Full Idea
Epiphenomenalism supposes something to exist in nature which has nothing to do, no purpose to serve, a species of noblesse which depends on the work of its inferiors, but is kept for show and might as well, and undoubtedly would in time be abolished.
Gist of Idea
Epiphenomenalism is like a pointless nobleman, kept for show, but soon to be abolished
Source
Samuel Alexander (Space, Time and Deity (2 vols) [1927], 2:8), quoted by Jaegwon Kim - Nonreductivist troubles with ment.causation IV
Book Reference
Kim,Jaegwon: 'Supervenience and Mind' [CUP 1993], p.348
A Reaction
Wonderful! Kim quotes this, and labels the implicit slogan (to be real is to have causal powers) 'Alexander's Dictum'. All the examples given of epiphenomena are only causally inert within a defined system, but they act causally outside the system.