Is free speech at risk at our universities?By Kathleen McCartneyUpdated 3:51 PM ET, Thu September 4, 2014People walk past the Alma Mater statue on the Columbia University campus in New York City.Story highlightsKathleen McCartney: Many people think freedom of speech is in danger at universitiesMcCartney: Anger and extremism prevail in debates; other views shouted downShe says students must learn to discuss provocative ideas with open minds, considerationMcCartney: We need to hear all opinions -- silencing a voice has no place at collegesFreedom of speech is the foundation of democracy. Yet many believe it is in jeopardy at our nation's colleges and universities, especially following last spring's commencement speaker controversies -- including one at Smith College, when the managing director of the International Monetary Fund decided not to address graduates after protests.This fall, as students return to our campuses, colleges must foster constructive conversations, not only about free speech but also about the need for civil discourse, a practice so absent from public life today. Discourse that is civil can still be challenging; however, it must be grounded in respect.Students arrive at college largely unprepared for debate. This is hardly surprising, given our culture. In many realms -- entertainment, government, politics -- acrimony and extremism prevail. Reality television passes off angry encounters as entertainment. Congress is stalemated by partisanship to the point where it cannot legislate. Niche cable outlets have eroded our confidence in media objectivity. For some, political party affiliation is personal: A recent Pew Research Center study found many of us would object to a family member marrying outside our own political party. Kathleen McCartneyThe ideological echo chamber extends to our customized Facebook and Twitter feeds. We create social worlds in which our views are constantly codified and reaffirmed, rarely challenged.We have lost sight of a key fact: Reasonable people disagree.Just WatchedFree speech lost at commencementsreplayMore Videos ...Free speech lost at commencements 02:54PLAY VIDEOJust WatchedProfessor: Free speech is human rightreplayMore Videos ...Professor: Free speech is human right 05:19PLAY VIDEOJust WatchedRisks and responsibilities of free speechreplayMore Videos ...Risks and responsibilities of free speech 01:55PLAY VIDEOHigher education must counter the prevailing narrative of polarization. Fundamental to the mission of colleges and universities is the promotion of diverse opinion and vigorous debate for all constituencies: faculty, staff, alumni, and especially students.College is a coming-of-age experience for most students, a time when they form identities of all kinds -- political, professional, intellectual, and ethical. Any worthy education must be grounded in exposure to myriad perspectives and thoughts. College communities, including mine, must seize this moment to model healthy debate. I offer two proposals.First, we need to make space and time for our communities to discuss provocative ideas, including ideas offensive to some or many. We must commit to talking about issues that are hard and heated.After this summer's violence in Gaza, our students want to discuss the campaign for a self-governing Palestinian people, Israel's right to exist, and the futility of war.In the wake of the police killing of teenager Michael Brown in Ferguson, Missouri, our students want to discuss racial inequality in our systems and institutions, from education to employment to criminal justice; the role of law enforcement; and violent forms of protest.Amid an unprecedented refugee crisis at our southern border, our students want to discuss immigration policies to address the needs of 51 million refugees across the globe, especially unaccompanied children from Central America trying to escape violence.These discussions may not lead to universally held views. That shouldn't be the goal. But we can learn to disagree without demonizing, to protest without personalizing.Second, we need to create forums where we hear voices across the political spectrum. Too often, we pre-empt healthy debate by applauding those with whom we agree and shouting down the rest. A form of protest whose aim is to silence a voice rather than engage it has no place at our colleges and universities. We need meta-conversations -- that is, conversations about our conversations. What are the parameters of campus discourse, if any? When does passion for a position cross the line to intolerance, if ever? When do our actions stray from protest to harassment, if ever? In tackling these questions, we will model the best of an engaged citizenry and intellectual community.The American moral and social philosopher Eric Hoffer wrote, "The beginning of thought is disagreement -- not only with others but also with ourselves." Disagreement is necessary; it is the way we learn. Productive disagreements are rooted in thoughtful argument with the goal of convincing others, and sometimes ourselves. But how we disagree matters.Read CNNOpinion's new Flipboard magazine.Follow us on Twitter @CNNOpinion.Join us on Facebook.com/CNNOpinion. 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