Asymmetric legibility is the deepest principle the measurement problem yields, and it runs against the usual institutional grain. Today an applicant for help must expose income, health, family, and history while the institution deciding their case stays opaque about how the decision is made, what scored them, its error rates, and who received their data. The principle reverses that: standing should not require maximal legibility to power, and power should require substantial legibility to those over whom it holds jurisdiction. It is not self-enforcing — it inverts the natural gradient of power, so the institutions that should be most legible are exactly those with the most leverage to resist audit. That makes it a norm the enforcement architecture has to win, not one a doctrine can grant. See measure power, not people.