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

Poisoning the well, dualist style


Is Christian physicalism really the child of naturalism that gives essentialism the heave-ho?

I really wish that evangelical institutions would pick the right fights to get into. A couple of days ago I got an email advertisement from that great bastion of substance dualism (or more importantly, that good and faithful opponent of Christian physicalism) in the modern Evangelical world, Biola University. The advertisement reads as follows:


October 4-5


La Mirada (Los Angeles), CA


With R. Scott Smith, Ph.D.

Brand new class! Naturalism is perhaps the dominant philosophical position not only in contemporary academia, but even in our daily lives. It is the taproot from which a number of problematic philosophies all derive their vitality, such as postmodernism, nominalism, and even Christian physicalism. These all have a common thread –they have no real place for essential natures. If you really want to be on the leading edge of apologetic work, this is a seminar you cannot miss.

Two claims in this advertisement stood out to me right away: Firstly that “naturalism” is the taproot from which a number of views, including Christian physicalism, derive their vitality, and that all of the views listed here, including Christian physicalism, has no place for essential natures. Both of these claims are false.

Naturalism and Christian physicalism

What is naturalism? Naturalism is just the view that nature is everything that exists. There is nothing at all in reality apart from the physical world of matter and energy. There is no God or anything relevantly similar to God, there are no angels or demons or anything of that nature, and there are no entities that cannot be accounted for by reference to natural properties of one kind or another (Plato’s form’s or abstract objects, for example, are not natural entities and therefore do not exist if naturalism is true).

Christian physicalism is the view that Christianity is true (summed up in, for example, the Nicene Creed) and human beings are physical beings.

What about Christian physicalism? Christian physicalism is the view that Christianity is true (summed up in, for example, the Nicene Creed) and human beings are physical beings. It denies substance dualism about human beings. That is, Christian physicalism says that there isn’t an extra substance added to the body to create the human mind or soul, but rather the human mind is something produced by or dependent on the body in some way (although virtually all Christian physicalists would deny that the mind is identical with the brain). It’s crucial to understand – but is also very well understood – that Christian physicalism is a claim about human beings (and presumably all other creatures in the space-time universe that we know of, like horses, rabbits and fleas, too). It would be a mistake to think that Christian physicalism implies, for example, that no “spiritual” entities exist (in the sense of entities that are not physical), for this would clearly imply that God does not exist, which is incompatible with any Christian point of view.

The claim made in this advertisement is that naturalism “is the taproot” from which Christian physicalism (among other views) “derive[s] [its] vitality.” This assertion is sufficiently vague that the author can probably get away with saying that strictly speaking, they did not assert that Christian physicalism is a subset of naturalism. It’s not crystal clear what it means for one view to “derive vitality” from another. That is part of what’s bad about the kind of rhetorical technique that the author is using, because no specific claim really needs to be made in order for prejudice to be aroused and innuendo to be made. The innuendo is that Christian physicalism is somehow the result of naturalism – the belief that God doesn’t exist and the physical world is all that exists. Almost unbelievably, in some of the popular literature that makes defensive strikes against Christian physicalism from an evangelical perspective, all physicalist views are simply lumped in together and named “naturalism.”1

The suggestion that Christian physicalism is somehow the child of naturalism – in addition to being rather naughty for its sneakiness when presented to a student audience (a clear-cut case of poisoning the well), with full knowledge of the impression one is creating, does not stand up to serious scrutiny. In what sense, exactly, is Christian physicalism supposed to depend on or derive support from naturalism?

Is the idea that if a person adopts naturalism then they are more likely than they would otherwise be to adopt Christian physicalism? This is surely untrue, because naturalism entails that Christianity is false, while Christian physicalism takes Christianity as its starting point.

Perhaps then the claim is meant to be that historically, Christian physicalism would not have existed were it not for the phenomenon of naturalism. It is very hard to see how this claim could be defended. Historic proponents of “Christian mortalism” can hardly be accused of depending on the rise of naturalism in academia or popular culture. Whether you regard those figures as heretics or not, as an historical claim about what conditions would need to exist in order for Christians to adopt a physicalist view of human persons, this one is not especially plausible.

I know that in my own case, I first came to adopt a physicalist view of human persons on the basis of biblical teaching (hardly a source of inspiration for naturalism).

