I have never been fond of dualism. I have confidence in the ability of science to explain the world, and so when I was first exposed to the mind-body problem it seemed plausible to me that science could explain consciousness. And this means that in some way consciousness and the mind must reduce to or be explainable in terms of the physical; in other words, that materialism is essentially correct and dualism essentially mistaken. From that perspective dualism seems unscientific or anti-scientific; it takes one of the phenomena we find in the world and says that it is off limits to science, that science will never be able to explain it. But does dualism have to take that form? Can’t we separate the ideas in dualism that make it attractive from this anti-scientific position? My goals in this paper are twofold: first to illustrate how I see the common arguments for dualism, and thus the common forms of dualism, as lacking; and secondly to describe a form of dualism that manages to avoid those problems.
A: Arguments From Ignorance
The major arguments for dualism are, at their core, arguments from ignorance. An argument from ignorance is one that proceeds from the fact that we don’t know how to do or explain something to the conclusion that it can’t be done or can’t be explained. This is what gives many forms of dualism their anti-scientific flavor; from the fact that science hasn’t yet explained that mind and the mind body connection it is concluded that science can’t explain the mind and the mind-body connection. Such arguments have no merit; our ignorance reveals nothing about the world, only our lack of knowledge about it. To reasonably argue that something can’t be done or can’t be explained by science requires some understanding of the things involved, and to show that this understanding rules out the proposal. This is, of course, not how dualism is argued for. The dualist does not come to the table with a fully developed and well supported theory of the mind and the mind-body connection which precludes a scientific theory.
Consider, for starters, the argument for dualism from the existence of the explanatory gap. The explanatory gap, in brief, is our current inability to explain the phenomenal character of consciousness – qualia, as some call it – in non-mental terms. And from this gap in our knowledge some conclude that there must be something non-physical involved that such explanations simply can’t capture. This is obviously a fallacious argument. The fact that we don’t yet know how to capture the mental in physical terms doesn’t say anything about whether the mental can – or can’t – be explained in such terms. There are many things we can’t yet explain, such as how quantum mechanics fits with general relativity (another explanatory gap that has been with us for quite some time). It would be absurd to leap to the conclusion that we can’t explain something every time we encounter difficulty in doing so.
Arguments for dualism are rarely put in that form, to accuse most dualists of using the argument above as I have described it would be uncharitable. But certain arguments that have made it into print are really just disguised versions of it. There is a class of arguments for dualism that attempt to refute the possibility of an explanation of the mind in physical terms by asking us to imagine such an explanation at work. Imagine someone without the ability to see colors, or without the ability to sense objects through sonar. No matter how much they study the mind of someone with such sensations they will never know what it is like to have those sensations. Thus we are asked to conclude that such explanations will never in principle capture the phenomenal character of consciousness. But how do we know that they won’t end up knowing what those qualia are like through such an explanation? Obviously we couldn’t, but we don’t know yet how to explain the consciousness in physical terms. Since we don’t know what such an explanation would look like we can’t know what knowledge it will or will not give us. Thus the argument is asking us to conclude, on the basis of our inability to imagine how a scientific explanation of the mind could give us knowledge of what various sensations are like, that it can’t possibly provide such knowledge. In other words, it is an argument from ignorance.
Dualism is also argued for on occasion by claiming that consciousness has some special property, such as subjectivity, phenomenal character, or a first person ontology, that simply can’t be explained in terms of of objective, non-phenomenal, things with a third person ontology. On the face of it this doesn’t look like an argument from ignorance, because it seems to be asserting that there is some logical incompatibility between two kinds of properties that prevents either from explaining the other. But what reason do we have to believe that such explanations are impossible? Certainly we don’t know how to explain one in terms of the other. Nor have we ever seen such an explanation. But – unless better reasons can be provided – this means that at its root the claim that these two sorts of properties are incompatible rests on an argument from ignorance, ignorance of how properties of one sort might be explained in terms of another. And thus, again, the argument as a whole is nothing more than a disguised argument from ignorance.
