Epiphenomenalism

sserts that mental events are causally inert (i.e. have no physical consequences). Physical events can cause other physical events, and physical events can cause mental events, but mental events cannot cause anything, since they are just causally inert by-products of physical events which occur in the brain (i.e. epiphenomena) of the physical world. This doctrine was first formulated by Thomas Henry Huxley in the 19th Century, although based on Thomas Hobbes' much earlier Materialism theories.