When a thirteen-month-old knocks a glass off the table and it breaks on the floor, the first reaction might be fear or anger, but punishing him would be pointless because he doesn’t understand what happened. He can’t really control his hands yet, or understand what the shiny shards near his foot could do to him, or how his own hand caused them to be there.

Once you clean it up, you behave like a grown-up, so you move everything breakable away from his reach.

By this time, you’ve calmed down. He’s forgotten all about the glass and has a new mission to figure out what a cat’s tail tastes like, so the day continues. You were probably angry at one point and maybe even thought for a second about punishing him, but you managed to remember he’s still a baby.

At some point, that changes. The same child, older, breaks something for whatever reason, and now it’s different. Now there is a person who knew he shouldn’t do it but did it anyway. We hold him accountable. Gently at first, then less gently, treating responsibility like a tooth, something everyone gets on the schedule.

Here is what has been bothering me.

A great deal of adult behavior is that same broken glass, only grown up and much harder to see. Someone who did not get enough as a child, who went hungry for attention or love and learned to survive that hunger in a particular way, carries that way of surviving it into every situation for the rest of their life. The clinginess, the jealousy, the flinch before a raised voice, the need that never quite fills. None of it was chosen. It was installed early, by people before the child could comprehend or refuse, back when he still could not fully control his hands.

We forgive the baby because it could not have done otherwise. Then we spend our adult lives condemning each other for doing the exact thing we were modeled into by circumstances none of us picked, and the only difference is that time has passed.

I’m trying to figure out when breaking glass turns from an innocent accident into a conviction.

We point to age as the thing that flips it, but after watching people for 40 years, age started to look like a coincidence. The real switch, as far as I can tell, is the moment you can see your own hand move before it throws. It comes earlier for a few and later for most, while some never catch it. The problem is our automatic response, which we see as normal, since it is the only one we have had since we became aware of ourselves.

I’ve been trying to pay attention to mine lately, so I started catching a few. I know, as a plain fact, that there are many others still moving on their own that I have not caught, because that is the nature of the thing. The reactions you cannot see are exactly the ones that shape everything. We justify them to ourselves as personality.

And now there is a boy in my house whose needs I’m trying to meet, precisely so that fewer of them harden into the kind of behavior he wouldn’t be proud of later. I’m trying not to mess him up beyond the point of return. I know I can’t make him flawless. I’m not trying to.

But I am doing it with hands I did not choose either, some of which I still cannot see, which means I have no reliable way of knowing what I am building into him while I am busy protecting him from it.

Nobody hands a baby a bill for the glass. We just wait, without ever agreeing on how long, until we have each privately decided enough time has passed, and then we start charging. I do not know how any of us settles on the moment. I know I’ll have to draw that line for him one day. I also know I’ll almost certainly draw it in the wrong place, too early for what he couldn’t help, too late for what he could.