Michael Egnor tries to solve the dualist problem of interaction


Yep, noticed the same problem with Egnor’s analogy right away. He’s not “solving” the interaction problem, he’s just declaring that the mind is some sort of form in the same way a physical structure’s shape is a “form” of it’s matter. But the problem is exactly that we can see and immediately understand how the matter, as atoms and molecules distributed in space, gives rise to it’s “form”. And this is what we are not having explained by Egnor with respect to mind, if that mind is supposed to be immaterial and distinct from the matter.

Oddly enough, Egnor seems to be implying that the material explains the mind, which means mind must be material. I don’t think that’s where he wanted to go.


If Egnor really means to imply that mind is an attribute, or “form” of matter, in the same way chirality is of molecules, then it would follow that altering the physical attributes of the matter would alter the mind, and if you destroy the matter you destroy the mind. No immaterial soul, no afterlife, your mind’s properties and your behvior are determined by the spatiotemporal interactions between the constituents of matter.

Egnor has literally argued himself into materialism, and he doesn’t seem to be aware of it. How’s that for irony?


It’s extraordinary that people still struggle with this. For people who don’t believe in an immortal soul, it’s all very simple. The mind is an emergent property of the brain. Nothing spooky about it.

1 Like

Even if there is nothing spooky, that seems to side step all the interesting questions about the mind.

I agree with this. There are many, many unanswered questions about how the mind and brain works. But just as we do not get any answers merely by stipulating that the brain generates the mind, neither do we get any by stipulating that it doesn’t.

1 Like

I don’t think it sidesteps them at all, it just provides a more useful basis for answering them.

No, we don’t get answers, but we do have a useful basis for seeking answers. We know this from decades of successful neuro-pharmacology and neuro-psychology. Consequently I am a strong supporter of the view that the mind is an emergent property of the brain.

In contrast, we do not get the same results by starting with “The mind is a property of the immortal soul”. I don’t think that basis gets us any useful results at all.


This is a good attempt to engage Egnor. I’m not an expert on the mind-body problem nor how hylomorphism interacts with it. Nor am I sure that Egnor fully understands hylomorphism either. That being said, I will still respond to your post based on my limited knowledge of A-T philosophy, which is likely where Egnor is coming from.

Aristotle considered the matter of a human being to be the body, and its form to be the soul. But, at the same time, he held that a body that has lost its soul (i.e. after death) is no longer a body, i.e. that the soul is an essential aspect of a body, and without it the body ceases to be. Therefore, there seems to be an inconsistency in Aristotle’s treatment of matter and form as distinct aspects of a substance which are related only contingently to one another.

Hylomorphists hold that the matter of the body to undergo a substantial change when the human dies. While the matter remains, its organizing principle (form) changes from “soul” to “accidental arrangement of dead organs/cells which resemble a living human body”, i.e. a corpse. I don’t see the inconsistency you’re referring to here. Can you clarify further?

A further problem: Egnor appears to equate matter with the “material”, and form with the “immaterial.” He views the “spirit”, by virtue of its providing the form of the mind, as immaterial, with the material brain providing the mind’s matter. However, the brain is, itself, composed of more basic physical constituents. So would it not be correct to consider the physical structure of the brain to be its form, and the cells and other tissue that make it up to be its matter? I cannot see why not. But, if that is the case and Egnor is correct in equating form with the “immaterial”, then we have the odd situation in which the brain is both material (with regard to the “spirit”) and immaterial (with regard to the cells that make it up). That does not make any sense, and suggests that Egnor is incorrect in his equation of form with the immaterial.

I’m not sure what you mean by “physical structure” here. I think you and @Rumraket misunderstand Aristotelian form to be literally the shape (or physical arrangement) of matter. But this is not quite right. (And I think Egnor is misleading in using chirality as an example of form, which seems inaccurate or a bad analogy.) Form is not just a list of spatial coordinates which say that “cell A is here, cell B is there, etc.”. Rather, form is the organizing principle of matter. The word principle is important, since principle implies something abstract or immaterial. An Aristotelian would say that the matter (cells, tissue) that makes up the brain is only held together and functions as a brain because of the form of the brain, which is “immaterial”, in the sense that you cannot point to a piece of matter that is identical with the form of the brain.

Now by investigating the bonds between cells and tissue and their spatial arrangement (which is what I take to be the conventional meaning of “physical structure”), one can investigate how the form of the brain works to hold the brain together. But it is the form that “breathes fire into the equations”, so to speak. @Eddie, @jongarvey, @AnonymousThomas or other people more experienced in Thomism can correct me if I’m wrong.

