On the left-hand side of the field equation we may add the fundamental tensor guv, multiplied by a universal constant, -λ, at present unknown, without destroying the general covariance.
Your fervent wishes can only find fulfillment if you succeed in attaining love and understanding of men, and animals, and plants, and stars, so that every joy becomes your joy and every pain your pain.
[Kepler] had to realize clearly that logical-mathematical theoretizing, no matter how lucid, could not guarantee truth by itself; that the most beautiful logical theory means nothing in natural science without comparison with the exactest experience. Without this philosophic attitude, his work would not have been possible.
If I were to start taking care of my grooming, I would no longer be my own self... so the hell with it... I will continue to be unconcerned about it, which surely has the advantage that I'm left in peace by many a fop who would otherwise come to see me.
Since I have introduced this term I had always a bad conscience. . . . I cannot help to feel it strongly and I am unable to believe that such an ugly thing should be realized in nature.
Academic chairs are many, but wise and noble teachers are few; lecture-rooms are numerous and large, but the number of young people who genuinely thirst after truth and justice is small