Abstract

My focus is on pragmatic arguments for various rationality constraints on a decision maker’s state of mind: on his beliefs or preferences. An argument of this kind purports to show that a violator of a given constraint can be exposed to a decision problem in which she will act to her guaranteed disadvantage. Dramatically put, she can be exploited by a clever bookie who doesn’t know more than the agent himself. Examples of pragmatic arguments of this kind are synchronic Dutch Books, for the standard probability axioms, diachronic Dutch Books, for the more controversial principles of reflection and conditionalization, and Money Pumps, for the transitivity requirement on preferences. It is suggested that the proposed exploitation set-ups share a common feature. If the violator of a given constraint is logically and mathematically competent, she can be exploited only if she is disunified in his decision-making, i.e., only if she makes decisions on various issues she confronts separately rather than jointly. In other words, exploitation is possible only if the decision problem has been framed in a certain way. Unification in decision making is relatively unproblematic in synchronic contexts, but it may be quite costly and inconvenient diachronically, especially when the issues under consideration are widely spread over time. On my view, therefore, pragmatic arguments should be seen as delivering conditional recommendations: If you want to afford disunification, then you’d better satisfy these constraints. The arguments of this kind fail to establish the inherent rationality of the constraints under consideration. Isaac Levis view of the status of pragmatic arguments is diametrically opposed to mine. According to him, only synchronic pragmatic arguments are valid. The diachronic ones, he argues, lack any validity at all. This line of reasoning is questioned in my paper.