The Extend to Which Organisms Construct their . . .

Those interested in the relationship between environment structure and behavior—the topic of this special issue of Adaptive Behavior —will find much of value in Peter Godfrey-Smith's new book, Complexity and the Function of Mind in Nature (hereafter CFMN; all page citations are to CFMN unless otherwise indicated). The writing is clear and concise, aptly balancing precision and breadth, and a host of relevant issues are raised and advanced. Although my comments here will focus only on the book's fundamental conceptual framework for how organisms relate to their environments, I enthusiastically recommend the entire book. My primary concern is the extent to which organisms construct their environments. Some definitions from CFMN will help us pursue this topic. Externalist explanations are "explanations of properties of organic systems in terms of properties of their environments", while internalist explanations explain "one set of organic properties in terms of other internal or intrinsic properties of the organic system" (p. 30). Constructivist explanations (the converse of externalist explanations) are "explanations of environmental properties in terms of properties of an organic system" (p. 30). To insure that constructivism and externalism are compatible, Godfrey-Smith adheres to a narrow conception of constructivism which requires that "an organic system changes or determines the intrinsic properties of objects external to it" (Godfrey-Smith, this issue, p. XXX; see also CFMN, pp. 145f). In other words, for an organic system to construct its environment in this narrow sense, it is not sufficient that the system's faculties determine what constitutes its environment; more than this, the organic system must actually intervene causally in the external world. This narrow conception of constructivism allows Godfrey-Smith to make a sharp contrast between, on the one hand, an organism constructing its environment and, on the other hand, an organism changing itself rather than its environment and so merely accommodating its environment (p. 147). (Hereafter I will always use "construct" and its cognates in Godfrey-Smith's preferred narrow sense.) Classifying explanations into these categories involves some subtleties. For one thing, although the definitions might suggest that the distinction between externalist and internalist explanations is dichotomous, Godfrey-Smith is clear that the distinction defines the poles of a continuous range of positions. The explanations of most organic systems invoke both internal and external factors (p. 51), so the degree to which an explanation is externalist or internalist depends on "[t]he amount of emphasis placed on the