picture a gym where the lockers have no locks. you can bring your own padlock if you want one. almost nobody does. then one morning a single locker has a padlock on it. the whole room sees it. somebody wonders out loud what is in there. now picture a second gym. every locker was built with a lock in the door. you turn the key without thinking, and so does everyone else. nobody wonders about anybody. the lock is the same in both rooms. what changed is whether it came with the building. i think networks work the same way. a network here means a shared system that many strangers use to move money or messages, with rules written into its software. some of those rules are there from day one. others get added years later as a choice you can switch on. a choice that most people leave off becomes a signal. if two people in a hundred use the private option, those two stand out, and standing out is the opposite of what they wanted. the feature still works. the crowd around it is missing. so my claim is this. a network can defend the properties it was built with, because everyone already uses them. a property added later as an option tends to stay small, and a small group is easy to treat as suspicious. the pushback is fair. networks upgrade all the time, and many upgrades are good. treating the first design as untouchable can be plain stubbornness, and it can block changes that would bring in more people. a seat belt was an add-on once, and now every car has one. that example also shows what it took. seat belts won when they stopped being a choice. what would show me wrong: a large network adds a foundational property years after launch, privacy by default for example, and within a few years most of its users are using it. bitcoin was born with a fixed supply of 21 million coins and with rules that anyone can check on a home computer. nobody switches those on. they came with the building, and seventeen years later every holder still runs on them. if this made you look at which locks came with the building, Zap ⚡

picture a sixteen year old opening her first bank account. she brings an id. a parent comes along to sign. a clerk looks at both of them and says yes. every step in that room needs a person. a face, a name, a signature, and somebody willing to vouch. now think about the software that is starting to do small jobs for you. a program that books the cheapest train. a program that buys one map lookup, or one minute of computing, from another program. people call these agents. an agent is software that acts for you without asking each time. an agent has no face and no parent. it cannot walk into that room. so today it borrows your card. that works for a train ticket. it works poorly when the job is ten thousand purchases of a tenth of a cent each, made at night, between two programs that have never met. card systems were built around a person who can be called, billed and refunded. the fee on each purchase is larger than the purchase. three words keep coming back to me. private means a rival cannot read every purchase your software makes. neutral means no single company decides which programs may pay. permissionless means a program can start paying without waiting for somebody to approve an account. i think software needs money that asks for a key and never asks for a name. bitcoin works that way. to hold it you need a secret number called a key, and a program can keep a key as easily as you can. lightning is a faster network built on top of bitcoin, and it sends tiny amounts in about a second for a very small fee. the pushback is fair. banks and card companies are building this too, with spending limits and refunds, and for most of what you buy those protections are worth having. a key has no refund desk. if your software gets tricked, that money is gone. what would show me wrong: two years from now, most payments between programs run on cards and bank accounts, including the tiny ones, and the fees did not get in the way. until then i watch the small payments. a tenth of a cent has no room for a clerk in it. bitcoin has never asked who is holding the key, and that old habit fits a customer with no face. if this made you picture software standing at a bank counter, Zap ⚡