This is a comprehensive discussion of complexity as it arises in physical, chemical, and biological systems, as well as in mathematical models of nature. Common features of these apparently unrelated fields are emphasised and incorporated into a uniform mathematical description, with the support of a large number of detailed examples and illustrations. The quantitative study of complexity is a rapidly developing subject with special impact in the fields of physics, mathematics, information science, and biology. Because of the variety of the (...) approaches, no comprehensive discussion has previously been attempted. This book will be of interest to graduate students and researchers in physics (nonlinear dynamics, fluid dynamics, solid-state, cellular automata, stochastic processes, statistical mechanics and thermodynamics), mathematics (dynamical systems, ergodic and probability theory), information and computer science (coding, information theory and algorithmic complexity), electrical engineering and theoretical biology. (shrink)

In this book, Newell makes the case for unified theories by setting forth a candidate.

Thomas S. Kuhn's classic book is now available with a new index.

Economists tend to represent learning as a procedure for estimating the parameters of the "correct" econometric model. We extend this approach by assuming that agents specify as well as estimate models. Learning thus takes the form of a dynamic process of developing models using an internal language of representation where expectations are formed by forecasting with the best current model. This introduces a distinction between the form and content of the internal models which is particularly relevant for boundedly rational agents. (...) We propose a framework for such model development which use a combination of measures: the error with respect to past data, the complexity of the model, the cost of finding the model and a measure of the model's specificity The agent has to make various trade-offs between them. A utility learning agent is given as an example. (shrink)

It is argued that complexity has only a limited use as a paradigm against reductionist approaches and that it has a much richer potential as a comparable property. What can complexity be usefully said to be a property of is discussed. It is argued that it is unlikely to have any useful value as applied to real object or systems. Further that even relativising it to an observer has problems. It is proposed that complexity can be only usefully applied to (...) constructions within a given language. It is argued that complexity is usefully differentiated from the concepts of size, ignorance, variety, minimum description length and order. A definition of complexity is proposed which can be summarised as follows: That property of a language expression which makes it difficult to formulate its overall behaviour even when given almost complete information about its atomic components and their inter-relations.. Some of the consequences of this definition are discussed. It is shown that this definition encompasses several existing varieties of complexity measures and is then applied to some examples pertaining to the evolution of complex' systems including: "What is the complexity that has evolved in organisms and has it increased?". (shrink)

This book presents an alternative to conventional ideas about the evolution of the human intellect.

Many special problems crop up when evolutionary theory turns, quite naturally, to the question of the adaptive value and causal role of consciousness in human and nonhuman organisms. One problem is that -- unless we are to be dualists, treating it as an independent nonphysical force -- consciousness could not have had an independent adaptive function of its own, over and above whatever behavioral and physiological functions it "supervenes" on, because evolution is completely blind to the difference between a conscious (...) organism and a functionally equivalent (Turing Indistinguishable) nonconscious "Zombie" organism: In other words, the Blind Watchmaker, a functionalist if ever there was one, is no more a mind reader than we are. Hence Turing-Indistinguishability = Darwin-Indistinguishability. It by no means follows from this, however, that human behavior is therefore to be explained only by the push-pull dynamics of Zombie determinism, as dictated by calculations of "inclusive fitness" and "evolutionarily stable strategies." We are conscious, and, more important, that consciousness is piggy-backing somehow on the vast complex of unobservable internal activity -- call it "cognition" -- that is really responsible for generating all of our behavioral capacities. Hence, except in the palpable presence of the irrational (e.g., our sexual urges) where distal Darwinian factors still have some proximal sway, it is as sensible to seek a Darwinian rather than a cognitive explanation for most of our current behavior as it is to seek a cosmological rather than an engineering explanation of an automobile's behavior. Let evolutionary theory explain what shaped our cognitive capacity (Steklis & Harnad 1976; Harnad 1996, but let cognitive theory explain our resulting behavior. (shrink)

Self-organized criticality, the spontaneous development of systems to a critical state, is the first general theory of complex systems with a firm mathematical basis. This theory describes how many seemingly desperate aspects of the world, from stock market crashes to mass extinctions, avalanches to solar flares, all share a set of simple, easily described properties. "...a'must read'...Bak writes with such ease and lucidity, and his ideas are so intriguing...essential reading for those interested in complex systems...it will reward a sufficiently skeptical (...) reader." -NATURE "...presents the theory in a form easily absorbed by the non-mathematically inclined reader." -BOSTON BOOK REVIEW "I picture Bak as a kind of scientific musketeer; flamboyant, touchy, full of swagger and ready to join every fray... His book is written with panache. The style is brisk, the content stimulating. I recommend it as a bracing experience." -NEW SCIENTIST. (shrink)

