Martin Luther King, Jr.’s debt to theology and natural law:
Those who praise the modern civil rights movement, but who also want to keep morality and theology absent from public discourse, seldom mention King’s reliance on natural law in his justly famous letter. Scholars such as the late John Rawls were at great pains to show how their thoroughly secularized theories of justice and public reason could make room for King, but in fact they could do so only at the cost of minimizing the seriousness of King’s argument.[From MLK’s Philosophical and Theological Legacy « Public Discourse]
And a question of moral philosophy: Was Martin Luther King, Jr. a Better Man than Adolf Hitler? It’s a ridiculous question on the face of it. But as Arthur Khatchatryan reminds us,
The only way in which we can be certain that the moral values of King was supreme to those of Hitler is if we had non-arbitrary objective moral laws that we were considering.
There are those (quoted here, for example) who deny that such non-arbitrary, objective moral laws exist. For them, the question cannot be so ridiculous after all, though they might want it to be; for without some real up and down on the scale of values, comparisons of moral elevation are necessarily meaningless. MLK’s morality could not really be higher or lower than anyone’s at all—not even Hitler’s—if there is no such real higher or lower morality.
If that conclusion is worthy of ridicule (as it obviously is), and if it follows ineluctably from the premise of moral anti-realism (which it does), then moral realism itself is equally ridiculous.