“The nature of thinking is one of the most important concerns of [Hannah] Arendt’s social and political theory. Thinking is the “habit of examining whatever happens to come to pass or to attract attention” in inner dialogue, in a sort of conversation with oneself, where every mental reaction is subject to criticism and in which the inner critic is also held to answer back and forth.
Arendt speculated that, in many circumstances, moral conduct seems to depend on this “intercourse of man with himself.” A person contemplates murder, for example, but says to himself or herself: “I can’t do this. If I did, I would have to live with a murdered for the rest of my life.” But thinking is also one of the most fragile features of human consciousness. Part of what Arendt meant by the banality of evil is the possibility of wrongdoing that opens up when this inner dialogue is no longer an importnat feature of people’s lives, so that the prospect of who I would have to live with in myself is no longer a concern.”
Jeremy Waldron, “What Would Hannah Say?”, New York Review of Books, March 15, 2007