Direction of Time

Ever a source of philosophical conjecture and debate, the concept of time represents the beating heart of physics. This final work by the distinguished physicist Hans Reichenbach represents the culmination and integration of a lifetime's philosophical contributions and inquiries into the analysis of time. The result is an outstanding overview of such qualitative, or topological, attributes of time as order and direction. Beginning with a discussion of the emotive significance of time, Reichenbach turns to an examination of the time order of mechanics, the time direction of thermodynamics and microstatistics, the time direction of macrostatistics, and the time of quantum physics. He offers coherent explanations of the analytic methods of scientific philosophy in the investigation of probability, quantum mechanics, the theory of relativity, and causality — methods that he not only applies here but also helped to develop and refine. Physics Today observed that "For a generation Professor Reichenbach has worked as almost no other man to bring to the interpretation of modern physics the critical and reflective thinking of a trained philosopher. Most physicists who retain an interest in philosophy, and many who wanted simply to understand physics, have read some of the earlier books of Reichenbach. This one is . . . the best by a good deal." Introduction. Appendix. Index.

Hans Reichenbach

I. Introduction 1. The Emotive Significance of Time II. The Time Order of Mechanics 2. The Qualitative Properties of Time 3. The Causal Theory of Time 4. Causality in Classical Physics 5. The Causal Definition of Time Order 6. Intervention III. The Time Direction of Thermodynamics and Microstatistics 7. Report on the Second Law of Thermodynamics 8. The Statistical Definition of Entropy 9. Extension of Statistics to Different Energy Levels 10. A Deterministic Interpretation of Thermodynamical Statistics 11. Determinism Versus Indeterminism in Classical Physics 12. The Probability Lattice 13. The Reversibility Objection 14. The Time Direction of the Space Ensemble 15. The Sectional Nature of Time Direction 16. The Hypothesis of the Branch Structure IV. The Time Direction of Macrostatistics 17. Macroarrangements and Macroentropy 18. Cause and Effect: Producing and Recording 19. The Principle of the Common Cause 20. Entropy and Information 21. The Time Direction of Information and the Theory of Registering Instruments 22. A Completely Macrostatistical Definition of Time Direction 23. The Mark Principle and Causal Relevance V. The Time of Quantum Physics 24. The Statistical Reversibility of the Elementary Processes of Quantrum Mechanics 25. The Indeterminism of Quantum Mechanics 26. The Genidentity of Quantum Particles 27. The Entropy Concept of Quantum Statistics 28. Extension of Quantum Statistics to Different Energy Levels 29. Particles Vanishing into Nonexistence 30. Particles Traveling Backward in Time Appendix Index