Hideki Yukawa quotes:

I do not want to write beyond this point, because those days when I studied relentlessly are nostalgic to me; and on the other hand, I am sad when I think how I have become increasingly preoccupied with matters other than study.

Reality is cruel. All of the naivete is going to be removed. Reality is always changing, and it is always unpredictable. All of the balance is going to be destroyed.

Nature creates curved lines while humans create straight lines.

Reality is complicated. There is no justification for all of the hasty conclusions.

Suppose there is something which a person cannot understand. He happens to notice the similarity of this something to some other thing which he understands quite well. By comparing them he may come to understand the thing which he could not understand up to that moment. If his understanding turns out to be appropriate and nobody else has ever come to such an understanding, he can claim that his thinking was really creative.