If I had known they were going to do this, I would have become a shoemaker.
A happy man is too satisfied with the present to dwell too much on the future.
Understanding physics is child's play when compared to understanding child's play.
Have the courage to take your own thoughts seriously, for they will shape you.
Nature conceals her secrets because she is sublime, not because she is a trickster.
At the same time, as social beings, we are moved in the relations with our fellow beings by such feelings as sympathy, pride, hate, need for power, pity, and so on.