1. David Hume, A Treatise of Human Nature (1738), II.3.3, 415.
2. David Hume, An Enquiry Concerning the Principles of Morals (1751), Section 1, paragraph 9.
3. See ‘Migrant Crisis: Migrant Europe Explained in Seven Charts’, 4 March 2016, at <http://www.bbc.com/news/world-europe-34131911>
4. Dale Carnegie, How to Win Friends and Influence People (New York: Simon & Schuster, 1936).
5. Oscar Wilde, The Happy Prince and Other Stories (London, 1888).
6. See Megan Phelps-Roper, ‘I Grew Up in the Westboro Baptist Church. Here’s Why I Left’, March 2017, at <https://www.ted.com/talks/megan_phelps_roper_i_grew_up_in_the_westboro_baptist_church_here_s_why_i_left/transcript?language=en>. See also Adrian Chen, ‘Unfollow: How a Prized Daughter of Westboro Baptist Church Came to Question its Beliefs’, The New Yorker, 23 November 2015. More examples of radical conversion in light of evidence can be found in The Best of Enemies: Race and Redemption in the New South by Osha Gray Davidson (New York: Scribner’s, 1996) about civil rights activist Ann Atwater and former Ku Klux Klan leader C. P. Ellis; in Matthew Ornstein’s documentary Accidental Courtesy: Daryl Davis, Race & America (2016) on Netflix about a black musician who befriended Ku Klux Klan members; and in stories about Derek Black, former white nationalist.
7. P. M. Fernbach, T. Rogers, C. R. Fox and S. A. Sloman, ‘Political Extremism is Supported by an Illusion of Understanding’, Psychological Science, 24 (6) (2013), 939–46. In their later book, The Knowledge Illusion: Why We Never Think Alone (London: Macmillan, 2017), Chapter 9, Sloman and Fernbach add two important qualifications. First, how-questions have different effects with regard to sacred values (such as abortion) compared to policy issues (such as cap and trade). Second, how-questions that expose people’s illusions and ignorance can also upset some people and make them less inclined to discuss the issue. Like all tools, questions work only in some contexts and need to be used carefully and sparingly.
8. Among their other works on accountability, see Jennifer S. Lerner, Julie H. Goldberg and Philip E. Tetlock, ‘Sober Second Thought: The Effects of Accountability, Anger, and Authoritarianism on Attributions of Responsibility’, Personality and Social Psychology Bulletin, 24 (6) (1998), 563–74.
9. Jaime Napier and Jamie Luguri, ‘From Silos to Synergies: The Effects of Construal Level on Political Polarization’, in Piercarlo Valdesolo and Jesse Graham (eds), Social Psychology of Political Polarization (New York and Abingdon: Routledge, 2016), pp. 143–61.
10. Pew Research Center, Washington, DC, ‘Political Polarization in the American Public’ (June 2014), p. 59.
11. As they are called by Avishai Margalit, On Compromise and Rotten Compromises (Princeton, NJ: Princeton University Press, 2009).