Principlev1
Conduct blameless post-mortems that ask what the team
Conduct blameless post-mortems that ask what the team believed about the system rather than who caused the failure, because schema-focused investigation produces structural learning while person-focused investigation produces defensiveness.
Why This Is a Principle
This derives from Schemas as Knowledge Organization Structures (schemas guide processing), Belief Perseverance Against Contradictory Evidence (systems maintain existing beliefs), and Most organizational outcomes are products of system design, (outcomes are products of system design not individual effort). Google's SRE practice grounds this. The principle prescribes investigation methodology that enables collective schema updating - not itself an axiom about how teams work.