Page:Popular Science Monthly Volume 67.djvu/319

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O the creative or initiatory faculties of the mind begin to wane at middle life? And would the ransacking of all historical data show that a majority of the greatest things in the world have been achieved by men under forty? To undertake anything like a positive solution of so great a problem is naturally out of the question; but one plain aspect of the matter may be shown—leaving it to the reader, or to some future writer having a passion for statistics, to determine upon which side are ranged the exceptions that prove the rule. It may be said with confidence that one fact is indisputable: We can mention no field in the broad domain of science—including astronomy, geology, biology, psychology, sociology, electromagnetism, electricity, engineering, invention, mathematics or medicine that does not owe much indeed to men of advanced years. This statement holds good of the fields also of mechanics, philosophy, statesmanship, letters, history, finance, music, art, discovery, exploration, navigation and many others.

A noteworthy beginning may be made with the five great savants who, within the hundred years just past, have given to mankind entirely new concepts, new understandings of the universe and of life; have revolutionized the greater sciences, and made it necessary to build anew from the beginning. We will take them in chronological order. Immanuel Kant died in 1804 at the age of seventy-six. His Kritik ('Critique of Pure Reason') was written, or appeared, after he had reached fifty-seven: a work of such vast comprehensiveness, such subtle, active and far-reaching intellectual resourcefulness, that the world has produced but a handful of men since his day who could fully appreciate or appraise him. His 'Contest of the Faculties' appeared when he had passed seventy. His primary formulation of the nebular hypothesis was when he was in the thirties; but much of its elaboration was concluded many years afterward. Pierre de Laplace, his coadjutor in the hypothesis which shook the world, died in 1827 at the age of seventy-eight. Laplace issued the earlier portion of his great 'Exposition du système du monde' at about the age of fifty; and the completion of this monumental work containing the nebular hypothesis was not published until he was past seventy years.

The next great step forward in enlightenment is from the field of astronomy to that of geology, and we come to Sir Charles Lyell, who