It is the hallmark of any deep truth that its negation is also a deep truth.

Prediction is very difficult, especially if it's about the future.

It is very difficult to make an accurate prediction, especially about the future.

An independant reality in the ordinary physical sense can neither be ascribed to the phenomenon nor to the agencies of observation.

A physicist visits a colleague and notices a horseshoe hanging on the wall above the entrance. 'Do you really believe that a horseshoe brings luck?' he asks. 'No,' replies the colleague, 'but I've been told that it works even if you don't believe in it.'

Those who are not shocked when they first come across quantum theory cannot possibly have understood it.

Einstein, stop telling God what to do!