 Frank Jackson (1982) has given an epiphenomenalistic argument that has spawned lively responses from many quarters. This argument turns on the concept of physical information, where “physical information” is information about ourselves and our world of the kind that is obtainable in the physical, chemical, and biological sciences. In Jackson’s argument, a brilliant scientist, Mary, has learned all the physical information there is about color vision. Having been confined to a black and white room, however, Mary has never had a color experience. Jackson asks whether Mary will learn anything when she is released from her confinement and thus comes for the first time to have color experiences. It seems compelling that she would learn something; but as she already has all the physical information there is, what she learns must be some other kind of information, which we may call “phenomenal information”. This “knowledge argument” has been regarded as a strong reason to accept a dualistic view of our experiences. When combined with the traditional arguments (Pro) given above, it becomes a potent source of support for epiphenomenalism. 