by Bruno SCHERRER (MSc in Knowledge Based Systems)
The End of Classical Science
In The End of Certainty, Ilya Prigogine's latest book, the author tries to make man face the real world's true complexity.
Ilya Prigogine, Nobel price in chemistry in 1977, is at the heart of a revolution in contemporary scientific thought. His books (of which some have been co-written with the philosopher Isabelle Stengers) have become references in Philosophy of Science. In 1979, he published The New Alliance that explained the necessity for renewing our scientific approach of natural phenomena. With The End of Certainty , he carries on with his revolution.
The aim of the whole book is to show that the Universe is not deterministic, as many people used to believe it so far. Of course, the equations of physics describe in a deterministic way the evolution of a system in time. The traditional conception, as well as quantum mechanics and relativity theory, claimed the foreseeability of future if the system's initial conditions could be known. But this vision only applies to very simple situations where dynamical systems are stable. First of all, from a mathematical point of view, it is not true that an ensemble of deterministic rules describe a deterministic system : one can calculate the trajectory of a stone that is falling whereas it is not possible for a three-corpse system like the Sun, the Earth and the Moon which is unstable (Poincare was the first to point out this instability and to study it). More generally, Ilya Prigogine stresses the fact that traditional physics describe an idealised world but not the unstable and evolutionary world in which we live.
Irreversible processes dominate the real world. For a very long time, the laws of physics have been considered as reversible. Because of that, many scientists thought that time was but an illusion. Nowadays we know that irreversibility is the cause of many phenomena such as whirlwind formation, chemical oscillations, and laser radiation. In all these events, time plays a fundamental and constructive role. And irreversibility can no longer be identified to a simple phenomenon that would disappear if we could access a perfect knowledge. Ilya Prigogine's book also deals with nowadays physical topics such as the Big Bang. According to him, it is really difficult to believe in an absolute beginning in the sense that this relies more on mysticism than physics. If for relativity theory, Big Bang is a beginning, it is rather a transition for quantum mechanics : it is a phase transition between virtual particles towards real particles. The Big Bang hypothesis seems then more admissible from the irreversibility point of view provided by the quantum mechanics theory.
And what about human beings? Could Chaos theories play a role in the understanding of human conflicts? Laws that are at the heart of Chaos are deterministic, even if eventually, the system is chaotic. As far as we know in human beings, there is no deterministic element at the root of decision-making. It is a mistake to draw too large a comparison: it is not anymore sensible to do a society physics . This myth has hopefully been abandoned. For many centuries, the Newtonian representation dominated human thought. This physical vision influenced the other fields. It is thus plausible that a radical change in the way we see nature could provoke a modification in the way we understand human beings. Ilya Prigogine believes that this change has to be hoped in science and that this is truer for human societies. This is actually the reason why he called his book The End of Certainty : we are living a transition phasis and we are going to reach a less conflicting situation; in front of the world complexity, in front of all the uncertainties, human beings will be more tolerant.
According to him, the revolution he is talking about is not for the future: it has already begun. The Universe appears to us with a very different way from the so-called Classical Universe. Classical science insisted on stability and equilibrium; nowadays, we see more and more instabilities and fluctuations. At the heart of this change, we see the time arrow, the irreversibility. All this leads us to a more unified vision of nature, involving both physics and biology. There is then no reason to keep the Cartesian dualism between matter and thought.
If his book is sometimes a bit technical, one really feels Ilya Prigogine's confidence about the reality of nowadays science's revolution. Even if one does not understand all the physical explanations in detail, general and essential ideas are exposed very clearly and can give any reader a very bright vision of the evolution of science during the last decades. Thus, this book will surely become a new reference in Philosophy and History of Science.
