Craft Note 001 · 26 September 2026Draft
Complexity Has to Live Somewhere
The principle behind it: Tesler's Law · Laws
01 The observation
Setting an alarm on an old phone meant scrolling through hours, then minutes, then AM or PM. On a new phone you say “wake me at six.” Waking up at six didn't get any simpler. Someone else just did the work.
02 The idea
Every task carries a minimum amount of complexity. You can't delete it. You can only move it.
So the real design question is rarely “how do we make this simple?” It's “who carries the hard part: the person, or the product?”
03 The science
Larry Tesler, who worked on interfaces at Xerox PARC and Apple, noticed that every application has a core of complexity that can't be removed. It has to be handled somewhere, either by the people who build the product or by the people who use it. It's often called the law of conservation of complexity.
04 In the wild
- Maps apps
You type a place name. The app works out the coordinates, the route and the traffic. The complexity is all still there, and none of it is yours.
- Apple Pay
Card number, expiry and security code are handled once, at setup. After that, paying is a double-click. The work moved from every purchase to one moment.
- Most government forms
The opposite. Forty fields, and every one is a question the system could have answered itself. The complexity is handed straight to you.
05 My take
At Nasiye we moved complexity away from people when we dropped passwords for SMS codes. Identity became the system's job, and the forgotten-password tickets mostly stopped.
But there's a trap. Hide too much and people lose the feeling of control. When money moves, I'd rather keep one clear confirmation screen than make the amount invisible. Moving complexity is almost always right. Making it disappear completely isn't.
06 The craft rule
Don't remove complexity. Decide who carries it.