Dr. Stoyan Karakashev 2008-06-24

0 of 1 people found the following review helpful:

This is one of the best books which I have ever read in my life.

Glenn L. E. May 2007-08-24

0 of 1 people found the following review helpful:

by the late Nobel Laureate on the controversial issue of time's arrow. It's not clear he succeeded but his passion was never missing. He has consistently held in his books that nature is probabilistic even though his explanation of the 2nd law of thermodynamics, that entropy can only hold constant or increase in an isolated system, has evolved. (For instance in acceding to Frank Tipler that gravity breaks invariance.) Much of his motivation seems to have been in sorting out why Boltzman and Gibbs failed to satisfy the science community that their statistical physics explained the 2nd law, due to reversible classical equations and Poincare recurrences. However in order to make his probabilistic argument he may have created a loophole. He points to the Langevin equation as an irreversible equation with noise (friction) and he says Poincare should have connected nonintegrability with irreversibility and most dynamics are nonintegrable. However everyone agrees some (simple) systems are reversible (pendulums etc) so how can all of nature be stochastic? Maybe because the noise terms tend to but never go to zero? However in addressing the arrow of time he suggests gravity which is ignored in thermodynamics as are all interactions; but this explanation is also used by others in deterministic models. So it may never be provable who is right; but if his loophole is real I think there may be a simpler explanation.

Statistical entropy in all of it's variations is an excellent inference tool but it is about an observer's measurements and not underlying properties of the system being measured (frequentist approaches come close but usually have to extrapolate). In this case Poincare recurrence maybe non-physical, a mere statistical fluctuation with no actuality. (Prigogine says it is false because he introduces new microscopic dynamics, I'm just saying it may not arise in reality but only through statistical assumptions which depend on observer uncertainty.) I agree with the explanation at the website secondlaw.com that the thermodynamic explanation of entropy is fundamental as it is a measure of energy diffusion, and not randomness or uncertainty as the tool of statistical entropy would imply. In this way the 2 approaches are not contradictory; the statistical is merely a measurement tool for observers while the thermodynamic is real dynamics requiring no observers (ice melts, water crystalizes etc long before man was around). The current argument in wikipedia that statistical entropy is considered more fundamental because the others can be derived from it is silly; there are many types of subjective entropy measures, the basic frequentist vs Bayesian approaches, there is volume entropy such as for measuring expanding gases, configurational entropy such as for crystals etc; however there is only one thermodynamic entropy, Clausius's dS = <>q/T (for reversible systems; calculations change of course with potential variables of volume, pressure and temperature). If anything this should be viewed as fundamental as it is a direct measurement of the physical movement of heat. One should not confuse information theory and measurement techniques with real underlying dynamics. When some authors say 'entropy is not a property of a system, it is a property of our description of the system' they are referring to statistical entropy measures and not real thermodynamics. As Prigogine says 'irreversability is not just in our minds', that it applies to nonintegral systems identified by Poincare but not the connection. The very same wikipedia current description, possibly by a different author, accedes the point: "The problem with linking thermodynamic entropy to information entropy is that in information entropy the entire body of thermodynamics which deals with the physical nature of entropy is missing...information entropy gives only part of the description of thermodynamic entropy. Some, authors, like Tom Schneider, argue for dropping the word entropy for the H function of information theory and using Shannon's other term 'uncertianty' instead."


If Boltzman had accepted that his equation was not fundamental but an inference tool then most of the debates would likely not have arisen, including Prigogine's criticism of an excellent tool that did not deserve to be criticized on that basis. However what he has done is to show mathematically how irreversibility can apply at the microscopic level for nonintegral systems (in agreement with macroscopics) due to non-local persistent interactions but has to be measured statistically at the level of ensembles and not individual trajectories. This is quite a feat even if controversial. Nevertheless the standard entropy calculations apply for equilibrium systems and the arrow of time is still mysterious though possibly linked to gravity as he says. It would have been nice to see some discussion of entropy of non-equilibrium systems for which there is no universal agreement. For instance it is said that 'the rate of change of entropy with time for a nonequilibrium stochastic process is always positive.' [B.C. Bag; the following references are also available on the net with a simple author search.] This might suggest he already solved the problem and gravity is not required? But-

R. Metzler et. al. say 'Prigogine introduced novel microscopic laws which are irreversible with time. One reason for this ongoing discussion is the absence of rigorous mathematical proofs of irreversible properties in the thermodynamic limit...ensemble averages do not give a basic explanation of irreversible properties, since they contain an average over infinitely many trajectories. Ergodic theory does not help either, since it needs time averages over infinitely many trajectories...In this model we introduce a model with deterministic time reversible dynamics which can be analysed in detail...The Poincare return time is known exactly...' However this takes us back to the usual complaints about statistical fluctuations. [Is there a real arrow of time if everything is eventually reversible?]

