Any power must be an enemy of mankind which enslaves the individual by power and by force, whether it arises under the Fascist or the Communist flag. All that is valuable in human society depends upon the opportunity for development accorded to the individual.

All our thinking is of this nature, a free play with concepts.

Learn from yesterday, live for today.

Marie Curie is, of all celebrated beings, the only one whom fame has not corrupted.

The future is of greater interest to me than the past, since that is where I intend to spend the rest of my life.

People like you and I, though mortal of course like everyone else, do not grow old no matter how long we live.

If someone feels that he has never made a mistake in his life, it only means that he has never tried anything new in his life.