Herbert Simon’s Silent Revolution

Werner Callebaut Faculty of Sciences, Hasselt University, Belgium & Konrad Lorenz Institute for Evolution and Cognition Research Altenberg, Austria [email protected] Abstract Simon’s bounded rationality (BR), the first scientific research program (as opposed to a purely philosophical one) to seriously take the cognitive limitations of decision makers into account, has often been conflated with his more restricted concept of satisficing—choosing an alternative that meets or exceeds specified criteria, but that is not guaranteed to be unique or in any sense “the best.” Proponents of optimization often dismiss bounded rationality out of hand with the following “hallway syllogism” (as formulated by Bendor 2003: 435, who disagrees with it): bounded rationality “boils down to” satisficing; satisficing is “simply” a theory of search for alternatives that takes into account the costs of computation. Hence, bounded rationality is “just a minor tweak” on optimal search theory. This article complements a psychologist’s plea for “striking a blow for sanity” in theories of rationality (Gigerenzer 2004). I amplify his argument that bounded rationality is not optimization under constraints from a more biological perspective. In order to do so, I first call attention to Simon’s evolutionary understanding of the nature of bounded rationality as grounded in the interactions between organisms and their environments, which has implications for niche construction and evolutionary theory generally. I then discuss the debate between “optimizers” and “satisficers” with particular attention to modeling in biology. I round off by briefly assessing the relevance of a ramification of bounded rationality, the neardecomposability of hierarchical systems, for modular theory, which predicts that hierarchical developmental processes generate hierarchical phenotypic units that can change independently. Interspersed are some remarks on Simon’s philosophical views.