Our universe, as a closed system, obeys the second law of thermodynamics, i.e., its entropy, its disorder, increases. Still, in the midst of this we are wit- nessing an opposite process, in which order is emerging. The picture we have is that the universe has evolved from a totally unstructured state of matter and radiation to a highly structured state. On the surface of our Earth, some of this structure takes highly sophisticated forms in living organisms and their complex interaction and in the social as well as material organization of human societies. What makes all this possible, thermodynamically, is, of course, the fact that over the universe as a whole the entropy increase is large enough to compensate for local creation of order.
The aim of this book is to sketch a perspective and to present a set of concepts, which can be useful in order to describe and understand processes in which structure emerges. The word describe gives a hint that information is an important concept. Information is a general concept, which can be applied not only to the description of a system but also to the described system as well. We shall use the concept as it was introduced by Shannon in information theory.
Then one may ask for the origin of structure (measured in terms of information) in the universe; one may ask how it is being transformed and how creative and destructive processesstructure formation and entropy productionare related to each other.
Many ideas and concepts have been developed which make information a very flexible and versatile theoretical tool.
In this book we deal with concepts and methods belonging to the lower levels in a hierarchy of information theory concepts. These concepts take into account some necessary aspects of life, including human life, but they are far from sufficient to capture the full concept of life.
The ideas used in this book have been collected from many fields, but we have no ambition to review the fields from where we have picked our material, and our collection of references is not systematic. We have mixed old material with new material, elementary discussions with more advanced, in order to make the book as a whole more self-contained. Since the book has not been written for a well-defined category of readers, we hope that in this way it will be more useful. Our aim has been to sketch a perspective on the great process of structure formation going on all the time around us, and to convey some of the most basic theoretical ideas which are useful for work in this perspective.
Singapore: World Scientific , 1987.