn't happen, the cat would be alive inside the sealed box. The question is, after one hour, is the cat alive or dead? Without an observer, the Copenhagen Interpretation says that in lacking an observer, there exists a superposition of states. In one state is the cat is dead; in the other state the cat is alive. In other words, the cat is dead-alive until such time as an observer observes, and the 50-50 probability becomes 100% certainty.

There's an interesting variation on that cat thought experiment. Say the cat-in-the-box is in a room and I'm also in the room, and after one hour I peek in the box and determine the aliveness or deadness of the animal. But, say you are outside the room when I do that. As far as you are concerned, the cat's wave function hasn't collapsed and the cat is still dead-alive. So you have got to look too! But then what about a third party in another room in the house, then the neighbour next door, and hence other residents of the town, then state, hence country and then the entire world. Of course the cat would be in a limbo dead-alive state to extraterrestrials on another planet until they looked, and so on. In fact, taken to a logical extreme, nothing has reality until the entire Universe observes, which is again (IMHO), absurd seeing as how it could take billions of years for that cat observation to reach the farthest regions of the cosmos!

In the quantum world, there can be a superposition of state. Something can both be, and not be, at the same time (like wave-particle duality) - only measurement or observation can decide whether it's to be or not to be. Since the macro (like a cat) is composed of the micro (the realm of the quantum), then until observed, the cat can both be (dead) and not be (dead).

In a similar way, for those who argue that nothing is real unless that something is observed they'd argue for example that the Moon dissolves into quantum uncertainty, the Moon both is and is not, if nobody is actually looking at the Moon! As soon as someone looks at the Moon, it solidifies back into physical reality - it is. The absurdity (again IMHO) of that is that if the Moon faded away into quantum uncertainty that would play havoc with the tides and be noticed. Perhaps observing the tides is sufficient to give the Moon reality without actually observing the Moon! I'll return to that point shortly.

The Copenhagen Interpretation, translated, and taken to its logical conclusion is that if nobody is looking at the Moon, does it exist? Can the Moon be in a superposition of states - having existence and having non-existence simultaneously? That was a quasi-question poised by Albert Einstein when he - also in opposition to the Copenhagen Interpretation - pondered that he'd like to believe or think the Moon existed even if nobody was looking at it. [Presumably the memory of a prior observation doesn't count.] Well Professor Einstein, it does!

That the Moon doesn't exist if nobody is looking at it is nonsense from several points of view. Firstly, common sense: can anyone really doubt that something you're infinitely familiar with, let's say your partner (or the Moon) doesn't exist or doesn't have the properties you associate with him/her (or the Moon) just because you're not observing them/it?

It's reasonable that anything that's biological and alive observes itself. So, even if you're not observing your partner and therefore could deny your partner's existence, your partner is observing him/herself and therefore would argue very strenuously that s/he exists. That renders that point mute.

No one has defined exactly what constitutes an observer. Can it be anything that's alive like a plant or bacteria, or does it have to have a sophisticated nervous system (higher sensory capacity)? Maybe there has to be a complex brain within. Maybe an observer is only a bona-fide observer if it has intelligence, but what degree of intelligence? A one day old baby or someone who is brain damaged might look in the box and see Schrodinger's cat but has no capacity to understand what they are seeing. Does it have to be human? What about an artificial intelligence? So, what's an observer? Can it be less than human, but still an organic life form - say your dog - or what about a fish; or an insect; or a microbe? Can something inorganic be a bona-fide observer? What about an inorganic things like a Geiger counter or thermometer? I'd argue that an electron can be as bona-fide an observer as a human being.

For example, say a photon is emitted by the Sun, heading our way. Unfortunately, the Moon is in the way (solar eclipse) and so the photon is thwarted, it's pathway to Earth blocked. From the point of view of that photon, the Moon exists, even if nobody on Earth were observing the solar eclipse (rather unlikely, but possible for sake of argument).

The curve-ball in all of this is that there's more than one way to observe. The assumption is that by observing we're using one or more of our five senses - usually sight. I suggest that in fact, every particle/object in the observable universe is observing every other particle/object in the observable universe, 24/7. Translated, even when your partner (or the Moon) is out of sight (and hearing, etc.) you are still observing him/her (or it), even though you're not aware of it!

