Causal Architecture Discrimination Protocol (CADP): An Experimental Design for Discriminating Organisational and Intrinsic Causal Power Accounts of Consciousness

The physical substrate of consciousness remains theoretically underdetermined. Two empirically tractable accounts occupy the field: the Organisational Substrate Hypothesis (OSH), which holds that the pattern of neural closure is itself sufficient for consciousness regardless of implementation, and the Intrinsic Causal Power Hypothesis (ICPH), which holds that the specific causal identity of implementing elements also matters. No existing experimental design discriminates between them.This paper specifies the Causal Architecture Discrimination Protocol (CADP), the first formally derived experimental design capable of making this discrimination. A valid CADP trial must satisfy three simultaneous conditions: causal rerouting of the system's directed architecture (C1), preservation of RCM closure metrics within pre-specified tolerance bounds throughout rerouting (C2), and independent assessment of conscious status through a measure logically isolated from the closure metrics used to verify C2 (C3). Failure of any single condition invalidates the trial.The paper also specifies the Causal Return Testbed (CRTB), a novel four-module artificial architecture designed specifically to satisfy the CADP protocol requirements. Every CRTB design decision is traceable to a protocol condition. The system can satisfy the RCM closure regime by design, implement precise causal rerouting across three distinct configurations, and assess conscious status independently through the Predictive Divergence Measure.CADP does not claim to solve the hard problem of consciousness. It claims to make the substrate identification question experimentally tractable for the first time.