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Comment by gus_massa

> Bohr postulated a distinction between the quantum world and the world of everyday objects. A “classical” object is an object of everyday experience. It has, for example, a definite position and momentum, whether observed or not. A “quantum” object, such as an electron, has a different status; it’s an abstraction. Some properties, such as electrical charge, belong to the electron abstraction intrinsically, but others can be said to exist only when they are measured or observed.

This is a common error. Macroscopic "everyday" objects don't have a definite position and momentum. Macroscopic objects are quantum objects. But when the mass is big enough, the position and momentum can be defined simultaneously with an error that is so small that you can just ignore the uncertainty and approximate them as classical objects.

(Looking at them as classical objects is just a good approximation, like ignoring the gravity force of the Moon in most common situations.)

Anyway, the measurement problem is a real problem and nobody knows how to solve it. The current fade is to use decoherence to explain it. It is a promising idea, so I hope that in a few years/decades/centuries we can give a good explanation of the measurements that avoid anything that looks like magic.

parent gus_massa 7 years ago

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