It Is A Very Grave Mistake To

We Should Be On Our Guard Not To Overestimate Science And Scientific Methods When It Is A Question Of Human Problems, And We Should Not Assume That Experts Are The Only Ones Who Have The Right To Express Themselves On Questions Affecting The Organization Of Society.

Imagination Is More Powerful Than Knowledge.

If You Cannot Explain It Simply, You Do Not Understand It Enough.

... On Principle, It Is Quite Wrong To Try Founding A Theory On Observable Magnitudes Alone. In Reality The Very Opposite Happens. It Is The Theory Which Decides What We Can Observe.

Freedom Of Teaching And Of Opinion In Book Or Press Is The Foundation For The Sound And Natural Development Of Any People.