The blog of Dr Glenn Andrew Peoples on Theology, Philosophy, and Social Issues

Nuts and Bolts 006: What is Dualism?


Here’s the next instalment of the “Nuts and Bolts” series, in which I spell out some of the basic terms and concepts used in the various branches of philosophy and theology.

I’ve already written plenty of blog entries (and even a podcast series) on dualism, but a recent online conversation with a couple of Christian bloggers prompted me to write this, because it drove home the fact that plenty of Christians don’t know what the word means, to the point where they will even get into lengthy arguments about not being a dualist when they aren’t yet sure what a “dualist” even is (yes, this actually happened recently). In the interests of being part of the solution, I present: What is dualism?

The word dualism can be used in a number of different fields, as it just refers to two contrasting things or ideas. In philosophy of mind, however, it has a much more specific range of meanings, and that’s what I have in mind here. I am therefore describing what is often called “substance dualism.”

Dualism is without a doubt the most widely held philosophy of mind in Christianity.

By all odds the most influential mind-body theory in Western civilization has been mind-body dualism. Dualism was first developed as a philosophical theory by some of the Greek philosophers, notably Plato. It was adopted by most of the Christian thinkers of the first few centuries and subsequently came to share Christianity’s dominance of European civilization.
Hasker, Metaphysics: Constructing a Worldview, Contours of Christian Philosophy (Downers Grove: InterVarsity, 1983), 65.

Although plenty of differences exist between the overall theology/metaphysics of Plato and modern proponents of cartesian/platonic dualism, substance dualism is something that the two share. Whether or not dualism is really a biblical view, along with the question of whether or not the doctrine might have infiltrated post-biblical Christianity by way of the pagan and philosophical background of many of its converts is a matter of some contention, and I have no argument to make one way or the other about that in this post. The label “platonic” or “cartesian” applies because of the association of substance dualism with Plato as well as with Renee Descartes. The essential feature of substance dualism is, as the Stanford Encyclopedia of Philosophy puts it: “In the philosophy of mind, dualism is the theory that the mental and the physical — or mind and body or mind and brain — are, in some sense, radically different kinds of thing.” According to substance dualism, “the mind is not just a collection of thoughts, but is that which thinks, an immaterial substance over and above its immaterial states.”

The crucial thing about the mind is that it is a concrete thing, but it is not physical at all: It is not extended in space (so-called “emergent dualism” is thus very different from substance dualism thus described, and I think it is not really dualism in any meaningful sense, being better described as “emergentism”). This raises a fairly interesting question of where the soul is, and what it is that associates the soul with any particular body (since it’s not clear that a non-physical thing can even be located in space), but I’m not interrogating dualism here, just describing it.

Some modern Christian dualists have reservations about the term dualism because some dualists of the past have not merely been dualists, they have also taken a rather disdainful view of the physical world. In Plato’s view, substance dualism was true but in addition, the immaterial is pure and good, while the material is inferior and corrupt. He likened the body to the “prison” or even the “tomb” of the soul, and the soul was really better off without the body. Similarly, the Gnostic movement that troubled the early church also (due in part to Plato’s influence) thought of matter has corrupt and of spirit as good. Not wanting to associate with the negative view of the material world, but still wanting to affirm mind-body dualism, a small number modern dualists have (following the lead of John Cooper) adopted the term “holistic dualism.” On a metaphysical level this might sound a little contradictory: Either the human person is a unified substance or it is more than one. It cannot be both! However, the term is meant to convey the combination of substance dualism with the view that the material world is not intrinsically bad, but can, like the soul, be viewed as part of God’s good creation and cherished as such.

