Gradually the conviction gained recognition that all knowledge about things is exclusively a working-over of the raw material furnished by the senses. ... Galileo and Hume first upheld this principle with full clarity and decisiveness.
Capitalism justified itself and was adopted as an economic principle on the express ground that it provides selfish motives for doing good, and that human beings will do nothing except for selfish motives
Thanks to my fortunate idea of introducing the relativity principle into physics, you (and others) now enormously overrate my scientific abilities, to the point where this makes me quite uncomfortable.
My interest in science was always essentially limited to the study of principles.... That I have published so little is due to this same circumstance, as the great need to grasp principles has caused me to spend most of my time on fruitless pursuits.
Love requires that true education should be easily accessible to all and should be of use to every villager in this daily life. The emphasis laid on the principle of spending every minute of one's life usefully is the best education for citizenship.
Friendship with the upright, with the truthful and with the well informed is beneficial. Friendship with those who flatter, with those who are meek and who compromise with principles, and with those who talk cleverly is harmful.