To succeed, planning alone is insufficient. One must improvise as well.

Radiation, unlike smoking, drinking, and overeating, gives no pleasure, so the possible victims object.

It's the writing that teaches you.

Until now in world's history, whenever we've had a dark age, its been temporary and local. And other parts of the world have been doing fine. And eventually, they help you get out of the dark age. We are now facing a possible dark age which is going to be world-wide and permanent! That's not fun. That's a different thing. But once we have established many worlds, we can do whatever we want as long as we do it one world at a time.

A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws.

Increasingly, our leaders must deal with dangers that threaten the entire world, where an understanding of those dangers and the possible solutions depends on a good grasp of science. The ozone layer, the greenhouse effect, acid rain, questions of diet and heredity. All require scientific literacy. Can Americans choose the proper leaders and support the proper programs if they themselves are scientifically illiterate? The whole premise of democracy is that it is safe to leave important questions to the court of public opinion - but is it safe to leave them to the court of public ignorance?

You can prove anything you want by coldly logical reason---if you pick the proper postulates.