Property dualism is a compromise position between substance dualism and materialism.
Like materialism, it holds that there is only one type of substance: physical. Property dualism denies the existence of immaterial minds that somehow interact with the physical world, animating unconscious bodies.
Where property dualism parts with materialism is that it does not attempt to reduce mental states to physical states. Mental states, according to the property dualist, are irreducible; there is no purely physical analysis of mind.
Property dualism thus holds that although there is only one type of substance--physical--there are two types of property--physical and non-physical. Our bodies have physical properties such weight and height, and mental properties such as beliefs and desires.
This position is intended to combine the plausible aspects of both dualism and materialism, while avoiding the problems of each.