Quote:
Originally Posted by Ernest Wilson
Why is "Uncertainty" a Principle. Before you grab the keyboard and tell me "How can anyone be so stupid as not to know about the "Uncertainty Principle"; THERE I have said it for you!! so put your thinking cap on and look into it.
Ernie.
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Uncertainty is a principle because it's one of the basic tenets which underlies QM (Quantum Mechanics). It governs the behaviour of matter on the scales that QM deals with. An example, with electrons....it deals with the uncertainty in the determination of both the position an electron has at any given moment in its orbit of the nucleus, and the direction (momentum) in which it's moving. If you try to accurately determine one of those values you find that you cannot know what the other is, for any certainty. So, you may know the electron is in position X, but you cannot know exactly where it is moving to. In actual fact, it could be moving in every direction simultaneously. Conversely, if you know it's moving in direction Y, the electron could be in all positions of its orbit simultaneously.
It's all because of a little thing known as quantum superposition or the superposition of state. What this means is until a quantum system is observed, the whole system is in a state of flux such that all the possible paths or events which can occur within that system are equally liable to be occurring all at the same time. In other words, there's an infinite number of probable states that the system can be in simultaneously and it's only when that system is observed that the system collapses into the state that the observer observes it in. Collapses meaning that the most probable state the system can be in, is the one the observer sees or chooses to see that system in. All those other states will either disappear (the Copenhagen Interpretation) or exists as parallel realities (Many Worlds Interpretation or Relative State Formulation) which exist as probabilities of decreasing value the further away from the ground (or collapsed) state they are. Another thing to remember is that the observer can be anything either within or outside that system, be it someone looking at it or a particle within that system interacting with anything within the system. For a system to be in quantum superposition there must be absolutely no interaction with or within it, the moment there is it becomes what the observation tells it to be or sees it as.
I hope that has cleared things up