A third popular argument to consider is the conceivably argument. In its simplest form the argument runs as follows: we can conceive of the mind as distinct from the body, thus it is possible for the mind to be distinct from the body, and thus the mind is not identical to the body. So materialism, which claims that the mind is in some way identical to the body must be false, and dualism true. But why can we conceive of the mind as distinct from the body? Indeed, what in general limits how we conceive of things? One limiting factor, among many, is how we understand them, which in turn involves how we explain them. Allow me to illustrate with gravity as an example. In modern times the phenomena of gravity is reduced to the curvature of space-time. Thus, if the argument for dualism presented makes sense, we must not be able to conceive of gravity as distinct from curvature in space-time. But of course not everyone is so conceptually bound; someone who lived before Einstein might have conceived of gravity as caused by tiny and invisible springs connecting things. They can conceive of gravity as distinct from curved space-time. If we can’t it must be because our explanation of gravity in terms of curved space-time puts limits on what we can conceive. But this means that the non-existence of an explanation of the mind in physical terms is a hidden premise in the argument (that underlies the claim that we can conceive of it as distinct from the body, along with whatever other factors limit conceivability). So either the argument begs the question or, more charitably, it essentially rests on an argument from ignorance.
Such arguments for dualism make it look like a very unappealing theory, at least in my eyes. They make dualism look like a theory that takes intuitions and superstitions more seriously than scientific inquiry, such that they can set the limits of what science can and cannot explain. They make dualism look like a theory cast from the same mold as vitalism, inasmuch as vitalism claimed that there was something special and irreducible about life that could never be explained in merely chemical terms. I don’t think that this has to be true of dualism; dualism does not have to be an anti-scientific philosophical position, and by casting it in such a light the arguments from ignorance discussed above do much more harm to the theory than good.
B: Ontological Dualism
So what then might a reasonable argument for dualism, and a reasonable form of dualism, look like? The first step towards such an argument is to stop playing the materialists’ game. The materialists cast the question as about how consciousness can be explained. They argue that it can be explained physically, and thus scientifically. Which means that if the dualist agrees to fight them on their own terms he or she will fall into a position that entails that consciousness is something outside the ability of science to explain (at least not unless some new basics mental entities or properties are added to science).
The dualist can and should deny this characterization of the question and of the difference between materialism and dualism. The materialist, so described, is not even doing philosophy proper. It is not the job of philosophy to explain how things work in terms of simpler things; that is a scientific problem (or at least it hasn’t been ever since since science was split off into its own discipline). What the materialist has been doing is no more than asserting that a scientific problem can be solved scientifically. But the task of philosophy is to say what things are; an explanation in philosophy is one that tries to explain the nature of things, not how they work. The mind-body problem, as a philosophical problem, is an ontological one – one that deals with how we categorize the world – which is orthogonal to whether consciousness can be explained in terms of or reduced to purely physical entities and properties.
Ontologically we are interested in what kinds of things there are in the world. Now we could construct a scientific ontology, where we divide the world along the lines of scientific explanations. But nothing forces us to adopt such an ontology – it is just one possibility. With an ontology we are trying to capture significant differences and similarities between things; even if one object in our ontology reduces to or can be explained in terms of some other items in it we aren’t forced to place them in the same category. A computer, for example, is nothing but silicon and electrons at the physical level. However, computers are of great interest to us. There are a number of properties that are peculiar to computers, such as the ability to run certain pieces of software, and often computers as a class are pertinent in ways that silicon and electrons in general are not. Thus it could be argued that it makes sense to treat computers as an ontologically different kind of thing than silicon and electrons in some contexts, despite the fact that there is nothing in a computer over and above silicon and electrons, and even though every property that the computer has can be shown to ultimately arise from properties that the silicon and electrons have.
For essentially the same kind of reasons it makes sense to treat the mind as a different kind of thing than neurons and amino acids, even if we admit that in some way every mental property can ultimately be shown to arise from (and thus reduce to) properties of the neurons and amino acids. Only in consciousness do we find genuine intentionality. Only in consciousness to we find a genuine perspective that the world is presented to. Only a consciousness can impose meaning onto the world. If we are interested in such things, and many philosophers certainly are, then it makes sense to treat minds as their own kind of thing. Yes, perhaps we could discuss intentionality one day by referring to some complicated neural structure. Doing so, however, would only serve to obscure the issue. It is intentionality that is interesting philosophically, not the particular neural structure that may or may not underlie it (although it is surely interesting to cognitive scientists). A change in the neural explanation of intentionality should have no consequences for a philosophical theory involving intentionality (which it would if we tried to replace any use of intentionality with such a neural explanation). I call a form of dualism that takes the ontological nature of the problem seriously, and which argues that there is a significant ontological distinction between the mental and the physical, ontological dualism. Ontological dualism is not forced to rest on arguments from ignorance, because ontological dualism is not an attempt to deny the possibility of certain explanations. Rather it aims to demonstrate something positive, namely that there is a philosophically significant difference between mind and body.
