THE IDEA
The weight of what came before
You’re walking through a forest with no path. At a fork between two ridges, you go left. Not for any deep reason - maybe it looked slightly easier, maybe you were already drifting that way. Half an hour later, you’re deep in a valley. The ridge on the right is now a hard climb away. Going back to the fork would cost you an hour. So you keep going left, even though the terrain is getting worse, because the cost of switching has become too high. The original choice - almost random - now determines everything that follows.
This is path dependence. The idea that a system’s current options are shaped by the choices it has already made, even when those choices were small, accidental, or made for reasons that no longer apply. History doesn’t just record what happened. It constrains what can happen next.
Path dependence matters because it explains why systems - organisations, technologies, cities, careers - often get stuck in suboptimal places and can’t easily shift. It’s not that people don’t see a better option. It’s that the cost of getting there from here is too high. Every past decision has created infrastructure, habits, relationships, and expectations that make the current path feel inevitable, even when it was never the best one. The decisions that matter most aren’t always the big, visible ones. They’re the early, small ones that nobody thought twice about - because by the time their consequences are clear, they’ve become the foundation everything else is built on.
IN PRACTICE
Small choices, long shadows
The QWERTY keyboard layout was designed in the 1870s to prevent mechanical typewriter keys from jamming. The mechanical problem disappeared a century ago, but the layout persists - because by the time better alternatives existed, millions of people had already learned to type on QWERTY. Switching would mean retraining everyone, redesigning every keyboard, and accepting a painful transition period for a modest improvement. The path was set before anyone realised they were choosing a path.
Cities are deeply path-dependent. London’s street layout follows medieval property lines and ancient tracks. Roads that made sense for horses and carts now carry buses and delivery vans through impossibly narrow turns. You can’t straighten them without demolishing buildings. You can’t widen them without buying land. Every generation inherits the physical infrastructure of the last, and builds on top of it - literally. The city you live in today is the accumulated weight of thousands of decisions made by people who couldn’t imagine your problems.
Career paths show the same pattern. An early decision to take a particular job leads to specific skills, specific relationships, and a specific reputation. Five years in, those accumulated assets - the stock of experience, the network, the identity - make it far easier to continue on the same path than to start fresh in another direction. People often describe feeling “locked in” to a career, not because they can’t do anything else, but because the cost of abandoning what they’ve built feels prohibitive. The path creates its own gravity.
WORKING WITH THIS
Pay attention to the forks
The most important implication of path dependence is that early decisions deserve more attention than they usually get. The moment of greatest freedom is at the beginning, when you haven’t committed to anything yet. Once you’ve chosen a technology platform, hired your first team, picked a location, or set a precedent - you’ve narrowed the corridor. You haven’t eliminated future options entirely, but you’ve made some of them much more expensive.
This doesn’t mean you should agonise over every small choice. Most decisions aren’t path-setting. The skill is recognising which ones are - which early choices will create infrastructure, dependencies, or expectations that are hard to reverse. Ask: if this turns out to be wrong, how hard will it be to change course in two years? If the answer is “very,” give that decision more time and thought than its current size suggests it deserves.
When you find yourself on a path that’s no longer serving you, be honest about the switching costs, but don’t treat them as permanent walls. Path dependence makes change expensive, not impossible. Sometimes the best investment is the painful, costly switch to a better path - because staying on the current one has its own accumulating costs that just aren’t as visible.
THE INSIGHT
The corridor narrows behind you
Every decision you make closes some doors and opens others. The further you walk down a path, the harder it becomes to reach the paths you didn’t take. The time to choose carefully is before the walls go up - not after.
RECOGNITION
Knowing it when you see it
You’re in a path-dependent situation when you find yourself saying “we’d never choose this if we were starting from scratch, but here we are.” When switching to a better option exists but feels impossibly expensive. When the reason for doing something a particular way traces back to a decision nobody remembers making. When an early, small choice has become the foundation that everything else depends on - and questioning it feels like questioning everything.