In contrast to the theories of relativity, quantum mechanics is not yet based on a generally accepted conceptual foundation. It is proposed here that the missing principle may be identified through the observation that all knowledge in physics has to be expressed in propositions and that therefore the most elementary system represents the truth value of one proposition, i.e., it carries just one bit of information. Therefore an elementary system can only give a definite result in one specific measurement. The (...) irreducible randomness in other measurements is then a necessary consequence. For composite systems entanglement results if all possible information is exhausted in specifying joint properties of the constituents. (shrink)

We show that three fundamental information-theoretic constraints -- the impossibility of superluminal information transfer between two physical systems by performing measurements on one of them, the impossibility of broadcasting the information contained in an unknown physical state, and the impossibility of unconditionally secure bit commitment -- suffice to entail that the observables and state space of a physical theory are quantum-mechanical. We demonstrate the converse derivation in part, and consider the implications of alternative answers to a remaining open question about (...) nonlocality and bit commitment. (shrink)

David Bohm is one of the foremost scientific thinkers of today and one of the most distinguished scientists of his generation. His challenge to the conventional understanding of quantum theory has led scientists to reexamine what it is they are going and his ideas have been an inspiration across a wide range of disciplines. _Quantum Implications_ is a collection of original contributions by many of the world' s leading scholars and is dedicated to David Bohm, his work and the issues (...) raised by his ideas. The contributors range across physics, philosophy, biology, art, psychology, and include some of the most distinguished scientists of the day. There is an excellent introduction by the editors, putting Bohm's work in context and setting right some of the misconceptions that have persisted about the work of David Bohm. (shrink)