Now a materialist may respond to this proposal by claiming that I am merely playing a game with words. If an ontology doesn’t bring with it entailments about how things are to be explained or about what properties are fundamental (in the sense that others can be reduced to them, but they themselves cannot be reduced) then what good is it? What does it matter if I divide the world up into categories if the categories don’t bear on such questions? By asking this the materialist would miss the point. By dividing the world up into categories we make a number of claims, they are just not of the sort the materialist is used to. By proposing an ontology we are making a claim about what the most philosophically significant and interesting divisions between things are. If we place minds in one category and mindless physical objects in another we are asserting that the distinctive properties of the minded category are substantially different than those in the mindless category and are of philosophical importance. This is why we would reject chairs and non-chairs as a division at the top level of an ontology. The difference between some chairs and non-chairs is not very substantial, and, more importantly, whether something is a chair or not is of little philosophical importance. No philosopher has ever given the property of being a chair play important role in their theories, but many have made the property of having a mind, or something only minds do, central. To call this enterprise merely semantic is thus to deny that how we categorize the world is of any importance. But it is of great importance. How we categorize the world shapes what “kinds” of phenomena we are interested in explaining. And how we categorize the world shapes what “kinds” of phenomena we develop our philosophical theories in terms of. Thus our choice of ontology shapes everything else we do in philosophy, both what we investigate, and what we find acceptable as results of such an investigation.
C: Ontological Materialism
Given my presentation of this new variety of dualism I may appear to be claiming that this version of dualism is correct and that materialism is wrongheaded. I do admit to accusing materialists of confusing philosophical issues concerning the connection between mind and body with scientific ones. But most dualists are no better; this is why dualism often ends up seeming anti-scientific. So while I would certainly agree that this version of dualism is more philosophically attractive than existing varieties of materialism there is nothing in principle preventing us from repairing materialism in the same way, of separating it too from scientific questions of reduction. My proposal is not an attempt to end the debate between dualism and materialism by proving one side or disproving the other. My proposal is rather that we shift the content of the debate so that neither side is entangled with scientific commitments.
Materialism can also be construed as a purely ontological theory, as one that proposes that there be no categorical divisions between mental and physical properties or beings with and without minds. Just as ontological dualism implies that the division between the mental and the physical is philosophically significant, ontological materialism asserts that those divisions should play no significant role in philosophical theories. This means, for example, that ontological materialism is incompatible with an ethical theory that limits ethical agency to entities with minds. Such a theory is committed to a substantial divide between the mental and the physical, inasmuch as ethics is only relevant to one of the two. To make this theory acceptable to ontological materialism we would have to characterize the requirements for ethical agency without appealing to minds or mental features. For example, the ontological materialist could make agency contingent on the ability to communicate and reason about ethical concepts. This might still sound like it has a mental flavor, but such a requirement can be understood as behavioral, as being really about how the entity interacts with others, and not about any consciousness, intentionality, experiences, or occurent beliefs it may or may not have.
The debate between ontological materialism and ontological dualism is not easily settled. Is the distinction between mental and non-mental a fundamental and significant part of philosophical theories, or can it be profitably dispensed with (possibly replaced with concepts such as the cognitive capacity to learn, interactions between agents, and linguistic behavior, all of which can be construed as independent from the mental)? Any attempt to definitively answer this question would involve examining theories that lean on a division between the mental and the non-mental and seeing whether that division is an essential and irreplaceable part of the theory. That examination in itself could be of great philosophical worth. To return to ethics again: considering whether having a mind plays an important and indispensable role in agent-hood, or whether it is just an easy way of ruling out rocks and trees, could provide new insights into ethical questions. A cursory inspection, though, makes ontological dualism appear to be the superior theory. Such a large number of philosophical positions appeal to minds or mental features that it is hard to see how the ontological distinction between mind and body could be removed from philosophy as a whole. Certainly ontological materialists have their work cut out for them.