Machines deprive us of two things which are certainly important ingredients of human happiness, namely, spontaneity and variety.

A sense of duty is useful in work but offensive in personal relations. People wish to be liked, not to be endured with patient resignation.

Laughter is the most inexpensive and most effective wonder drug. Laughter is a universal medicine.

Teachers are more than any other group the guardians of civilization.

Aristotle and Plato considered Greeks so innately superior to barbarians that slavery is justified so long as the master is Greek and the slave barbarian.

The most savage controversies are about matters as to which there is no good evidence either way.

I remain convinced that obstinate addiction to ordinary language in our private thoughts is one of the main obstacles to progress in philosophy.