Epiphenomenalism is the view in philosophy of mind according to which physical events have mental effects, but mental events have no effects of any kind. In other words, the causal relations go only one way, from physical to mental. In recent times it is usually considered a type of dualism, because it postulates physical events but also non-physical mental events; but historically is has sometimes been thought a kind of monism, because of its sharp divergence from substance dualism.

Put simply, if Pierre eats a candy bar and experiences pleasure, that experience is caused by his eating the candy bar. On the other hand, if he goes to get another candy bar, it is not his experience that is causing him to do this. Mental events, like Pierre's pleasurable experience, are just epiphenomena – side-effects, or by-products – of physical processes in the nervous system.

A powerful critique of epiphenomenalism would hold that Pierre's later verbal expression of satisfaction from eating the candy bar is not a matter of knowledge since the verbal expression is not caused directly by the satisfaction. More importantly, in an epiphenomenal world devoid of mental causality, the very case for epiphenomenalism itself is prohibited from being a matter of knowledge. There is no direct causal link between the mental events of the epiphenomenalist and her theory of epiphenomenalism. Put another way, all arguments for and against epiphenomenalism could logically exist independent of any mental activity at all.

External link

• http://www.consciousentities.com/deadends.htm#epiphenomenalism
• http://plato.stanford.edu/entries/epiphenomenalism/