AND ITS LIMITS
Enough for what?”counter the instrumentalist please that we seem to grant his view in asking our question. But the issue is whether instrumental rationality is the whole of rationality.
The instrumental notion of rationality can be formulated in decisiontheoretic terms within the framework of causal decision theory, whose notion of (probabilistic) causal connection captures the central notion of instrumental rationality: the means-ends connection. We (and causal decision theory, too) must construe this connection broadly, though, so as to include the relation of an action to broader actions that it specifies and is a way of doing—as flying to Chicago is a way of traveling to Chicago. Among the goals to be achieved may be the performance of an action, and one way to achieve this is to do it one particular way; instrumental rationality, as the efficient and effective achieving of goals, will include this. So instrumental rationality does not always involve bringing about something else, something completely distinct. And instrumental rationality can acknowledge that doing an action (or having done it) might itself have some value, a value that (with some stretching, perhaps) can be included in what the act produces. (In what follows, when I speak of “causal” and of “instrumental,” I mean to include the instantiation aspect and the utility of doing the act itself.)
The notion of instrumental rationality is a powerful and natural one. Although broader descriptions of rationality have been offered, every such description that purports to be complete includes instrumental rationality within it. Instrumental rationality is within the intersection of all theories of rationality (and perhaps nothing else is). In this sense, instrumental rationality is the default theory, the theory that all discussants of rationality can take for granted, whatever else they think. There is something more, I think. The instrumental theory of rationality does not seem to stand in need of justification, whereas every other theory does. Every other theory must produce reasons for holding that what it demarcates is indeed rationality. Instrumental rationality is the base state. The question is whether it is the whole of rationality.