Sometimes my kids ask me questions that rattle my mind like a cold, brass church bell. My skull had only just stopped reverberating from their last confounding query (“Mom, what does nothing look like?”) when my teenager riddled me this: “Why don’t old people at least try to be cool?”

It was an honest question, and it struck me as kind of brilliant — in the way that one often chooses to focus on her children’s refreshing curiosity rather than dwell on their astounding lack of manners or perspective.

I considered telling him that the answer lies in simple physics: Cool is a fast-moving target. And old people are slow. Then it occurred to me that by “old people,” he might very well mean me. I needed more information.

“If they would just put on a pair of skinny jeans and a V-neck T-shirt,” my son said, “they’d be cool.”

“According to whom?” I asked, cautiously. The parenting books say that active listening encourages your kids to speak openly. They also say it’s bad to call them idiots. So I listened.

“According to us,” he said. “To my generation.”

“Well,” I offered, “it’s because we — er, they — don’t care what you think of them.”

“I know. That’s my point,” he countered. “Why don’t they?”

“Because it’s not worth any effort to them,” I retorted. “They see no value in earning your admiration. They don’t feel the need to seem cool to you.”

“But they could!” he insisted. “They could seem cool if they tried.”

It went round and round like this, him unable to fathom why anyone wouldn’t want to impress his inexperienced, judgmental, and capricious peers — and me unable to recall why I had thought, for a brief moment, that his question was smart.

I sought advice from, ahem, old friends: “Remind me why old people don’t try to be cool.”

Their responses:

“Because when we do, it backfires. Look at Jon Gosselin.”

“Because our generation is still so freaking cool that adapting for his would be a compromise in quality.”

“Isn’t trying to be cool totally uncool?”

“But … I do try!”

And bingo, that did it. Their disparate comebacks reminded me of why I had thought my son’s inquiry so ingenious from the start: because it answers more questions than it poses.

Why don’t old people at least try to be cool? The question itself is a treatise on what it means to chase cool: The erroneous assumption that one group defines cool. Owns it. The faulty reasoning that another group wants a piece of it. Or is even aware of it. The mistaken belief that cool can be faked. Some day, when my son is old people, he’ll realize that cool isn’t the cut of your clothing (especially if your clothing is skinny jeans). But neither is it a “state of mind” or whatever nonsense we old people tell ourselves to feel better about being socially irrelevant. Cool is whatever you don’t have and can’t truly get; it’s the audacious style, enviable skill, and unorthodox outlook that’s just barely — but forever — out of your reach.

Eventually my kid will learn that cool is a punishing paradox: that chasing it is a fool’s errand because the damned thing won’t be caught, and if it could, it wouldn’t be worth having in the first place.

He’ll discover that it’s shifty and ephemeral, and that from birth to death, there’s not a single point on life’s continuum where you can get a clear, full-frontal view of cool — no vantage point that isn’t blocked by bias, shaded by age, or blurred by loyalty. He’ll understand, finally, that cool is a restless little bastard, a transitory trophy, a mirage in the desert.

And it will rattle his mind.