CONCEPT
Substrate Independence (IIT)
IIT's claim — both liberating and terrifying — that consciousness depends on causal structure, not on material composition, applying equally to biological neurons and silicon transistors if the structural conditions are met.
IIT is a substrate-independent theory. Its axioms describe experience; its postulates describe causal structure. Neither level specifies what material the causal structure must be implemented in. Consciousness, on IIT's account, is a property of any physical system that satisfies the postulates — biological, silicon, optical, quantum, or substrates yet to be invented. This implication is central to IIT's engagement with AI: if the theory is correct, then artificial consciousness is possible in principle, contingent only on whether the right architecture can be built. The implication is also disquieting: it severs the intuitive link between biology and consciousness, forcing honest confrontation with what makes experience real.
In The You On AI Field Guide
Substrate independence follows logically from IIT's axiomatic structure. The axioms are derived from phenomenology — from what any conscious experience must be like. They do not specify neurons, carbon, or any particular material. The postulates translate phenomenological requirements into requirements on cause-effect structure. But causal structure is abstract: it