I am a bit confused about the UP. I raise this question to help me deal with free-will issues but it belongs in physics. What does the UP REALLY say? I here one side promoting it as proof that humans cannot predict both the momentum and position of a particle at the same time. The other side I read is that it is proof that the universe is not deterministic. Which side is truly correct? Please Register or Log in to view the hidden image! From what I understand, it's the former that is true.
i look at it this way, after taking a basic physics/chemistry class that only slightly delved into QM, and having several involved discussions on this very topic: particles like the electron are so small and are moving so quickly within such a miniscule area that it is impossible to pinpoint just where it is at any given moment. there is no specific point in space at which the electron is, it is more like a wave moving around the nucleus. quantum mechanics shows that there is a probability of where the electron is, within a range. it is not completely chaotic, but it is not distinct either. my view of time and space is that these quantum events are the cause of everything you sense around you--the cause of even your conscious thought--but that they occur in such a vast continual amount that we percieve them as being deterministic. each quantum event is like a single pixel on your computer screen, but from a few feet away you can only see the big picture.
So you are saying that you understand UP to mean that things happen without a cause? That does not make sense to me. Please Register or Log in to view the hidden image!
The usual version of the UP says that, beyong the limits specified by the principle, it is meaningless to talk about a particle having a particular position and momentum. A weak statement of the principle is to say that humans can't measure both the position and momentum simultaneously beyond certain limits, but the principle goes deeper than that, to say when it is actually meaningful to talk about specific positions and momenta.
no, not really. every action around you is just a collection of quantum events occuring on a level that are too small to notice individually. the cause is the particle wave function, but it is so small and travels with such a momentum that we are not able to track it down to one point as we may with a single molecule. this goes against determinism in that (for all intents and purposes) everything that happens is the effect of tiny unpredictable waves, smaller than anything you can imagine, yet having no definite measure. but there is still a sense of determinism in that there is a range of probability in which these waves act and that it is determined by their state.
I can´t realy see why they exclude eachother. UP just says that humans can never(or any time soon) know one of those things. That doesn´t mean that the universe is not deterministic.
So we do not know if the universe is deterministic, we just know we cannot use things like light to pinpoint the location and momentum of a particle. RIght?
Well because on a few threads, I have been countered by saying that quantum mechanics proves the universe isn't deterministic. I find it hard to see what on Earth they are talking about.
