Life is short, the art is long, the problems pressing.

Nature always strikes back. It takes all the running we can do to remain in the same place.

Gauss replied, when asked how soon he expected to reach certain mathematical conclusions, that he had them long ago, all he was worrying about was how to reach them!

It is possible to analyze the biological and social influences that make each human being unique, unprecedented, and unrepeatable, but this analysis does not explain how and why each feels different from all other human beings.

Human diversity makes tolerance more than a virtue; it makes it a requirement for survival.

As long as mankind is made up of independent individuals with free will, there cannot be any social status quo. Men will develop new urges, and these will give rise to new problems, which will require ever new solutions. Human life implies adventure, and there is no adventure without struggles and dangers.

Each civilization has its own kind of pestilence and can control it only by reforming itself.