If the observer does some thought experiment, he will only visualize something. He will only observe his imagination, which may not have any reality at all. So, what interaction may be happening in this observation of 'visualization of reality'?
Nothing, but do you call this as observation in true sense? Actually what he is saying is that to observe or measure something you need to interact with certain signals. Unfortunately he failed to pick up this 'certain signal' aspect and got it messed up and on top of that became abusive too.
Well, thoughts really do occur, right? Imagining or visualising a thought experiment means neurons in your brain must communicate, this means interactions must occur. So you observe this sum of interactions (assuming the whole isn't greater than the parts) in an internal sense, rather than externally. Of course evolved animals with brains have an internal sense of interaction, brains and neurons are mostly internal organs, apart from the specialised neurons that function as detectors. Of course these specialised 'input neurons' are near the outside, where all the events in the external world that might have some causal effect on you and your survival are easier to interact with. In particular, humans have a very evolved sense of vision. We don't however have more than we need in that department. What we have is the product of a long evolutionary process that gave us a vision system which is fit for the purpose (of survival) but not more than fit. Evolution is parsimonious, and moreover, subject to the same interactions (events, or what have you) as anything else.
Even having a single neuron is not necessary in order to be an "observer" in the sense one is required to flip quantum entanglement states in physics. Electrons or photons do not have neurons. Neither does a simple focusing lens. Or photographic film. But in all cases, a direction in which to observe must be chosen. I can't make it clearer than that.
Consider a decaying atom of poitonium. When the electron and the positron reach the point that their degenerate wave functions come in contact with each other, FREEZE THAT INSTANT IN TIME for the purposes of this thought experiment. In the next instant, their respective wave functions will completely unravel each other and produce a pair of gamma rays, axially oriented and propagating away from each other at c in opposite directions. We are going to do something else before this mutual annihilation happens. Consider two mutually relativistic observers traveling in opposing directions along the same axis as those photons are poised to leave. One observer will eventually see a blue shifted (higher energy) gamma ray coming toward them, and a red shifted (lower energy) one leaving that central area in the opposing direction. The observer traveling in the opposite direction will of course see the same thing, with red shifted substituted for blue shifted and verse vicea. But the instant before the collision, if the timing is right, one observer sees the two charged particles spiraling in right handed, the other observer seeing them spiraling in left handed. This is how we know, these positions are distinguished in terms of both wave functions. No separation in terms of light travel time is really necessary for the flip from right-to-left, or left-to--right handed spirals (you may assume, this is happening in a cloud chamber) to occur instantaneously, because this operation occurs FTL So fast, in fact, that if the record of the event is viewed at all, it must be recorded in a manner that it is viewed from the point of view of a acompendium of past history. The instant before their respective wave functions begin to unravel, IS THAT EVENT SIMULTANEOUS IN ALL REFERENCE FRAMES IN RELATIVE MOTION OR AT REST, or is it not? This is what makes this situation unique. Special Relativity simply doesn't apply here because the events REALLY ARE simultaneous, and this is disallowed by SR for events separated by light travel time. This is demonstrating both the nature of time and its relation to quantum entanglement. We have demonstrated in this case that entanglement is instantaneous in all inertial reference frames AND ALSO at c. We have also demonstrated that the observation of an instantaneous quantum event and , by means of extension, ENTANGLEMENT ITSELF, is equivalent to a change in the direction of spin. This is what localizes particles of matter physically, and also perpetuates them indefinately with respect to time. If you wished to explore chirality and quantum entanglement on a more intimate basis in physics, you could easily do so by making your hadrons collide in the vicinity of decaying atoms of positronium. I suspect this process may actually be involved with heavier amounts of particle nucleosynthesis, as well as yield clues to how it is that matter and not antimatter dominates as the most abundant constituent of our universe, because if this process orients itself in a particular direction just prior to another kind of high energy interaction, the discrepancy (matter:antimatter) would be of a dramatic difference. It might even be possible to stack the deck of positronium playing cards in the other direction. The control of a lot of energy may actually be possible. Interested yet? This experiment should help you solve dozens of yet unsolved high energy physics riddles.
