The problem of interaction
A. The Problem of Interaction
One of the most popular arguments for materialism is the argument that dualism saddles the dualist with the problem of interaction: the problem of seeing how something nonphysical can interact with something physical. William Lycan, for example, provides four arguments against mind-body dualism.
First, Lycan argues that Cartesian minds do not fit in with our otherwise physical and scientific picture of the world. However, I have been arguing that a truly scientific understanding of the world has to include scientists who engage in mathematical and scientific reasoning, and that we need something non-physical to explain the existence of scientists. Absent an effective reply to my arguments on this score, I can maintain that my dualism, not his materialism, is the truly science-supporting world-view. Further, it is not the case that we know nothing about such a soul. We know that it is the sort of thing whose essence it is to act for reasons, possibly because it was created to do so.
Second, Lycan argues that human beings evolved over aeons through a purely physical process of natural selection and random mutation. However, it is the thrust of my argument that our minds couldn’t be the product of “blind watchmaker” evolution, and it begs the question against my argument to insist that it does, absent a good explanation of how reason is possible in a physicalistic universe. Hence to insist that our minds are the product of “blind watchmaker” evolution in the face of an argument that suggests otherwise is to beg the question.
Third, according to Lycan, if minds are nonspatial, how could they interact with physical objects in space? However, I did not argue that minds are non-spatial, I am just arguing that the basic explanation of their activity is rational rather than non-rational. Second, if nothing non-spatial can interact with anything spatial, then we would have an argument that a creator God is impossible. Have atheists been missing out on a good argument here? Nevertheless, where is the analysis of cause that shows that an effect in space can only have a cause in space? It certainly seems logically possible for something that is not in space to interact with something that is. The claim that it is impossible is often simply made as a bald assertion, without supporting argumentation.
Fourth, Lycan argues that a soul interacting with the body would be a violation of conservation laws. However, I don’t see a problem here either, because the conservation laws tell us only what will happen within a closed physical system all things being equal, and cannot tell us what will happen in something outside the physical system interferes. So once again, the argument assumes the truth of physicalism, and so begs the question.
Jaegwon Kim has asked what connects a soul with a body, so as to enable causal connections between them. Now, my argument, as I have indicated earlier, does not actually contend that the soul must be non-spatial. What I have been arguing is that some thing must exist whose can act independently of the nexus of non-rational causation so as to be determined by reasons and not physical causes. It could be in space or not in space.
If the soul is not spatial, then the body might have some identifying characteristic, unique to itself throughout its career, that the soul can identify. Or perhaps God creates and sustains the causal interaction between the soul and the body.
Another option is a Thomistic form of dualism, according to which the person is a single thing that is a combination of form (the soul) and matter (the body). On a Aristotelian-Thomistic view, there are, in the final analysis, no purely material objects, and everything is a combination of matter and form.
There is also Hasker’s emergent dualism, which involves the matter having potentialities to produce a soul distinct from itself. If the soul is somehow produced by the body, then the soul should be able to identify the body that produced it. Of course, these sorts of potentialities in matter would be hard to accept within a naturalistic framework, though if theism is accepted, the antecedent probability is lessened.
I do not want to underestimate the difficulties that Kim is posing here. However, I have argued that there must be something inherently rational which is responsible for the rationality we find in the world. It seems that that can be cashed out in a variety of ways, all of which have the advantage of not requiring is to somehow identify our reason with a set of mechanistically defined, inherently non-rational states.