Subsistence Needs, Human Rights, and Imperfect Duties

I address the usefulness of thinking about a human right to subsistence within conceptions of human rights grounded in ordinary moral reasoning. I argue that that natural rights should be understood as rights in rem , with their dynamism constrained by the requirements of justification and their scope constrained by the distinction between perfect and imperfect duty. I then suggest that many of the most pressing demands which the moral significance of subsistence needs create are plausibly imperfect duties, and so cannot correlate to a natural right to subsistence. This restricts the helpfulness of a human right to subsistence in our reasoning about what we owe to others.