Aren't all actions selfish? Even those that are technically considered "selfless" and for the benefit of others are always done for some reason that is justified because of the benefit to oneself. For example, if I choose to rescue a child from a burning building with the risk of myself dying, I still perform the action because it makes ME feel good, or I feel that it is the morally right thing to do. Therefore, isn't it impossible to perform a truly selfless act, because the reasons for performing an action are always MY reasons? The selfless monk who goes on a fast is actually selfish because he wants something and performs the action to get it, shouldn't whether it benefits someone else be irrelevant? Is there any way to be truly selfless?
Just because an action makes you feel good it does not follow that you performed the action to attain that good feeling. If I buy lunch for someone who is hungry and it happens that I feel a burst of good will and fellow feeling afterwards, the feeling was not the goal of my action. I would have done it even if I felt depressed after doing it. It is, however, true that we can never be sure of what our motives are, and that are actions are usually overdetermined, that is, the fruit of more than one cause.