Perhaps the claim is that if a Christian adopts a physicalist view of human beings, it must be because they are either sympathetic to naturalism or somehow influenced by naturalism. In this case the claim is a biographical claim about those who adopt Christian physicalism. I do not know how this claim would be defended, nor am I aware of any attempts to defend it. Speaking anecdotally for myself and the evangelicals I know or have read who hold to Christian physicalism, the claim appears to be false. I know that in my own case, I first came to adopt a physicalist view of human persons on the basis of biblical teaching (hardly a source of inspiration for naturalism). The author of this advertisement might think that my understanding of the biblical teaching is lacking, but it would be incredibly unfair to say that this amounts to sympathy on my part for naturalism! Of all of the literature that Evangelical Christians have written in support of physicalism (the sort of literature that prompts other evangelicals to write books and run conferences construing apologetics as, among other things, defending dualistic portraits of human beings as an integral element of our faith), a common theme that runs throughout is that dualistic views of human nature owe more to the absorption of ideas from non-Christian culture (especially Greek philosophy) than to proper sources of Christian theology such as Scripture. The argument they make – successfully in my view – is that a biblical worldview happily incorporates, even supports, a physicalist view of human beings.

Is it possible that a Christian who just wants to look more respectable in the eyes of her unbelieving counterparts might promote a physicalist view of human beings to avoid embarrassment? Yes, of course. A Christian might also declare belief in big bang cosmology or evolution for the same reason. But it would never be acceptable to stack the deck against those beliefs by suggesting that they “derive their vitality from naturalism.” It’s equally true that many, many Christians hold to dualism not because they can think of any good arguments for it, but just because they know that it’s what most Christians believe. Ordinarily this is a silly reason to believe things, but of course it would be unfair to imply that popularity is the taproot from whence dualism derives its vitality.

The fact is, naturalism would not give “vitality,” which I take to be something like initial plausibility, to Christian physicalism. If naturalism were true, the universe would not exist, or if it did, it would be unlikely to be a life-supporting place, or if it was, certainly the resurrection of Jesus or the existence of moral facts would not be even remotely probable (so say I). The suggestion of any sort of link between naturalism and Christian physicalism is, in my view, to sink to the rhetorical lowest common denominator that Evangelical polemics, regrettably, appeals to all too often.

Christian physicalism and essentialism

What about the second claim – that Christian physicalism has no place for essential natures? We already know what Christian physicalism is, but what about “essential natures”? That’s a big subject, but in brief this assessment is entirely false.

An essential nature or “essence” is a philosophical concept conveying the idea of what it is to be an X. In classical philosophy (from whence the idea of an essential nature comes to us), there are two dominant views of what it is to have an essential nature. In Plato’s view, to have the nature of being an X is to resemble the form of an X. Forms are universals that exist in the world of forms or ideas. They are immaterial entities that represent the ideal X. What all men have in common, and what makes them men rather than something else, is the fact that they resemble the form of a man. If naturalism is true, then essential natures of this kind obviously do not exist.

The other major option in essential natures is that of Aristotle. In Aristotle’s view forms still existed, but they were not free-standing universal entities that somehow exist out there independently of other objects. In order to save a bit of time and effort, I’ll quote myself from the podcast episode In Search of the Soul Revisited:

So what exactly was a form in Aristotle’s view? Maybe the easiest way of explaining this is to explain the way in which forms work together with other things. Imagine some matter. Just physical stuff, quite undifferentiated from other stuff, not organised into any particular object, just the raw material for making objects. It isn’t any thing, but clearly it’s not nothing. It’s that from which anything could, in theory, be made. To use the traditional language when discussing Aristotle, this stuff is what’s called prime matter. Now take a completed object – a rubber ball, a tree, or even a human being. … How do you get from prime matter to the finished product of a human being? The answer is this: You add a form.

To the ears of a platonic dualist, saying that we “add” something might sound like the addition of an extra substance. Such dualists might think that this is how the physical life of a human being comes about – you take some matter, shape it into a body with all the right parts, and you add to this an immaterial conscious soul. This is how they might read Genesis 2:7, when God formed man and then breathed into him the breath of life. Now, I think that’s a laughably poor understanding of the Hebrew Scriptures, but that’s another matter – I covered that back in episode 33, the last installment of the In Search of the Soul series where I looked at the biblical material, so I won’t go off on that tangent now. The point here is that is not the kind of thing that Aristotle thought of when he talked about adding a form to matter.

