Safeguards of a disunified mind

The papers focuses on pragmatic arguments for various rationality constraints on a decision maker’s state of mind: on her beliefs or preferences. An argument of this kind typically targets constraint violations. It purports to show that a violator of a given constraint can be confronted with 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 herself. 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 acyclicity requirement on preferences. The paper suggests that the proposed exploitation set-ups share a common feature. If the violator of a given constraint is logically and mathematically competent, and if she prefers to be better off rather than worse off, she can be exploited only if she is disunified in her decision-making, i.e. only if she makes decisions on various issues she faces separately rather than jointly. Unification in decision making is relatively unproblematic in synchronic contexts, but it may be costly and inconvenient diachronically. On this view, therefore, pragmatic arguments should be seen as delivering conditional recommendations: If you want to afford disunification, then you’d better satisfy these constraints. They identify safeguards of a disunified mind. Isaac Levi’s position on these matters is diametrically different. According to Levi, only synchronic pragmatic arguments are valid (indeed, categorically so). The diachronic ones, he argues, lack any validity at all. This line of reasoning is questioned in the paper

From values to probabilities

According to the fitting-attitude analysis of value (FA-analysis), to be valuable is to be a fitting object of a pro-attitude. In earlier publications, setting off from this format of analysis, I proposed a modelling of value relations which makes room for incommensurability in value. In this paper, I first recapitulate the value modelling and then move on to suggest adopting a structurally similar analysis of probability. Indeed, many probability theorists from Poisson onwards did adopt an analysis of this kind. This move allows to formally model probability and probability relations in essentially the same way as value and value relations. One of the advantages of the model is that we get a new account of Keynesian incommensurable probabilities, which goes beyond Keynes in distinguishing between different types of incommensurability. It also becomes possible to draw a clear distinction between incommensurability and vagueness (indeterminacy) in probability comparisons

Value and Unacceptable Risk: Temkin's Worries about Continuity Reconsidered

Consider a transitive value ordering of outcomes and lotteries on outcomes, which satisfies substitutivity of equivalents and obeys ‘continuity for easy cases’, i. e., allows compensating risks of small losses by chances of small improvements. Temkin (2001) has argued that such an ordering must also - rather counter-intuitively - allow chances of small improvements to compensate risks of huge losses. In this paper, we show that Temkin's argument is flawed but that a better proof is possible. However, it is more difficult to determine what conclusions should be drawn from this result. Contrary to what Temkin suggests, substitutivity of equivalents is a notoriously controversial principle. But even in the absence of substitutivity, the counter-intuitive conclusion is derivable from a strengthened version of continuity for easy cases. The best move, therefore, might be to question the latter principle, even in its original simple version: As we argue, continuity for easy cases gives rise to a sorites