Teshuvah for Engineers

Yom Kippur ended two days ago. Every year, the season from Rosh Hashanah to Yom Kippur asks the same thing of us: look back honestly at the year, name where you went wrong, make it right where you can, and resolve to do better.

The Hebrew word for this is teshuvah. It’s usually translated as “repentance,” but it literally means “return.” The idea is not that you become someone new. It’s that you return to who you were supposed to be.

I’ve been thinking this year about how much of good engineering is a version of the same practice.

The blameless postmortem is teshuvah

When a system fails, good engineering teams write a postmortem. The best ones follow a few principles that would be familiar to any rabbi.

You state plainly what happened, without minimizing it. You look for causes, not culprits - the goal isn’t to punish but to understand. You identify what you’ll change so it doesn’t happen again. And you share it openly, so others can learn.

Maimonides describes complete teshuvah as the moment you find yourself in the same situation again and choose differently. That’s exactly what a postmortem is for: so that the next time the same conditions arise, the system, and the people in it, respond better.

I wrote about postmortems many years ago as an engineering practice. I see now they’re also a moral one.

Admitting the error comes first

Teshuvah begins with vidui: confession, saying out loud what you did. Not “mistakes were made.” I made them.

In engineering, the equivalent is the hardest sentence in the profession: “I broke it.” Every experienced engineer has said it, and every one remembers how hard it was the first time. The teams I’ve most admired make that sentence easy to say. People who can admit mistakes quickly get them fixed quickly. People who are afraid to admit them hide them, and hidden mistakes grow.

This matters more now, not less. When so much work is done with AI, it’s tempting to locate the error in the tool. “The model hallucinated.” “The agent did it.” Sometimes that’s accurate. But someone chose the tool, gave it the task, and approved the result. Teshuvah doesn’t accept “the machine did it” any more than it accepts “the devil made me do it.”

Some things can’t be fixed by apology

There’s a teaching that Yom Kippur atones for wrongs between a person and God, but not for wrongs between people - for those, you have to go to the person you wronged and make it right with them directly.

In engineering terms: an internal postmortem fixes the system. It doesn’t fix the customer whose data you lost, or the colleague you blamed unfairly in the heat of an incident. Those need a direct conversation. An honest apology. Sometimes restitution. The technical fix and the human repair are different acts, and you need both.

Return, not reinvention

What I find most beautiful about teshuvah is the “return” part. It assumes you already know, somewhere, what good looks like, and that the work is to come back to it.

I think that’s true of engineering, too. Most of us know what good work looks like: simple, honest, careful, made for the people who’ll use it. We drift. Deadlines, ego, fatigue, the excitement of a new tool. Every so often it’s worth stopping to ask where we’ve drifted from, and to come back.

So here, in the spirit of the season, is my own short list. I shipped some things this year that I didn’t fully understand. I was sometimes more confident than I’d earned. I was, now and then, impatient with people who were learning. I’d like to return from all three.

Every system drifts. The practice is to return.