For bound energy (matter or antimatter) locality in space = persistence in time. Relative motion alters relative rates of the passage of time INTERVALS, but not the persistence in time for matter or antimatter, for all relative v<c. No absolute positions are meaningful, in the uncertainty principle or anywhere else. But we are defining an instant of absolute time for the present instant only. For unbound energy propagating in space, non-locality in space = persistence in time. Here is the key observation that derives of these two statements: ALL FORMS OF OF ENERGY SEEK PERSISTENCE IN TIME. Or to put it another way somewhat older, energy is conserved. I just derived that idea raw from a combination of Special Relativity and quantum entanglement. There is power in knowing what inertia is. Either form of energy, or even the quantum field that is space itself, may be entangled, which basically explains everything in a universe of energy transfers. Quantum foam included. The virtual energy of the quantum foam remains virtual because it is not entangled, and therefore not conserved. It is energy minus the permanence provided by time. Can't wait to see what cosmologists may make of that. Stop removing time from proportional equations, or using c as the basis of, or something proportional to time, which it is NOT. The basis of time cannot be a velocity, and not the speed of light in particular. Your math will take you much further if you abandon the whole idea that it is. Leave your string and group theories on the shelf to collect pixie dust or something as real as they aren't. This is the relation I have evidently been seeking for a very long time. Tricky. No wonder that statement took so long to hatch. It is not something that can be derived from first mathematical principles, and is more confusing than obvious, unless you make the fullest use of the observations of the positronium thought experiment. It's all there. You can do physics without knowing this, but it's harder, and not as certain as more esoteric math is added. Bindings to reality and especially time are easily lost.
That's in line with the OP, there isn't anything special about observers. If, however, you want to observe "thoughts", which was more or less the thrust of my response to hansda, you do need neurons. Lots and lots of neurons. On the other hand, we don't know that much about what neurons do collectively, or what constitutes thinking, to say a whole lot about what 'observing thoughts' means. But it must be because of interactions, like everything else with a physical basis which is a collection of particles in some configuration. Physics can give us the simple end of that, but we're still trying to figure out how brain-programming actually works (we don't really know what thoughts are, although we can understand thought experiments). I don't know so much about choosing a direction to observe; particles "just" interact, they exchange something which I suppose has to mean a direction is chosen for the exchange (of quantum information). This is what a Feynman diagram says (in the context of interaction), essentially.
And here we have the animated version (!). Please Register or Log in to view the hidden image! Time is the vertical axis, the photon has a real path through space and time (it isn't virtual). The electrons can be any two electrons; one could be on the moon, say, and the other in your eye. To see a moon, how many electrons are needed? That's obviously a naive question, how do electrons see? If it's asking how many electrons need to capture photons from the moon before "we" see a moon, that probably has an answer on the back of some envelope.
I'm not suggesting this is necessarily an original idea, but this does not surprise me. Feynman was brilliant.
In order for a (real, not virtual) photon to be emitted from an electron, a force must be provided to that electron from another electric charge; either a proton within the context of an energy change within an atom, or another electron. Of course, in the Standard Model, the photon is the boson force carrier for EM. This model is fine. You will "see" a photon before you can identify that it came from something identifiable as a moon, but seeing even a single photon from there is an observation. The full moon viewed from Earth substends about 1/2 degree of arc, and you would need to see enough of them to perceive its outline.
Some interactions may be happening within our brain, in our thoughts/visualisation of the things. Unless some signals interact with our brain, can we observe that? In the case, if the signals dont interact with our brain; the event may be happening in the real world but the observer will not be able to observe it.
You are talking about visual analysis. You see an event, and your brain does analysis, that sort of observation. That's day today stuff. What if the object/event does not emit signal in visual EM range? Or in audible db range? Neither you can see nor you can hear, so you take the help of instruments. It happens that you record data continuously, and then do the data analysis. Any data recording device will have some kind of self or external signal interaction. But these interaction may not have anything to do with the event as such. Interaction is a two way process. When you record signal from some far off galaxy, you do not interact with galaxy, you just record the light emitted by that galaxy and apply your data interpretation tools. Thought visualisation or dreams, say you visualize making out with someone, where is the interaction? It's funny if someone calls the body functioning during this visualisation or dreaming process as interaction with the event. Infact during this process you are observing nothing, you are just visualizing. Yes there is one more type of observation, that is you send some probe signal and record the return signal. That could be classified as actual interaction based observation.
I do not see this 'direction' significance. How does it matter? Talk to any ATC, he will tell you about rotary motion of his observation device...Radar.