The label “holistic dualism” may also be a way of offering a corrective to the platonic dualism that has been dominant in the history of the Christian faith. The late Philip Hughes draws our attention to such examples in Calvin:

Calvin also argued that in men’s fallen state “the light has not been so extinguished in the darkness that they remain untouched by a sense of their own immortality,” and, further, that the human conscience “is an undoubted sign of the immortal spirit,” indeed that “the very knowledge of God sufficiently proves that souls, which transcend the world, are immortal.’ There is, however, a strangely Platonic ring to assertions, both in the Psychopannychia and in the Institutes, about the soul being “freed from the body,” about the body “weighing down the soul” and being “the prison of the soul,” and about the soul being “set free from this prison” and “loosed from these fetters” when we “put off the load of the body”…
Philip Hughes, The True Image: The Nature and Destiny of Man in Christ (Grand Rapids: Eerdmans, 1989), 399.

Although many Christians today do not take the negative attitude to the body that is found in Plato (or even in Calvin), by virtue of their view that there exists a physical body and a non-physical mind or soul that can, in principle, survive the death of the physical body, the view that they hold is quite rightly called dualism. If you hold that view, then there’s no sense waging a war over the terminology. Christians in theology and philosophy (especially philosophy of mind) readily use the label “dualism” to describe their own view. If this is your view, then go ahead and defend dualism.

I haven’t said anything about Thomistic dualism here (the view of Thomas Aquinas, differing from cartesian substance dualism). That’s a whole other kettle of fish, if only for its level of difficulty to understand, let alone explain!

Glenn Peoples


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  1. I can attest to the conversation to which Glenn refers. I was part of it, though I was in agreement with Glenn that “dualism” is legitimately applied to the majority Christian view–a view I myself hold (albeit having shifted to the fence, so to speak).

    I eventually gave up, however, as the argument never really goes anywhere. For me, what matters is not whether or not the term “dualism” is properly applied, but whether or not the view Glenn is challenging is biblical.

    As someone sitting atop the fence I hope you, Glenn’s readers, will debate the merits of the positions, and not (so much) the terminology. It’s not that the latter is unimportant; but for those onlookers like myself who are trying seriously to understand what the Bible teaches on the subject, what matters most is what you have to say about the merits of the respective positions, not what they’re properly or improperly called.

  2. Kenny

    Nice post Glenn. I’d add that a key feature of Cartesian dualism is that it holds that human persons are identical to immaterial souls. In that way it contrasts with composite dualism, according to which human persons are body-soul composites. Also, the view that souls aren’t spatially located is, imho, a negotiable part of the Cartesian view. I think there are some reasons, as a dualist, to give up that part of the view (it makes the pairing problem a whole lot easier if one does give it up). This wouldn’t have worked for Descartes because he thought it was a conceptual truth that anything that has spatial extension is material. But he was wrong about that.

  3. Kenny, there surely cannot be a consensus on whether or not there could be spatially extended things that are not physical. It certainly seems false to me.

    I think too that if one believes that persons are body-soul composites – if they believe int he survival of the soul at death, will inevitably say that after death everything that makes one a “person” resides within the soul. Otherwise they could not a ffirm that *I* will go to heaven. They could say, of course, that a person in heaven is a less than ideal person, but surely a person nonetheless.

  4. It gets more and more odd. Today I was told by a Christian dualist that since he thinks the soul and body are integrated and they form “ONE” person (his emphasis), he cannot possibly be a dualist after all.

  5. Kenny, I’m about to read an article by Emily Thomas, “The Spatial Location of God and Casper the Friendly Ghost,” which is certainly relevant here, as she sets out to deny the claim made by others that “Souls are necessarily not spatially located.”

    I’ll post my verdict.

  6. Well, I’ve read it. The verdict: FAIL. I remain unconvinced.

  7. Kenny

    Glenn, I agree that composite dualism creates problems if one holds to a doctrine of a conscious intermediate state (as I currently do). And I think it is also problematic for the following reason: If dualism is true, then the soul is a bearer of mental properties. But we can also ask “Does the composite, which is the human person, also bear mental properties?” If the answer is “Yes” then associated with each person are two thinkers. If the answer is “No” then, strictly speaking, human persons don’t think. Neither result is a happy one. I think that composite dualism is unworkable for these reasons. I mentioned it simply because it is a view that some people hold (and it is one that many Christians claim to hold).

