[Time, the fundamental dimension of our existence, has fascinated artists, philosophers, and scientists of every culture and every century. All of us can remember a moment as a child when time became a personal reality, when we realized what a "year" was, or asked ourselves when "now" happened. Common sense says time moves forward, never backward, from cradle to grave. Nevertheless, Einstein said that time is an illusion. Nature's laws, as he and Newton defined them, describe a timeless, deterministic universe (...) within which we can make predictions with complete certainty. In effect, these great physicists contended that time is reversible and thus meaningless. (shrink)

Unexpected discoveries in nonequilibrium physics and nonlinear dynamics are changing our understanding of complex phenomena. Recent research has revealed fundamental new properties of matter in far-from-equilibrium conditions, and the prevalence of instability-where small changes in initial conditions may lead to amplified effects.

La science classique s'est trouvée associée à un désenchantement du monde. C'est la leçon que Jacques Monod entendait tirer des progrès de la biologie : "L'ancienne alliance est rompue. L'homme sait enfin qu'il est seul dans l'immensité indifférente de l'Univers d'où il a émergé par hasard." Notre science n'est plus ce savoir classique, nous pouvons déchiffrer le récit d'une "nouvelle alliance". Loin de l'exclure du monde qu'elle décrit, la science retrouve comme un problème l'appartenance de l'homme à ce monde. Les (...) théories scientifiques ne peuvent plus supposer la possibilité d'un savoir omniscient : nous lisons, jusque dans leurs principes, les traces d'une activité d'exploration au sein d'une nature en évolution. (shrink)

In this book, after discussing the fundamental problems of current science and other philosophic concepts, beginning with controversies between Heraclitus and Parmenides, Ilya Prigogine launches into a message of great hope: the future has not been determined. Contrary to globalisation and the apparent contemporary mass culture society, individual behaviour is beginning to increasingly become the key factor which governs the evolution of both the world and society as a whole. It is a message that challenges existing widespread views, implicitly or (...) explicitly, through mass communication, moreover the importance of the individual's actions implies a reflection of each person on the responsibilities that each one assumes when taking or acting upon a decision. This responsibility is associated with the freedom of thought as well as a critical analysis of fashions, customs, preconceived ideas, and ideologies, externally imposed: exactly contrary to the ideas of those who wish us to be "perfect consumers" in a world dominated only by monetary wealth. Challenging this drive towards the elimination of freedom of though in the individual is now imperative if we are to save man and his planet from catastrophe which seems to be ever imminent and (unfortunately) irreversible. This last book of Ilya Prigogine provides a small, disputable, but nonetheless valuable contribution towards that end. (shrink)

Central among problems in cosmology is the crucial question of the articulation of natural and historical time: how is human history related to natural processes described by science? A deterministic world view in which natural processes are reversible, as emphasized by classical Western science, is obviously not the answer. Recent research in fields such as far‐from‐equilibrium thermodynamics and statistical mechanics reveals irreversibility in natural processes and allows us to explore new forms of dialogue between science and the humanities.

Le prix Nobel de chimie montre comment ses résultats les plus récents en physique théorique lui permettent de résoudre les problèmes qui rendent invraisemblables, malgré leur succès retentissant, tant la physique classique que la mécanique quantique : le paradoxe du temps et le paradoxe quantique. ©Electre 2021.

The formulation of the second law of thermodynamics in the frame of general relativity is reconsidered in the case of an istotropic homogeneous universe. We show that there appears then a direct link between the cosmological state of the universe, as expressed in terms of conformal coordinates, and quantities such as energy density, pressure, and entropy associated with the description of nature. In the early universe there appears a kind of phase transition due to transfer of gravitational energy to matter (...) associated with the cosmological expansion if the universe starts with a non-Euclidian (space) state. As a result, we may envisage the possibility of a “cold big-bang model,” in which the universe would start at zero temperature and entropy. The temperature goes then through a maximum before entering the present area of cooling related to adiabatic expansion. (shrink)

The role of passion and more generally irrational elements in processing knowledge are discussed. This seems to be a paradox, as science by definition is beyond passion. At the same time science is the expression of a culture. This paradox is examined through the experience and work of crucial figures in physics such as Newton and Einstein. Science is a dialogue between man and nature: part of the search for the transcendental which is common to many cultural activities: art, music, (...) literature. Our time is one of expectation, anxiety, and bifurcation. Far from there being an ?end? of science, our period will see the birth of a new vision, a new science whose cornerstone encloses the arrow of time: a science that makes us and our creativity the expression of a fundamental trend in the universe. (shrink)

In recent papers the authors have discussed the dynamical properties of “large Poincaré systems” (LPS), that is, nonintegrable systems with a continuous spectrum (both classical and quantum). An interesting example of LPS is given by the Friedrichs model of field theory. As is well known, perturbation methods analytic in the coupling constant diverge because of resonant denominators. We show that this Poincaré “catastrophe” can be eliminated by a natural time ordering of the dynamical states. We obtain then a dynamical theory (...) which incorporates a privileged direction of time (and therefore the second law of thermodynamics). However, it is only in very simple situations that this time ordering can be performed in an “extended” Hilbert space. In general, we need to go to the Liouville space (superspace) and introduce a time ordering of dynamical states according to the number of particles involved in correlations. This leads then to a generalization of quantum mechanics in which the usual Heisenberg's eigenvalue problem is replaced by a complex eigenvalue problem in the Liouville space. (shrink)

The Norbert Wiener Memorial Gold Medal address delivered by the Nobel Laureate recipient. Considers Norbert Wiener and the idea of contingence. Refers to Wiener's book The Human Use of Human Beings and in particular to the preface entitled "The idea of a contingent universe" and to the epilogue of the book by Rosenblith. This raises the question faced by Wiener: how to reconcile a deterministic world à la Newton with the intrinsically probabilistic universe of Gibbs, the relativistic universe of Einstein (...) and the Heisenberg uncertainty principle? Notes the parallelism among the questions Wiener is asking with the ones to which the Gold Medallist has devoted most of his scientific life. Presents a different point of view, as a tribute to the visionary ideas developed by Wiener. Discusses the "new physics" and the problems facing physics today, at the end of the twentieth century. (shrink)