It matters a great deal. In all variations of the double slit experiment, including the entangled version, choosing a slit is equivalent to choosing a direction. You either look at one slit, or the other. They aren't separated by a wide angle, but an angle separates them, and that is enough. Choosing to observe one photon of an entangled pair, or one electron of an entangled pair makes a difference too, and for the same reason. Choosing to view "bound or unbound" energy as a particle or a wave, equivalent to the uncertainty principle, makes a difference in terms of what one means by "locality", or position. Unbound energy only persists in time by propagating at c (being non-local). Bound energy only persists in time by being local. Together these two principles are simply the law of the conservation of energy, (energy persisting with respect to time) the most important principle in all of physics. No matter how you observe energy, as a particle or as a wave, it is conserved. Of course, it will change the precision with which you can observe one (position or velocity, particle or wave) simply by observing the other kind of behavior. The difference in locality with respect to time is the reason. Unbound (wave) energy has inertia in only one direction. Bound energy has inertia in all directions at once, but can also be viewed as a wave. Choosing to view a pair of simultaneous events separated by light travel time from a rest frame, or from opposing relativistic frames of reference along the line connecting those events will yield three different observations as to which event happened first, last, or at the same time. It is chiefly relativity that explains what an "observation" is, and why. Choosing a direction from which to observe is literally all there is to understand. No other feature of an observer is important in any respect, least of all possessing cognition, which is possible with or without neurons anyway. Paramecia do it throughout their entire short life spans. No neurons. No brain cells or brain. Finally, you are all viewing some really original stuff I am posting. This is a good deal deeper and much thicker than the stuff I posted when I first started here. I don't expect you to get it all at once, but thanks in advance for reading a little of it.
Ok. I got it all. Don't worry. Now pl just look at the patterns not at the slits! Secondly keep adding slits, why 2, why not 3,4 or so, and keep checking patterns.
If you have two different coins, one copper the other silver, you can always tell which coin is which and which face is showing. Not so if they are quantum coins. You need a copper or silver measuring device, and a heads or tails measuring device. Copper or silver could be spin in the x direction, heads or tails could be spin in the y direction, or any two incomparables.
Those items marked "LENS" in the diagram shown above are the only observers. Those lenses have neither brains nor neurons, yet focusing or defocusing them results either in the familiar double slit interference pattern, or the LACK of one, in either the delayed or the undelayed version of the entangled double slit experiement. Note that the delay need not be limited by the length of the fiber optic delay line. The quantum entangled spin flips are simultaneous; "FTL", and the same goes for the entangled photon(s) they produce. Note that A PAIR of electric charges for accelerating electrons is necessary in order to produce a photon, or a pair of photons. In a hydrogen atom, one of the charges happens to be a positive one. I'm not interested in adding more slits. ONLY A PAIR of entangled electrons is responsible for producing an entangled photon. ONLY A PAIR of slits is relevant to observing one or the other. If this model were a Bohr atom (it is not), you could think of it in terms of the pari of electrons as particles tracing a relativistic path. This is equivalent to Minkowski's simultanaeity experiment of simultaneous events viewed by observers in relativistic relative motion in diametrically opposed directions. Except in the case of a pair of electrons producing entangled photons, ANY TINY ANGLE of separation of the observers will yield the same causality reversal it does for a diameter for any chord of the electron orbitals. The latter works for other kinds of electron probability density clouds, Gryzinski, free fall electrons, or for any other model you care to throw in to the mix. Relativity WITH ENTANGLEMENT is key to understanding any of them. By WITH ENTANGLEMEMY, I mean, NOT using Minkowski's determination that a time interval or a velocity was proportional to the instant of time that is entanglement in all inertial frames of reference, and certainly not his edict that no two events can ever be simultaneous. I mean, look at this experiment. This is an example of simultaneous entangled events. Nothing more. Nothing less. This is science in its purest observational form, and I have just explained why it works the way it does. So much for Doctor Quantum and his spooky quantum mysteries. Relativity with entanglement wins. When Minkowski made that mistake, he trashed the conservation of energy. That happens the instant you try to equivocate an instant of time with a time interval. An instant of time exists, but does not require inertia in order to change entanglement state. Freezing an instant of time robs inertia from anything that otherwise would have it, EXCEPT FOR unbound energy, which requires propagation at c in order for it to persist in time. You have to understand what it is you are doing, temporally speaking. The double slit mystery is completely, utterly, solved.
