I’ve finally had a chance to get back to considering Titus Rivas’s paper, in which he and Hein van Dongen argue that the mind-brain model known as epiphenomenalism — which says that subjective mental phenomena are indeed ontologically real, that they are “irreducible” to physical processes, and that they exert no causal influence on the physical world — is false. In a previous post I agreed that their principal objection, which has to do with how the brain might ever come to express a belief in subjective mental phenomena in the first place if epiphenomenalism were true, is a good one. But if we are to discard epiphenomenalism, what alternatives are we left with? Rivas and van Dongen see only two alternatives: eliminative materialism and interactionist dualism — but I think they narrow the field unnecessarily. I’d like to go over the paper in some detail, and see where there might be implicit assumptions that could be leading us astray — a job that will require several posts (and which, given my lack of free time at the moment, may unfortunately be a slow go). Readers can find the original here.
But before beginning, I’d like to make clear the most important aspect of the view that I incline toward: first and foremost, I think that the mind is the result of the activity of the brain. This in itself does not rule out certain sorts of dualism, and that is what I’d like to focus on tonight.
Dualism has long been the model of choice for those who, for religious or “spiritual” reasons, have wished to introduce the notion of a “soul” as an ontologically distinct substance that interacts closely with the physical body during our lifetime, but which is capable of an independent existence (variously described) upon our death. In fact, it seems that most interactionist dualists progress quite naturally from an initial rejection of the mind as anything that matter might be capable of to a full-blown two-party system in which the immaterial mental part has a robustly independent existence, in which its association with the physical body is only a temporary phase, or is perhaps only one of a series of such associations. This is “interactionist substance dualism”, and there are some assumptions here that I’d like to have out in the open.
It is often suggested that we are driven to positing an ontologically distinct “mental” substance because it is quite plain that “mere” matter cannot be the substrate of subjective experience. Do we know this? Is our understanding of what subjectivity actually is sufficient to warrant such an axiom? Can we say that we have exhaustively enumerated all of matter’s properties and capabilities? One might argue, by varying what we take as the more parsimonious assumption, that we plainly haven’t, as we see special bits of matter — our brains — that seem to be doing just the thing that we are declaring that matter is incapable of.
And if we do posit a new kind of philosophical substance in the world’s ontological inventory, call it “mind”, and declare it to be ontologically distinct from “matter”, what have we achieved? Have we gained any insight into what it is about mind-substance that bestows upon it its gift for subjectivity? Have we any deeper understanding? No, we have simply added, rather arbitrarily, a new class of thing about which we can say nothing other than that it is able to be the locus of subjective experiences. How does this improve upon the view that matter, under conditions that are not yet understood, might do the same? If nobody had ever seen a magnet, it might seem equally reasonable to deny that a chunk of metal could push another chunk of metal around without touching it — to insist that for one piece of iron to move another they would have to be in direct contact — but as it turns out, that is not the case: magnets exist, and they show us that matter is capable of odd, counterintuitive tricks.
But let us assume that this substance-dualistic axiom is a good one, and that there are two kinds of substance — mind and matter — and that they can causally influence one another. As we know, this fits nicely with the “soul” model, in which the mental “self” is capable of independent existence. But it also allows for another description: that the mental is brought into existence, and sustained in that existence, by the action of the physical (why not, if we’re already allowing them to interact?). A two-way causal interaction between mind and body could take the form of a physical event A causing mental event B, which in turn causes mental event C, which then causes physical event D, and so on. In this view the mental, although ontologically distinct, still supervenes on the physical body, which acts as a sort of generator. Damage to the brain will cause an imperfectly generated mind (as certainly seems to be the case), and shutting off the brain would shut off the mind as well. Our mental part would “come on line” gradually, as the construction and outfitting of our brains progressed during embryonic development and infancy (as again seems to be the case), and upon our deaths our minds would simply cease to be.
This is a very different notion from the conventional “soul”-based model: it is interactionist dualism with the dog wagging the tail. I have contended that, in principle, at least, any view that posits a causally efficacious non-physical mental susbstance will be amenable to scientific verification, as it should leave footprints in the form of causal-closure violations, and this model would do so as well.
But as mentioned above, I don’t see that we gain much by insisting that mental phenomena are an ontologically distinct non-physical substance; to do so we simply deny by arbitrary fiat that matter can muster up subjectivity, then invent a new type of substance that can, about which we can say nothing else.
In the next post we’ll look at some of the other assumptions made in this paper, in particular having to do with axiology and morality. We also need to take a look at the concept of “reducibility”.