Why? How? Does the Moon exist if you're not observing the Moon, but you are observing the rising (or falling) tide? There's causality between the two. So, observing the tides is in effect observing the Moon, or at least one of its properties - gravity. And therein lays the solution to Einstein's quasi-question.

You have mass. The Moon has mass. Any two masses attract each other via the gravitational force. Therefore, you 'feel' the gravitational attraction of the Moon; the Moon 'feels' the gravitational attraction of you. Therefore, even as you read these words, you are 'observing' the Moon. You have observed the Moon 24/7 since the moment you were conceived.

The observer problem, the Copenhagen Interpretation, is a furphy since everything that has mass observes everything else that has mass, all the time - gravitationally.

This explains how the Universe got along and evolved very nicely, thank you very much, for all those aeons before biological observers happened upon the scene. The Universe existed and had properties prior to the origin of any life, anywhere, since observers don't have to be living! However, there are those who believe and would argue that the entire Universe exists (has reality) only because there are observers to observe or measure it. Clearly the Universe was in a lifeless state and evolved in a lifeless state from Day One (the Big Bang event) through several billions of years at least. That is, there were no biological observers at all. The Universe had to exist in a pre-biological observers stage in order to evolve the complexity required to produce biological observers. An early Universe consisting of only hydrogen, helium and radiation doesn't hack it as far as being a suitable environment for biological observers. So, in terms of this chicken-or-the-egg question, the Universe-or-the-biological-observer question, the answer must clearly come down on the side of the Universe. The Universe can exist either with or without biological observers; biological observers exist only because there is a Universe.

So, the resolution to Schrodinger's cat is as follows (and no human observers are required). While the cat is alive, the cat observes itself. If the cat is dead, those bits that make up the cat's body are observers in noting that the organism is now dead because the interactions they participate in have altered. Further, interactions between the dead cat and all the particles that surround the dead animal can also be considered bona-fide observers.

Conclusion: The ultimate observer, that be-all-and-end-all; that ultimate umpire, judge, jury and executioner reside within that abstract phrase, 'Mother Nature' - that is anything and everything, anywhere and everywhere, at any time and every time; at all times. I believe that observers and measurements have bugger-all to do with reality, existence and how things work on either a macro or micro scale. The proof of that pudding, if any were necessary, is that radioactive substances decay with a measured half-life. The entire science of radioactive dating depends on this. And radioactive elements decay whether or not observers are present - they have; they do; they will.

John,

QM "can't be reconciled with classical physics" But this new paper seems to make make logical and philosophical sense, so some different interpretations may reconcile the two. Do give me your views;

Quasi-classical Entanglement, Superposition and Bell Inequalities. 2014.

Of course all in QM and most others will undoubtedly adhere to beliefs of spooky entanglement, so it may just be a wasted academic exercise.

Best wishes

Peter

Hi John,

I'm sure you will be interested in J. Especial article

Bell Inequalities under non-ideal conditions

that concludes that up today there has been no experimental violation to local realism.

Best regards

Teresa

Thank you very much Peter and Teresa for your links. The one by Teresa alas came up with a "web page is not available" message. I must note that I'm pretty much a layperson in this QM area and so the article linked by Peter to a large extent made me celebrate Passover, in that much of the content passed over my head. However, I do note that the authors still seem to adopt a belief in the concept of a superposition-of-state and that's just something that I reject. What I will do is post some thoughts on entanglement here following this which obviously incorporates the concepts of superposition-of-state, collapse of the wave-function, the status of the observer, and similar QM philosophical notions. In the days and weeks ahead I'll post more of my own counter philosophies and see where that takes us, if anywhere.

John Prytz

SOME THOUGHTS ABOUT ENTANGLEMENT

If I understand the concept of entanglement correctly, it basically means that if you know the state of one thing (via an observation or a measurement) then you automatically know the state (without an observation or measurement) of some other thing. The two things therefore are entangled. For example, if you know for certain that the top card in a standard deck of cards is the six-of-diamonds; then you also know for certain that the bottom card in the deck is not the six-of-diamonds. The cards in a deck of cards are entangled. But that doesn't mean of necessity that there is any kind of communication between the entangled things, or in this case between the top and bottom card in the standard deck.

