Why are you here? Why do you plan to spend four years of your life, and more than a quarter of a million dollars of your or your parents’ money on your education?

One practical reason is that a bachelor’s degree from a respectable university is necessary to be considered for almost any midlevel or higher job in the modern economy. In some fields, such as engineering and computer science, it is the minimum preparation for a career. In others, such as medicine and law, it is required for admission to professional school. Those are good reasons.

But you should expect more out of your education than that. In the College of Arts and Sciences few of your courses are specifically required for any profession. Rather, their purpose is to teach you how to think critically, but not what to think. No one has the right to pressure you to change your opinions, or to shame you for them. The purpose of education is to teach you the necessity of thinking for yourself, the necessity of asking critical questions of yourself and of others and how to find perceptive and penetrating questions to ask. It is also to show you how other people may think, or may have thought, differently from you and the people around you. It is to take you into their world, to overcome the foreignness of their thought, to show you how they arrived at their conclusions and to ask if there is merit in their way of thinking. It is to lead into the minds of others remote from you, in time, space or ideology.

Confrontation with unfamiliar ideas may make you uncomfortable, or even feel ‘unsafe’ in your ideas. That is the purpose of education. For example, a few hundred years ago many people believed in the divine right of kings to absolute rule. That seems bizarre to most of us today, but it was a belief widely held, not just by kings’ PR flacks. Its supporters had arguments that they took seriously; we should try to enter into their minds and understand how and why they thought so differently than we do. The idea survived into the 20th century in Russia, the Ottoman Caliphate and the Chinese Mandate of Heaven. It was revived only a few years ago in the Caliphate of ISIS. John Locke found it necessary to refute it at length in his Treatises of Government, one of the root documents of democracy.

Whenever anyone tries to convince you of something, you should ask why and whether you should believe it. You should ask the same question about your own beliefs: Why should I believe this? “Everyone knows” or “everyone believes” are not good reasons.

In questions of fact, usually the truth is ascertainable: The sun rises in the east because of the way the Earth rotates, and that rotation changes only very slowly and imperceptibly (the technical term for that is the conservation of angular momentum). Columbus, and every mariner and educated person of his time, knew that the world is round because they could see distant ships “hull down” (the sails visible but not the hull, hidden by the curvature of the Earth). We know that George Washington was president because of an enormous body of documents that he signed as president, or that refer to him as president. We know that the climate is warming because of a great body of temperature records.

Sometimes finding the truth requires more effort. Some years ago it was widely asserted that 50,000 American children disappeared (without explanation — murdered by molesters? Sold into a fate worse than death?) every year. That would have been more than one out of every hundred children. A little thought showed that could not be: If anyone known to you, or known to anyone known to you, had disappeared, social circles very much larger than a hundred members, you would surely have known about it. It turned out that the actual number of disappeared children was a few dozen each year; the larger number was the number of missing persons reports filed, most of which were matters of someone staying at a friend’s overnight and not telling parents, or of custody disputes or other comparatively harmless events.

But many other questions are not so easily answered. We cannot know for sure the intentions of Russia, China, Iran or North Korea. We do not know if climate change leads to more intense or frequent storms (statistical evidence, to the extent it exists, indicates it hasn’t in the past, but there is no sound basis for extrapolation to the future).

Political or moral questions cannot generally be decided empirically; historians will argue forever about the causes of the American Revolution. But experience may be a valuable guide, although people will disagree about how to interpret it. As absurd and pernicious the divine right of kings may seem to us today, it is probably preferable to a state of frequent civil war, as was the case during much of the Roman Republic and Empire.

When someone makes a confident assertion, ask why he believes it. Unless it is a matter of demonstrable or verifiable fact, it is your job to make him uncomfortable and ‘unsafe’ in his beliefs. If your professors aren’t doing that to you, we are not doing our job.