"I don't know, but I'll figure it out."

I say "I don't know" a lot. To clients, on calls, in the middle of meetings where I'm theoretically the expert in the room. I say it more, not less, the longer I do this. And it has done more for my credibility than any confident answer I've ever given.

This runs against every instinct people have about expertise. The assumption is that an expert is someone who knows, and that admitting you don't know is a crack in the facade — a thing to hide, or bluff past, or cover with enough vocabulary that nobody notices. So a lot of smart people perform certainty they don't have, and clients can usually smell it, and it quietly erodes the trust it was meant to protect.

Performed certainty is fragile

Here's the problem with bluffing. The moment you assert something you're not sure of, you've put your credibility on a bet you might lose. And in technical work you will eventually lose it — the thing won't behave the way you confidently said it would, and now the client is wondering what else you were sure about that you shouldn't have been. One bluff caught poisons every real answer you ever gave.

"I don't know" has the opposite property. It's unbluffable. When I say it, the client learns that my "I do know" actually means something — that I'm not just generating confident-sounding noise, that there's a real line between what I'm certain of and what I'm not. The admission is what makes the rest of my answers trustworthy.

“"I don't know" is what gives "I do know" its value. Without the first, the second is just noise.”

The second half is the whole thing

But the sentence has two halves, and the second one is where the trust actually lives: but I'll figure it out.

Because clients don't actually need you to know everything on the spot. What they need is the confidence that you'll get them to the answer — that the not-knowing is temporary and you own it. "I don't know" alone is a dead end. "I don't know, but I'll figure it out" is a promise, and it's a promise I've kept enough times that people believe it when I say it.

In a market full of people performing certainty they don't have, being honest about the edge of your knowledge — and confident about your ability to push past it — turns out to be rare enough that it stands out. Try it on your next call. Say the true thing. Watch the room relax.