Epiphenomenalists believe that mental events have no causal effect on the physical. They may differ in what they consider "mental events" but it seems all of them would consider qualia / phenomenal experiences mental events. Now, if someone writes a book about qualia -- clearly a physical event -- what are the ways in which the epiphenomenalist can make sense of this? It seems that if the author was genuinely writing about her own qualia, then those qualia would have affected the book, which is impossible according to the epiphenomenalist. This would seem to make any discussion of qualia meaningless for the epiphenomenalist. That, in turn, would make epiphenomenalism a strange view to hold. Or is there some way out of this conclusion?
Mind-body dualism is defined by the Encyclopaedia Britannica as:
in philosophy, any theory that mind and body are distinct kinds of substances or natures. This position implies that mind and body not only differ in meaning but refer to different kinds of entities. Thus, a dualist would oppose any theory that identifies mind with the brain, conceived as a physical mechanism.
Simply stated, the mind is an entity that is not physical; it is another kind of substance which does not exist as a physical thing. It is a non-physical entity; it is not matter nor is it some type of "energy" that the physical world contains. It is immaterial.
The problem that you proposed is a well-known one. It seems obvious to us that our actions are caused by our thoughts. There is an obvious problem of interaction between these entities of differing nature.
Possible solution to the interaction problem from The Internet Encyclopedia of Philosophy:
Some, such as Ducasse (1961, 88; cf. Dicker pp. 217-224), argue that the interaction problem rests on a failure to distinguish between remote and proximate causes. While it makes sense to ask how depressing the accelerator causes the automobile to speed up, it makes no sense to ask how pressing the accelerator pedal causes the pedal to move. We can sensibly ask how to spell a word in sign language, but not how to move a finger. Proximate causes are "basic" and analysis of them is impossible. There is no "how" to basic actions, which are brute facts. Perhaps the mind's influence on the pineal gland is basic and brute.
A proximate cause means that cause and effect are immediate in relationship; we cannot possibly seperate them since their relationship is too fundamental. There is no analysis that can be made of why picking your pencil up causes it to be lifted. Ducasse argues that this proximate relationship is akin to the affect the body has on the mind.
However, I have my own personal criticism. We can definitely analyze the relationship in my example and in the provided quote in the realm of physics. Our muscles expend energy on an object, so it can overcome its inertia or its gravitational attraction to the earth. It seems we cannot analyze the interaction problem as we can with these physical events.
Another solution is this: There is simply some mechanism that allows effects from physical events to translate over to the mental realm. Since the mental realm does not affect our physical realm, though, epiphenomenalism also concludes that there is no free will if we are truly conscious entities and not our bodies.
The Internet Encyclopedia for Philosophy mentions a possible mechanism, occasionalism:
Occasionalism, version of Cartesian metaphysics that flourished in the last half of the 17th century, in which all interaction between mind and body is mediated by God. It is posited that unextended mind and extended body do not interact directly. The appearance of direct interaction is maintained by God, who moves the body on the occasion of the mind’s willing and who puts ideas in the mind on the occasion of the body’s encountering other material objects. For example, when a person actualizes his desire to pick up an apple, his mind does not act on his body directly, but his willing of the action is the occasion for God to make his arm reach out; and when his hand grasps the apple, the apple does not act on his mind directly, but the contact is the occasion for God to give him ideas of the apple’s coolness and softness.