Duties to siblings: A neglected topic in ethics

There is significant philosophical reflection on the parent-child relationship and the associated duties. But the sibling relationship is, as far as I know, largely neglected. But it's very interesting. Few have a choice whether to be a sibling. Many of us are already siblings from the first moment of our existence, and those who became siblings later were rarely consulted by their parents on whether they wanted to do so. Most of us who are siblings became siblings in childhood, and I suppose we could say that our parents had the authority to make us into siblings at that time. But one can become a sibling in adulthood, too.

Parenthood can be at least in part (and only in part, I've argued) ceded to another by adoption. But while Western culture historically does have siblingmaking (adelphopoiesis) rituals, these are merely the creation of a new sibling relationship rather than the transfer of the relationship. (One might think that adoption transfers the sibling relationship. I am not sure about that. But in any case, adoption is typically a decision by the parents.)

So not only do we typically become siblings with no initial choice, but we have no choice whether to remain siblings. This is made easier by the fact that in the ordinary course of things, duties to one's siblings are less onerous than duties to one's children. But that is only in the ordinary course of things. A stepmotherly nature--or a Providence that cares more about character than comfort--can throw us into circumstances where our duties to siblings are extremely onerous. (This also illustrates a comment from Mark Murphy that we should not expect moral burdens to be equally distributed.)

But what are the duties we have to our siblings? How do they change with the age of the siblings and other differences in circumstances? How are these duties spread among a multiplicity of siblings if there more than two?

Siblings and moral theory

1. We have special duties, independent of communal enactments, to take care of our siblings, precisely because they are siblings.

This is true.

Notice that (1) creates problems for a number of moral theories. Utilitarians will deny (1). The mere fact that someone is our brother or sister only makes it easier for us to know how to help him or her, which does not make a for a special duty to take care of him or her precisely because he or she is our brother or sister. It is difficult to see how Kantians could justify (1) without relying on something like a dollop of Natural Law (which Kant himself, but not so much contemporary Kantians, is happy with).

Contractarians can accept (1) minus the "independent of communal enactments" proviso. For perhaps it would be irrational for us to reject a communal tradition of a network of duties of special care that is below a certain level of onerousness, and our community's network includes siblinghood. But the contractarian probably could not object if the community instead had a network of duties of special care that put similar emphasis on, say, first-cousins-of-the-same-eye-color instead of siblings: what one gets from the contractarian structure is at most the irrationality of rejecting whatever one's community network of duties of special care is.

Divine command theorists can perhaps accept (1), though one might worry if the "precisely" in (1) is correct if this happens also because of divine command.

Natural law, of the well-developed moral theories, is probably the theory that best passes the test of fitting with (1). So, (1) provides a kind of argument for natural law theory (and to a lesser degree for divine command theory).

Does (1) matter? I think so. It is an important moral insight that somehow all human beings are brothers and sisters, but this moral insight is unhelpful, and maybe harmful, apart from (1).