It was 2016. I was sitting in a classroom during the negotiation workshop, one of Harvard Law School’s flagship courses. During the session, the professor quoted Donald Rumsfeld with a line that, at the time, sounded almost like a riddle.
“There are known knowns, things we know we know. There are known unknowns, things we know we don’t know. But there are also unknown unknowns, things we don’t know we don’t know.”
A few people smiled, as if it were a clever word game. I didn’t smile. Something clicked.
We spend most of our energy on the first category: the things we know. Our skills, our experience, what we’ve studied, the deals we’ve closed, the mistakes we’ve already made. This is comfortable territory. It’s where confidence lives.
Then there’s the second: the things we know we don’t know. A foreign market we haven’t entered yet. A regulation we haven’t read. A competitor we haven’t studied. We can hire people, read reports, ask better questions. It’s a solvable problem.
But the third category is different. Unknown unknowns are the risks you never considered because the question itself never crossed your mind. The opportunity you missed because you didn’t know it existed. The assumption you didn’t realize you were making.
This is where the real damage happens. And where the real breakthroughs happen too.
Think about negotiation. You prepare. You map the other party’s interests, define your BATNA and WATNA, and rehearse your opening. You cover what you know and what you know you don’t know. Good. But the moment that changes the outcome, the thing that shifts everything, almost always comes from something you didn’t see coming. A piece of information that rewrites the whole picture. A motivation you never imagined the other side had. A constraint that was invisible until the last minute.
The same is true in business. In strategy. In life.
The decisions that hurt us most are rarely the ones we debated carefully and got wrong. They’re the ones we never knew we had to make.
You can’t prepare for what you can’t imagine. But you can build a mindset that accounts for it. You can stay curious beyond your own field. Talk to people who think differently than you do. Challenge your own frameworks, especially the ones that feel the most solid. Ask, “What am I not seeing?” more often than, “What do I already know?”
After ten years, that line still clicks. Especially these days, when pieces are moving in unexpected ways. I guess it’s impossible to eliminate unknown unknowns. But we can shrink the space they occupy by staying open, by staying humble, and by never assuming our map of the world is complete.
Because it isn’t. It never is.
