Durch eine Untersuchung der Stoßvorgänge wird die Auffassung entwickelt, daß die Quantenmechanik in der Schrödingerschen Form nicht nur die stationären Zustände, sondern auch die Quantensprünge zu beschreiben gestattet.

This excellent, semi-technical account includes a review of classical physics (origin of space and time measurements, Ptolemaic and Copernican astronomy, laws of motion, inertia, and more) and coverage of Einstein’s special and general theories of relativity, discussing the concept of simultaneity, kinematics, Einstein’s mechanics and dynamics, and more.

The notion of reality in the physical world has become, during the last century, somewhat problematic. The contrast between the simple and obvious reality of the innumerable instruments, machines, engines, and gadgets produced by our technological industry, which is applied physics, and of the vague and abstract reality of the fundamental concepts of physical science, as forces and fields, particles and quanta, is doubtlessly bewildering. There has already developed a gap between pure and applied science and between the groups of (...) men devoted to the one or the other activity, a separation that may lead to a dangerous estrangement. Physics needs a unifying philosophy, expressible in ordinary language, to bridge this gulf between "reality" as thought of in practice and in theory. I am not a philosopher but a theoretical physicist. I cannot provide a well balanced philosophy of science that would take due account of the ideas developed by differing schools, but I shall endeavor to formulate some ideas which have helped me in my own struggle with these problems. (shrink)

For this eighth edition he also wrote a new chapter on the quantum theory of solids.