Castagnino and Lombardi have developed an interesting approach to the question of the arrow of time. [Clearly Prigogine failed by his own admission and his gravity conjecture!] 'In fact time reversal invariant equations can have irreversible solutions. [e.g. the pendulum is time-reversal invariant...however the trajectories...are irreversible...]...The traditional local approach owes its origin to the attempts to reduce thermodynamics to statistical mechanics...[however] only by means of global considerations can all decaying processes be coordinated. This means that the global arrow of time plays the role of the background scenario where we can meaningfully speak of the temporal direction of irreversible processes, and this scenario cannot be built up by means of local theories that only describe phenomena confined in small regions of spacetime...the geometrical approach to the problem of the arrow of time has conceptual priority over the entropic approach, since the geometrical properties of the universe are more basic than its thermodynamic properties.'

Obviously the debate continues. While Prigogine may not have solved the arrow of time, his work on correlations is important as these are assumed away in classical physics but they are critical to life!

Konstantin Momot 2005-03-12

6 of 6 people found the following review helpful:

Reading this "popular science" book, written by one of the greatest contemporary chemical physicists, was both difficult and satisfying. To avoid a fit of sycophancy, let's just say that I wish I had it when taking my postgrad Statistical Mechanics class. The only negative thing I can cay about this book is that the discussion is somewhat eclectic; it often oscillates between almost trivial philosophy and very high-level, cutting-edge science. It is not clear what the reader is expected to know before starting on this book. That said, if you can work your way through it, you will likely come out with a new understanding of non-equilibrium statistical mechanics and the physics of complex systems.

Juan R. Gonzalez-Alvarez 2003-08-13

37 of 39 people found the following review helpful:

I did buy this book some time ago and then I was fascinated. I studied the basis of his theory, but unfortunately, Prigogine passed away recently, before I can discuss with he some topics in more detail.

The greater part of the book is written in a natural style, but some sections are highly mathematical even for the majority of scientists! This mathematical presentation has a curious explaining. There are several version of Prigogine's theory, but the first versions had been "abandoned", and then Prigogine details the new approach: "Star-unitary theory for LPS outside of Hilbert space".

An earlier reviewer said that the book provides a solution to three of the most important problems in science: (1) Time's arrow. (2) The measurement problem in QM. (3) The existence of freewill. Precisely, I am working in those and other questions, and I do not believe that claim was completely correct (and perhaps Prigogine believed the same, because in his last communication, said me "The questions that you ask are very difficult."). In my opinion, the novel theory is conflictive both in mathematical and physical details, but I consider that, at least, the aim of the School is correct one. Irreversibility and uncertainty are two fundamental features of our universe. I see that orthodox physics (including particle physics and the so-called String-M theory) is incorrect and/or inapplicable. I believe that, whereas other "popular" books (The Quark and The Jaguar, The Elegant Universe, etc.) should be "relics" in 21st century physics, Prigogine's book will be then a basic work.

The contributions of Prigogine's physics to the understanding in other disciplines, as chemistry, are not clear. In fact, I believe that the impact of recent Prigogine's ideas into fundamental chemistry has been "insignificant", because his revolutionaries ideas in physics are an outcome of their previous chemical investigations (Nobel Prize for Chemistry). For example, in his complex spectral theory, energy is an imaginary quantity, and this is in direct conflict with standard quantum theory postulates. However, in theoretical chemistry, one always defines a transition state by means of an imaginary frequency. As said Prigogine in a recent Solvay conference, "all of Chemistry deals with irreversible processes". I cannot say the same of physics.

The book is very good one, but I disagree in one point. When one writes a scientific paper for publication in a specialized journal (as Physical Review), one can write about everything. Referees and other scientist can either accept or reject your work in scientific grounds. When one writes a popular book for non-expertises, one must be the most "neutral" possible. If this is not possible, one must to "alert" to the reader. This book is not neutral and, in some restricted sense, shows several theories and ideas as been of broad acceptance or current use in science. Of course, this overemphasizes the scientific status of the so-called Brussels School and minimizes the importance of other interesting points of view. In my opinion, this is not a correct attitude. For example, the "diagrammatic" method developed by Brussels School in the 60's (and illustrated in the book) is broadly not used by scientific community. See, for example, "Nonequilibrium Statistical Mechanics" by Robert Zwanzig for a view in more standard formalisms. In addition, I also must say that some previous Prigogine's ideas in dissipative structures, kinetic potentials, etc. are not standard, and other, as the "universal" criterion of evolution (following production of entropy), was experimentally shown to be false. Of course, other contributions of called Brussels School are simply impressive, for example the extension of scattering theory of particle physics to more general situations of chemical kinetics. Effectively, you have read fine, orthodox S-matrix of "fundamental" physics can be derived as an idealized asymptotic version valid for typical accelerator experiments! I am sorry, but I must said that Chemistry is not applied QED.

Conclusion: The book describes an excellent philosophical view in a "new" physics, and for this reason it may be a central piece on your collection. Nevertheless, I consider that the scientific way proposed is a little conflictive and some mathematics may be modified!

Yonatan Fishman 2002-11-01

23 of 37 people found the following review helpful:

If you want a simple, elegant, responsible, well-informed book on the origin of the macroscopic arrow of time and on how time-revesibility at the microscopic level resolves many of the quantum paradoxes, read Physics Prof. Victor Stenger's "Timeless Reality". You will get much more out of it.