We address the question, in decision theory, of how the value of risky options (gambles) should be assessed when they have no finite standard expected value, that is, where the sum of the probability-weighted payoffs is infinite or not well defined. We endorse, combine and extend (1) the proposal of Easwaran (2008) to evaluate options on the basis of their weak expected value, and (2) the proposal of Colyvan (2008) to rank options on the basis of their relative expected value.

This paper explores the contrast between mentalistic and behaviouristic interpretations of decision theory. The former regards credences and utilities as psychologically real, while the latter regards them as mere representations of an agent's preferences. Philosophers typically adopt the former interpretation, economists the latter. It is argued that the mentalistic interpretation is preferable if our aim is to use decision theory for descriptive purposes, but if our aim is normative then the behaviouristic interpretation cannot be dispensed with.

Should people who perform equal work receive equal pay? Most would say ‘yes’, at least insofar as this question is understood to be asking whether employers should be permitted to discriminate against employees on the basis of race or sex. But suppose the employees belong to all of the same traditionally protected groups. Is (what I call) nondiscriminatory unequal pay for equal work wrong? Drawing an analogy with price discrimination, I argue that it is not intrinsically wrong, but it can be deceptive, in which case it is wrong.

Proponents of behavioural policies seek to justify them as ‘evidence-based’. Yet they typically fail to show through which mechanisms these policies operate. This paper shows – at the hand of examples from economics and psychology – that without sufficient mechanistic evidence, one often cannot determine whether a given policy in its target environment will be effective, robust, persistent or welfare-improving. Because these properties are important for justification, policies that lack sufficient support from mechanistic evidence should not be called ‘evidence-based’.

According to some accounts of exploitation, most notably Ruth Sample’s (2003) degradation-based account and Robert Goodin’s (1987) vulnerability-based account, exploitation occurs when an advantaged party fails to constrain their advantage in light of another’s disadvantage, regardless of the cause of this disadvantage. Because the duty of constraint in these accounts does not depend on the cause of the disadvantage, the advantaged’s duty of constraint is what I call a ‘come-what-may’ duty. I show that come-what-may duties create moral hazards that can themselves be exploited by the disadvantaged parties. In such cases these accounts of exploitation are either self-frustrating or over-demanding.

The Pareto principle states that if the members of society express the same preference judgement between two options, this judgement is compelling for society. A building block of normative economics and social choice theory, and often borrowed by contemporary political philosophy, the principle has rarely been subjected to philosophical criticism. The paper objects to it on the ground that it applies indifferently to those cases in which the individuals agree both on their expressed preferences and on their reasons for entertaining them, and those cases in which they agree on their expressed preferences while differing on their reasons. The latter are cases of ‘spurious unanimity’, and it is normatively inappropriate, or so the paper argues, to defend unanimity preservation at the social level for such cases: thus the Pareto principle is formulated much too broadly. The objection seems especially powerful when the principle is applied in an ex ante context of uncertainty, in which individuals can disagree on both their probabilities and utilities, and nonetheless agree on their preferences over prospects.