Boasts are wind and deeds are hard.

It is the writer who might catch the imagination of young people, and plant a seed that will flower and come to fruition.

I would argue that a truly developed country would be beyond Presidents and Kings. In a world with some semblance of equality, each liberal-minded woman, each gay person, and indeed almost every person could be their own President. In a world of equals, what real service does a ruler provide?

To test a perfect theory with imperfect instruments did not impress the Greek philosophers as a valid way to gain knowledge.

I figure that if God actually does exist, he is big enough to understand an honest difference of opinion.

The vast majority, who believe in astrology and think that the planets have nothing better to do than form a code that will tell them whether tomorrow is a good day to close a business deal or not, become all the more excited and enthusiastic.

At two-tenths the speed of light, dust and atoms might not do significant damage even in a voyage of 40 years, but the faster you go, the worse it is--space begins to become abrasive. When you begin to approach the speed of light, hydrogen atoms become cosmic-ray particles, and they will fry the crew. ...So 60,000 kilometers per second may be the practical speed limit for space travel.