“People will hold an opinion because they want to keep the company of others who share the opinion, or because they think it is the respectable opinion, or because they have publicly expressed the opinion in the past and would be embarrassed by a “U-turn,” or because the world would suit them better if the opinion were true, or . . . Perhaps it is better to get on with your family and friends, to avoid embarrassment, or to comfort yourself with fantasies than to believe the truth. But those who approach matters in this way should give up any pretensions to intellectual seriousness. They are not genuinely interested in reality.”