If we are thinking about persuading our fellow human beings about the moral value or material benefit of any mode of action or artefact, we would do well to consider this spectrum of moral behaviours.
The common man/woman, we might consider central to the spectrum, though we have to acknowledge that individuals will tend away from the norm. However, though by definition the common man/woman should be the centre of the “Bell curve” of humanity’s positioning on this moral spectrum, our arguments must address the attitudes veering away from this position. Just as we cannot rely on altruism, we mustn’t forget the self-seeking. Somewhere in this diagram lies a wisdom that we need to tap into if we are to influence basic human behaviour.