Dualistic interactionism is the view that MentalEvents and PhysicalEvents both exist, but neither type of event can be reduced (see ReducTion) to the other type, and mental events are both causes and effects of physical events. It is also called Cartesian dualism, because it is the kind of dualism that the great 17th-century French philosopher Descartes advocated.
This is one kind of dualism--probably the most popular and well-known, but still only one kind. In addition to the claim that the mental cannot be reduced to the physical and vice-versa, which this theory shares with all other kinds of DualIsm, dualistic interactionism includes the claim that there is a causal interaction between mental events and physical events. When Johnny touches a hot stove and burns his skin, he feels a pain. Touching the stove and burning his skin are physical events; feeling pain is a mental event. And when he feels the pain, he says, "Ouch!"--and his saying a word is a physical event. This sort of interaction between the mental and the physical is commonplace, and that it actually happens seems as obvious as anything can be. If we put the belief in that interaction together with DualIsm, we have got a very CommonSense theory of mind.