Things are always more complicated than most people believe.

It is characteristic of all deep human problems that they are not to be approached without some humor and some bewilderment.

In the long run, the only solution I see to the problem of diversity is the expansion of mankind into the universe by means of green technology... Green technology means we do not live in cans but adapt our plants and our animals and ourselves to live wild in the universe as we find it... When life invades a new habitat, she never moves with a single species. She comes with a variety of species, and as soon as she is established, her species spread and diversify further. Our spread through the galaxy will follow her ancient pattern.

Intelligence may indeed be a benign influence creating isolated groups of philosopher-kings far apart in the heavens... On the other hand, intelligence may be a cancer of purposeless technological exploitation, sweeping across a galaxy as irresistibly as it has swept across our own planet.

For me too, the periodic table was a passion. ... As a boy, I stood in front of the display for hours, thinking how wonderful it was that each of those metal foils and jars of gas had its own distinct personality.

Science is my territory, but science fiction is the landscape of my dreams.

In the history of science it has often happened that the majority was wrong and refused to listen to a minority that later turned out to be right.