Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Historical sketch
- 3 Probability
- 4 Statistical explanation
- 5 Equilibrium theory
- 6 Describing non-equilibrium
- 7 Rationalizing non-equilibrium theory
- 8 Cosmology and irreversibility
- 9 The reduction of thermodynamics to statistical mechanics
- 10 The direction of time
- 11 The current state of major questions
- References
- Index
10 - The direction of time
Published online by Cambridge University Press: 04 December 2009
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Historical sketch
- 3 Probability
- 4 Statistical explanation
- 5 Equilibrium theory
- 6 Describing non-equilibrium
- 7 Rationalizing non-equilibrium theory
- 8 Cosmology and irreversibility
- 9 The reduction of thermodynamics to statistical mechanics
- 10 The direction of time
- 11 The current state of major questions
- References
- Index
Summary
The Boltzmann thesis
Let us review once more the basic components of Boltzmann's final account of the asymmetry of the world described by the Second Law of Thermodynamics. In his final picture of statistical mechanics, we would expect to find an isolated system almost always at or near equilibrium. Excursions to states of very low entropy ought to be rare, and we should expect to have higher-entropy states immediately after and immediately before improbable excursions from a close to equilibrium condition. How can we reconcile this account of the probabilities of micro-states in the world with what we actually find? What we find is a universe apparently quite far from equilibrium. It seems to be approaching equilibrium in the future direction of time, but, as far as we can tell, seems to be ever further from equilibrium as we move back in time into the past direction. In addition, this entropic asymmetry of the universe as a whole is matched by the parallelism of entropic increase of branch systems temporarily isolated from the main system.
Boltzmann, the reader will remember, offers a multi-faceted story about the world to reconcile his probability attributions with the observed facts. First, it is posited that the universe available to our inspection is only a tiny fragment of the whole universe.
- Type
- Chapter
- Information
- Physics and ChancePhilosophical Issues in the Foundations of Statistical Mechanics, pp. 375 - 412Publisher: Cambridge University PressPrint publication year: 1993