Altogether it will be found that a quiet life is characteristic of great men, and that their pleasures have not been of the sort that would look exciting to the outward eye.

From India to Spain, the brilliant civilization of Islam flourished. What was lost to christendom at this time was not lost to civilization, but quite the contrary.

What else is there to make life tolerable? We stand on the shore of an ocean, crying to the night and to emptiness. Sometimes a voice of one drowning, and in a moment the silence returns. The world seems to me quite dreadful, the unhappiness of many people is very great, and I often wonder how they all endure it. It is usually the central thing around which their lives are built, and I suppose if they did not live most of their lives in the things of the moment, they would not be able to go on.

So far I have been speaking of theoretical science, which is an attempt to understand the world. Practical science, which is an attempt to change the world, has been important from the first, and has continually increased in importance, until it has almost ousted theoretical science from men's thoughts.

Unfortunately, however, power is sweet, and the man who in the beginning seeks power merely in order to have scope for his benevolence is likely, before long, to love the power for its own sake.

The human race may well become extinct before the end of the century. Speaking as a mathematician, I should say the odds are about three to one against survival.

I can't tell whether I am living in a dream or a nightmare.