“The brave man is not the one who has no fear, he is the one who triumphs over his fear.”

— Nelson Mandela

My friend Kamal is a world traveler. He has meditated with Tibetan monks in the Dalai Lama’s monastery, trekked the Himalayas, and hiked the Camino Real in Spain. He served in the U.S. Army and studied to be an ER doctor. He has launched tech companies, runs his own venture capital firm, and is a bestselling author. Up close, he makes quite the striking impression with his flowing mane of silver hair, quiet voice behind a steely gaze, and the super-calm demeanor of a Buddhist master. Here is a guy with all the ingredients for success on a mega scale. But I recently learned a secret about Kamal.

He couldn’t swim.

At first, I had a hard time believing it. I thought he had to be exaggerating. To me, swimming comes as naturally as breathing. I grew up on and in the water. My family lived for years on a sailboat. I spent more than a decade in the navy, trained, and deployed as a U.S. Navy SEAL. The idea of not knowing how to swim was beyond my comprehension. But here was my friend, this amazing, talented guy who had accomplished so much in his life… and he couldn’t swim.

I gave him kind of a hard time about it. I pointed out that the human body is more than 60 percent water. Did he realize he was already floating around inside his own skin? I wondered aloud if, when his parents conceived him, the egg cell had to swim down to meet the sperm cells, instead of the other way around.

“Dude,” I said, “how can you possibly not know how to swim?”

The answer was simple.