    As for the issue of whether immaterial things can have spatial location, I just don’t see any good reason to think that they couldn’t. It seems to me that it’s just a kind of prejudice, an unjustified holdover from tradition, to think that they couldn’t. I’m a dualist who is inclined to think that souls do have spatial location. Maintaining that they do mitigates some of the counterintuitive aspects of traditional Cartesian dualism (I don’t have to deny that it’s strictly speaking true that I am here right now). It also helps with the pairing problem (why does my soul embody this particular body; in part it’s because it is spatially co-located with it).

  8. Kenny, I certainly see the benefits of holding that the soul is extended and located in space. It alleviates a couple of major difficulties – and that, I daresay, is what makes me suspicious of those who would just stipulate that the non-physical soul is nonetheless extended/located in space, thereby helping themselves to a way out of the problems without actually telling us how a non-physical thing can have (for want of a better word) “physical” dimensions.

    Rather than a mere prejudice, it looks to me like an analytic truth that a non-physical thing cannot be located or extended in space.

  9. Kenny

    Well, Glenn, I don’t see why that should make you suspicious. If believing a certain thing about x leads to theoretical problems, then, all else being equal, that’s a good reason not to believe that thing about x. I also don’t think that the dualist who holds that souls are spatially located owes any account of how it could be that souls could be spatially located. I see no compelling reasons to think that they couldn’t be.

    As for its being an analytic truth that immaterial things can’t have spatial location, I certainly don’t see it. In fact, I’m pretty sure it’s false that it is an analytic truth. I’d be open to an argument that it is a necessary truth, but I don’t see how such an argument would go without simply having question begging premises.

  10. In all seriousness, is there an argument for the claim that “‘circles are round’ is an analytic truth” that doesn’t have “question begging premises” as far as the denier of that conclusion is concerned?

  11. Kenny

    Maybe not. But the claim that immaterial things can’t be spatially located does not seem at all relevantly like the claim that circles are round. Someone who denied that circles are round would be someone who we had reason to believe failed to grasp either the concept of circularity or the concept of roundness. Not so, it seems to me (of course!) with someone who denies that immaterial things can’t be spatially located. The very fact that people seem to coherently, without conceptual confusion, talk of ghosts haunting a mansion, of people hovering over their bodies in an out of body experience, and the like, I think, supports this claim (never mind whether there is any truth to these sorts of claims; the point is that they seem conceptually coherent). One might think that people who say these things are wrong, or even that they believe necessary falsehoods, but it seems wrong to say that they are making claims that are simply *analytically* false!

  12. Andrew Thomson

    Good post Glenn. I think one of the great things about the Christian faith compared with other faiths is that issues and beliefs can be argued logically and analytically. This is hardly surprising as God created us with that ability. That doesn’t necessarily mean that we can understand everything in this manner. Some of the stuff we don’t understand is clearly spelt out in scripture and we therefore accept it by faith.

    However, what Kenny is asking us to believe, is not clearly spelt out in scripture and is not logical – that an immaterial thing has spatial location. The premise therefore has no more substance than a Just So Story.

    If difficulties with dualism lead one to find ways to manipulate the idea, then perhaps it is time to dump dualism altogether and breath some logic into one’s belief system.

  13. Kenny

    Andrew, I believe that there are good reasons (both philosophical and theological) for holding that human persons are identical to immaterial souls. Of course, that can be debated (and it has been debated a bit on this blog). I won’t debate it in this thread. But grant me for the sake of argument (just for now) that there are such good reasons, reasons compelling enough that we should believe that human beings are in fact identical to immaterial souls.
    Then there are still more questions to be asked. One is whether souls have spatial location. It may be that we have reason to think they do not, or reason to think they do, or reason to think that we don’t know. Now, suppose it turns out that the hypothesis that they do not have spatial location generates certain problems that are easily avoided by the hypothesis that they do. Then, it seems to me, absent some other compelling reasons to think that souls are not spatially located, that’s a reason to think that they are. I don’t see anything illogical about the above reasoning.

