We like to think that all people feel empathy to the same degree. In reality, it varies a lot from one person to the next, like most mental traits. We are half-aware of this when we distinguish between “normal people” and “psychopaths,” the latter having an abnormally low capacity for empathy. The distinction is arbitrary, like the one between “tall” and “short.” As with stature, empathy varies continuously among the individuals of a population, with psychopaths being the ones we find beyond an arbitrary cut-off point and who probably have many other things wrong with them. By focusing on the normal/abnormal dichotomy, we lose sight of the variation that occurs among so-called normal individuals. We probably meet people every day who have a low capacity for empathy and who nonetheless look and act normal. Because they seem normal, we assume they are as empathetic as we are. They aren’t.