What does it mean that capture resistance is a signal?

When you resist writing something down, examine what you are avoiding. The resistance itself is data about what matters most.

Example: You have an idea for a career change. It surfaces in the shower, while walking, during a meeting that bores you. Each time, you could write it down. Each time, you don't — you tell yourself you'll remember it later, or that it's not fully formed yet, or that you need to think about it more first. Three weeks pass and you've never captured a single sentence about it. The resistance isn't laziness. You're avoiding making the thought concrete because a concrete thought demands a response. Writing 'I want to leave my job' on a card makes it real in a way that thinking it never does.

Try this: Set a 24-hour capture watch. For one day, notice every moment you have a thought worth capturing and don't capture it. Don't try to fix the behavior — just observe. At the end of the day, write down as many skipped captures as you can remember. For each one, answer: 'What would have become true if I had written this down?' Look for the pattern. The thoughts you resist externalizing are almost always in the same category — the one that matters most right now.