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quote:Originally posted by harryneildAlso does Heisenberg's uncertanity principle mean that it isn't possible to measure a particle's velocity and position accurately? Or does it mean that the particles in fact haven't got a definite velocity or position?
quote:The basic debate between Einstein and Bohr (including Heisenberg's Uncertainty Principle) was that Einstein was in essence saying: "Of course, we can know where something is; we can know the position of a moving particle if we know every possible detail, and thereby by extension, we can predict where it will go." Bohr and Heisenberg were saying the opposite: "There is no way to know where a moving particle is ever even given every possible detail, and thereby by extension, we can never predict where it will go."Einstein was convinced that this interpretation was in error. His reasoning was that all previously known probability distributions arose from deterministic events. The distribution of a flipped coin or a rolled dice can be described with a probability distribution (50% heads, 50% tails). But this does not mean that their physical motions are unpredictable. Ordinary mechanics can be used to calculate exactly how each coin will land, if the forces acting on it are known. And the heads/tails distribution will still line up with the probability distribution (given random initial forces).Einstein assumed that there are similar hidden variables in quantum mechanics which underlie the observed probabilities and that these variables, if known, would show that there was what Einstein termed "local realism", a description opposite to the uncertainty principle, being that all objects must already have their properties before they are observed or measured. For the greater part of the twentieth century, there were many such hidden variable theories proposed, but in 1964 John Bell theorized the Bell inequality to counter them, which postulated that although the behavior of an individual particle is random, it is also correlated with the behavior of other particles. Therefore, if the uncertainty principle is the result of some deterministic process in which a particle has local realism, it must be the case that particles at great distances instantly transmit information to each other to ensure that the correlations in behavior between particles occur. The interpretation of Bell's theorem explicitly prevents any local hidden variable theory from holding true because it shows the necessity of a system to describe correlations between objects. In the years following, Bell's theorem was tested and has held up experimentally time and time again, and these experiments are in a sense the clearest experimental confirmation of quantum mechanics. It is worth noting that Bell's theorem only applies to local hidden variable theories; non-local hidden variable theories can still exist (which some, including Bell, think is what can bridge the conceptual gap between quantum mechanics and the observable world).With theories, it is pointless to try to decide whether Einstein's view or Heisenberg's view is right or wrong in the quantum mechanical world. The test of a theory is which is more scientifically useful, and testing has shown to date that Heisenberg's view has been more useful in explaining physical subatomic phenomena.
quote:Originally posted by harryneildAn atom cannot choose where to go and what to react with, it is just purely statistical chance that it is where it is. Humans, and indeed all life, consist of these particles that aren't living, yet somehow they work together to form an astonishingly complex lifeform. If i think about a simple process such as me moving my arm at will and i go back to the basic starting events, there will be an initial chemical reaction in a neuron somewhere in my brain, right?What causes this chemical reaction? The chemicals that make me don't think and realise that they want my arm to move and so start off the long chain of events that lead up to it. If it was started by a previous chemical reaction, then you could say that it's starter reaction was initialised by another starter reaction and so on. This brings me to the conclusion that we do no have free will and that the whole idea of destiny and an inevitable series of events is true.I don't believe this because i prefer thinking that i choose to behave and act the way i do and that if i wanted, it could be different.
quote:There is a greater problem with the debate between free will and determinism – the very nature of the question itself. If we remove the notion of free will from our model, then how can you ask a question, for is not the nature of questioning the universe itself an act of free will, and if free will is an illusion, then so too is the question, and so to is its answer.