Members of the Class of 2013, I salute you.

As everyone keeps telling you, you are graduating at a difficult, even frightening time. I wish my generation was bequeathing you a finer world. We aren't. The world into which you are entering is rich with challenges. Many are scary.

This does not make your generation unique. Through the nation's history, America's colleges and universities have sent forth graduates in times of war, of fear, of economic risk.

Eighty years ago, the world was mired in a four-year-old economic depression. Seventy years ago, many schools skipped commencement exercises entirely because their graduates were all heading off to World War II.

Fifty years ago, Bull Connor was setting fire hoses and police dogs on civil-rights marchers in Birmingham, Ala. And 45 years ago, today's exercises would have been sandwiched between the murders of Martin Luther King Jr. and Robert Kennedy.

In short, there was never a golden age — a period when new graduates could step into the world and simply start building careers and families without worry.

So what is the great challenge of your generation? Protecting the environment? Increasing equality? Abating poverty? Achieving world peace?

I am going to suggest that it is none of the above. Instead, your great challenge is to regain the high ground my generation once championed and has long forgotten — the freedom to think for yourselves.

I mean this quite seriously.

We live in the era of groupthink, when to disagree is to be tagged as either wicked or stupid — either way, as part of the enemy. We baby boomers marched on campus in the 1960s and '70s for the right to make up our own minds, but now that we hold positions of power, we seem to view opposition or even criticism as dangerous. And yet, given the complexities of the modern world, there has never been a time when thinking for yourself is more vital.

The philosopher Isaiah Berlin once wrote that most of the great evil in the world has come about because of people who have decided that they have found the one true idea, an idea before which everything else must yield. I think his argument is incomplete. The great evil comes about because large groups of people agree on the one true idea — and other groups of people, often larger, find it easier to go along than to raise a voice in opposition.

My father used to say that the best place for an intellectual is where it's least crowded. What he meant was that it's important for us to pursue our own ideas, rather than join the herd.

Bertrand Russell, in his essay "In Praise of Idleness," warned that it's vital for us to spend time alone with our thoughts, away from any other influences. We must put down even our books for a time — if he were alive today, he might advise us to put down our iPhones — because only when we are alone with our thoughts do we actually have any thoughts of our own. The rest of the time, we are simply responding to the ideas of others.

The great tragedy of my generation is how little space we have left for truly independent thought. Criticism of political leaders is equated with hatred for them — and so naturally the supporters of whoever is being criticized wind up hating right back.

I suppose what I am asking, then, is that you not be like us. That, it seems to me, is the key to your generation's ability to build a better America. Make politics a smaller piece of your lives. When you look at those with whom you disagree on issues large or small, see them as neighbors rather than enemies. Consider the possibility that some issues are hotly divisive precisely because both sides are making good arguments. Perhaps we fight hardest over the issues that are actually hard.

So much of politics is devoted to the silly proposition that enormously complex questions can be reduced to the size of a bumper sticker. The theory seems to be that if you only find the right slogan, the argument is already half won.

We see this in such phrases as "Death Tax" and "The War on Women" — slogans that are almost adolescent in their tragic oversimplification, but that nevertheless have been enormously successful through their tendency to shortcut such democratic niceties as recognizing that the other fella might have a point.

And adolescent is the right word. My generation has an alarming tendency toward what the novelist John le Carre refers to as "a militant simplicity." This is the trap that your generation must avoid.

Here it is useful to consider the wisdom of the always profound Ray Bradbury. Most of us remember his most famous novel, "Fahrenheit 451," as the story of a society in which the job of "firemen" is to burn any books that might be discovered. But, as Bradbury himself noted on more than one occasion, to read this as simply a cautionary tale against censorship is to miss the point.

In Bradbury's telling, the book burning didn't originate from above. It was what we nowadays refer to as a grass-roots movement. And the movement wasn't to ban unpopular ideas. It was to ban complex ideas. Books were the enemy because books were difficult, and deep, and had the terrible property of changing people's minds. People didn't want their minds changed. They didn't want their beliefs challenged. They wanted not complexity but simplicity.

Therein lies the problem. Few ideas of genuine value can fit on a bumper sticker, or in a sound bite or blog post or even an opinion column. Some ideas really do need to be argued for thousands and thousands of words. To the extent that we find arguments of that length no longer interesting, we are already in Bradbury's world, the books merrily burning away, all in the cause of keeping ideas simple.

This is the greatest challenge facing your generation. Yes, there is an economy that must be repaired; yes, there is an educational system that must be revitalized; yes, there are enemies abroad who must be defeated.

But none of these achievements will matter unless you also make war upon my generation's celebration of the slogan and the applause line.

Simplicity is the enemy of serious thought, and serious thought is what this world desperately needs. And if we Americans find ourselves unable or unwilling to take the time to think deeply, then some wiser, more serious, more reflective culture will supersede ours. And our defeat will be entirely deserved.

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Stephen L. Carter is a Bloomberg View columnist and a professor of law at Yale University.