[deleted]
Cristi
"Do you think that QM was invented by some guys to look cool, and that there was no need for it?"
No. As I said, it was developed because the actual circumstance was not fully understood, so that got 'relegated' to classical, and the new concepts took over.
And here, in the next paragraph, is an example of that process: "You think that "what happened has already happened". Yes. And I do not need to look at Max-Zehnder, or anybody else to say that, just consider the irrefutable generic physical facts. The photon, or indeed anything else which has physical presence, must be in some physically existent state at any given time, otherwise how is it physically existent? There is a fundamental contradiction in the stance. On the one hand discrete definitive states are presumed, otherwise there would be nothing to consider, but then they are imbued with some form of indefiniteness, which means they cannot be what they are being considered to be in the first place.
"If "what happened has already happened", one should be able to say what happened at this point." Only if we understood all the circumstances of the previous physically existent state in the sequence. Whether we can explain/differentiate something is irrelevant to whether it occurred or not. And the simple fact is that discrete physically existent states cannot be identified by experimentation. The degree of alteration and duration involved is vanishingly small. What is happening here is that at the conceptual level of 'objects' we are deeming physical existence on the basis of superficial physical characteristics. We even, assert that the 'object' persists in existence but has changed, which is a contradiction. We even know this is not the case. We know any given 'object' involves difference, ie alteration, but we do not take that to its logical conclusion, ie it is physically a sequence of discrete definitive physically existent states. And when we consider its reality, we are really considering one of those, although we are actually unable to differentiate them.
Now, QM is positively trying to consider reality at the existential level. And part of the problem is that we are still only identifying parts or amalgams of states. But it was thought necessary, wrongly, that to do so rested on a new presumption about how physical existence occurred, which can be summed up as involving some form of non-definitiveness (relativity has the same problem). Which it does not, obviously, because otherwise there could not be existence and difference. The immediate questions in that situation are, so what exists, and what becomes what? Because if nothing else, we know there is physical existence independently of the mechanisms whereby we are aware of it, and we know that if we compare such inputs there is difference. Something (definitive) has happened (definitive), and something else (definive) then happened (definitive), etc.
Which brings me back to the main point. Observation, or any form of sensing, involves the receipt of physical input. Receipt, ie it exists independently and if the right mechanism is in the line of travel it will be received. The brick wall behind you received similar light, it just cannot then process it. What happens subsequently is irrelevant to the physical circumstance, because that involves the development of a perception as to what was received, and is subsequent. To receive something, means that that something has already occurred. So the concept that observation, etc, has an effect on the physical circumstance is nonsense. That alone kills any physical theory which invokes observational intervention stone dead. However, just in case(!), what is physically received is not what physically occurred anyway, but a physically existent representation of it, eg light. At most one can say that its physically existent form ceased to exist on the interaction of receipt (just as it does with a brick). Again what existed up to that point did so. The act of measuring which is often not differentiated from the act of observation, just involves the selection of a time at which observation is deemed to have occurred, and a reference to enable comparison in order to identify difference.
The real lesson here is that we should have adhered to basic rules about physical existence (and understood them in the first place), and not have overturned them when confronted by problems/occurrences when trying to consider it at its elementary level. When I was young television broadcasting was prone to problems, so often a message would be shown which said, 'please do not adjust your set we are having problems with the transmission'.
Paul