I'm not thinking about anything when I'm climbing, which is part of the appeal. I'm focused on executing what's in front of me.

We are apes - we should be climbing.

I've never really understood the criticism that climbing is inherently selfish, since it could equally be argued about virtually any other hobby or sport. Is gardening selfish?

I've tried to approach environmentalism the same way I do my climbing: by setting small, concrete goals that build on each other.

I have a journal of everything I've ever climbed since 2005. For the entry about free soloing Half Dome, I put a frowny face and added some little notes about what I should have done better, and then underlined it. Turns out that is one of my biggest climbing achievements.

Free soloing is almost as old as climbing itself, with roots in the 19th century. Climbers are continuing to push the boundaries. There are certainly better technical climbers than me. But if I have a particular gift, it's a mental one - the ability to keep it together where others might freak out.