Back in 1971, after seeing an oil spill in San Francisco Bay, I gave up the use of motor vehicles—after taking some responsibility for what was washing up onshore. It was looked at as a crazy thing to do.

People told me, 'One person can't make a difference.' I realized I didn't want to spend my life arguing. So on my birthday, I gave up speaking for one day.

It was sort of a gift to my community, of my silence. During that day, I realized I hadn't been listening. So I decided to be quiet for another day. As I entered into the silence, I discovered lots of things about myself—some painful; all illuminating. It became a journey of self-discovery, and the silence lasted for 17 years.

It's not so much that we get to where we're going; it's that we're on our way there.

During this time, I founded a nonprofit (Planetwalk.org) and started walking across the country. It took me seven years, and along the way, I earned a master's and then a PhD in environmental studies at the University of Wisconsin—all without speaking. When Exxon Valdez happened, my thesis—which was on oil spills in a marine environment—was in great demand. I ended up writing oil pollution regulations for the U.S. Coast Guard, which was a close to the circle that began in '71.

I started talking again on the 20th anniversary of Earth Day, and the first words I said were, 'Thank you for being here.' Because if we are to communicate, it takes two. Someone has to listen. In our society, sometimes we forget that the listener is as important as the person sending the message. Communication is a shared responsibility.

I'm married now, and I have a 5-year-old boy. I don't like to be away from him that much. But every year I go for a walk. I encourage people to go on these journeys. Start from where you are, walk as far as you walk, and see what you learn.

—John Francis, PhD, author of Planetwalker (Elephant Mountain Press, 2005)