The philosopher Iris Marion Young provided a classic formulation of the liberal demand: “Unconscious racism, sexism, homophobia, ageism, and ableism occur not only in bodily reactions and feelings and their expression in behavior, but also in judgments about people or policies. When public morality is committed to principles of equal treatment and the equal worth of all persons, public morality requires that judgments about the superiority or inferiority of persons be made on an individual basis according to individual competences.”2
Without disagreeing with the basic sentiment expressed here, I think it’s important to recognize is that Young is basically demanding that people stop using an entire part of their brain. Our heuristic reasoning is powered by pattern recognition and association. When applied to social interaction, this makes us natural stereotypers. When we see people, we classify them automatically and without conscious thought. This primes us to remember certain things, feel certain ways, and expect certain actions. Some of these associations are positive; some are inevitably negative. When they are negative, you get all the “isms” on the list that Young rattled off, and more. Because of this, the difference between people who are racist (or sexist, or homophobic, etc.) and people who are not racist is typically not that the former engage in stereotyping while the latter do not. Everyone engages in stereotyping; the only difference is how far people go to suppress or override it. A lot of energy has been invested by psychologists in showing that even people who do not have overtly racist attitudes nevertheless have underlying racist sentiments and reactions, which they are constantly having to suppress. (There are some very fine-grained experimental methods that demonstrate this quite clearly. When people are suppressing a thought it slows them down, so if you show them a picture, followed by a word-selection task, you can tell by reaction time when they are vetoing their initial impulse.3)
お、あった。ピンカーせんせいのは、Better Angels of Our Nature から：
People sort other people into mental pigeonholes according to their affiliations, customs, appearances, and beliefs. Though it’s tempting to think of this stereotyping as a kind of mental defect, categorization is indispensable to intelligence. Categories allow us to make inferences from a few observed qualities to a larger number of unobserved ones. If I note the color and shape of a fruit and classify it as a raspberry, I can infer that it will taste sweet, satisfy my hunger, and not poison me. Politically correct sensibilities may bridle at the suggestion that a group of people, like a variety of fruit, may have features in common, but if they didn’t, there would be no cultural diversity to celebrate and no ethnic qualities to be proud of. Groups of people cohere because they really do share traits, albeit statistically. So a mind that generalizes about people from their category membership is not ipso facto defective. African Americans today really are more likely to be on welfare than whites, Jews really do have higher average incomes than WASPs, and business students really are more politically conservative than students in the arts—on average.