“It has often been said that, if the human species fails to make a go of it here on the Earth, some other species will take over the running. In the sense of developing intelligence this is not correct. We have or soon will have, exhausted the necessary physical prerequisites so far as this planet is concerned. With coal gone, oil gone, high-grade metallic ores gone, no species however competent can make the long climb from primitive conditions to high-level technology. This is a one-shot affair. If we fail, this planetary system fails so far as intelligence is concerned.”

“For the first time in history, the human species as a whole has gone into politics. Everyone is in the act, and there is no telling what may come of it.”

“We have intelligent species on our planet that we are not even trying to communicate with.”

“Here we are, the most clever species ever to have lived. So how is it we can destroy the only planet we have?”

“It is high! It is far! It is gone!”

“The High-Intelligence Life Forms of the planet, of which there were at least three species, all of low technological achievement, they would ignore or enslave or extirpate, whichever was most convenient. For to an aggressive people only technology mattered.”

“Intelligence is ongoing, individual adaptability. Adaptations that an intelligent species may make in a single generation, other species make over many generations of selective breeding and selective dying. Yet intelligence is demanding. If it is misdirected by accident or by intent, it can foster its own orgies of breeding and dying.”

“Species evolve to meet the environment. An intelligent species changes the environment to suit itself. As soon as a species becomes intelligent, it should stop evolving.”

“For the first time in human history the psychology that is a prerequisite for intimacy has become the psychology that is a prerequisite for species survival.”

“Lamarck, after having first studied botany with success, had then turned his attention to conchology, and soon became aware that in the newer (or tertiary) strata of the earth's crust there were a multitude of fossil species of shells… He also observed that other shells were so nearly allied to living forms, that it was difficult not to suspect that they had been connected by a common bond of descent. He therefore proposed that the element of time should enter into the definition of a species, and that it should run thus: 'A species consists of individuals all resembling each other, and reproducing their like by generation, so long as the surrounding conditions do not undergo changes sufficient to cause their habits, characters, and forms to vary. He came at last to the conclusion, that none of the animals and plants now existing were primordial creations, but were all derived from pre-existing forms, which, after they may have gone on for indefinite ages reproducing their like, had, at length, by the influence of alterations in climate and in the animate world, been made to vary gradually, and adapt themselves to new circumstances, some of them deviating, in the course of ages, so far from their original type as to have claims to be regarded as new species.”