Prime matter can, in theory, be used to make anything, but when you combine it with a form, you have made it into something. The form is the organising principle. Take a rubber ball. What is its form? It’s as simple as it sounds: It is a ball. You could say that its form is ball-ness. It is the set of attributes that makes it a ball. The form is what differentiates the matter from other things. The prime matter has been morphed into something. In fact the Greek word for form that Aristotle uses is morphe, and to morph from one thing into another is quite literally to take another form. Matter in this everyday sense, that is, the stuff that exists in objects like balls, apples and trees, is secondary matter. It is matter that has a form. In fact it’s helpful to think of the way the words prime or primary and secondary are used by comparing them to their use in economics. The primary industries take raw ingredients from the earth: Wood, coal, fish etc. The secondary industries take those raw ingredients and manufacture products with them. So it is with prime and secondary matter. Prime matter is formless stuff. Secondary matter is stuff as part of an object.

The Greek word for matter is hule or hyle, and the Greek word for form is morphe. If you put prime matter and a form together, you get a substance, a hylemorph. Balls, dogs, trees, apples and human beings, therefore, are substances (more precisely, they are called primary substances). The type of substance that matter composes will depend on the form that it takes. The matter of a tree becomes a tree because it has the form of a tree. But the form is more than just shape, size, colour and so on. It’s deeper than that. To see how, consider Aristotle’s comment in the Physics, where he says that the form “is the end [telos], and since all the rest is for the sake of the end, the form must be the cause in the sense of “that for the sake of which.” What Aristotle was getting at the is that the form directs the substance towards its proper end or goal. The form – if we know what it is – tells us what something is for. It’s more than just the blueprint, in a sense it is the operating manual as well.

So how are things categorised? They are categorised according what they are for – what their proper end is, and this is bound up with their form. That is what their essence is. “Thus,” said Aristotle, “the essence of a house is assigned in such a formula as ‘a shelter against destruction by wind, rain, and heat’; the physicist would describe it as ‘stones, bricks, and timbers.’” So while a particular house might be made of stone, bricks and timbers, if it doesn’t serve as a good shelter, then it’s not a very good house. This is one reason why many, including me – don’t think you can be an Aristotelian philosopher if you’re an atheist. Because if you’re an atheist, you don’t think that human beings are really for anything. We aren’t here to meet some goal that is inherent to our humanity, because that goal, thinking in Aristotelian terms, is a proper end that we are here to fulfill. it’s certainly not one that we can make up ourselves. As a Christian theist I can ask, “what is the chief end of man,” to which the Westminster Catechism gives the answer, “the chief end of man is to glorify God and to enjoy him forever.”

So again – the form is the collection of properties, crucially including the purpose, that can be applied to matter to make a finished object, a substance. In saying all of this I admit to simplifying the language here by not introducing all of the terminology that is used in Classical Philosophy (that is, ancient Greek or Roman philosophy). The form is also called the substantial form, since it is the form of a certain substance. In Plato, this isn’t the case, because the form isn’t found in any material substance (heaven forbid), it is in the world of forms, determining categories of objects by the extent to which those objects resemble the form, but in Aristotle, forms of things just are substantial forms, and substances belong in a certain category of things depending on what form that substance has.

This is a brief description of Aristotelian essentialism – the idea that there can be an essential human nature or what it is to be a human being without introducing any non-material substances. Is this view compatible with naturalism? I don’t think so, as indicated above, so the advertisement is partly right. Naturalism leaves no room for essential natures. But to claim that all of the views listed (including Christian physicalism) leave no room for essential natures is simply not true. It is true that some thinkers who adopted an Aristotelian view of natures (e.g. Thomas Aquinas) were also substance dualists (Aquinas maintained that the conscious mind survives the death of the body in an immaterial form), but that is a separate, historical question. The point is that Christian physicalism quite obviously does have a place for essential natures.

