There is one thing that I don't understand when considering quantum mechanics for macroscopic bodies. It is said that classical mechanics is a valid approximation and that macroscopic bodies that we encounter on everyday basis have a small uncertainty in position and momentum.(adsbygoogle = window.adsbygoogle || []).push({});

So far, so good.

But when the many-worlds interpretation is invoked, there are suggestions that the branching in the macroscopic world is occuring. The problem with this is the probability. If we just consider things from a probabilistic perspective, there is an enormous chance that the things around us will behave approximately classicaly and follow classical paths without some miracoulous deviations, like my monitor suddenly turning left without any force applied to it. So if we strictly try to give probabilities for macroscopic behaviour, one outcome has something like 99.9999..% probability and sudden deviations have very, very small amplitudes.

But in MWI, all outcomes occur. In fact it is ridicoulous to say all, it's better to say one that we would expect (high amplitude branch) and many, many low probability branches. So does quantum mechanics actually give probabilities for macroscopic behavior like I mentioned and do MWI supporters really believe that the branching occurs on this weird way, where one branch is always extremely probable and others are negligible?

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# I Born rule for macroscopic objects

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