Some Brief Thoughts on the Interaction Problem

I was reflecting on the Interaction Problem today and had a few thoughts about it.  The problem is an objection against Cartesian Mind/Body Dualism, and goes roughly something like this: we can think of no possible mechanism for how an immaterial soul can interact with a material body.  If we can't come up with a mechanism, then it is likely that no such mechanism exists.  If no such mechanism exists, then an immaterial mind could not interact with a material body.  But the mind does interact with the body.  Therefore the mind must not be immaterial, and Cartesian Dualism is false.

Ignoring the potential issue with the Noseeum inference made in the argument (I don't see X, therefore X probably does not exist), another issue came to mind.  The whole argument revolves around the idea that it seems counter-intuitive that an immaterial substance (such as the Cartesian mind) could interact with a material substance (such as the body).  Perhaps even worse than counter-intuitive, it just seems strange. [1]

Let's also disregard the fact that counter-intuitiveness, and strangeness, are not good defeaters for an argument unrelated to those concepts (there are arguments from the Cartesian Dualist for why an immaterial soul must exist).  I still don't think the problem is as cutting as those who advance it would like to think.  Why? Well, when you think about it, it's really just as strange that material substances can interact with other material substances.  What is the mechanism for that type of interaction? Why think that such an interaction can take place?

But wait, you might say. We know that material substances interact with each other because we observe such interactions all the times in science (Or, you know, by just being aware of the world that we live in. But it's obviously more effective to shout "science" when objecting to something)!

Well, I might respond by saying that if Cartesian Dualism is true, then we regularly observe material and immaterial substances interacting together all the time, too.  Perhaps I'm just begging the question here, because we would have to assume that those type of interactions can take place in order to posit that Cartesian Dualism is true.  But if I am, then so are those who believe in material/material interactions.

This is because if we accept a broadly Humean metaphysics (a type of empiricism which most opponents of Cartesian Dualism seem to accept, implicitly or explicitly), then when we do science, we are not observing causal interactions at all.  Hume argued that we are really just observing the constant conjunction of events.  Humans have, Hume argued, a psychological tendency to infer from such constant conjunctions that a causal interaction has indeed taken place.  But let's be clear: if Hume is right, then we do not in fact observe the interaction of material substances.  Rather we infer such an interaction. So we have not directly observed such mechanisms for material/material interactions.  Given this lack of observation, these types of interactions appear just as strange as those being objected to!

Let's wind this up by summarizing what I am intending to show.  No, actually let's start by summarizing what I am not trying to show. I am not trying to show that Hume was right about causation, nor that Cartesian Dualism is true. I happen to dispute both of those theses personally (though I dispute the former much more strongly than the latter, and my view on the latter is closer to Cartesian Dualism than it is to modern Physicalism). What this post does show is that most people who put forth this objection prove too much and therefore have reason to discard it.

Objection

A possible objection to this post (brought to my attention by Steve) is that we do know the mechanisms for material/material interaction. These mechanisms are the fundamental forces, or the physical laws.  But I don't think this solves the problem. First, there is widespread disagreement over the actual nature of these concepts.  Are they prescriptive, or are they simply descriptive?  Do these laws or forces actually compel materials to interact with each other in certain ways (which seems, again, very strange), or are they simply names and descriptions we have given to certain behavior that we perceive. And that leads me to my second point: regardless of whether these fundamental laws or forces are descriptive or prescriptive, have we actually observed them? Or are we inferring them from the constant conjunction of events that we do observe? I submit that we have not observed them, and these concepts (though they sound more eloquent) fall to the same argument that Hume put forth from the start.

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Notes:
1.  The term I have most often seen in philosophical literature in this context is "queer."  Due to the charged nature with which this word has come to be perceived, I have chosen to use the word "strange" instead.