This article was originally published in Inc.

Steve Jobs, Mahatma Gandhi, Susan B. Anthony or Nelson Mandela. Pick one, or another great leader from history. It’ll give you the courage to dream big—unabashedly—despite the odds. 

You are lucky in life if you have the right heroes. I advise all of you, to the extent you can, to pick out a few heroes.” —Warren Buffett, Warren Buffett Speaks (2007)

We’re all so jaded nowadays by any talk of heroes. Our icons keep falling from grace, in politics, business and sports. (At least our comic book heroes seem safe for now.) Why then, you may ask, is Warren Buffett recommending that you look for heroes to study?

In my MBA and executive classes on personal leadership at Columbia Business School, and in my corporate and nonprofit work at the Mentora, I actively study the lives of great leaders. I blend this view with rigorous findings from the science of human nature to forge a set of universal laws on what makes people flourish, rise to their best selves, and explore the principles of leadership and success.

Okay, so why should you have heroes?

Great leaders demonstrate that it is in fact okay to dream the impossible, to rebel against the mindsets of your times, as long as you are committed to relentlessly pursuing this dream.

Consider Steve Jobs. Here was his dream, recounted by John Sculley, who left a career at Pepsi to join Jobs at Apple in the 80s and later had a fallout that led to Jobs’s departure from Apple soon after. In his memoir, Sculley wrote: Jobs was “a zealot, his vision so pure that he couldn’t accommodate that vision to the imperfections of the world. Apple was supposed to become a wonderful consumer products company. This was a lunatic plan. High tech could not be designed and sold as a consumer product.”

Let’s remember what that era of the 80s looked like for personal computers. It was the glory days of IBM-DOS computing—gigantic user manuals, blinking cursors, cryptic commands to “print” and “save” and “copy.”

Now fast forward to today. We have powerful technology so elegantly wrapped in intuitive interfaces that even a three-year-old can learn to use an iPhone on her own. Funny thing is, a three-year-old still won’t know how to open a Pepsi can.

The point here isn’t just that Steve dreamt big—he also pursued it steadfastly despite the naysayers and imperfections that stood in his way. In fact, there was a period in the 80s and 90s where it appeared that his dream was just that—a dream. But he kept going, and he made it happen.

That is a big lesson we can all learn from great leaders. They are all hungry enough to dream big dreams, and to pursue them despite the odds. In the 21st century, we owe a big debt to these bold dreams that some have pursued despite the limited mindsets of their times, to help us steadily march forward technologically, materially, socially and morally since the Dark Ages.

Take Gandhi’s vision. He believed in a nation of 300 million people that would peacefully win their freedom from the British Empire. It took him 33 years to oust that regime, and his hardest work was not external, in influencing his adversary, but internal, in training himself and the Indian masses on how to put insurmountable pressure on their British rulers without resorting to violence. He dismissed the popular view that the end, of winning freedom, justifies the means, of using violence. In a tract titled Hind Swaraj, he wrote in 1908: “The means may be likened to a seed, the end to a tree; and there is just the same inviolable connection between the means and the end as there is between the seed and the tree.”

While other leaders may have favored more aggressive and expedient measures to pursue the cause of freedom, his patient pursuit of his dream led in 1947 to the peaceful handover of power from the British and the establishment of what is by far the largest democracy on our planet, one of a few stable ones in the developing world.

Recall Susan B. Anthony’s dream. In the 19th century, she imagined American women, who in her time had little education and few rights, would be the equal of men in determining the affairs of society and state. Her pursuit of getting women the right to vote prompted a Seattle paper to describe her in 1871 as someone “aiming at nothing less than the breaking up of the very foundations of society.”

She pursued this relentlessly for over 50 years, and then died without savoring any official breakthroughs in women’s voting rights. And yet, in her last speech at a convention in Baltimore, she asserted: “Failure is impossible.” 

It may have sounded foolhardy in those times, but 14 years after her death in 1906, as Congress enacted the Susan B. Anthony amendment to the Constitution granting women the right to vote, it proved to be prophetic.

Then there’s Nelson Mandela. He dreamt of an apartheid-free South Africa, which he not only kept alive for 27 years in prison, but diligently pursued for each of those days. His early reflections on when he was thrown in jail in 1964, as he mentions in his autobiography, were: “I was now on the sidelines, but I also knew that I would not give up the fight. I was in a different and smaller arena, an arena for whom the only audience was ourselves and our oppressors. We regarded the struggle in prison as a microcosm of the struggle as a whole. We would fight inside as we had fought outside. The racism and repression were the same; I would simply have to ride on different terms.”

Several accounts from his fellow prisoners reveal the discipline and commitment with which Mandela kept the fight alive during that long, 27-year walk to freedom.

Do you have dreams of how people, products, technologies, organizations or communities could be different and better than they are today? Do you let these dreams die away when the world doesn’t support or cheer you or when it scoffs at you, and do you submit instead to pursuing the lesser dreams of others—because you get discouraged, don’t want to be unpopular, or can’t wait so long for success to show up? Isn’t there something for all of us to learn from great leaders about the power, when it feels like the right thing to do from deep inside us, of dreaming and relentlessly pursuing the impossible?

This article was originally published in Inc.