What does it mean that reality testing through action?

The most reliable way to test a schema is to act on it and observe the results.

Example: You believe that your team performs better with less oversight — that autonomy drives motivation. Instead of debating this internally forever, you run a two-week experiment: remove your daily check-ins for one project. You track output, morale, and blockers. After fourteen days, the data either supports, refines, or falsifies your schema. The belief is no longer theoretical. It has been tested against reality, and reality answered.

Try this: Identify one schema you currently hold about how something works — in your career, a relationship, your health, or a creative practice. State it as a testable prediction: 'If I do X, then Y will happen within Z timeframe.' Commit to actually doing X within the next 48 hours. Before you act, write down what you expect to observe. After you act, write down what you actually observed. Compare the two. The gap between prediction and observation is where your schema gets refined.