As it happens, at least one contemporary philosopher, William Jaworski, appeals to hylomorphism as a possible solution to the hard problem of consciousness, and draws an analogy between those who would insist otherwise and adherents of the discredited concept of vitalism: writing: “(T)he hard problem of consciousness does not arise within a hylomorphic framework. It arises only for a view of the natural world that rejects hylomorphic structure. If conscious experiences are structured activities, as hylomorphism claims, then they can be exhaustively accounted for by describing the powers of conscious beings, the subsystems in which those powers are embodied, and the kind of coordination or structure that unifies the activities of those subsystems into conscious events. To insist that such a description fails to capture phenomenal character is analogous to an obstinate vitalist claiming that a physical description must fail to explain life because it fails to accommodate vital spirit. “2 I am not endorsing Jaworski’s viewpoint nor claiming that he has succeeded in solving the “hard problem.” I am merely pointing out that, at the very least, it would appear that hylomorphism is a double-edged sword that can be used to argue against dualism, and that by merely invoking the concept Egnor has not demonstrated that dualism is a viable position.

I completely don’t understand your point here. So Jaworksi argues that within hylomorphism, there is no hard problem and substance dualism is superfluous just like vitalism is. If Jaworksi is right, how is that a point against Egnor, given that he rejects substance dualism and endorses hylomorphism, which is a completely different sort of dualism?


This is my biggest problem with dualist models, is that its proponents do not even have a way of invesigating its claims. Even in attempting to discuss or conceptualize the "immaterial’ we are forced to do so in terms of familiar, physical terms. So we imagine “souls” or “spirits” possessing conciousness and will as we experience as embodied subjects, and having effects on the world in the same manner as physical acts and forces do. If the immaterial exists, it likely is so removed from our experience that to even speak of it is at best extremely difficult, if even possible.


The inconsistency I see is in his position that the body is the matter to the form of the soul when we are alive, but when dead the body does not remain as matter which is now organized according to the form of “corpse”, but instead ceases to exist altogether.

Yes, and it is not hylomorphism per se that I am criticizing (I wouldn’t even know where to start), but Egnor’s use of the concept. Conceiving of form as an organizing principle does not answer the question that Egnor purports to answer, which is “How does the immaterial interact with the material?”

For instance, if I hold the form of a bicycle in my mind, in the sense of an organizing principle regarding what a bicycle is intended to do and how physical objects can be arranged to achieve this purpose, that does not bring a bicycle into existence.

An emergentist could view this form as the product of the same brain that controls the physical movements of our body that construct the bicycle and brings it into being. That still leaves the “hard problem” unsolved, ie, how do the chemical processes occurring in our brain lead to the subjective experience of understanding a design for a bicycle?

But Egnor, if I understand him correctly, is suggesting that the form of the bicycle exists immaterially and this somehow interacts with our brain to allow us to have the subjective experience of it as an idea, and then to build a bicycle. He still has not explained how this would happen. The problem of interaction remains.

I admit I may be reading more into what Egnor intended here, but my point is simply that if one accepts hylomorphism, this still does not entail that substance dualism is true. So if Egnor wishes to argue that, he needs to do more than persuade us to accept hylomorphism. Admittedly, that does not mean that hylomorphism does not provide a model that makes substance dualism coherent and resolves some of its more intractable problems. But, as I hope I have demonstrated, Egnor does not succeed with that, either.


Agreed. The mind as a product of physical processes in the brain helps make sense of a huge number of observations that relate to the fact that physical and chemical changes to the brain affects behavior, cognitive performance, and even conscious experience.


I don’t see a contradiction there. When the human body dies, it loses its form (organizing principle), becoming a hunk of matter with a different form (called a corpse) which immediately starts decaying. For Aristotle, to cease to exist doesn’t mean the matter goes “poof” and disappears into thin air. The matter keeps existing, but the form is different, so there is a new substance (ousia) that appears. (Note again, substance is a technical Aristotelian term referring to form + matter.)

Yes, that’s correct. But Aristotle held that form doesn’t only exist in the minds of observers. They are not just an abstraction that your mind invents in order to process sense data. Instead, forms have objective, observer-independent existence; they inhere in the things themselves. How forms affect matter to give rise to a substance is called formal causation, which is different from efficient causation, which is the more commonly known sort of causation that happens when say, one billiard ball pushes another billiard ball.

The interaction problem arises in substance dualism because it is trying to figure out how an immaterial substance (the soul) can interact with a material substance (the body) via efficient causation - a sort of “ghost in the machine”. In hylomorphism, there is only one substance: the living human body (hence we don’t call it substance dualism), which exists because the soul formally causes the matter to function as a living organism. Here, the soul is not a separate ghost in the machine but an inseparable part of the “machine” itself.

(You can think of the soul/form as organizing the bits of matter together into one coherent, unified thing. But even this might be misunderstood by a modern reader because for Aristotle, every piece of matter you encounter has some form - even lifeless grains of sand on the beach are each matter + form composites. Form is not just a concept that Aristotle invented up for the case of the soul. It pervades his entire metaphysics and is fundamental to how he conceives the way the world works.)

Of course! If hylomorphism is true, then substance dualism is false.

He does not wish to argue that substance dualism is true. He literally says:

From the modern materialist perspective, this question has no obvious answer. The materialist discards Cartesian dualism on that basis. I am not a Cartesian dualist and I believe that Cartesian dualism is on the whole an unsatisfactory metaphysical framework but it is a stronger framework that materialists claim.

Of course it doesn’t! Hylomorphism is not a subset of substance dualism. Neither is it the same as materialism. It’s an entirely different philosophical framework. The Aristotelian notion of the soul is different from the Cartesian, substance dualist notion.


