Being of secondaryconsequence to a causalchain of processes, but playing no causal role in the process of interest.Huettel, Function Magnetic Imaging, 2004.
2002, Daniel Dennett, "‘Epiphenomenal’ Qualia?", in Mental Causation and the Metaphysics of Mind: A Reader, ed. Neil Campbell, Broadview, p. 211,If qualia are epiphenomenal in the standard philosophical sense, their occurrence can't explain the way things happen (in the material world) since, by definition, things would happen exactly the same without them.