For about a hundred years we have so concentrated on one of the virtues - ‘kindness’ or mercy - that most of us do not feel anything except kindness to be really good or anything but cruelty to be really bad.
Such lopsided ethical developments are not uncommon, and other ages too have had their pet virtues and curious insensibilities. And if one virtue must be cultivated at the expense of all the rest, none has a higher claim than mercy - for every Christian must reject with detestation that covert propaganda for cruelty which tries to drive mercy out of the world by calling it names such as ‘Humanitarianism’ and ‘Sentimentality’.
The real trouble is that ‘kindness’ is a quality fatally easy to attribute to ourselves on quite inadequate grounds. Everyone feels benevolent if nothing happens to be annoying him at the moment. Thus a man easily comes to console himself for all his other vices by a conviction that ‘his heart’s in the right place’ and ‘he wouldn’t hurt a fly’, though in fact he has never made the slightest sacrifice for a fellow creature. We think we are kind when we are only happy: it is not so easy, on the same grounds, to imagine oneself temperate, chaste, or humble.
By C.S. Lewis
From The Problem of Pain
Compiled in A Year with C.S. Lewis