It wouldn’t necessarily be the end of the world if Christian physicalism did not have a place for essential natures (or maybe it would – that is a different conversation to be had). But anyone who is worried about the prospect of giving up essential natures certainly need not fear Christian physicalism on that account. There is also (and certainly) no grounds for being worried about Christian physicalism because it owes some sort of philosophical debt to naturalism of all things. This is an unfortunate case of poisoning the well and dialing up the rhetorical heat. A Christian physicalist can go on her way without giving naturalism so much as a glance, and she can quite happily believe in essential natures with no internal conflict.

Glenn Peoples

  1. One example is the book edited by Mark C. Baker and Stewart Goetz, The Soul Hypothesis: Investigations into the Existence of the Soul (New York: Continuum, 2011). []


On Reform – short thoughts


Coming to Texas in July 2014


  1. Kenneth

    Interesting observation, Glenn. It’s especially ironic that Bill Craig, Biola’s leading scholar, is a sworn nominalist. This advertisement is a bit embarrassing, surely!

    And yes, I’ve noticed a somewhat slippery tendency to shift the boundaries on things like naturalism (and materialism / physicalism for that matter) depending on what someone is defending. You don’t really see it in the more mainstream literature, but when it comes from certain evangelicals – and especially from certain voices at Biola – it’s rife. They’re trying to change the linguistic landscape. He who controls the language determines the outcome of the argument!

  2. AMC

    If you don’t mind a second query, also :-)…

    You say “so again – the form is the collection of properties, crucially including the purpose, that can be applied to matter to make a finished object, a substance.” Is there anything about humans that (which on your view are wholly physical entities), in terms of their physical makeup, implicates Christian Physicalism over against naturalism?

  3. Hi AMC – I’m not sure what you mean by “implicates.”

  4. AMC


    I mean confirms. Is there anything about the physical makeup of humans that would confirm Christian Physicalism is true over against the view that naturalism is true? Is there anything that, from a physical examination, would imply a form has been applied (including purpose) as opposed to the human body being wholly explicable on naturalistic terms?

  5. Ah, OK – so it’s about whether or not the physical evidence provided by the human body points one way or the other: Christian physicalism or naturalism.

    The answer to this question is to say that what we find in the human body and the sciences related to it are supportive of physicalism (although they do not show that it is true), but that evidence says nothing at all about naturalism. The evidence is supportive of physicalism about human beings because it conforms to what we would expect to find if physicalism were correct (i.e. the close relationship between mind states and brain states, the effect of the material on the mental). In order for this to be Christian physicalism, we would also need evidence for Christianity, and I think we do. Naturalism and Christian physicalism are not alternative claims about the nature of human persons. Naturalism is an overall metaphysical outlook on everything: Humans, the universe and everything that exists. No amount of evidence about what the human body is like could supply credible evidence for naturalism, no matter what our findings are. Within naturalism there are numerous views of the human person (generally all materialist in regard to substances, like emergentism, property dualism, nonreductive physicalism and other things besides, no doubt), but supporting evidence for those views on human beings is not supporting evidence for naturalism.

  6. Oh by the way, I should have added: Christian physicalism does not require that we be Aristotelians, believing in a traditional metaphysical scheme of matter and forms. It only requires that we be Christians and that we have a physicalist view of human beings.

    As for whether or not a physical examination can show that this scheme is correct or likely, no I wouldn’t think so. Perhaps some Aristotelians can offer their thoughts.

  7. JJ


    I enjoy your blog and podcast…keep it up! So if I may ask – why don’t you come out of the theological closet, as it were, and just admit thay you are (or were raised) a Seventh Day Adventist? You could skip most of the philisophical reasoning and just point to the book of Eccesiates…lol. But in all seriousness, if one is a Christian physicalist because of ” the close relationship between mind states and brain states,” then how does the physicalist explain the affect of the Holy Spirit on the mind. The Spirit gives: “remembrance” (John 14:26), “utterance” (Acts 2:4 ), “revealation” (1Cor. 2:10 ), “spiritual gifts” (1Cor.12:11), and “strength and power in the inner being” (Eph.3:16 ) – all of which appear to interact with the mind. If the Christian physicalist accepts that the Holy Spirit “dwells” within him and affects his mind, how is this in principle different from body-soul dualism?

  8. It’s “effect,” not “affect.” 🙂

    JJ, The reason that I adopted a materialist view of human beings was not of “the close relationship between mind states and brain states,” but firstly because I became convinced that it was a more biblical position than substance dualism.