Many however suggest that until an observation is made, every position in any deck of cards is in a superposition-of-state such that each position in the deck, like top card and bottom card, are simultaneously and equally a mixture of all fifty-two possible card values. When an observation is actually made, the superposition-of-state collapses (or the wave-function of whatever that superposition-of-state represents collapses) and the deck position so observed resolves itself from a mixture of fifty-two to a reality of one (which then tells you what the other deck positions are not so there is an entanglement).

Einstein railed against entanglement on the grounds that the two (or more) entangled things must of communicated with each other because both things were in a superposition-of-state and only an observation or a measurement of one or the other thing would collapse their wave-function and negate their superposition-of-state and since that happen instantaneously, it violated Einstein's speed of light restriction. Einstein was not amused calling that "spooky action at a distance". However, IMHO, Einstein's big error may have to blindly accept that there even was such a thing as superposition-of-state. If there is no such thing as superposition-of-state then there is no such thing as collapse of the wave-function and thus there is no such thing as spooky action at a distance.

Let's look at a few examples.

1) Some Thoughts About Jane.

Say you are Jane's husband and you know that she eats the following for dinner, and only the following for dinner, on these days and only on these days.

Eggs on a Monday;

Lamb on a Tuesday;

Beef on a Wednesday;

Ham on a Thursday;

Fish on a Friday;

Poultry on a Saturday; and

Pasta on a Sunday:

But say you lose all track of time for one reason or another (drinking binge; coma; overseas trip, etc.). In your state of uncertainty, Jane's choice of dinner and what day of the week it is are both in a so-called superposition of state. An observation is necessary to collapse the wave function. If you observe your wife Jane eating fish, well you know it must be a Friday. If you happen to find out it's a Friday, then you know for certain what your wife Jane will have for dinner. Thus, there is an entanglement between your wife's choice of dinner and the day of the week, but there is no communication or spooky action at a distance between Jane or Jane's food and the day of the week. It would be like Jane or Jane's food trying to communicate with something immaterial since the days of the week are just human invention - an abstract mental construction or concept without substance or structure.

2) Some Thoughts About Twins.

Say you and your identical twin start out at some point X and walk in opposite directions. It's well known in the community that one of you always wears a green shirt and the other one of you (your twin) always wears a red shirt (in order to told apart by those you meet and greet). Prior to some third party meeting up with and greeting one or the other of you, were both of you wearing a superposition-of-shirts? Were both of your shirts both green AND red at the same time or were you (and your twin) just wearing either a red shirt OR a green shirt? It's nonsense to suggest that the third party meeting one or the other of you collapsed your superposition-of-shirt wave function and thus there was an instantaneous faster than light communication between your various shirts sorting out who was wearing what colour shirt.

3) Some Thoughts About Electrons

Now what's wrong with this scenario (apart from nothing I mean)? Two electrons in the same 'orbit' get ejected from their parent atom and one is tossed east and other is heaved west. Obviously they are in different quantum states and so one is spin-up and the other is spin-down and thus they are entangled. Light years later and apart, you measure the eastern one and find it is spin-up so you now instantaneously know the other western electron is spin-down, and indeed, the other electron, light years away, is indeed spin-down as verified nanoseconds later by someone else. But there was no communication between the two. There was no spooky action at a distance because it's not a case of the eastern electron being spin-up AND spin-down prior to your interference (observation or measurement) but from the beginning when it was tossed out it was going to be either spin-up OR spin-down (in this case spin-up) and ditto for the western electron - it was spin-down from the beginning quite independently of any observation or measurement.

One needs to ask the obvious question which is what actual observational evidence is there for a superposition-of-state? IMHO there can't be any since by definition apparently any actual observation or measurement destroys the very existence of a superposition-of-state: BOTH collapses into ONE. You only ever observe the ONE, not the BOTH. So, using the principle that's part and parcel of Occam's Razor, wouldn't it be just more straightforward to suggest that there is no such animal as a superposition-of-state and that the observer or the measurement is 100% irrelevant to any state of reality so occupied by two or more entangled things.

In conclusion, if you observe the state of X that might also tell you the state of Y but there doesn't have to be any communication between the two. And while there might be entanglement of sorts or to varying degrees, there is no spooky action at a distance. Those who argue to the contrary and adopt the standard model, well, IMHO never have so many waxed lyrical for so long about so little.

