forums open to all, a system of free speech shows its affirmative side. In a well-functioning democracy, the right to free speech certainly protects dissenters, but it cannot do what it is supposed to do unless listeners are willing to give dissenters a respectful hearing.

Rights and duties aside, many of the Constitution's institutions increase the likelihood that important information and alternative points of view will receive a public airing. The most distinctive contribution of the American framers consisted in their commitment to heterogeneity in government, seeing (in Alexander Hamilton's words) the "jarring of parties" as a method for "promoting deliberation." Because of the harmful effects of conformity, this jarring is desirable for both public and private institutions. The system of bicameralism is the most obvious example. In such a system, laws are made by two institutions with different cultures, thus creating a potential check on unjustified movements of opinion.

If we understand the role of social influences, we will also see why it is so important to ensure a high degree of diversity on the federal judiciary. Of course, Republican appointees as a class differ from Democratic appointees. We should also appreciate the value, on any panel of judges, of having a potential whistleblower, in the form of one judge of a different party from the other two. American judges are almost never lawless. But like any other group of like-minded people, a set of like-minded judges is prone to go to unjustified extremes. If a court includes potential dissenters, it will do much better. What is true for most institutions is true for courts as well.

An understanding of social influences also shows why colleges and universities should attempt to ensure heterogeneity along many dimensions. Real learning is unlikely to occur in a classroom in which everyone agrees with everyone else. Like a good legislature, a good education depends on some "jarring of parties." In some settings, racial diversity is likely to improve discussion simply by increasing the range of experiences and perspectives. An appreciation of the risks of conformity and polarization helps to explain


why institutions of higher education should promote diversity of many different kinds.

There is a larger theme in these particular claims. It is usual to think that those who conform are serving the general interest and that dissenters are antisocial, even selfish. In a way this is true. Sometimes conformists strengthen social bonds, whereas dissenters endanger those bonds or at least introduce a degree of tension. But in an important respect, the usual thought has things backwards. Much of the time, it is in the individual's interest to follow the crowd, but in the social interest for the individual to say and do what he thinks best. Well-functioning societies take steps to discourage conformity and to promote dissent. They do this partly to protect the rights of dissenters, but mostly to protect interests of their own.