Philosophical discourse traditionally distinguishes between ontology and epistemology and generally enforces this distinction by keeping the two subject areas separated. However, the relationship between the two areas is of central importance to physics and philosophy of physics. For instance, many measurement-related problems force us to consider both our knowledge of the states and observables of a system and its states and observables independent of such knowledge. This applies to quantum systems in particular. This contribution presents an example showing the importance (...) of distinguishing between ontic and epistemic levels of description even for classical systems. Corresponding conceptions of ontic and epistemic states and their evolution are introduced and discussed with respect to aspects of stability and information flow. These aspects show why the ontic/epistemic distinction is particularly important for systems exhibiting deterministic chaos. Moreover, this distinction provides some understanding of the relationships between determinism, causation, predictability, randomness, and stochasticity. (shrink)

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 di .erent 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. (shrink)