One must be reasonable in one's demands on life. For myself, all that I ask is: (1) accurate information; (2) coherent knowledge; (3) deep understanding; (4) infinite loving wisdom; (5) no more kidney stones, please.

Be a half-assed crusader, a part-time fanatic. Don't worry to much about the fate of the world. Saving the world is only a hobby. Get out there and enjoy the world, your girlfriend, your boyfriend, husbands wives; climb mountains, run rivers, get drunk, do whatever you want to do while you can, before it's too late.

I would not sacrifice a single living mesquite tree for any book ever written. One square mile of living desert is worth a hundred 'great books' - and one brave deed is worth a thousand.

Where all think alike there is little danger of innovation.

The hawk's cry is as sharp as its beak.

All men are brothers, we like to say, half-wishing sometimes in secret it were not true. But perhaps it is true. And is the evolutionary line from protozoan to Spinoza any less certain? That also may be true. We are obliged, therefore, to spread the news, painful and bitter though it may be for some to hear, that all living things on earth are kindred.

How can I be so evil? It ain't easy.