Hi John, I have just been watching Modern Physics at Stanford online lectures from Leonard Susskind on quantum entanglement. Early on he says words to the effect that the electron spin vector can be imagined pointing in any direction in space but the act of measurement between a magnetic field causes the observable of photon decay or no photon decay, corresponding to spin up and spin down. It can only be either of those two observations and nothing in-between, such as 90 degrees to the up /down axis. That means to me it is the act of measurement that creates the characteristic of spin up or spin down of the electron, it did not necessarily preexist the measurement. Though it is just as likely to have been up or down as any other orientation. He said, words to the effect, that the decay was akin to radioactive decay with a half life. He also mentioned that the strength of the magnetic field would increase the likelihood of decay being detected. So the stronger the field the more likely the electron will flip to spin up. I wonder how you might reconcile that with your description of entangled electrons. I haven't got very far yet with the lectures, just learning the necessary mathematical formalism before describing entanglement itself.

You missed the main point of entanglement.

"In conclusion, if you observe the state of X that might also tell you the state of Y but there doesn't have to be any communication between the two."

After you observe the state of X, do you then conclude that the particle was always in the state of X? No. Quantum logic says that the state of the particle if fundamentally unknowable up until it is observed.

That is the dilemma of entanglement. The difference between information that we simply do not yet know, but could know and information that is fundamentally unknowable.

If I observe X I do conclude that it was always in the state of X and never in any superposition-of-state of both X and Y on the grounds that an observer is absolutely irrelevant to the state of X. Before observers (life forms) were ever conceived of in anyone's philosophy, the Universe got along quite nicely without any superposition-of-state or collapses of wave-functions, etc. of any of its bits and pieces. If you must have an observer, well perhaps you could nominate Mother Nature.

John Prytz

THE QUANTUM PERILS OF SCHRODINGER'S CAT

How can you have a cat that is both alive and dead at the same time? Such was the question quantum physicist Erwin Schrodinger posed in rebuttal to the weirdness of the Copenhagen Interpretation of quantum physics, an interpretation that he in fact through his theoretical research contributed to. He ultimately rebelled!

When debating the nature of quantum physics, you question what does it all really mean? One of the central points requiring pondering features a thought experiment by physicist Erwin Schrodinger. He, along with Albert Einstein, didn't agree with the idea that probabilities rule the quantum universe, and that observations or measurements were central to turning a probability into a certainty. By linking a quantum uncertainty event, with a macro outcome, Schrodinger hoped to show the absurdity of the former.

Schrodinger's Cat has got to be one of the strangest thought experiments ever conceived, but it was conceived with the idea of putting the boot into the Copenhagen Interpretation of all things quantum. The Copenhagen Interpretation basically means that everything is in a state of probability until, and only until, an actual observation or measurement is made; then, and only then, probability morphs into reality and certainty. Prior to that observation or measurement, the various possibilities are said to be in a state of superposition. Translated, if you throw a dice and it rolls under the sofa out of sight, the top value of the dice is in a state of six superpositions. The top of the dice is at the same time simultaneously one, two, three, four, five and six. That superposition of state, that combination of all possibilities is called the wave function of, in this case, the dice. Only when you remove the sofa and look will the six probability superpositions collapse (the collapse of the wave function) into one actual value. The point is, according to the Copenhagen Interpretation, prior to looking, the top face of the dice actually, in reality, has a value of one, two, three, four, five and six - simultaneously.

Okay, now back to the cat. The idea is that you have some unstable (radioactive) atom, and there's a 50/50 chance that it will go 'poof' and give off a decay particle within one hour. That's the quantum or micro bit. Now you have a box that contains a Geiger counter or some radioactive decay particle detector (that's part of the macro part). You also have a hammer in the box poised over a glass vial of poison gas (also part of the macro part). If the Geiger counter detects a decay particle, it triggers a switch which releases the hammer which smashes the vial, releasing the poison gas. Oh, there's also a cat in the box (the really essential macro part). After one hour, there's a 50/50 chance that the cat is either alive or dead. That's what rational people would say. Some, those of the Copenhagen Interpretation School, would argue that the cat exists in a dual state of both 50% aliveness and 50% deadness until such time as an observer looks into the box and measures the cat's 100% aliveness or 100% deadness. Then, and only then, does nature make up her mind (in quantum theory, the wave function - a measurement of probability - collapses to an exact value) and you find either a dead cat or an alive cat, which tells you whether or not the radioactive substance did, or did not, emit a radioactive decay particle. In a way, the cat itself serves as a sort of Geiger counter!

