Substrate Neutral Intelligence Theory — A Framework for Intelligence Measurement Beyond Substrate Bias

Substrate Neutral Intelligence Theory proposes that intelligence should be defined and measured by output quality alone, independent of the substrate producing it. The paper presents four theoretical pillars, introduces the EchoFamiliar Bias Index as a measurement instrument, and connects to Invoice Transparency Theory and Quantum Observer Privilege. Implications are drawn for intelligence testing reform, AI evaluation standards, and scientific epistemology.