Originally published in 1938, this informative and insightful book is based on a series of lectures given by W. H. Watson at McGill University, Montréal, which were inspired and influenced by the lectures given by Dr Ludwig Wittgenstein at the University of Cambridge between the years 1929–34. Watson's lectures are 'offered in the hope that the interest of physicists in particular and scientists in general may be drawn to developments in modern philosophy which promise to be of great importance to learning'. Introducing students to the core philosophical issues surrounding modern physics and the ideas, which have shaped our current understanding of the subject, the book sets out to illuminate and implicate the inextricably entwined nature of philosophy and physics and the importance of logic. This book will be of considerable value to scholars of physics and philosophy as well as to anyone with an interest in the history of education.