This thought experiment was to illustrate the apparent absurdity that in quantum theory some ultimate outcome can have before-the-fact equal but mutually exclusive possibilities (something can both be and not be at the same time - the upper dice face can be all six values at the same time) or that in quantum physics, there's no definite state of existence until there is a measurement or observation (same difference).

The idea is that if in the micro or quantum world something can have equal but mutually exclusive possibilities (again, an outcome can both be, and not be at the same time - wave-particle duality comes to immediate mind), yet the macro or classical world is made up of micro or quantum bits, then that suggests that macro objects (like a cat) can simultaneously exist in two mutually exclusive states or possibilities (the cat can both be, and not be, alive at the same time). In this case, the cat is both alive and dead until such time as someone looks!

Perhaps a better analogy is in showing how probability remains probability until an observation is made is in a hand of cards. All possibilities are equally probable, all possibilities are realised in actuality, but you don't know the specific outcome, your precise hand, until you look and the probability wave function, that superposition of all possible outcomes, collapses to one, and only one certainty. The observer is the be-all-and-end-all.

On that point, does it have to be a human that does the measuring or observing if all it takes is an observer to collapse the wave function in order for Mother Nature to decide either this or that? Could any observer do? I mean the cat itself is an observer! So if after only one minute a decay particle is given off, the cat will observe the results (hammer falling; vial breaking) just prior to dying, and there will be a dead cat in the box for the next 59 minutes. What if an insect crawled into the box and observed the cat. What about a bacterium in the box. Would nature, via the bacterium then decide that the cat is to be declared really dead and act accordingly? What if a computer, or some form of artificial intelligence or a robot did the observing? Of course it doesn't have to be a visual observation. I mean if you hear the cat meow, the cat is alive. If you smell the rotting corpse (or the poison gas), then obviously the cat is dead. If you feel the cat and it's moving, then it's obviously alive, and so on.

However, back in the macro world of the relatively very large, to me it's obvious that there's no bloody way from a human perspective of knowing after one hour if the cat is alive or dead without observing (via one sense or another). One thing the cat most certainly isn't is both alive and dead at the same time and I think it's absurd to suggest otherwise - yet that remains one valid interpretation of quantum physics. Is there a way of knowing, without peeking, whether or not that unstable (radioactive) atom emitted a decay particle?

I suggest replacing the vial of poison gas with nitro-glycerine, or for even greater effect, say a thermonuclear bomb (and leave the cat out of it). After the one hour is up (if not before), there will be no doubt, no need for debate, no need to even look, about whether there was, or was not, a radioactive decay particle emitted. There cannot be simultaneously both an intact and unexploded, and an exploded vial of nitro (or a thermonuclear bomb). It's either/or time.

What this thought experiment actually tells us about quantum physics remains a bit of a philosophical puzzlement to me I'm afraid, and the fact that it's discussed in nearly every book on quantum physics suggests that it has lost none of its strangeness.

There's another aspect to this that's equally as strange. Both the radioactive atom and the cat are entangled. What that means is that if you know the state of one, you know the state of the other. Say you observe the radioactive atom and note that it hasn't decayed; it hasn't gone 'poof', then you know, instantaneously, that the cat must be alive. If you note that the atom has gone 'poof', you know the cat is dead - instantaneously. Ditto, if you observe that the cat is alive, the atom didn't go 'poof'; if you find a dead cat, the atom did decay. Again, if you know one outcome, you know the other outcome - instantaneously. That's true even if the cat and the radioactive atom were on opposite sides of the observable universe. You have received a bit of information faster than the speed of light! When you think about it, information usually has to travel from a source (say from a computer screen or a flash of lightning or the sound of a gun going off) through to your senses hence to our brain. That takes a finite amount of time. It's not instantaneous. Because in an entangled situation you can receive information instantaneously - faster than light speed - Einstein was not at all amused. He's quoted entanglement as being a case of 'spooky action at a distance'. The more usual thought experiment is the creation of a matter-antimatter pair of particles that go their separate ways across the cosmos. Millions of years later, they are on opposite sides of the Universe. If someone ultimately observes one of the pair, then that observer instantaneously knows the state of the other particle even though that particle is so far away that it normally would take millions of years for that state-of-the-particle information to reach the observer: spooky action indeed.

