A post-Newtonian understanding of matter includes immaterial forces; thus, the concept of ‘physical’ has lost what usefulness it previously had and Cartesian dualism has, consequently, ceased to support a divide between the mental and the physical. A contemporary scientific understanding of mind that goes back at least as far as Priestley in the 18th century, not only includes immaterial components but identifies brain parts in which these components correlate with neural activity. What are we left with? The challenge is no (...) longer to figure out how a physical brain interacts with a nonphysical mind, but to try to unify theories of mind and theories of brain that to date do not share a single property. The challenge is enormous, but at least we can be quite clear about what its nature is, as there is no reason to be distracted by the idea of two distinct substances. In the present volume, many historical perspectives on the mind-body problem are discussed. In what follows, we follow major currents of thought regarding the mind-body problem so that it can be seen how we arrived at the modern conception that it makes sense only to talk about theory unification. (shrink)