Copyright © 1954, 1955, 1956 by the American Association for the Advancement of Science Library of Congress catalog card number: 56-11541 The papers published here were first presented at the annual meet- ing of the American Association for the Advancement of Science in Boston, Massachusetts, December 1953, and sponsored by the Insti- tute for the Unity of Science, the Philosophy of Science Association, and Section L (History and Philosophy of Science) of AAAS; co- sponsored by the National Science Foundation and the American Academy of Arts and Sciences. These articles were published in the September, October, November 1954, and January and February 1955 issues of The Scientific Monthly, and permission to reproduce any of the papers or parts therefrom must be obtained from The Scientific Monthly. Printed in U.S.A. -iv- |