Contingency, arbitrariness, and the basis of moral equality

Hardly anyone denies that (nearly) all human beings have equal moral status and therefore should be considered and treated as equals. Yet, if humans possess the property that confers moral status upon them to an unequal degree, how come they should be considered and treated as equals? It has been argued that this is because the variations in the degree to which the status-conferring property is held above a relevant threshold are contingencies that do not generate differences in degrees of moral status. Call this the contingency argument for the basis of moral equality. In this paper, I reject the contingency argument. Instead, I develop an attitude-based account of the basis of moral equality: according to this account, the basis of moral equality lies in a fitting, basic, and independent moral attitude which is owed to human beings qua moral status-holders, and provides a coherent and plausible explanation for why the variations above the threshold for moral status do not matter.