Last night, my son and I alone in the truck, running an errand:

“Dad?”

“Yes?”

“You know about cards?”

“What cards?”

“You know, like birthday cards?”

“Sure,” I said.

I looked in the rearview mirror. He was seated directly behind me, his face turned out of the window and toward the mountains, where the setting sun cast his tanned face in a red glow. Sometimes I do that with my kids—just look at them. I’ll look at them now and I’ll try to remember them as they were and try to imagine them as they will be.

“What about them?” I asked. “The cards.”

He didn’t hear me. Or maybe he wasn’t going to say. Sometimes my kids (any kids) are like that. Their conversations begin and end in their own minds, and we are allowed only tiny windows into their thoughts.

“Do you like Target?” he asked.

“Sure.”

“Don’t ever buy cards at Target, Dad.”

“Why’s that?”

“They’re inappropriate.”

Another look into the mirror. His face was still toward the mountains, still that summer red. But there was a look to him that said he was turning something large and heavy over in his head, thinking on things.

“Why are they inappropriate?”

“They’re bad,” he said. “On a lot of them, do you know what they have?”

“What’s that?”

“Butts.”

“They have butts on the cards?”

“Yeah. Big ones.”

Silence. More driving. I thought that little talk is over. I kind of hoped it was. I didn’t know where it was all going. I was pretty sure that was a ride I didn’t want to go on.

Then, “Do you know what else they have besides big butts?”

“No.”

“Bad words.”

“That a fact?”

“Surely.”

He likes that word, my son. Surely. Uses it all the time. And upon such occasions I like to say, “Don’t call me Surely.” I did then, too. There was no effect. Still toward the mountains, still the red glow. Still turning things over. I tried turning the radio up, found a song he liked. Whistled. Anything to stop that encroaching train wreck of conversation.

“Really bad words,” he said.

“Bad words aren’t good.”

“No.”

I had him then. Conversation settled.

Then, “A-s-s.”

“What?”

“That’s what the cards have on them. A-s-s.”

“Don’t think I like that,” I said.

“Me, neither,” he said.

I looked in the mirror one more time. He still faced outside, out in the world, and in his tiny profile I saw the babe he was and the boy he is and the man he would be. Saw it all in that one moment, all of his possibilities and all of his faults, how high he would climb and how low he could fall.

He looked out, and in a voice meant only for himself and one I barely heard, he whispered,

“Ass.”

And there was a smile then, faint but there, as the taste of that one vowel and two consonants fell over his lips. It was a taste both sweet and sour, one that lowered him and raised him, too.

I could have scolded him. Should have, maybe. But I didn’t. We rode on together, talking about anything but asses. Sometimes one lesson must be postponed in favor of another. And last night, right or wrong, I decided that more important than teaching my son what to say was letting him discover alone the awesome power of a single word.