Voici un ouvrage qui surprendra. Car on n'y retrouvera pas les êtres qui nous sont familiers : ici, point de groupes, de classes sociales, d'ouvriers, de cadres, de jeunes, de femmes, d'électeurs auxquels nous ont habitués les sciences sociales ; point de ces personnes sans qualités que philosophie politique et économie nomment individus ; point, non plus, de ces personnages grandeur nature que nous dépeignent histoire et anthropologie. Non, ici, c'est de vous, de nous tous qu'il est question, dès lors (...) que, vivant en société, nous vivons en situation, c'est-à-dire dans les rapports aux autres et aux choses. A chaque instant, nous cherchons à rendre compréhensibles nos conduites, afin d'assurer, à quelque niveau que ce soit - le groupe, l'entreprise, la collectivité -, la coexistence avec autrui par l'accord : tels sont le rôle et la nature de la justification. La sociologie traditionnelle, quelle qu'en soit l'école, prétend que les personnes rationalisent leurs conduites au nom de motifs apparents et fallacieux alors qu'elles sont, en réalité, déterminées par des forces cachées et objectives qu'il revient, bien évidemment, au sociologue de dévoiler... En rupture de ban avec la perspective cavalière que la philosophie politique et la sociologie ont longtemps adoptée face à l'ordre social, Luc Boltanski et Laurent Thévenot ont pris le parti de traiter sérieusement les personnes et leurs prétentions à la justice. Ils ont voulu comprendre quels sont les principes, les équivalences, les valeurs de référence - ce qu'ils appellent les grandeurs - auxquels les acteurs en appellent lorsqu'ils veulent manifester leur désaccord sans recourir à la violence. S'éloignant en cela des théories de la justice, les auteurs montrent comment les personnes prennent appui sur des objets communs, présents dans la situation pour asseoir leurs justifications. Il en résulte un ouvrage original qui construit un cadre permettant d'analyser la relation entre accord et discorde, et qui nourrit ses réflexions de l'analyse serrée de la littérature de management comme de lettres de dénonciation adressées aux grands quotidiens ou de classiques de la philosophie politique. Il en résulte un ouvrage ambitieux qui ouvre la voie à une approche qui ne réduise plus les acteurs à des agents donnés par des forces extérieures, mais qui les étudie en situation de maîtrise de leur conduite et de leur coexistence dans le monde de tous les jours. (shrink)

The introductory chapter, entitled 'The Subject, Method and Scope of this Enquiry,' details how anthropology is to be pursued as a science and advocates the method of participant observation.

The 'Evolution of Cooperation' addresses a simple yet age-old question; If living things evolve through competition, how can cooperation ever emerge? Despite the abundant evidence of cooperation all around us, there existed no purely naturalistic answer to this question until 1979, when Robert Axelrod famously ran a computer tournament featuring a standard game-theory exercise called The Prisoner's Dilemma. To everyone's surprise, the program that won the tournament, named Tit for Tat, was not only the simplest but the most "cooperative" entrant. (...) This unexpected victory proved that cooperation - one might even say altruism - is mathematically possible and therefore needs no hidden hand or divine agent to create and sustain it. A great roadblock to the understanding of all sorts of behavior was at last removed. The updated edition includes an extensive new chapter on cooperation in cancer cells and among terrorist organizations. (shrink)

At the end of a thoughtful article on the future of nuclear war, Wiesner and York concluded that: "Both sides in the arms race are... confronted by the dilemma of steadily increasing military power and steadily decreasing national security. It is our considered professional judgment that this dilemma has no technical solution. If the great powers continue to look for solutions in the area of science and technology only, the result will be to worsen the situation.".

Game theory has proved a useful tool in the study of simple economic models. However, numerous foundational issues remain unresolved. The situation is particularly confusing in respect of the non-cooperative analysis of games with some dynamic structure in which the choice of one move or another during the play of the game may convey valuable information to the other players. Without pausing for breath, it is easy to name at least 10 rival equilibrium notions for which a serious case can (...) be made that here is the “right” solution concept for such games. (shrink)

What makes a living system a living system? What kind of biological phenomenon is the phenomenon of cognition? These two questions have been frequently considered, but, in this volume, the authors consider them as concrete biological questions. Their analysis is bold and provocative, for the authors have constructed a systematic theoretical biology which attempts to define living systems not as objects of observation and description, nor even as interacting systems, but as self-contained unities whose only reference is to themselves. The (...) consequence of their investigations and of their living systems as self-making, self-referring autonomous unities, is that they discovered that the two questions have a common answer: living systems are cognitive systems, and living as a process is a process of cognition. The result of their investigations is a completely new perspective of biological (human) phenomena. During the investigations, it was found that a complete linguistic description pertaining to the ‘organization of the living’ was lacking and, in fact, was hampering the reporting of results. Hence, the authors have coined the word ‘autopoiesis’ to replace the expression ‘circular organization’. Autopoiesis conveys, by itself, the central feature of the organization of the living, which is autonomy. (shrink)

