 These features characterize substantial threads of contemporary naturalist thought—threads that arise repeatedly in discussions of constructionism. Still, it is worth noting that something may be naturalistic in one sense but not another, and that the various threads we have characterized may sometimes be at odds. For example, rational choice explanations in economics might count as naturalist in that they attempt to reduce complex macro-level phenomena to simple, micro-level phenomena at the level of individuals (exhibiting some variety of metaphysical fundamentalism), and in the sense that they employ idealized causal modeling to do so (as in 1c). But they seem nonnaturalist insofar as they offer a highly idealized account of human behavior, one that seems frequently contradicted by the psychological facts about human reasoning (see, e.g., Nisbett and Ross 1980, Tversky and Kahneman, 1974) (against, perhaps, 1a and b, and 3).