We’re driving home from an onsen, a benefit of living in a land filled with natural hot springs. Boy and Girl are in the back seat.

“Hey, Papa?” It’s Boy, and all conversations start with “Hey.” And given that only two people on earth speak English to him, there’s a disturbing chance that, unknown to me, my conversations also start with “Hey.” (I’m also to blame, it would seem, for “awesome.”)

“Yeah?” It’s raining hard outside. It’s the season. So we half-shout a lot when we drive.

“When you make a bath, you have to check if the water is too hot or too cold.”

“Mmm, I guess that’s right.” Boy always thinks the water is too hot. He thinks everything is too hot. I spend half of every meal time blowing his food to room temperature. I ask, “So how do you check the water? Do you check with your hand or with your foot?”

“Papa?”

“Yeah?”

“You have to do it with your whole body.”

At this, my ears perk up. This sounds like something I might say. It also sounds a little crazy.

“Your whole body? Do you just jump in?”

“Yep. You just jump in! And Papa?”

“Mm-hmm?”

“When you run, you have to run with your whole body, too.”

I’m smiling. I like this. I get this. I’ve given talks about this, about the physicality of Zen practice, about never holding back, about committing completely to each action.

He keeps going: “When you do yoga, you have to do it with your whole body. When you fight, you have to fight with your whole body. When you play, you have to play with your whole body.”

This is dead on. But I’m starting to wonder where he’ll take it. After all, these are already whole-body activities.

Then he makes the turn: “When you hold hands, you have to hold hands with your whole body. And when you say ‘thank you,’ you have to say it with your whole body.”

There it is. My 4-year-old son has just come close, in his little way, to summing up my total understanding of spiritual practice. And why should I be surprised? If I imagine myself trying to lift a car off of a baby, I know I still wouldn’t use as much of myself as he does just when he cries. Everything he does is total. Even sleep, for him, is an unrestrained act of plunging into something. It’s a complete investment of himself.

He will lose this understanding. He’s losing it moment by moment. It’s not something he’s arrived at, or something he can see from the outside. It’s just that right now, at a moment in his life when his body does not yet feel in any way separate from his own sense of self, he cannot imagine it any other way. He’ll lose that sense of singularity, and along the way, he’ll discover the dangerous idea of conserving energy. He’ll come to appreciate efficiency. He’ll see his body as a tool, something to use or not at his discretion.

And then, if he’s lucky, he’ll cross over. He’ll find, on one hand, that “his” body isn’t really his, and on the other, that it is inseparable from who he is. And he’ll realize, probably the hard way, that negotiating with himself about what to give and what to keep is what makes him tired in the first place, that a total commitment to this action and this life is what makes that commitment possible. Giving feeds giving. Saying “thank you” with the whole body is exactly what you’ve been saving up for.

Boy’s been quiet for a while, and I’ve been lost in my own musings about this unformed wisdom of his, hypnotized by the windshield wipers.

He pipes up again. “But Papa?”

“Yeah?”

“When you look at a picture, you don’t look with your whole body.”

“What? Why not? How do you look at a picture?”

He sighs, another mannerism that comes from me. “With your eyes. If you use your whole body, that would be weird.”

And we’re home.