The experience requirement on well-being

According to the experience requirement on well-being, differences in subjects' levels of welfare or well-being require differences in the phenomenology of their experiences. I explain why the two existing arguments for this requirement are not successful. Then, I introduce a more promising argument for it: that unless we accept the requirement, we cannot plausibly explain why only sentient beings are welfare subjects. I argue, however, that because the right kind of theory of well-being can plausibly account for that apparent fact about welfare subjects even if the requirement is false, this argument does not succeed. I tentatively conclude that no compelling case can be made for the requirement.