Now the Empire is stronger than we; it always has been. But this is the first time we are in danger of its direct attack, so that strength becomes te… - Isaac Asimov

What, then, of human activities? Is humankind itself hastening its own end? Man has, for instance, been burning carbon-containing fuel — wood, coal, oil, gas — at a steadily accelerating rate. All these fuels form carbon dioxide. Some is absorbed by plants and the oceans but not as fast as it is produced. This means the carbon dioxide content of the air is going up — slightly but nevertheless up. Carbon dioxide retains heat, and even a small rise means a warming of the Earth's atmosphere. This may result in the melting of the polar ice caps with unusual speed, flooding the world before we have learned climate control. In reverse, our industrial civilization is making our atmosphere dustier so that it reflects more sunlight away and cools the Earth slightly — thus making possible a glacial advance in a few centuries, also before we have learned climate control.

no uniformity, but the primitive diversity of a strong mind, untouched and unmolded except by the manifold disorganizations of the universe.

The robot said, 'I have been trying, friend Julius, to understand some remarks Elijah made to me earlier. Perhaps I am beginning to, for it suddenly seems to me that the destruction of what should not be, that is, the destruction of what you people call evil, is less just and desirable than the conversion of thi sevil into what you call good.' He hesitated, then, almost as though he were surprised at his own owrds, he said, 'Go, and sin no more!