In 1894 Pierre Curie announced what has come to be known as Curie's Principle: the asymmetry of effects must be found in their causes. In the same publication Curie discussed a key feature of what later came to be known as spontaneous symmetry breaking: the phenomena generally do not exhibit the symmetries of the laws that govern them. Philosophers have long been interested in the meaning and status of Curie's Principle. Only comparatively recently have they begun to delve into the (...) mysteries of spontaneous symmetry breaking. The present paper aims to advance the discussion of both of these twin topics by tracing their interaction in classical physics, ordinary quantum mechanics and quantum field theory. The features of spontaneous symmetry that are peculiar to quantum field theory have received scant attention in the philosophical literature. These features are highlighted here, along with an explanation of why Curie's Principle, though valid in quantum field theory, is nearly vacuous in that context. (shrink)

First published in English in 1953, this important book from eminent philosopher Karl Jaspers deals with the philsophy of the history of mankind. More specifically, its avowed aim is to assist in heightening our awareness of the _present_ by placing it within the framework of the long obscurity of prehistory and the boundless realm of possibilities which lie within the undecided future.This analysis is split into 3 parts: World history The present and the future The meaning of history.

An astrophysicist offers an introduction to the theoretical principles, practical applications, and far-reaching implications of quantum physics and quantum mechanics.