I would replace the word selfish with information manipulator.
I define the self as the brain and what the brain does. What the brain does is take in information, make sense of it, then formulate predictive decisions for what to do next. So selfish, for me, means being 100% vested in optimizing one’s predictive decisions based upon how one is able to take in, interpret, and manage information.
I define information as everything that exists outside of a brain. Thus, if I am evaluating my daughter’s level of fatigue and whether or not I should drag her to the grocery store, I consider it an act of information management. In order to consider my own needs or the needs of others, I must rely upon my information management skills. Evaluating information about people, animals, numbers, laws of physics, etc. is immaterial to our brain. It simply evaluates whatever information crosses its path in order to produce a predictive decision for what to do next.
To our brain, information management to come up with a constant stream of predictions for what to do next is a matter of life or death. So being able to interpret events from one’s perspective and have one’s perspective validated is what the brain craves.
Understanding the brain as an information manager as opposed to an appendage of a god’s imperative or as a product of psychological morality or immorality reframes how we describe humans. It also allows us to have a more realistic picture of ourselves and others in ways that can help us maintain better individual mental health and group cohesion. We can figure out how to solve for our information management needs (what psychologists call selfishness), in ways that minimize power imbalances.