That seems to me to be essentially materialism. What you’re describing are the laws of physics. There are the materials and how they act according to the laws of physics.


It depends on what you understand the laws of physics to be. What causes the laws of physics to be true - what makes things behave according to the laws? An Aristotelian would say that the laws of nature arise from the intrinsic causal powers of things. A Cartesian would say that the laws exist in the mind of God, who directly moves every particle in the universe. Clearly this is not an option for the materialist, although today we still feel the aftereffects of the Cartesian view. I’m not sure what you believe as a naturalist materialist.

(A helpful past discussion on this is What are Laws of Nature?, started in response to a lecture by Feser on the different philosophical frameworks to understand a law of nature.)

That being said, Aristotelianism is very different from most conceptions of modern materialism. Firstly, form is not merely an abstraction in the mind, but inheres in the things themselves. Each thing has its own principle which is spatially localized to where the thing is. (Forms don’t exist in some abstract Platonic space.) Secondly, the top-down, holistic character of hylemorphism distinguishes it from the bottom-up, reductionist modern philosophy which is more commonly assumed among modern materialists.

1 Like

That’s the part that is unclear. Some scholars seem to read him as saying that body, which is the matter of a human, ceases to exist on death (i.e. after the body has lost the form of the soul). As you say, it should be that the matter persists thru the change, and in this case “matter” is the “body.”

Now, that could of course be a misreading. I’m just going by what other sources have said.

Yes. But does he understand “Cartesian dualism” to mean “substance dualism”? I am not sure that he does. For instance, he recently endorsed the video I discussed in another post:

Not only does the video explicitly argue for substance dualism, but at 50:10 the lecturer cites Michael Egnor (and only him) as a contemporary proponent of substance dualism. Now, I would find it very odd if Egnor failed to correct such an error when going to the trouble to post the video on his own blog post.

This is all consistent with my perception that Egnor is trying to use a non-dualist concept to support dualism. I don’t think we can presume he is well-versed in the details and nuances of the ideas he attempts to discuss. (Not that one should presume that about me, either!)


I’m not familiar with Egnor’s previously articulated views. You may be right that Egnor’s views are not fully coherent, or he is still not very decided on what to believe. He certainly doesn’t seem deeply acquainted with hylomorphism at this point, despite invoking it to defend substance dualism. I think Feser is a much better contemporary defender of the hylomorphic view of the soul. Here is him on the interaction problem specifically: Part I, Part II, Part III. I am very confident that hylomorphism is diametrically opposed to substance dualism, regardless of what Egnor thinks. If he wants to become a hylomorphist, he should stop thinking of the soul in Cartesian terms.

Substance dualism almost always refers to Cartesian dualism (see here for an example). Basically, it believes that the soul can exist on its own outside of a body, in contrast to Aristotle’s belief that the soul is always attached to something.

1 Like

I am fairly surprised, to be honest. I thought Catholics are dualists, but you are saying they aren’t. Are Thomists anti-dualist? Is there any version of Thomism that is dualist?

Thomists are not substance dualists, for sure. Hylomorphism is sometimes classed as a type of dualism (as Thomas does regard the human intellect as immaterial, and that the soul is immortal), but it’s normally considered its own thing. Hylomorphism is fundamental to Thomistic anthropology; I don’t think a substance dualist philosophy can be called Thomist at all.

Hylomorphism seems to be endorsed by the Catholic Church even today, see the Catechism of the Catholic Church, Part 1, Section 2, Chapter 1, Article 1, 365:

The unity of soul and body is so profound that one has to consider the soul to be the “form” of the body: i.e., it is because of its spiritual soul that the body made of matter becomes a living, human body; spirit and matter, in man, are not two natures united, but rather their union forms a single nature.

This cites the decision from the ecumenical Council of Vienne (1312), which gives an even stronger endorsement:

We, therefore, directing our apostolic attention, to which alone it belongs to define these things , to such splendid testimony and to the common opinion of the holy fathers and doctors, declare with the approval of the sacred council that the said apostle and evangelist, John, observed the right order of events in saying that when Christ was already dead one of the soldiers opened his side with a spear. Moreover, with the approval of the said council, we reject as erroneous and contrary to the truth of the catholic faith every doctrine or proposition rashly asserting that the substance of the rational or intellectual soul is not of itself and essentially the form of the human body, or casting doubt on this matter. In order that all may know the truth of the faith in its purity and all error may be excluded, we define that anyone who presumes henceforth to assert defend or hold stubbornly that the rational or intellectual soul is not the form of the human body of itself and essentially, is to be considered a heretic.


What do you mean by materialism?

One of the smartest things I heard from @Faizal_Ali was when he pointed out that as a physician, he did not know enough about the complexities of philosophy to know whether he was a materialist or not, even though he is an atheist. That seems to be on point.


I would add that, given the the continued lack of even a semblance of consensus on this issue among the experts, that no one has sufficient reason to commit to a position either way.

That said, this does not mean that @Rumraket cannot determine whether a particular claim entails the truth of materialism.