Is it possible that, at the moment of observation, a timeline is created where an object is in a state which contrasts its state in the current timeline?

Using Schrodinger's cat as an example, let's assume that the Copenhagen interpretation is correct and say that the cat is both alive and dead before observation, by consequence, when I open the box and see the cat dead, there should be a timeline split, creating a universe where the cat is alive instead of dead. Is this possible? I know we can't really know for sure, but is it possible?


closed as primarily opinion-based by CuriousOne, sammy gerbil, user36790, knzhou, John Rennie Jul 27 '16 at 8:53

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ As far I know, there is no difference in the math, only in the interpretation. Thus it is more phylosophical question as physical (although I think it is still ontopic). $\endgroup$ – peterh Jul 27 '16 at 1:46
  • $\begingroup$ What is more likely, that the world is what the world is or that there are infinities of infinities potentiated to infinity of worlds that nobody can see? How can we rule out that the ones we can't see are populated by fairies? :-) $\endgroup$ – CuriousOne Jul 27 '16 at 1:52
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    $\begingroup$ I am voting to close this question as off topic because it is asking for an opinion. $\endgroup$ – sammy gerbil Jul 27 '16 at 1:53
  • $\begingroup$ en.wikipedia.org/wiki/Many-worlds_interpretation $\endgroup$ – Wolphram jonny Jul 27 '16 at 2:03
  • $\begingroup$ Why not ask a real question about the decoherence interpretation of collapse that arose out of our understanding of entanglement? There is real physics there. $\endgroup$ – Bob Bee Jul 27 '16 at 3:10

when I open the box and see the cat dead, there should be a timeline split, creating a universe where the cat is alive instead of dead. Is this possible? I know we can't really know for sure, but is it possible?

One has to keep in mind clearly that physics is about mathematical models that fit data and predict new observations.

One can have an infinity of mathematical models but they are irrelevant to physics unless tied up with predictions for observations.

The particular mathematical model of many worlds is a way of looking at the mathematical model of quantum mechanics , the functions, and giving them reality, i.e. proposing that they predict many worlds. Unfortunately, they do not give a single prediction that will be distinguishable from the usual quantum mechanical predictions, so there is not meaning to "possible". It is mathematically possible but physically indistinguishable from the usual interpretation.

From then on, it is science fiction, that can invent both physics and mathematics.


Interaction between a physical object in a superposition, and another object, usually causes the second object to also go into a superposed state, that will be correlated in some way with the original superposed state. For example, this is true of the quantum-mechanical description of a measurement interaction - some part of the measurement device has to physically interact with the measured object - and the situation where the experimenter opens the catbox falls into this category in a complicated way (the eyes of the experimenter become entangled with the quantum state of the interior of the box, which will include photons that exit the box).

For a good measurement, you want the measuring device to have multiple states which are cleanly correlated with the different quantum states of the measured object. That way, the state of the measuring device can be regarded as a reliable proxy for the state of the measured object - e.g. if the Geiger counter clicked, it should mean, with close to 100% probability, that a charged particle really did pass by.

To put it another way, the whole system of detector+object, if described quantum-mechanically, should go into a superposition which mostly consists of "object in state i, detector shows state i", summed over i, plus a small contribution from mismatch states like "object in state i, detector shows state j". There is a whole branch of quantum mechanics called quantum measurement theory, which analyzes the physics of measurements.

The many-worlds theorists certainly want to regard this as a situation in which there are now multiple worlds, one for each state of the detector. But when you try to argue this in detail, it falls apart somewhat. There isn't an objective way to divide up the total detector+object superposition into the alleged worlds; and when you try to do this, the probabilities come out wrong - some observations should be more common than others, yet you just get one world for each possible measurement, implying that they are equally common.

(In fact, in the most rigorous version of many-worlds theory, "many interacting worlds", all the parallel worlds are actually distinct from the beginning to the end of time - they don't actually split in two. Instead, they converge and diverge in similarity.)

By the way, the original and true version of the Copenhagen interpretation does not say that the cat is both dead and alive until you look. It just says that you don't know, until you look. The quantum superposition is not interpreted as the reality, it's just a statement about possibilities. That might sound simple and sensible and fair, but the problem is that it is very hard to come up with a theory beyond quantum mechanics, that gives the same predictions, and which also makes definite statements about what the physical reality actually is, at every moment.


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