The very act of observing disturbs the system.

It will never be possible by pure reason to arrive at some absolute truth.

What we observe is not nature itself, but nature exposed to our method of questioning.

[T]he atoms or elementary particles themselves are not real; they form a world of potentialities or possibilities rather than one of things or facts.

Only a few know, how much one must know to know how little one knows.

It was about three o'clock at night when the final result of the calculation [which gave birth to quantum mechanics] lay before me ... At first I was deeply shaken ... I was so excited that I could not think of sleep. So I left the house ... and awaited the sunrise on top of a rock.

Natural science, does not simply describe and explain nature; it is part of the interplay between nature and ourselves