Many have claimed that unspecific evidence sometimes demands unsharp, indeterminate, imprecise, vague, or interval-valued probabilities. Against this, a variant of the diachronic Dutch Book argument shows that perfectly rational agents always have perfectly sharp probabilities.

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.

A defense of imprecise credences (and other imprecise doxastic attitudes).

It seems natural to choose whether to have a child by reflecting on what it would be like to actually have a child. I argue that this natural approach fails. If you choose to become a parent, and your choice is based on projections about what you think it would be like for you to have a child, your choice is not rational. If you choose to remain childless, and your choice is based upon projections about what you think it (...) would be like for you to have a child, your choice is not rational. This suggests we should reject our ordinary conception of how to make this life-changing decision, and raises general questions about how to rationally approach important life choices. (shrink)

Just as there are rational requirements on thought, there are rational requirements on action. This book defends a conception of ethics, and a related conception of human nature, according to which altruism is included among the basic rational requirements on desire and action. Altruism itself depends on the recognition of the reality of other persons, and on the equivalent capacity to regard oneself as merely one individual among many.

(No abstract is available for this citation).

Some experiences are transformative in that it is impossible to imagine experiencing them until one experiences them. It has been argued that pregnancy and parenthood are like that, and that therefore one cannot make a rational decision whether to become a mother. I argue that pregnancy and parenthood are not like that; but that if even if they are, a woman can still make a rational decision by relying on testimony about the value of these experiences. I then discuss an (...) objection that such testimony will be unreliable because parents will reflect on their being glad that their children exist, and will not realize that it’s reasonable to be glad their children exist even if the parents’ lives are thereby worse. I argue that despite this possible route to unreliable testimony, in general it is reasonable to rely on others’ testimony about the value of their lives. (shrink)

We use “I’ll be glad I did it” reasoning all the time. For example, last night I was trying to decide whether to work on this paper or go out to a movie. I realized that if I worked on the paper, then today I would be glad I did it. Whereas, if I went out to the movie, today I would regret it. This enabled me to see that I should work on the paper rather than going out to (...) a movie. This looks like excellent reasoning: Paper argument: 1. If I work on my paper, I’ll be glad I did it. 2. Therefore, I should work on my paper. When we’re having trouble making a big life decision, we often try to picture what will happen each way we might choose, and imagine how we’ll feel in that outcome. When choosing between two jobs, we might use this reasoning. Suppose you are choosing between two jobs and you know quite a lot about what the two jobs will be like. In one, you will make a lot of money but have to work eighty-hour weeks and see little of your family. In the other, you will make considerably less money—though enough to support yourself and your family. You’ll have much more time for your family. The money is attractive. But overall, you realize you’ll be glad to have the time with your family if you take the second job—you’ll be glad you made that choice. It seems this is a good way of realizing that you should take the second job. (shrink)

It is a platitude among decision theorists that agents should choose their actions so as to maximize expected value. But exactly how to define expected value is contentious. Evidential decision theory (henceforth EDT), causal decision theory (henceforth CDT), and a theory proposed by Ralph Wedgwood that this essay will call benchmark theory (BT) all advise agents to maximize different types of expected value. Consequently, their verdicts sometimes conflict. In certain famous cases of conflict—medical Newcomb problems—CDT and BT seem to get (...) things right, while EDT seems to get things wrong. In other cases of conflict, including some recent examples suggested by Andy Egan, EDT and BT seem to get things right, while CDT seems to get things wrong. In still other cases, EDT and CDT seems to get things right, while BT gets things wrong. It's no accident, this essay claims, that all three decision theories are subject to counterexamples. Decision rules can be reinterpreted as voting rules, where the voters are the agent's possible future selves. The problematic examples have the structure of voting paradoxes. Just as voting paradoxes show that no voting rule can do everything we want, decision-theoretic paradoxes show that no decision rule can do everything we want. Luckily, the so-called “tickle defense” establishes that EDT, CDT, and BT will do everything we want in a wide range of situations. Most decision situations, this essay argues, are analogues of voting situations in which the voters unanimously adopt the same set of preferences. In such situations, all plausible voting rules and all plausible decision rules agree. (shrink)

Orthodox decision theory gives no advice to agents who hold two goods to be incommensurate in value because such agents will have incomplete preferences. According to standard treatments, rationality requires complete preferences, so such agents are irrational. Experience shows, however, that incomplete preferences are ubiquitous in ordinary life. In this paper, we aim to do two things: (1) show that there is a good case for revising decision theory so as to allow it to apply non-vacuously to agents with incomplete (...) preferences, and (2) to identify one substantive criterion that any such non-standard decision theory must obey. Our criterion, Competitiveness, is a weaker version of a dominance principle. Despite its modesty, Competitiveness is incompatible with prospectism, a recently developed decision theory for agents with incomplete preferences. We spend the final part of the paper showing why Competitiveness should be retained, and prospectism rejected. (shrink)

I argue that standard decision theories, namely causal decision theory and evidential decision theory, both are unsatisfactory. I devise a new decision theory, from which, under certain conditions, standard game theory can be derived.

How should we make choices when we know so little about our futures? L. A. Paul argues that we must view life decisions as choices to make discoveries about the nature of experience. Her account of transformative experience holds that part of the value of living authentically is to experience our lives and preferences in whatever ways they evolve.

the symmetry of our evidential situation. If our confidence is best modeled by a standard probability function this means that we are to distribute our subjective probability or credence sharply and evenly over possibilities among which our evidence does not discriminate. Once thought to be the central principle of probabilistic reasoning by great..