The Recursive Bayesian Net formalism was originally developed for modelling nested causal relationships. In this paper we argue that the formalism can also be applied to modelling the hierarchical structure of mechanisms. The resulting network contains quantitative information about probabilities, as well as qualitative information about mechanistic structure and causal relations. Since information about probabilities, mechanisms and causal relations is vital for prediction, explanation and control respectively, an RBN can be applied to all these tasks. We show in particular how (...) a simple two-level RBN can be used to model a mechanism in cancer science. The higher level of our model contains variables at the clinical level, while the lower level maps the structure of the cell's mechanism for apoptosis. (shrink)

U.S. doctrines have introduced a third approach within Operational Art, called the design approach, which has evoked military professional and academic debate as well as influenced NATO doctrines. Allied Joint Doctrine for Operational-level Planning states that a Force Commander should choose one out of three approaches when conducting Operational Art and conducting operational planning: a traditional, a systemic or a design approach. The difference between the causalist- and the systemic- approach concerns the clash between reductionism and holism, but the difference (...) between the design- and the systemic- approach is methodologically vague. Hence the following question concerning methodology and Operational Art arises: What methodological implications could constitute an argument for choosing the design approach when conducting Operational Art within a battlespace? Neither NATO doctrine, planning framework nor previous research offer any explicit methodological argument for choosing, or preferring, the design- over the systemic- approach. This article concludes that one possible argument for preferring a design approach is adherence to value-focused thinking, but this requires that the Force Commander can and is willing to focus on stakeholders’ values within the battlespace. This conclusion is implied by two methodological implications identified and discussed in this article. If the design approach is to be a relevant option, then further conceptual development, experimentation and education is required. To conclude, NATO should review the description of their approaches within Operational Art since the argument for preferring one approach over another is lacking and this could hamper the Force Commander’s management of the battlespace. (shrink)