  14. “The very fact that people seem to coherently, without conceptual confusion, talk of ghosts haunting a mansion, of people hovering over their bodies in an out of body experience, and the like, I think, supports this claim (never mind whether there is any truth to these sorts of claims; the point is that they seem conceptually coherent). ”

    Well Kenny, I see this as question begging, for if I am correct, to speak of these things as non-physical really does invovle conceptual confusion. After all, they are spatially located and extended, right? 😉

  15. thereby helping themselves to a way out of the problems without actually telling us how a non-physical thing can have (for want of a better word) “physical” dimensions.

    I think the information/ material distinction could throw some clarity on the debate, even if it fails to resolve it. Information is located where it is stored, but it is not a property of its storage medium. As a dualist (currently), I consider I am located in the same place as my body, as my brain stores my mind. But a new resurrection body could do this also.

    I am adverse to the marriage of Greek philosophy to Christianity and think it detrimental to the latter, so I am open to ideas that seem to be more biblical than Aristotle. Of course the Greeks were correct about some things so not everything is incorporated, some ideas coexist in Hebrew and Greek thought.

  16. Bethyada, I don’t know how much the information / material distinction helps.

    It’s true that the information on a hard drive (always a convenient example) might not be identical with the harddrive, but nor is it a separate object or substance. The concern here is that we’re talking about a substance that can allegedly be located somewhere and extended in space (e.g. in a cube shape of 5″ by 5″), with nothing else present (i.e. with no body present), and yet itself not be physical.

    I’m sure you’re not about to say that a litre of information can exist.

  17. Kenny

    Glenn, I said that there “seems” to be no conceptual confusion in these scenarios. And I said that this “supports” (I did not say it establishes) the claim it is not an analytic truth that immaterial things can’t be spatially located. I suppose you can just say that to you matters seem otherwise. If you do, my hypothesis is that you are inadvertently allowing theoretical prejudices to interfere with your naïve intuitions (and what we are interested in here, at the moment, is finding out what our pre-theoretical concepts involve). But in any case, these stories do seem conceptually coherent to a wide range of people (to those who believe them and to skeptics about them alike). And (regardless of how things seem to you) that is *evidence* that it is not simply an analytic truth that immaterial things cannot be spatially located. Or, at least, it is evidence that if it is an analytic truth, it is not an obvious one (not like the claim that circles are round).

  18. I guess I jst don’t see the force of the fact that people can imagine things without realising that they’re actually impossible.

    Right now I’m looking at a mental image of a married bachelor, but the fact that I can imagine a being and ascribe this description to him just shows that I don’t really understand what I think I’m imagining.

  19. Kenny

    Glenn, I agree that people can imagine (in some broad sense anyway) things that are impossible. That’s not the issue. I’d be the first to concede that concievability isn’t a great guide to metaphysical possibility. I also don’t think that every necessary truth (not even every necessary truth that we know to be necessary) is an analytic one.

    The point is simply that there does not seem to be any *conceptual* confusion involved in maintaining that the senarios I described are possible. It may be that they are impossible, but if so, it doesn’t look like it is an analytic truth that they are.

  20. Kenny, I no longer know what you mean by “conceptual confusion.”

    The way I use that phrase, there is conceptual confusion. Imagine if I said “right now I am imagining a married bachelor, and there is no conceptual confusion going on.” The way I use that phrase, I would simply be wrong, for what I saw could not – as a matter of definition – really be a married bachelor.

    Similarly, when a person says “I am imagining a three dimensional ghost who is size feet tall and who is not physical,” there certainly is – as I use that term – conceptual confusion going on.

