Jaegwon Kim's well known Pairing Problem is supposed to show that it is impossible both that immaterial souls cannot have causal efficacy in the physical world as well as to other immaterial souls. The problem, in brief (super-brief) is that for event A to cause event B, there must be some further factor X in virtue of which A causes B. There is no such further factor X in the case of the mental events (willings, actings, intendings) of souls and physical events. So, souls cannot be causally related to the physical world. This argument is supposed to apply to ALL souls.
I just finished (most of) Plantinga's really nice article "Materialism and Christian Belief" in Persons: Human and Divine, and he proposes that broadly logical necessity is that relation. He writes,
According to classical theism, it's a necessary truth that whatever God wills, takes place. It's a necessary truth that if God says, "Let there be light," then there is light. Necessarily, if God says, "Let Adam come into existence," Adam comes into existence. So what is it that makes it the case that God's intentions cause what they cause? To ask that question is like asking, "What is it that makes an equiangular triangle equilateral?" The answer is (broadly) logical necessity; it's necessary that whatever God wills comes to be just as it's necessary that every equiangular triangle be equilateral. Accordingly there isn't a problem about that factor X in the divine case... (p. 133)
So Kim's Pairing Problem that it is impossible that souls be causally related to the world fails. Plantinga goes on to show that once you have theism, there is no problem for human souls having causal interaction in the world as well.
This seems compelling to me. Anybody see any problems with it?
