A complete account of rational choice must incorporate internal organismic constraints, not only external environmental ones.

we must be prepared to accept the possibility that what we call “the environment” may lie, in part, within the skin of the biological organisms. That is, some of the constraints that must be taken as givens in an optimization problem may be physiological and psychological limitations of the organism (biologically defined) itself. For example, the maximum speed at which an organism can move establishes a boundary on the set of its available behavior alternatives. Similarly, limits on computationa