Marriage seems at first to be a counterexample to the VP and a clear case in which the associated role-related moral responsibilities are voluntarily assumed . But when we look more closely we see evidence to the contrary. When we try to describe marriage merely in terms of a contract, we encounter difficulties; provisions, penalties, terms and many other aspects of a contract are either completely absent or not strictly defined. While it is true that a marriage often looks like, can be acted out as, and can be terminated like, a contract, what must be acknowledged are the mutual dependencies that characterize marriages, whether they are officially recognized by means of marriage licenses or not.
Of course, Goodin says, one should not overlook that, usually, such relations are voluntarily assumed but this more accurately points to how special obligations arise in marriage, and not what their specific content is. Many of the responsibilities which cohabiting partners have towards one another seem to reflect more the fact that they have placed themselves in one another's power emotionally, financially, and physically. Cohabiting spouses, whether they have been legally married or not, have made themselves vulnerable to each other by extending trust to their partners, and it is this mutual vulnerability that accounts for the moral responsibilities and special obligations between spousal partners, rather than any explicit contractual agreements they may have made.
The marriage ceremony and the marriage license, the exchanging of matrimonial vows, only ratify and publicize an interpersonal relationship characterized by intimacy and trust between two persons in which each is made vulnerable in numerous ways to the actions and decisions of their partner. Cohabiting spouses have strong moral responsibilities to care for one another due to these pre-existing relationships of dependency and vulnerability whether or not they have explicitly agreed to abide by a marriage contract or performed a public ceremony of some kind in which they have explicitly exchanged marriage vows.
In a marriage, or other close intimate relationship, the parties to the relationship are mutually vulnerable to one another in many specific ways, and each is depending on the other not to betray their trust. In this sense, marriage partners are specially vulnerable to one another in ways in which they are not vulnerable to other people with whom they have no intimate relationship. To have a relationship based on trust and intimacy is to give another person a certain kind of power over you, a power that they can deploy responsibly or not. Not all aspects of this kind of moral responsibility can be delegated to others; it is often important that one's own partner be the one who cares and not anyone else.
Using parental responsibilities and marital responsibilities as paradigm cases, Goodin attempts to generalize the VP to other kinds of interpersonal relationships: "What seems true for children in particular also seems true for other kin, neighbors, countrymen, and contractors. To some greater or lesser extent, they are all dependent on you to do something for them; and your varying responsibilities toward each of them seem roughly proportional to the degree to which they are, in fact, dependent upon you (and you alone) to perform certain services" (33-34).The moral intuitions upon which this argument rests are strengthened considerably by the qualification inserted parenthetically, that the bearers of the responsibility in question is uniquely able to assume and discharge the responsibility in question towards the beneficiary. This is not always the case, and we must broaden Goodin's account to include shared and collective responsibilities of various kinds. But, as Goodin points out, "[w]hat the vulnerability model emphasizes is not just their special need, however, but also your special ability to help. That is the crucial factor in imposing the duty upon you in particular" (34).
I will take up this suggestion in greater detail at a later stage in the argument, and discuss the forms of power, knowledge, special competences or skills, resources, and positional considerations, which need to be taken into account in order to account for the ascription of special moral responsibilities to particular agents. But for the moment suffice it to note that the existence of a special responsibilities of care generated by a relationship of vulnerability depends both upon the characteristics of the subjects or bearers of those responsibilities as well as those of the beneficiaries or objects of those responsibilities, the C and D arguments in the vulnerability and corrigibility relationships.
In some other kinds of familial relationships we find that individuals have entered roles which they might not have, or at least only partially, chosen. Where this is the case, the inherent responsibilities of that role being voluntarily assumed might be a slightly inaccurate characterization. As was indicated above, where such roles have been self-assumed, it seems that the voluntary nature of assuming such responsibilities answers the specific question as to why we have certain responsibilities to family members, but not, necessarily what these responsibilities include. In such cases, Goodin asserts the vulnerability model as superior in terms of both explaining why we have such responsibilities and what they those responsibilities are and entail. One of the bits of evidence for this assertion is that actions in accordance with self-assumed contractual obligations have the character of narrow reciprocity. Debts are incurred and discharged after which, the parties stand again in the same relation as before the debt was incurred (89). But such a characterization for the special moral relationships that exist among family members, he notes, seems to be "out of place in family relationships" (90). But let's test this by looking at some other familial relationships.