“The need is not really for more brains, the need is now for a gentler, a more tolerant people than those who won for us against the ice, the tiger and the bear. The hand that hefted the ax, out of some old blind allegiance to the past fondles the machine gun as lovingly. It is a habit man will have to break to survive, but the roots go very deep.”

“And there was no longer a single race who bred blindly and without question. Time and its agonizing nostalgia would touch the heart each season, and be seen in the fall of a leaf, or, most terrible of all, a loved face would grow old. Cronos and the Fates had entered man's thinking, and try to escape as he might, he would endure an interior Ice Age. He would make, and then unmake fables. Then at last, and unwillingly, comprehend an intangible abstraction called space-time, and shiver inwardly at the endless abysses of space as he had once shivered, unclothed and unlighted before the Earthly frost.”

“...on the other hand the machine does not bleed, ache, hang for hours in the empty sky in a torment of hope to learn the fate of another machine, nor does it cry out with joy nor dance in the air with the fierce passion of a bird.”

“Great minds have always seen it. That is why man has survived his journey this long. When we fail to wish any longer to be otherwise than what we are, we will have ceased to evolve. Evolution has to be lived forward. I say this as one who has stood above the bones of much that has vanished, and at midnight has examined his own face.”

“A world like that is not really natural, or (the thought strikes one later) perhaps it really is, only more so. Parts of it are neither land nor sea and so everything is moving from one element to another, wearing uneasily the queer transitional bodies that life adopts in such places. Fish, some of them, come out and breathe air and sit about watching you. Plants take to eating insects, mammals go back to the water and grow elongate like fish, crabs climb trees. Nothing stays put where it began because everything is constantly climbing in, or climbing out, of its unstable environment.”

“If one could run the story of that first human group like a speeded-up motion picture through a million years of time, one might see the stone in the hand change to the flint ax and the torch.”

“There is nothing more alone in the universe than man. He is alone because he has the intellectual capacity to know that he is separated by a vast gulf of social memory and experiment from the lives of his animal associates.”