This compilation thesis identifies and addresses four types of puzzling cases of harm involving individual agents. These types of cases are puzzling due to uncertainty, not regarding the nature of harm, but regarding its normative implications and instantiation under particular circumstances. The relevant types of cases can be divided into two broad categories. In the first category are cases in which we think individuals do harm or act wrongly on account of being involved in harm, but it is not clear what the relationship between the individual act and the harm is, or how the harm makes the act wrong. These cases arise for instance in collective impact situations, where many individual acts together bring about harmful outcomes. In the second category are cases in which it seems that individuals are harmed, but it is not clear whether or how the harm is instantiated. Puzzling cases of the second kind often arise where the alleged harm is tied to the person's coming into or going out of existence, or where birth or death separates the subject of harm from the act or event that supposedly causes it. Papers 1 and 2 each address a puzzling case of harm within the ethics of collective action, while Papers 3 and 4 each address a puzzling case of harm within the philosophy of death and non-existence.

The desire-satisfactionist defense of the existence of posthumous harm faces the problem of changing desires. The problem is that, in some cases where desires change before the time of their objects, the principle underlying the desire-satisfactionist defense of posthumous harm yields implausible results. In his prominent desire-satisfactionist defense of posthumous harm, David Boonin proposes a solution to this problem. First, I argue that there are two relevantly different versions of the problem of changing desires, and that Boonin's proposed solution addresses only one of them. Second, I argue that modifying the underlying principle is a better approach to overcoming the problem of changing desires since it addresses both versions of the problem. I defend this approach against objections by showing that the problems raised are problems for the principle as a general theory of harm, not for the principle as part of the desire-satisfactionist defense of posthumous harm.

The possibility of extraterrestrial intelligence (ETI) exists despite no observed evidence, and the risks and benefits of actively searching for ETI (Active SETI) have been debated. Active SETI has been criticized for potentially exposing humanity to existential risk, and a recent game-theoretical model highlights the Hobbesian trap that could occur following contact if mutual distrust leads to mutual destruction. We argue that observing a nearby ETI would suggest the existence of many unobserved ETI. This would expand the game and implies that there may be a mechanism that prevents ETI from attacking us. As a result, the Hobbesian trap would be avoided if both parties assumed the other is not likely to attack.

If it is bad for a person to come into existence, wouldn't it be best for those of us who do exist to kill ourselves? This is a reasonable question to ask philosophical pessimists, but, as it turns out, the answer is not obvious. In this chapter, I explore the inference from the pessimist claim that it is a serious overall bad for a person to come into existence, to the view that it is better for an existing person to end their own life than to continue living. More specifically, I consider some pessimist views that support this claim, and discuss whether it follows from these views that it is better for an existing person to end their own life than to continue living. First, I argue that it follows from the relevant pessimist views that it is better for an existing person to die than to continue living. Second, I argue that, given that it is better for a person to die than to continue living, it is also better for them to end their own life than to continue living in those instances. Hence, it does follow from the pessimist views in question that it is better for an existing person to end their own life than to continue living.

Many people are worried about the harmful effects of climate change but nevertheless enjoy some activities that contribute to the emission of greenhouse gas (driving, flying, eating meat, etc.), the main cause of climate change. How should such people make choices between engaging in and refraining from enjoyable greenhouse-gas-emitting activities? In this chapter, we look at the answer provided by decision theory. Some scholars think that the right answer is given by interactive decision theory, or game theory; and moreover think that since private climate decisions are instances of the prisoner’s dilemma, one rationally should engage in these activities provided that one enjoys them. Others think that the right answer is given by expected utility theory, the best-known version of individual decision theory under risk and uncertainty. In this chapter, we review these different answers, with a special focus on the latter answer and the debate it has generated.

Collective impact cases are situations where people collectively bring about a morally significant outcome by each acting in a certain way, and yet each individual action seems to make no, or almost no difference to the outcome. Intuitively, the beneficial or harmful outcomes give individuals moral reason to act (or refrain from acting) in collective impact situations. However, if the individual action does not make a difference to the outcome, it is not clear what those moral reasons are. The problem of collective impact is the challenge of identifying such moral reasons. Julia Nefsky has presented an account of how an individual action can help without making a difference - call it the Helping Account - that claims to provide a general solution to the problem of collective impact while avoiding problems faced by previously suggested solutions. I present an internal critique of Nefsky's work. First, I argue that, based on the problems that Nefsky has raised against previously suggested solutions, three success conditions for a general solution to the problem of collective impact can be formulated: The Weightiness condition, the Generalizability condition, and the Connectedness condition. Second, I argue that the Helping Account fails to satisfy the three success conditions, thereby failing, by Nefsky's own standards, to provide a general solution to the problem.

In this paper, I argue that an individual wrongful act that is part of the oppression of a social group is pro tanto morally worse than an otherwise morally equal act that is not part of the oppression of a social group. I do this by drawing on insights from the discussion of the problem of collective harm. In collective harm situations, where many individual acts together bring about a harmful outcome, we think that there is moral reason for each individual (not) to act. Assuming it is true that an act's being part of a collective harm situation is reason-giving, I suggest that an individual act's being part of a collective harm situation affects its normative status, i.e. that it is a worse-making feature of the act. More specifically, the idea is that there is a morally significant relationship between an individual act and the outcome in collective harm situations such that standing in this relationship is a worse-making feature of the act.

Based on proposed solutions to the problem of collective harm, I identify two accounts of the morally significant relationship between an individual act and the outcome in collective harm situations, and suggest that there is a third, normatively akin way of specifying this relationship. I then argue that a relationship of this third kind holds between oppression and individual acts that are part of it, and thus oppression is a collective harm situation in the normatively relevant sense. Hence, given that an act's being part of a collective harm situation is a worse-making feature of the act, an individual wrongful act that is part of oppression is pro tanto morally worse than an otherwise morally equal act that is not part of oppression.