Passage Two Questions 51 to 55 are based on the following passage. One of the most interesting paradoxes in America today is that Harvard University, the oldest institution of higher learning in the United States, is now engaged in a serious debate about what a university should be, and whether it is measuring up ( 符合标准). Like the Roman Catholic Church and other ancient institutions, it is asking still in private rather than in public whether its past assumptions about faculty, authority, admissions, courses of study, are really relevant to the problems of our society. Should Harvard or any other university be an intellectual sanctuary, apart from the political and social revolution of the age, or should it be a laboratory for experimentation with these political and social revolutions; or even an engine of the revolution? This is what is being discussed privately in the big clapboard ( 即形板) houses of faculty members around the Harvard Yard. The issue was defined by Walter Lippmann, a distinguished Harvard graduate, many years ago. "If the universities are to do their work," he said, "they must be independent and they must be disinterested ... They are places to which men can turn for unbiased judgments. Obviously, the moment the universities fall under political control, or under the control of private interests, or the moment they themselves take a hand in politics and the leadership of government, their value as independent and disinterested sources of judgment is impaired...“ This is part of the argument that is going on at Harvard today. Another part is the argument of the militant and even many moderated students: that a university is the keeper of our ideals and morals, and should not be "disinterested" but activist in bringing the Nation's ideals and actions together. Harvard's men of today seem more troubled and less sure about personal, political and academic purpose than they did at the beginning. They are not even clear about how they should debate and resolve their problems, but they are struggling with them privately, and how they come out is bound to influence American university and political life in the 21st century. 1. A "paradox"(Line 1, Paragraph 1) is ( ).