    But actually the issue of the influence of the Holy Spirit woudn’t be a problem even if I had become a materialist about human beings simply because of the relationship between brain states and mind states. All I would need to say is that the Holy Spirit brings about a brain state, which in turn brings about a mind state.

    It’s not mind-body dualism to think that an immaterial God can have an effect on the human mind. This just seems to be an implication of omnipotence.

  9. JJ

    It’s also “Ecclesiastes” not “Eccesiates,” but such are my writing skills at the moment. 😉

    I suppose my point was that one doesn’t appear to fully escape substance dualism even as a Christian physicalist, which is why I don’t agree that “dualistic views of human nature owe more to the absorption of ideas from non-Christian culture.” I see dualism throughout Scripture.

    And to extend what you said, whatever work the Spirit can do on a brain state for the physicalist is presumably the same work the immaterial soul is capable of doing on a brain state for the dualist.

    “It’s not mind-body dualism to think that an immaterial God can have an effect on the human mind. This just seems to be an implication of omnipotence.”

    Perhaps, but we have clear dualistic examples when omnipotence isn’t involved, such as demonic possession (ex. “Then Satan entered into Judas,” Luke 22:3), which suggests that omnipotence may not be the explanation.

  10. “one doesn’t appear to fully escape substance dualism even as a Christian physicalist”
    That’s true as far as overall metaphysical outlooks go. God isn’t physical, so sure, there are non physical things. But the ability of an immaterial and all powerful God to influence a physical human being doesn’t count against a physicalist view of human nature.

    This is why I didn’t say that belief in non-physical things owes more to surrounding pagan culture than to Christian theology. I said that “dualistic views of human nature owe more to the absorption of ideas from non-Christian culture.”

    And to extend what you said, whatever work the Spirit can do on a brain state for the physicalist is presumably the same work the immaterial soul is capable of doing on a brain state for the dualist.

    If there is an immaterial soul then sure, perhaps it could work on a brain. I didn’t deny this. But the fact that an all-powerful, non material God can act on the brain is no reason to suppose that there is such a soul. God can do anything.

    You now talk about examples where non-omnipotent beings or forces are at work, e.g. Satan entering into Judas. Fair enough – if the Holy Spirit is omnipotent then of course it can influence brains. But you’re right, that doesn’t mean that omnipotence is required in order to influence brains. Even human beings can influence each other’s brains.

    But I’m not sure what the point is. For one I’m not sure what it means that Satan entered Judas. However, even if it means that the person who is the devil possessed Judas, it’s hard to see how this would show that human beings have souls that are immaterial substances. My mind can be influenced by physical things too, like drugs. Does that show that my mind is a physical substance? If it doesn’t, it’s not clear to me why the fact that an immaterial thing could influence my mind shows that my mind is a non-physical substance. It just doesn’t seem to follow.

  11. JJ

    Just as you don’t see Christian physicalism deriving from naturalism, I don’t see a Christian dualistic view of human nature deriving from paganism. The basic principle of the immaterial interacting with the material mind is a thoroughly Biblical concept, and beyond that, it seems to me that both physicalism and dualism can simply be a result of one’s hermeneutics.

    “My mind can be influenced by physical things too, like drugs. Does that show that my mind is a physical substance? If it doesn’t, it’s not clear to me why the fact that an immaterial thing could influence my mind shows that my mind is a non-physical substance. It just doesn’t seem to follow.”

    So without dragging the specific conversation out too long, does this then suggest that the same evidence supportive of physicalism would also support dualism?

  12. Oh, don’t get me wrong. To say that those who are dualists hold beliefs that were derived from paganism, JJ is a very strong claim. I have never said that. Unfortunately, the author of this email from Biola suggested that non-dualists hold views that derive their vitality from naturalism, which is a shame. All I would say is that dualism owes more to the pagan environment into which Christianity was born than to biblical teaching. Influence happens, like it or not. But deriving beliefs from pagan worldviews is another matter. I think the influence was more accidental. I have spent time elsewhere arguing that dualism really isn’t as biblical as some people think.

    In regard to your last question, no I wouldn’t think so. There’s evidence that is compatible with physicalism that is also compatible with dualism, I suppose, in which case it does not support either. But if evidence supports one, then it works against the other.

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