After years of finding mathematics easy, I finally reached integral calculus and came up against a barrier. I realized that this was as far as I could go, and to this day I have never successfully gone beyond it in any but the most superficial way.

In life, unlike chess, the game continues after checkmate.

One of Walt Whitman's best-known poems is this one: When I heard the learn'd astronomer,.... The trouble is, Whitman is talking through his hat, but the poor soul didn't know any better

Science is dangerous. There is no question but that poison gas, genetic engineering, and nuclear weapons and power stations are terrifying. It may be that civilization is falling apart and the world we know is coming to an end. In that case, why no turn to religion and look forward to the Day of Judgment, ... [being] lifted into eternal bliss ... [and] watching the scoffers and disbelievers writhe forever in torment.

During the century after Newton, it was still possible for a man of unusual attainments to master all fields of scientific knowledge. But by 1800, this had become entirely impracticable.

No one can possibly have lived through the Great Depression without being scarred by it. No amount of experience since the depression can convince someone who has lived through it that the world is safe economically.

The dangers that face the world can, every one of them, be traced back to science. The salvations that may save the world will, every one of them, be traced back to science.