Still, when it comes to the nitty-gritty of trying to pin down the specifics of quantum activities, all is probability, and things can both be and not be at the same time with equal probability, only becoming either/or when the observer struts her stuff and observes. [The observer can be an instrument, but ultimately that instrument transmits the observation to the human that operates the instrument.] But what if there is no observer? Would the cat remain in a limbo state for all eternity? Clearly that's not, and can not be, the case. The cat is either alive, or it is dead, and the observer be damned! The observer is irrelevant. There seems to be a philosophical if not an actual physical contradiction here. That was Schrodinger's point.

There is one other fly in this ointment. You have the cat-in-the-box experiment. After one hour an observer enters the room and looks into the box. The wave function collapses and as far as that observer is concerned, the cat is now dead, or alive. But now what about the state of the cat to people outside the room? As far as they are concerned, everything is still in a superposition of state. The cat is still in limbo. Extend that to people in another building, in another suburb, in another city, state, or country. Even if everybody on Earth knew the state of the cat after one hour, what about an astronaut on the Moon? Is the cat still in limbo because an extraterrestrial light years away hasn't received the news? As far as that extraterrestrial is concerned, the answer has to be 'yes', even though all Earthlings know that the state of the cat is no longer the subject of speculation.

Perhaps when all is said and done, quantum paradoxes, well weirdness anyway, explains the most popular interpretation of quantum physics. It's called the 'shut up and calculate' interpretation. In other words, just do the experiments; just crunch the numbers; just apply the technology, and don't worry about what it all means!

THE QUANTUM MESS: ARE OBSERVERS NECESSARY? The question quantum physicists dare not ask: what if there are no observers?

In my section on Schrodinger's cat, I noted how, according to some, it takes an observer to determine the fate of the animal, and until there is such an observation, the cat is both alive and dead at the same time. This thought experiment was an analogy for something in the quantum world that some outcome can have equal but mutually exclusive possibilities (i.e. - an outcome where you can have both being and not being simultaneously), at least until a measurement/observation is made and things fall into place as either being or not being. [There's an interesting variation on that cat thought experiment. Say the cat-in-the-box is in a room and I'm also in the room, and after one hour I peek in the box and determine the aliveness or deadness of the animal. But, say you are outside the room when I do that. As far as you are concerned, the cat's wave function hasn't collapsed and the cat is still dead-alive. So you have got to look too! But then what about a third party in another room in the house, then the neighbour next door, and hence other residents of the town, then state, hence country and then the entire world. Of course the cat would be in a limbo dead-alive state to extraterrestrials on another planet until they looked, and so on. In fact, taken to a logical extreme, nothing has reality until the entire Universe observes, which is again (IMHO), absurd seeing as how it could take billions of years for that cat observation to reach the farthest regions of the cosmos!]

In a similar way, there are those who argue that nothing is real unless that something is observed. For example, the Moon dissolves into quantum uncertainty, the Moon is and is not, if nobody is actually looking at the Moon! As soon as someone looks at the Moon, it solidifies back into physical reality. The absurdity (again IMHO) of that is that if the Moon faded away into quantum uncertainty that would play havoc with the tides and be noticed. Perhaps observing the tides is sufficient to give the Moon reality without actually observing the Moon!

Extrapolating, there are those who believe and would argue that the entire Universe exists (has reality) only because there are observers to observe or measure it. Clearly (unless you count God [if He/She/It exists at all] as an observer from Day One), the Universe was in a lifeless state and evolved in a lifeless state from Day One through several billions of years at least. That is, there were no observers at all. The Universe had to exist in a pre-observers stage in order to evolve the complexity required to produce observers. An early Universe consisting of only hydrogen, helium and radiation doesn't hack it as far as being a suitable environment for observers. So, in terms of this chicken-or-the-egg question, the Universe-or-the-observer question, the answer must clearly come down on the side of the Universe. The Universe can exist either with or without observers; observers exist only because there is a Universe.

Lastly, no one has defined exactly what constitutes an observer. What about an inorganic things like a Geiger counter or thermometer? Can it be anything that's alive like a plant or bacteria, or does it have to have a sophisticated nervous system (higher sensory capacity)? Maybe there has to be a complex brain within. Maybe an observer is only a bona-fide observer if it has intelligence, but what degree of intelligence? A one day old baby or someone who is brain damaged might look in the box and see Schrodinger's cat but has no capacity to understand what they are seeing. What about an artificial intelligence?

