Life is like a bicycle; keep moving on to maintain balance.
Even a fool is wise after an event.
I have never obtained any ethical values from my scientific work.
The distinctions separating the social classes are false; in the last analysis they rest on force.
Without creative, independently thinking and judging personalities the upward development of society is as unthinkable as the development of the individual personality without the nourishing soil of the community.
A model should be as simple as it can be but no simpler