In the future, when we compare the welfare of a being of one substrate (say, a human) with the welfare of another (say, an artificial intelligence system), we will be making an intersubstrate welfare comparison. In this paper, we argue that intersubstrate welfare comparisons are important, difficult, and potentially tractable. The world might soon contain a vast number of sentient or otherwise significant beings of different substrates, and moral agents will need to be able to compare their welfare levels. However, this work will be difficult, because we lack the same kinds of commonalities across substrates that we have within them. Fortunately, we might be able to make at least some intersubstrate welfare comparisons responsibly in spite of these issues. We make the case for cautious optimism and call for more research.

This paper offers a unified explanation for the procreation asymmetry and the non-identity thesis – two of the most intractable puzzles in population ethics. According to the procreation asymmetry, there are moral reasons not to create lives that are not worth living but no moral reasons to create lives that are worth living. I explain the procreation asymmetry by arguing that there are moral reasons to prevent the bad, but no moral reasons to promote the good. Various explanations for the procreation asymmetry have failed to explain the non-identity thesis: if one could create a person with a good life or a different person with a better life, one has a moral reason to create the better life. I argue that reflections on the misfortune of unfulfilled potential allow us to circumvent the non-identity problem.

Must we always pursue economic growth? Kogelmann answers yes. Not only should poor countries pursue growth, but rich countries should as well. Kogelmann aims to provide a wealth-insensitive argument – one demonstrating all countries should pursue growth regardless of their wealth. His central argument – the no halting growth (NHG) argument – says no country experiencing growth should stop it, because doing so requires undermining the conditions causing it and those conditions are independently morally desirable, so they should not be undermined. For countries not growing, he may argue that they have an obligation to implement the conditions that cause growth because they are independently morally desirable. Call this the implementation argument. I contend that neither argument is wealth-insensitive as each fails to establish an obligation to pursue growth. I attempt to diagnose how this could be and propose that it is a product of attempting to answer three questions about growth simultaneously.

In this paper, I argue for Fit, a prudential version of the claim that attitudes must fit their objects, the claim that there is an extra benefit when one's reactions fit their objects. I argue that Fit has surprising and powerful consequences for theories of well-being. Classic versions of the objective list theory, hedonism, desire views, and loving-the-good theories do not accommodate Fit. Suitable modifications change some of the views substantially. Modified views give reactions a robust role as sources of well-being, and they accept that objects call for some attitudes but not others. I argue that objective list theories and loving-the-good theories require the most minimal changes to accommodate Fit, so we have a pro tanto reason to favor these views over alternatives.

What justifies differences in the acceptance of paternalism towards competent minors and older people? I propose two arguments. The first argument draws on the widely accepted view that paternalism is easier to justify the more good it promotes for the paternalizee. It argues that paternalism targeting young people generally promotes more good for the people interfered with than similar paternalism targeting older people. While promoting people's interests or well-being is essential to the justification of paternalism, the first argument has certain unfair implications in that it disfavours paternalism towards the worse off. The second argument caters to such fairness concerns. It argues that priority or inequality aversion supports age-differentiated paternalism because young people, who act imprudently and thereby risk their interests or well-being, are worse off than older people who act in similar ways. I suggest that both arguments are pertinent in evaluating specific paternalistic acts and policies.