We can make a similar examination, but with greater uncertainty, of the extraterrestrial hypothesis that holds that a wide range of UFOs viewed on the planet Earth are space vehicles from planets of other stars.
Carl SaganWe've arranged a civilization in which most crucial elements profoundly depend on science and technology.
Carl SaganEvery thinking person fears nuclear war, and every technological state plans for it. Everyone knows it is madness, and every nation has an excuse
Carl Sagan