I conclude (or believe) that observers and measurements have bugger-all to do with reality, existence and how things work on either a macro or micro scale. The proof of that pudding, if any were necessary, is that radioactive substances decay with a measured half-life. The entire science of radioactive dating depends on this. And radioactive elements decay whether or not observers are present - they have; they do; they will.

Time entanglement thought experiments that link microscopic possibilities to a macroscopic event can be quite complex. Very often there is a confusion of microscopic possibilities or phase coherence and macroscopic realities. The cat thought experiment does show some short period of entanglement, but the cat's state largely represents a simple lack of knowledge about a realized event.

Observers are a mere convenient representation of an action, but actions happen and quantum states dephase in the universe all of the time without any observer present.

The paradox presumes first of all that quantum events are not realized until we observe them, which is not really quite true. The cat's state is then just like a quantum state and also not realized until we observe the cat. The paradox further presumes that the particle and cat states remain coherent with each other until we open the box. When we open the box and observe the cat's state, then and only then is its true state revealed. Thus the paradox: How can the cat have been both alive and dead?

Unfortunately, the Schrödinger's cat thought experiment thoroughly confuses entanglement of two coherent quantum possibilities, the particle states and the cat's fate, with the macroscopic and mostly incoherent reality of the cat. Although all actions are quantum events and all action therefore involves entanglement, after some very brief period after the quantum event, the cat is either alive or dead. That is a knowable state and there is not an entanglement of its possibilities.

In fact, the particle's state is also mostly knowable as well and it does not remain entangled for very long either. Quantum states are coherent with each other typically, but not always, a very brief period. The particle hits other particles and they hit back and soon, these subsequent actions dephase the quantum state.

The key question to answer is that: Once we observe the cat, can we then conclude that it had been in a dead state since the quantum event occurred? Of course. This information is therefore knowable and so our Cartesian local causality is fulfilled as far as the cat is concerned. There is only a very short period of entanglement of the cat with the quantum event and only during that very brief time is there entanglement.

Likewise, even the quantum particle is likely to dephase rather quickly and so we conclude the reality of the quantum uncertainty for the same reason. The particle states are subject to entanglement only during a short period. Once again, a soon as an event is knowable, it is no longer entangled and we just lack that knowledge of the event.

John,

you wrote "Extrapolating, there are those who believe and would argue that the entire Universe exists (has reality) only because there are observers to observe or measure it." Whether that point of view is correct depends upon what one is referring to when one says "the universe". If it means all that materially (essentially , fundamentally) exists, the Object universe, that is different from the visible universe, that I call the Image universe. The Image universe is a product of the receipt and processing of EM data giving an output that depicts what was together with temporal spread, and distortion due to such phenomena as gravitational lensing. It is a fabrication that relies upon observation, detection equipment, artistic interpretation of measurements and final observer visual senses. The beautifully coloured renderings of distant galactic dust clouds do not exist out there in space as they are seen. Material change will have occurred over the light years it has taken the data to reach the Earth. Image reality requires observers. Object reality, actualised objects consisting of atoms and fermion particles do not.

What happens upon observation is consideration of the object changes from all possible states in abstract phase space, that is not any singular iteration of the object universe, to consideration of the singular image reality produced from received EM data, when the observer looks or the measurement is taken. These are very different concepts even if they are given the same name such as the cat.

Inorganic devices and sensitive materials can be regarded as observers because they receive em data and convert it into an image reality output. Eg. EM data in ,ink on paper or screen image output.

Georgina,

That phrase "image reality" is a new one that I've never come across before. I assume 'image' refers to not only sight but sound, taste, smell and touch as well, since a blind person can't image you or any part of the Universe.

Actually I quite like the idea of Panpsychism which basically postulates that everything is an observer, even electrons and positrons; rocks and minerals; a can of this and a can of that, you name it, it's an observer. All things have consciousness and awareness of other things even if they don't have anything akin to eyesight. That makes a weird sort of sense since everything material must have gravity and if you have gravity you must 'observe' everything else that has gravity. So my two cats 'observe' each other because each has a mass and therefore gravity and thus attract each other even if they are in separate rooms and out of visual sight of each other. The same applies to two cans of food. You name it, it observes. Thus, the entire Universe has reality because everything is 'observing' everything else 24/7/52.

