When a person or group of people lack a particular good, others will sometimes act in solidarity with them by depriving themselves of that good too. For example, while leading his army through the desert, Alexander the Great is fabled to have refused a helmet filled with water, preferring to undergo the soldiers’ suffering with them than to accept something which they couldn’t have. Or again, imagine that a group of soldiers has been captured as prisoners of war. After some weeks, one of the POWs is approached and offered early release, as his father is a high-ranking officer. Yet he refuses, choosing to remain captive with his fellow soldiers. (As some readers may recognize, this example is based on the experiences of the late Senator John McCain during his service in the Vietnam War.) Here’s one last example. In the 1940’s, an Indian woman—call her ‘KC’—is travelling across the American South by train. At a stop, the train conductor informs her that she is seated in a carriage reserved for White passengers. However, thinking …