Isolated material particles ...

Isolated material particles are abstractions, their properties being definable and observable only through their interaction with other systems .
Isolated material particles are abstractions, their properties being definable and observable only through their interaction with other systems .
 Niels Bohr

More phrases

Effort only fully releases its reward after a person refuses to quit.
Never complain and never explain.
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 George S. Patton
Problems are not stop signs, they are guidelines.
 Robert Schuller
Never give up, for that is just the place and time that the tide will turn.
 Harriet Beecher Stowe

Quotes from the same author

How wonderful that we have met with a paradox. Now we have some hope of making progress.
 Niels Bohr
Never express yourself more clearly than you are able to think.
 Niels Bohr
When asked ... [about] an underlying quantum world, Bohr would answer, 'There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about Nature.'
 Niels Bohr
There are two sorts of truth: trivialities, where opposites are clearly absurd, and profound truths, recognised by the fact that the opposite is also a profound truth
 Niels Bohr
There is no hope for any speculation that does not look absurd at first glance.
 Niels Bohr