In search of Schroedingers cat - john gribbin

•  In the classical world, everything has its cause. You can trace the cause of any event backward in time to find the cause of the cause, and what caused that, and so on back to the Big Bang... But in the world of the quantum... no outside agency pushes the electron... it just happens, for no particular reason, now rather than then.
• In the world of the very small, where particle and wave aspects of reality are equally significant, things do not behave in any way that we can understand from our experience of the everyday world.
• There is no physical analogy we can make to understand what goes on inside atoms. Atoms behave like atoms, nothing else
• electron... something unknown is doing we don't know what
• even without understanding why the recipes (formula) work people are able to cook so effectively with quanta
• we cannot predict the future. But it is quite within the rules ... to calculate backwards and work out exactly what the position and momentum of an electron, say, was at some time in the past. The future is inherently uncertain - we do not know exactly where we are going: but the past clearly defined.
• This is the really fundamental feature of the quantum world. It is interesting that there are limits to our knowledge of what an electron is doing when we are looking at it, but it is absolutely mind-blowing to discover that we have no idea at all what it is doing when we are not looking at it.
• The world seems to keep all its options, all it probabilities open for as long as possible
• The physics is impossible, but the math is clean and simple, familiar equations to any physicist. As long as you avoid asking what it means, there are no problems.
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