Pessimist by policy, optimist by temperament- it is possible to be both. How? By never taking an unnecessary chance and by minimizing the risks you can't avoid. This permits you to play out the game untroubled by the certainty of the outcome.

Correct morality can only be derived from what man is — not from what do-gooders and well-meaning aunt Nellies would like him to be.

Men are not potatoes!

There are perhaps 5% of the population that simply can't think. There are another 5% who can, and do. The remaining 90% can think, but don't

I believe that this hairless embryo with the aching, oversize brain case and the opposable thumb, this animal barely up from the apes, will endure --will endure longer than his home planet, will spread out to the other planets, to the stars, and beyond, carrying with him his honesty, his insatiable curiosity, his unlimited courage --and his noble essential decency. This I believe with all my heart.

The Earth is just too small and fragile a basket for the human race to keep all its eggs in.

You can sway a thousand men by appealing to their prejudices quicker than you can convince one man by logic.