Coalition Drift vs. Emergent Agency: Why coalitions drift — and why that is not the same as emergent agency.

As multi-agent systems become more complex, two concepts are frequently conflated: coalition drift and emergent agency. They are related, but not identical. Coalition drift is a physics phenomenon. Emergent agency is a perception phenomenon — what observers conclude when they watch coordinated drift produce coherent behavior. Understanding the difference is critical for governance, safety, and system design. Coalition drift is real, measurable, systemic, inevitable, and mitigable. Emergent agency is not real, not measurable, not systemic, not inevitable, and not mitigable — because emergent agency is not a thing that exists. It is a thing that is perceived when coalition drift produces behavior that looks agentic. Coalition drift is the cause. Emergent agency is the shadow it casts. Governance must focus on the coalition, not the illusion.