Textbooks often write of “the mind-body problem” as if there was some single problem that deserves that title. In Descartes’s days, there was not believed to be merely one such problem. Descartes had recognized that there are at least two problems that deserve to be called mind-body problems. One is whether minds are material. The other is whether minds intervene in (more generally, interact with) the physical world. The first is the Metaphysical Problem of Mind. The second is the Problem of Mental Causation.
It is possible that the physical world is causally self-contained or closed and that physical laws cannot be contravened. If so, and if minds are immaterial, this renders minds causally impotent in the physical world.
Consider your decision, a mental event, to raise your arm, and your right arm’s subsequently moving. If the mental is immaterial, and the physical world is causally closed, then the causal history of your arm’s movement cannot include your decision. An immaterialist or dualist solution to the metaphysical problem of mind, combined with a causally self-contained physical world, means that the mind is causally idle.
If the mental is material and the physical world is closed, the causal history of the arm’s movement may include your decision. This is because decisions somehow are physical events. A materialist or physicalist solution to the metaphysical problem of mind, combined with a self-contained physical world, means that the mental may carry causal clout.
Materialism appeals because it places the mind squarely in the physical world and seems to solve both the metaphysical problem of mind and the problem of mental causation (Kim 1998). However materialism also fails to appeal for this very same reason. It purchases causal clout for mentality at the cost of denying that the mind as mental (or decision as decisional) carries causal clout. Just insofar as the mind is physical does it intervene in the physical world.
Northoff seems neither to recognize nor to understand the distinguishability of the two mind-body problems. He tends to run the two problems together. He also tends to collapse differences between two ways in which the two problems sometimes are framed or described.
Way One, the layered way, goes like this: The world contains levels of objects and properties. These levels are posits introduced to describe and explain the phenomena in the world. Each level is somehow based or grounded on lower level ontological strata.
Northoff writes as if he believes that lower-level neurophysical activities and properties causally determine higher-level mental activities and properties, which may appear, epistemically, to be causally autonomous, but which are dependent, causally, on lower level strata. He offers a fascinating sketch of those lower level strata, echoing (with his own distinctive twists) work being done on the neurobiology of dynamic and distributed neural networks as well as on the role of [End Page 223] the environment in shaping brain development and behavior.
Way Two, the perspectival way, goes like this: The world consists of objects and properties that can be viewed or described from two different perspectives. One perspective consists of how things appear to perceivers. This is the first-person perspective. The other consists of how things are from no point of view at all; or more precisely, how things appear from an objective, third-person point of view. This is the third-person perspective.
Northoff writes of perspectives and layers interchangeably. He seems to think that they are semantically equivalent ways of speaking. They are not. Layers and perspectives are not one and the same. Different perspectives can be had on the same level. Different levels can be described from the same perspective.
Northoff points out that one and the same object may be described in different ways. So, just because descriptions are many does not mean, he wisely notes, that many things are described. However, mental events, he unwisely adds, can be described both in the first personal and the third personal. One and the same perceptual experience, for example, can be understood from subjective and objective points of view.
Is Northoff right? Can each and every mental...