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The mathematical physicist David Ruelle takes what he calls
a "walk among the scientific results of the twentieth century." It is,
he says, a "walk guided by chance, literally, since the study of chance will
be the thread that I will follow." How do scientists look at chance, or randomness,
and chaos in physical systems? In answering this question for a general audience,
Ruelle writes in the best French tradition: he has produced an authoritative and
elegant book -- a model of clarity, succinctness, and a humor bordering at times
on the sardonic. Even those with no special knowledge of mathematics or physics
can comfortably follow him on his "walk," as he views several kinds
of chaotic systems -- the complicated, erratic course of a stream, for instance,
or the data that produce certain varieties of "computer pictures," or
the weather, as unpredictable except over a very short term. Using
the weather as an example of chaos par excellence Ruelle shows how an absurdly
small event can produce dramatic results in only a few weeks. After short discourses
on probabilities, lotteries and horoscopes, determinism, and the theory of games,
he explains the situation of chaotic systems: any tiny alteration in their state
at time zero creates later changes that grow exponentially with time. These systems
thus exhibit a startling "sensitive dependence on initial condition."
Besides examining such situations, Ruelle explores their relationship to entropy,
information, complexity, black holes, algorithmic complexity, Gödel's theorem,
and the mysterious phenomena of hydrodynamic turbulence and "strange attractors."
He also comments perceptively on the role of chance in genetics, meteorology,
economics, and history. Anyone who joins him on this skillfully guided tour will
gain new insight into many of the most important ideas underlying modern science.
David Ruelle, Professor of Theoretical Physics at the Institut
des Hautes Etudes Scientifiques, Bures-sur-Yvette, is the author of Statistical
Mechanics (Benjamin), Thermodynamic Formalism (Addison-Wesley), and
Elements of Differentiable Dynamics and Bifurcation Theory (Academic). |
