SCIENCE AND EDUCATION A SERIES OF VOLUMES FOR THE PROMOTION OF SCIENTIFIC RESEARCH AND EDUCATIONAL PROGRESS Edited by J. McKEEN CATTELL VOLUME I—THE FOUNDATIONS OF SCIENCE UNDER THE SAME EDITORSHIP SCIENCE AND EDUCATION. A series of volumes for the promotion of scientific research and educational progress. Volume I. The Foundations of Science. By H. Poincaré. Containing the authorized English translation by George Bruce Halsted of “Science and Hypothesis,” “The Value of Science,” and “Science and Method.” Volume II. Medical Research and Education. By Richard Mills Pearce, William H. Welch, W. H. Howell, Franklin P. Mall, Lewellys F. Barker, Charles S. Minot, W. B. Cannon, W. T. Councilman, Theobald Smith, G. N. Stewart, C. M. Jackson, E. P. Lyon, James B. Herrick, John M. Dodson, C. R. Bardeen, W. Ophils, S. J. Meltzer, James Ewing, W. W. Keen, Henry H. Donaldson, Christian A. Herter, and Henry P. Bowditch. Volume III. University Control. J. McKeen Cattell and other authors. AMERICAN MEN OF SCIENCE. A Biographical Directory. SCIENCE. A weekly journal devoted to the advancement of science. The official organ of the American Association for the Advancement of Science. THE POPULAR SCIENCE MONTHLY. A monthly magazine devoted to the diffusion of science. THE AMERICAN NATURALIST. A monthly journal devoted to the biological sciences, with special reference to the factors of evolution. THE SCIENCE PRESS NEW YORKGARRISON, N. Y. THE FOUNDATIONS OF SCIENCE SCIENCE AND HYPOTHESIS THE VALUE OF SCIENCE SCIENCE AND METHOD BY H. POINCARÉ AUTHORIZED TRANSLATION BY GEORGE BRUCE HALSTED WITH A SPECIAL PREFACE BY POINCARÉ, AND AN INTRODUCTION BY JOSIAH ROYCE, HARVARD UNIVERSITY THE SCIENCE PRESS NEW YORK AND GARRISON, N. Y. 1913 Copyright, 1913 By The Science Press PRESS OF THE NEW ERA PRINTING COMPANY LANCASTER, PA. CONTENTS HENRI POINCARÉ Sir George Darwin, worthy son of an immortal father, said, referring to what Poincaré was to him and to his work: ‘‘He must be regarded as the presiding genius—or, shall I say, my patron saint?” Henri Poincaré was born April 29, 1854, at Nancy, where his father was a physician highly respected. His schooling was broken into by the war of 1870–71, to get news of which he learned to read the German newspapers. He outclassed the other boys of his age in all subjects and in 1873 passed highest into the École Polytechnique, where, like John Bolyai at Maros Vásárhely, he followed the courses in mathematics without taking a note and without the syllabus. He proceeded in 1875 to the School of Mines, and was Nommé, March 26, 1879. But he won his doctorate in the University of Paris, August 1, 1879, and was appointed to teach in the Faculté des Sciences de Caen, December 1, 1879, whence he was quickly called to the University of Paris, teaching there from October 21, 1881, until his death, July 17, 1912. So it is an error to say he started as an engineer. At the early age of thirty-two he became a member of 1’Académie des Sciences, and, March 5, 1908, was chosen Membre de 1’Académie Française. July 1, 1909, the number of his writings was 436. His earliest publication was in 1878, and was not important. Afterward came an essay submitted in competition for the Grand Prix offered in 1880, but it did not win. Suddenly there came a change, a striking fire, a bursting forth, in February, 1881, and Poincaré tells us the very minute it happened.