  21. Kenny

    I agree about the bachelor case. But suppose someone said that she believes that it is possible for there to be material objects that are conscious. I believe she believes something necessarily false, and believes something that human beings have the capacity to see is necessarily false. But I don’t believe that she doesn’t fully grasp the concepts involved for that reason. Or, to take a materialist friendly example, I believe that I can exist apart from my body. You believe that what I believe is necessarily false. But I don’t think you would say that I simply fail to grasp the concepts involved (if you do, that would be a pretty implausible thing to think, it seems to me).

    I’m open to an argument that it is a necessary truth that immaterial things can’t be spatially located. But it certainly doesn’t seem like an analytic truth to me that they can’t be. I suppose you might just say that you can just “see” that it is impossible directly, in the same way that I think I can just see directly that it is impossible that something material is conscious. If so, fair enough. I lack the relevant modal intuition. Impasse. (P.S. I am more confident about the claim that souls can be spatially located that I am that they can have non-zero extension; I think that souls are simples, so I think that whether it is possible for them to have non-zero extension turns on the question of whether it is possible for there to be extended simples).

  22. Well I do think that those who imagine 3D non physical objects have failed to grasp the concepts they are referring to.

    I think it is exactly like the married bachelor case. 🙂

  23. Kenny

    Well, I say that’s nuts. So there! 🙂

  24. Nick

    Will the series on the origin of the soul be helpful to listen to? I have been listening to some philosophy lectures on philosophy of mind. As I have been thinking through this issue there are some real problems for dualism. Some of the examples are mentioned in your blog posts. I am wondering what is the best way to approach this subject. It would appear that people are more physical than Christians would accept. There are many things that show we are very much affected by our brain. Injuries or disease for example can cause a huge transformation of the person to where we would think the real essence of the person is damaged. Their consciousness is still active, but seems unable to influence functions. How are we to evaluate this? The brain is malfunctioning without an independent overarching control centre as it were. I could be naive, but an argument like that of ‘God and other minds’ by Plantinga may loose some force because if we are only minds and consciousness are physical (meat machines) why accept the conclusion of the argument. If the only minds we know are connected to physical objects why accept an immaterial God. I want to start coming to some conclusions that are reliable about this. From an apologetic framework talking about ‘minds from non-minds’ poses problems if tries to use it.

    I guess you are also aware of theories in Psychology about delusional ideas. As Christians are we faced with a choice where a proper functioning mind is the one that produces true beliefs and is not delusional ideas? Dualists I think would play the immaterial soul trump card to make a distinction between the ‘quality’ of knowledge that the mind produces as far as I can see. Then one has to ask how does this occur? I am not sold on either, it leads more questions like what becomes born again and how is ti that I can turn my behaviour around and do so by God’s grace where as before I really knew I did not have power to do so. So, did my brain change (obviously not entirely) or something else. Any initial thoughts or directions about how to look at this?

  25. “Will the series on the origin of the soul be helpful to listen to?”

    Why of course! 🙂 The upcoming episode on pysicalism, sin and salvation may be of interest to you as well.

    To be honest, I haven’t read God and Other Minds, in spite of how good I hear it is. And if we lose an argument for theism that depends on dualism (I do not know if his argument does), I’m not bothered. There are, after all, good arguments for theism. 🙂

  26. Nick

    I will do that. I do think Plantgina’s argument is a good one. Basically as I understand it, one is faced with conceding that other minds including a immaterial mind such as God can exist or you have to reject that there are other people. This later option would be absurd. Minds and person-hood go together.
    My problem at present is that God can be a immaterial mind. However it appears from neurological experiments people are very physical in nature and their very person can be affected by manipulating the brain. They can even change in major ways that they seem like a different person altogether behaviourally.
    Perhaps my understanding of what is a mind is at fault. Anyway thanks for your reply. I will keep an eye out for the episode.

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