B asked where Steve was. He was a regular at Suffer Club, but then he disappeared. “He got a hip replacement,” I said. She made a pained face and commented on how young he was. “I think he just decided not to be in pain anymore,” I said. “And Steve’s an active guy, a surfer, a skier, a hiker, and really, what is the value of now?”

This is a pretty constant theme for me.

The first time I thought about doing something before I got too old to do it, I was 39, which is funny in retrospect. I didn’t have any clue what I was capable of then. I ran a mountain half-marathon that year. I didn’t know that I’d do more and bigger things a decade later.

I didn’t know. That’s another constant theme.

John got his shoulder replaced. It was a big deal, both in terms of the toll it took on his body, but also in the way it relieved a chronic pain he stopped being able to disassociate from. The pain had become so constant and intense, he didn’t even realize how it was warping his thinking.

Until it stopped.

We are, none of us, getting younger. Entropy, the persistent loss of heat in any system, the inexorable tendency toward disorder, gives time its direction. Forward, conventionally. It’s a sad story, but by the Doctrine of Radical Acceptance we have to put it behind us and rage against the dying of the light.

It’s a big deal to decide to have a whole joint replaced, but it’s maybe a bigger deal not to. There you are in a crystalline moment of choice, to move forward and live more, or to retreat into pain and stillness.

And so we replace body parts if we have to in order to do the things that give us joy and make us feel still alive. That’s the mind-bending value of now, and the eternal motivator to keep moving, keep saying yes, keep pushing through the next injury and the next, keep getting up, keep making plans.