(Reply on what constitutes scientific proof:)"The question is much too difficult for me.

Germany had the misfortune of becoming poisoned, first because of plenty, and then because of want.

We have penetrated far less deeply into the regularities obtaining within the realm of living things, but deeply enough nevertheless to sense at least the rule of fixed necessity... what is still lacking here is a grasp of the connections of profound generality, but not a knowledge of order itself.

The step between genius and insanity is very short.

One should never impose one's views on a problem; one should rather study it, and in time a solution will reveal itself.

People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.

True religion is real living; living with all one's soul, with all one's goodness and righteousness.