Title: Is Quantum Uncertainty All in the Mind? - SAND
Headings: Is Quantum Uncertainty All in the Mind?
Is Quantum Uncertainty All in the Mind?
“A physicist is just an atom’s way of looking at itself.”
Frequently wrong
End of observers

Content: According to this provocative idea, the world is not uncertain – we are. The idea that an objective, universally valid view of the world can be achieved by making properly controlled measurements is perhaps the most basic assumption of modern science. It works well enough in the macroscopic, classical world. Kick a football, and Newton’s laws of motion tell you where it will be later, regardless of who is watching it and how. Kick a quantum particle such as an electron or a quark, though, and the certainty vanishes. At best, quantum theory allows you to calculate the probability of one outcome from many encoded in a multifaceted wave function that describes the particle’s state. Another observer making an identical measurement on an identical particle might measure something very different. You have no way of saying for sure what will happen. So what state is a quantum object in when no one is looking? The most widely accepted answer is the Copenhagen interpretation, so named after the site of many early quantum musings.