Emergence is defined as a process which cannot be described by a fixed model, consisting of invariant distinctions. Hence emergence must be described by a meta‐model, representing the transition of one model to another one by means of a distinction dynamics. The dynamics of distinctions is based on the processes of variation and selection, resulting in an invariant distinction, which constrains the variety and thus defines a new system. A classification of emergence processes is proposed, based on the following criteria: (...) amount of variety, internality/ externality of variation and selection, number of levels, and contingency of constraint. It is argued that traditional formal and computational models are incapable of representing the more general types of emergence, but that it is possible to generalize them on the basis of the dynamics of distinctions. (shrink)

This book argues that a realist analysis of the structures and processes which make up the social world can provide a way out of its present impasse.

It is argued that complexity is not attributable directly to systems or processes but rather to the descriptions of their `best' models, to reflect their difficulty. Thus it is relative to the modelling language and type of difficulty. This approach to complexity is situated in a model of modelling. Such an approach makes sense of a number of aspects of scientific modelling: complexity is not situated between order and disorder; noise can be explicated by approaches to excess modelling error; and (...) simplicity is not truth indicative but a useful heuristic when models are produced by a being with a tendency to elaborate in the face of error. (shrink)

Compositional verification aims at managing the complexity of theverification process by exploiting compositionality of the systemarchitecture. In this paper we explore the use of a temporal epistemiclogic to formalize the process of verification of compositionalmulti-agent systems. The specification of a system, its properties andtheir proofs are of a compositional nature, and are formalized within acompositional temporal logic: Temporal Multi-Epistemic Logic. It isshown that compositional proofs are valid under certain conditions.Moreover, the possibility of incorporating default persistence ofinformation in a system, is (...) explored. A completion operation on aspecific type of temporal theories, temporal completion, is introducedto be able to use classical proof techniques in verification withrespect to non-classical semantics covering default persistence. (shrink)

The SDML programming language which is optimized for modelling multi-agent interaction within articulated social structures such as organizations is described with several examples of its functionality. SDML is a strictly declarative modelling language which has object-oriented features and corresponds to a fragment of strongly grounded autoepistemic logic. The virtues of SDML include the ease of building complex models and the facility for representing agents flexibly as models of cognition as well as modularity and code reusability.

Abstract.Reliable Darwinian theory shows that pure altruism cannot persist and expand over time. All higher organisms show inheritable patterns of caring and discrimination. The principal forms of discriminating altruisms among human beings are individualism (different from egoism), familialism, cronyism, tribalism, and patriotism. The promiscuous altruism called “universalism” cannot endure in the face of inescapable competition. Information can be promiscuously shared, but not so matter and energy without evoking the tragedy of the commons. Universalism is not recommendable even as an ideal. (...) Survival now requires the creation of an intellectual base for a new patriotism. (shrink)

The extent to which trust prevails can be measured by the subjective probability with which an agent expects another one to act in desired ways. An agent´s trust in other agents forms in repeated social interactions which typically have the structure of an elementary game of trust. The process of trust formation in such interactions may be described by a reputation function. It is argued that in view of real world processes of trust formation any adequate reputation function must satisfy (...) certain conditions. A simple model conforming to these conditions is presented. Analysing this example it is shown that there is a co-operative Nash equilibrium in a trust supergame which is in line with the basic conditions of trust formation. However, it is also proved that no process of trust formation can be reasonably similar to real world mechanisms and at the same time lead to subgame perfect equilibria in a trust supergame. (shrink)

Genetic Programming (GP) is a technique which permits automatic search for complex solutions using a computer. It goes beyond previous techniques in that it discovers the structure of those solutions. Previously, if one were trying to find an equation to fit a set of data, one would have had to provide the form of the equation (for example a fourth degree polynomial) and the computer could then find the appropriate parameters. By contrast, GP can experiment with a whole range of (...) different functional forms , building equations from a menu of functions, symbols and arithmetic operations. Thus GP can be seen as an essentially creative technique. It is good at finding novel solutions where not much is known about the form of the solution.. (shrink)

An investigation into the conditions conducive to the emergence of heterogeneity amoung agents is presented. This is done by using a model of creative artificial agents to investigate some of the possibilities. The simulation is based on Brian Arthur's 'El Farol Bar' model but extended so that the agents also learn and communicate. The learning and communication is implemented using an evolutionary process acting upon a population of strategies inside each agent. This evolutionary learning process is based on a Genetic (...) Programming algorithm. This is chosen to make the agents as creative as possible and thus allow the outside edge of the simulation trajectory to be explored. A detailed case study from the simulations show how the agents have differentiated so that by the end of the run they had taken on qualitatively different roles. It provides some evidence that the introduction of a flexible learning process and an expressive internal representation has facilitated the emergence of this heterogeneity. (shrink)