Epiphenomenon
Etymology
From Greek "epi," upon, and "phainomenon," appearance. In philosophy of mind, epiphenomenalism holds that consciousness is exactly this — produced by the brain yet doing nothing, like a shadow cast by a working machine.
noun · /ep-ih-fuh-NOM-uh-non/
A secondary effect thrown off by a process but having no causal power of its own.
What it names
A byproduct that looks important but drives nothing — the smoke, not the engine.
Example
He argued that office politics was an epiphenomenon of the real driver — the budget — and would vanish once the money did.
Related idea
A special case within the territory of phenomenology; unlike an emergence that feeds back and matters, an epiphenomenon is merely along for the ride.