Other ways morality limits itself

In the previous post I noted that in some sense morality limits itself. Living a virtuous life may come at considerable cost to oneself and one's duty to be fair to oneself may have to be taken into consideration and this consideration is a moral consideration itself. There may be other reasons to see certain moral ideals as being limited by morality. Consider the moral ideal some people may have of being completely selfless. Some people may value this and there may even have been a few people in history that were. All of their interests and time and effort were taken to relieve the suffering of other people or to increase their happiness. But I think that this kind of life has something against it. It is not universalizable under the categorical imperative for one.

Consider a "society" of two such completely selfless individuals, A and B. A's interests all lay in furthering B's interests and vice versa. But what are all of B's interests? Well, they are A's interests and so on. This would be a kind of infinite regress of the worst kind. This reasoning would work for a society of any size greater than two as well. So we seem to need some selfish interest that further our end in itself under such a scheme.