Within APS, Vulnerability is central to Moral Evaluation because it helps explain why some forms of treatment become morally significant.
Living systems differ in their capacities, dependencies, protections, and exposures. These differences influence how actions, institutions, norms, and policies affect them.
Vulnerability does not by itself determine moral conclusions. It is one consideration among several involved in Moral Evaluation, alongside Standing, affectedness, responsibility, treatment, legitimacy, and justification.
Vulnerability is therefore neither identical with weakness nor sufficient as a complete moral principle. Rather, it identifies conditions under which harms, burdens, exclusions, or losses may become morally relevant.
Standing ↓ Vulnerability ↓ Moral Evaluation
APS treats Vulnerability as a key component in understanding why the consequences of organised action matter morally.