Volume 4, Issue 2, 2006

Pragmatic Information: Historical Exposition and General Overview
Dieter Gernert, Technische Universität München, Germany

Pragmatic information, understood as the impact of a message upon a receiving system, represents a matured and comprehensive concept of which earlier proposals are special cases. The different kinds of recipients and reactions to incoming message are characterized. In a historical exposition the principal approaches to the definition and operationalization of information are critically reviewed. From a modern point of view, the measurement of pragmatic information is possible but requires novel and specific procedures. As a perspective notion, pragmatic information will be analyzed in its relationships with other perspective notions, particularly 'meaning' and 'interpretation'. Main fields of application include physics, general systems theory and cognitive science. Together with some reflections on information and meaning, these areas of application point forward to connections with the mind-matter problem.

Pragmatic Information in Dynamic Semantics
Peter beim Graben, Department of Clinical Language Sciences, University of Reading, United Kingdom

In 1972, Ernst Ulrich and Christine von Weizsäcker introduced the concept of pragmatic information with three desiderata: (i) Pragmatic information should assess the impact of a message upon its receiver; (ii) Pragmatic information should vanish in the limits of complete (non-interpretable) 'novelty' and complete 'confirmation'; (iii) Pragmatic information should exhibit non-classical properties since novelty and confirmation behave similarly to Fourier pairs of complementary operators in quantum mechanics. It will be shown how these three desiderata can be naturally fulfilled within the framework of Gärdenfors' dynamic semantics of Bayesian belief models. (i) The meaning of a message is its impact upon the epistemic states of a cognitive agent. A pragmatic information measure can then be quantified by the average information gain for the transition from a prior to a posterior state. (ii) Total novelty can be represented by the identical proposition, total confirmation by the logical consequence of propositions. In both cases, pragmatic information vanishes. (iii) For operators that are neither idempotent nor commuting, novelty and confirmation relative to a message sequence can be defined within Gärdenfors' theory of belief revisions. The proposed approach is consistent with measures of relevance derived from statistical decision theory and it contains Bar-Hillel's and Carnap's theory of semantic information as a special case.

Pragmatic Value and Complex Sentences
Robert van Rooij, Institute for Logic, Language and Computation, University of Amsterdam, Netherlands

We investigate to what extent it is possible to determine a reasonable default pragmatic value of complex sentences in a compositional manner, and - when combined with a Boolean semantics - to see under which conditions it gives rise to reasonable predictions. We discuss  several notions of pragmatic value, or relevance, and compare their behavior over complex sentences. Although the goal-oriented notions of relevance give rise to the same ordering relations between propositions, the conditions under which they behave 'compositionally' vary significantly.

Pragmatic Information and Gaian Development - First Thoughts
Edward D. Weinberger, New York, USA

The scientific community believes in the theory of evolution with a passion that rivals that of any religious belief. This passion extends beyond the irrefutable evidence of the fossil record to the familiar claims of 'survival of the fittest' and random mutation. Yet the theory of natural selection has, to the knowledge of the present author, never been tested against the alternative hypothesis that evolution is, in fact, the ongoing development of a single, world-spanning super-organism. Just what kind of evidence would settle this question is not clear, so this paper is intended to begin the discussion. It does so by suggesting how a new,  quantitative theory of 'pragmatic information' could analyze the widespread temporal and inter-species connections that a developmental view of evolution would imply.

Information, Evolution, and 'Error-Friendliness'
Ernst Ulrich von Weizsäcker, School of Environmental Science and Management, University of California, Santa Barbara, USA
Christine von Weizsäcker, ECOROPA, Bonn, Germany

Information can be conceived as being composed of two complementary components: novelty and confirmation. Whenever either of the two is zero, information is zero. Genetic information, too, requires both novelty and confirmation. Evolution can be seen as the history of diversification. Selection alone reduces diversity. Recessivity appears to serve as a mechanism to protect diversity against selection. So does the geographical and behavioral 'separation' of species. Both recessivity and separation can be seen as 'error-friendly', a broader concept that is supportive of diversity, learning and further evolution. This concept should also be obeyed in technological applications.

Last revision: 6 December 2006