There Are Things That Are So Serious

What We Observe Is Not Nature Itself, But Nature Exposed To Our Method Of Questioning.

It Seems Sensible To Discard All Hope Of Observing Hitherto Unobservable Quantities, Such As The Position And Period Of The Electron... Instead It Seems More Reasonable To Try To Establish A Theoretical Quantum Mechanics, Analogous To Classical Mechanics, But In Which Only Relations Between Observable Quantities Occur.

The Violent Reaction On The Recent Development Of Modern Physics Can Only Be Understood When One Realises That Here The Foundations Of Physics Have Started Moving; And That This Motion Has Caused The Feeling That The Ground Would Be Cut From Science

...separation Of The Observer From The Phenomenon To Be Observed Is No Longer Possible.

Thus, The More Precisely The Position Is Determined, The Less Precisely The Momentum Is Known, And Conversely.