If such groups, such future nations, existed, he asked himself how they would build? What manner of world they would strive for—knowing what they knew?... This, at least, was certain: it would not be the world of their fathers, of their own youth. They had seen their civilization laid waste by the agency of science combined with human passion; hence, if they rejected the alternative of ignorance and held to their perilous treasure of science, their problem was the mastery of passion. He came to believe that the problem—like all others—had been faced in forgotten generations; that old centuries had learned the forgotten lesson that the Ruin was teaching anew. To a race that had realized the peril of knowledge there would be two alternatives only; renunciation—the creed of blind ignorance and savagery—or the guarding of science as a secret treasure, removed from all contact with the flame that is human emotion. There had been elder and long-past civilizations in which knowledge was a mystery, the possession and the privilege of a caste; tradition had come down to us of ancient wisdom which might only be revealed to the initiate.... A blind fear massacred its scientific men, a wiser fear exalted them and set them apart as initiates. When science and human emotion between them had wrought the extreme of destruction and agony, there passed the reckless and idealistic dream of a world where all might be enlightened; the aim and tradition of a social system arising out of ruin would be the setting of an iron barrier between science and human emotion. That, and not enlightenment of all and sundry—the admission of the foolish, the impulsive and the selfish to a share in the power of destruction. The same need and instinct of self-preservation which had inspired the taking of the Vow of Ignorance would work, in higher and saner minds, for the training of a caste—an Egyptian priesthood—exempt from blind passion and the common impulse of the herd; a caste trained in silence and rigid self-control, its way of attainment made hard to the student, the initiate. The deadly formulæ of mechanics, electricity and chemistry would be entrusted only to those who had been purged of the daily common passions of the multitude; to those who, by trial after trial, had fettered their natural impulses and stripped themselves of instinct and desire.