The Ladder of Inference

I’ve always liked the phrase “putting 2 and 2 together and making 5.” It’s a polite way of telling someone they’ve jumped to a conclusion nobody actually handed them. I got a proper education in that a few years back, and it cost me a friendship I didn’t see coming apart until it already had.

There’s a concept called the Ladder of Inference, developed by Chris Argyris, that explains how this happens without either party being deliberately unreasonable. You start with something you observe. You select which bits of it matter to you. You attach meaning to those bits. You layer on assumptions built from your own history and biases. Then you draw a conclusion, form a belief, and act on it, all before checking whether the first rung actually supported the weight of everything stacked on top.

What struck me looking back isn’t the model itself, honestly, it’s how invisible the climb is while you’re doing it. Nobody experiences themselves as jumping to conclusions. You experience yourself as simply seeing clearly. The other person, several rungs up their own ladder, feels exactly the same. Two people can walk away from the same conversation both convinced they were the reasonable one, and both be partly right about their own logic and completely wrong about where it landed them.

I’d taken a real shine to this fellow. Same age group, same wavelength I thought, came across as properly mature in how he thought things through. Then business got involved, and somewhere in there he climbed his own ladder rung by rung until there was no path back down. I don’t think he woke up one day and decided to end things. I think he just kept adding assumptions to a story he’d already half written, the way we all do, until the story became more real to him than I was.

The lesson I took wasn’t “be more careful” in some vague sense. It was narrower than that. The gap between what I observed and what I concluded is where all the damage happens, and that gap is always wider than it feels in the moment. Business has a way of accelerating the climb too, because money and reputation raise the stakes on being right, which makes people less willing to climb back down and ask a clarifying question instead.

Pity, really. Good business partners are replaceable. Good friends who also happened to be good business partners are not, and I’m not sure that combination survives contact with a bad quarter or a missed call unless both people are actively watching their own assumptions, not just the other person’s.

C’est la vie, as I said back then. I still believe it. I just understand a bit better now why it happened.