Big, Small and Medium

I want to focus on some of the limits of decision theory that are of interest to the philosophical concern with practical reasoning and rational choice. These limits should also be of interest to the social-scientists' concern with Rational Choice.

Let me start with an analogy. Classical Newtonian physics holds good and valid for middle-sized objects, but not for the phenomena of the very little, micro, sub-atomic level or the very large, macro, outer-space level: different theories, concepts and laws apply there. Similarly, I suggest that we might think of the theory of decision-making as relating to middle-sized, ordinary decisions, and to them only. There remain the two extremes, the very ‘small’ decisions on the one hand and the very ‘big’ decisions on the other. These may pose a challenge to the ordinary decision theory and may consequently require a separate treatment.

By ‘small’ decisions, I have in mind cases where we are strictly indifferent with regard to the alternatives before us, where our preferences over the alternatives are completely symmetrical. Every time I pick a bottle of Coke or a can of Campbell soup from the shelves of the supermarket, I have made a small decision in this sense. To the extent that we take choosing to be choosing for a reason, and choosing for a reason to presuppose preferences, it looks like we have to conclude that in such cases rational choice is precluded.