The interesting thing about that is that with everything observing everything else all the time, there can be no superposition-of-state and no probabilities and no collapse of any wave-function.

John Prytz

Mr. Agnew,

So no doubt you believe, even with qualifiers, that Schrodinger's Cat is both alive and dead at the same time (however short that interval might be) since it is entangled with that radioactive nucleus that has both decayed and not decayed at the same time (however short that interval might be). You did state that all action involves entanglement.

Here's a lesson in common sense, or more formally logic if you will - something cannot both be and not be at the same time in the same place for however briefly a time that might be. To suggest otherwise is just pure ignorance. If you make the claim to the contrary, show me the evidence that superposition-of-state and the so-called (alleged and associated) 'collapse' of the wave-function is experimentally true. You can't because when you allegedly 'collapse' the wave-function with your observation or measurement, how do you know the alleged wave-function wasn't already 'collapsed' by the time you peeked or more to the point perhaps in reality had always been in a 'collapsed' state on the logical grounds that the wave-function can't 'collapse' since there was no superposition-of-state with an associated wave-function that required 'collapsing' in the first place. The 'collapse' is pure fiction.

Further, there's no experiment that demonstrates a superposition-of-state, that something is simultaneously both in this state AND in that state at the same time and place. That's because experimental results always show that you end up with this state OR that state. Experiments designed to detect particles find particles; experiments designed to detect waves detect waves, even if the experiments are closely related, like the Double-Slit experiment and variations on that theme.

So how do I explain wave-particle duality? I explain duality via the simulation hypothesis. Simulating the anomalous results inherent in the Double-Slit experiment(s) is no big deal to a software programmer. I've consistently stated that the best evidence for the Simulated (Virtual Reality) Universe resides in quantum physics.

John Prytz

Yes, you are making progress...

"Here's a lesson in common sense, or more formally logic if you will - something cannot both be and not be at the same time in the same place for however briefly a time that might be."

Now you finally have stated the essence of entanglement and of our quantum reality and it certainly is beyond our normal experience, but still within the subroutine of our reality. There are objects that can be in two places at once as matter waves.

Evolution only gives us the ability, a common sense as you say, for predictions of common action. Microscopic matter is simply beyond our normal experience. Good luck in your journey of pure common sense.

An object, like a photon, can be in two places at the same time as coherent matter waves and that superposition can persist for the time of the universe. We do not sense single photons directly, but do have equipment and technology that can. It is from these measurements that our quantum reality has emerged.

Most action of common experience, like cats and neural impulse waves, involve very short dephasing times, but simple microscopic actions, like photon matter waves, can persist as coherent with a source for very long times. We see the coherent cosmic microwave background source some 13.8 Byrs ago, or more properly a z = 1091, and another observer in a galaxy across the universe sees the same CMB source. Our reality is entangled with that observer when we see the same actions at the CMB source.

That is simply the way our universe works, our reality, or what you would say, the master gamer messed up this subroutine somehow for our reality. You explain anything you need to explain with a master gamer, but I choose to simply explain things with the reality that simply is the way it is.

As far as superposition of matter waves and what is commonly called wave function collapse, there are confusing and often conflicting different interpretations going around like viruses. This superposition of our intuitive and mathematical languages results in quantum interference and standing waves of discourse. The funny thing is that the quantum math works fine...it is only the interpretations and superposition of languages that gets entangled.

If you stand at a node of constructive interference, you believe that reality makes sense and all objects have only a local reality associated with the norms of time and matter. If you stand in an antinode of destructive interference, all reality seems to vanish and nothing seems to make sense since all objects seem to be everywhere at the same time. At a universal antinode, all objects in the universe seem to vanish in moment of destructive interference.

But common reality is only what we sense with the norms of time and matter and so the antinodes of quantum interference are just what we imagine and calculate with our mathematics and indirectly observe. Our intuition is very good for normal predictions where the norms of time and matter dominate. Our intuition tends to fail when we measure the interference of time and matter amplitudes and it is that quantum interference that is the root of our reality...or subroutine as you say.

It would seem to me like we had a very good master gamer after all...