What does it mean that other people test your schemas?

Explaining your schema to someone else and hearing their objections is a form of validation.

Example: You've built a mental model that says 'senior engineers resist process because they've been burned by bad process.' It feels airtight — until you explain it to a colleague who points out that the senior engineers on her team actively champion process, but only process they helped design. Your schema isn't wrong; it's incomplete. The variable isn't seniority or past trauma — it's ownership. You would never have found that gap alone, because the schema felt complete from the inside.

Try this: Choose one schema you currently rely on — a belief about how something works in your domain. Write it down in two or three sentences, as clearly as you can. Then explain it to someone: a colleague, a friend, a partner. Don't ask them if they agree. Ask them to tell you where it breaks. Write down every objection, even the ones you want to dismiss. Each objection is a coordinate where your schema meets reality through another mind.