Politics is for the present, but an equation is for eternity.

Everything that is really great and inspiring is created by the individual who can labor in freedom.

Men like Henry George [ the pioneer of land value taxation] are rare, unfortunately. One cannot imagine a more beautiful combination of intellectual keenness, artistic form, and fervent love of justice.

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

Most people say that it is the intellect which makes a great scientist. They are wrong: it is character.

I see in Nature a magnificent structure... that must fill a thinking person with a feeling of humility.

If you can't explain what you are doing to a nine-year-old, then either you still don't understand it very well, or it's not all that worthwile in the first place.