Students all over the world are hard at work in school at this time of year. There’s a buzz on every campus as young women and men learn the rules of life, challenge them, and try to develop their own ideas, values, and principles.

For people in business, especially those who graduated a long time ago, it’s time they went back to school in order to, for want of a better phrase, de-learn and un-graduate. That’s the only way we will learn to challenge all that we have so far accepted as time-tested truths.

Although it isn’t easy, executives should shed their fear of the unknown and display childlike enthusiasm for radical ideas. They need to ask tough questions even if there are no answers to them — yet. In business, unlearning entails changing the manner in which markets are defined and the way companies are run. It also involves rethinking perceptions about competition and collaboration.

As it is, executives tend to gravitate toward their zones of comfort as they grow older — and then wonder why the magic has disappeared from work.

Revisit your youth and ask yourself: Was I looking for simple and practical solutions then? Or did I ask tough questions that challenged people’s assumptions, beliefs, and values? History suggests that people who challenge the status quo — like Isaac Newton and Albert Einstein — often come up with great inventions.

Most important, executives have to change their approach to business and society. They usually believe they have all the answers and that their ways of doing things are the best. However, leaders must accept the fact that they don’t have all the answers and re-program themselves for a world of infinite possibilities.

Great leaders are often lonely thinkers who ask uncomfortable questions, walk tough paths, and challenge popular perceptions. Only in retrospect are Mahatma Gandhi and Nelson Mandela — who faced criticism for most of their lives — regarded as great leaders who fought for the right causes. They loom large even now not because they had the answers, but because they dared to question. And by doing so, they achieved results whose value can’t be questioned.

When was the last time you dared question the status quo?

*This blog had first appeared on Vineet Nayar’s Blog site on Harvard Business Review.com @ http://blogs.harvardbusiness.org/hbr/nayar/2009/11/back-to-school.html