In this paper, I take Aquinas's metaphysics of human nature as my point of departure and take inspiration from Dante's concept of transhumanization to sketch a metaphysics of the afterlife according to which a human person in the interim phase between death and resurrection is not a disembodied soul. I begin by offering some theological reasons for thinking that our bodily human nature is essential to what we are and for thinking that we can survive the destruction of our bodies at death. Despite the apparent inconsistency of these claims, I argue that they are not inconsistent, provided we hold that our bodily human nature, while essential to what we are, is not necessary to what we are. I argue for this distinction between essence and necessity. I then raise a mereological puzzle about the relation between a disembodied soul and the person whose soul it is, and argue that, if we are to avoid the Cartesian conclusion that this relation is identity, we must hold that a human person, even in the interim phase, is composed of a soul and something else. Drawing on Dante's concept of transhumanization, I argue that this something else is God himself or some specially created divine grace or energy.

Descartes asks, What am I? And he answers: a thinking thing; an immaterial mental substance contingently related to a body.Footnote ¹ But Aquinas answers: a human being; a rational animal composed of matter and form, or body and soul.Footnote ² Whatever its philosophical merits, Cartesianism commends itself to religious philosophers interested in a philosophical account of the afterlife because it offers a straightforward way to understand an individual's persistence through death: let's just say that death is the separation of mind and body. You are your mind, not your body. Your mind is immaterial and simple and is therefore naturally incorruptible. So at your death you go on existing while your body commences its return to the elements. You are what you always were; you've just shuffled off your mortal thingummy, as Lord Peter Wimsey says.Footnote ³ Despite this elegance, however, Cartesianism fits awkwardly with a theologically rich characterization of human immortality: there is the earthy anthropology of the Scriptures of both Testaments to be reckoned with, and also Gregory of Nanzianzen's prolegomenal maxim for Christology: what was not assumed was not redeemed: human beings, not Cartesian minds, are the target of God's salvific work, so God the Son assumes the whole of human nature, body and soul.Footnote ⁴

Hylomorphism, by contrast, promises an account of human nature that makes our flesh and blood animality part of what we really are, part of our essence, while still offering resources for a philosophically satisfying account of immortality. Our bodies are not immortal, not in the present world order, anyway; but our souls are. So when you die a part of you, your soul, literally lives on, preserving your personal identity until all the dead are raised on the Last Day and you are united with a body once again to live out your redeemed human nature for all eternity.

But there's a problem. If you are essentially a human being, and if a human being is essentially a composite of body and soul, then you are essentially a composite of body and soul. Death is or involves the decomposition of body and soul. It seems to follow therefore that you can't survive your death. Your soul perhaps does survive your death, but what has that to do with you? You are essentially a human being, not a disembodied soul.

Well, so what? The Christian view about afterlife has it that we're all bound to be embodied at the end. Why not bite the bullet and grant that at your death you will indeed cease to exist, but since your soul will go on existing and will at some point be reunited with a body, you will eventually exist again and your soul will have provided just the right sort of link between your pre-mortem and resurrected self, the sort of link that will make it the case that that resurrected human being is you and not someone else.

Biting this bullet has two sorts of problems, one metaphysical and the other theological. Let's start with the theological. Most Christians throughout history and in the present day believe that the dearly departed are existing right now, and that we can even have a certain kind of interaction with at least some of them. How could it possibly make sense to ask the saints or would-be saints for intercession if they don't currently exist? It would be as charming and futile as writing a letter to Santa Claus. Additionally, it's a widespread belief among Christians that the dead receive judgment and suffer in hell or purgatory or delight in heaven, foretastes of the greater intensity of suffering and delight after the resurrection. How could it make sense to subject a disembodied soul to suffering or delight if it were not identical with or an essential part of the person who merited perdition or blessedness? And now the metaphysical: even granting that the soul is a very special sort of part, it's not at all clear why the continued existence of one part of a human being should make it the case that a human being at some future time with that one part as one of its own should be exactly the same human being as the original owner of that part.Footnote ⁵ We'd all deny that the persistence of just any part from anything suffices to make a new thing identical with an old thing just in case the new thing has that part: suppose I take apart my bicycle and use its handlebars as a component in a new bicycle. The new bike isn't therefore the same bike as the old. And if the survival of just any part sufficed, then the physicalist about human beings would have an equally good account of the numerical identity of our resurrected and present selves as the hylomorphist: the continued existence of any old physical part of a human being could play the needed role just as well as a soul. At this, however, intuitions reel: some particle that partially composed me at some time (the moment of my death? the moment of my conception? the present moment?) with some long cosmic career of composing lots and lots of things before and after it was a part of me, surely can't be the sort of thing that can guarantee the numerical identity of my resurrected self. Or if it can, then why am I not numerically identical with any human being, past or future, that has one of my particles as one of its? The temptation to lapse into Cartesianism looms: what makes the soul so special, what lets it suffice for the numerical identity of the original and resurrected human beings, is not that it was a part of you but that it is you. You're essentially a thinking thing after all; that stuff about theologically rich anthropology was just piety getting in the way of metaphysics. We can go on praying to saints because even if currently they are disembodied souls, they still exist because what they, and we, are essentially, are souls, not bodies or composites of bodies and souls.

So there are strong reasons to resist biting the bullet and conceding that you cease to exist at death but that you'll begin to exist again when your soul is reunited with a body. But this resistance leaves us with a tall order: theologically motivated hylomorphists need a way both to uphold their central anthropological doctrine—that things like you and I are essentially human beings—and to claim consistently that things like you and I continue to exist when we die (where death is understood to be the decomposition of soul and body and hence the ceasing to exist of a human being.)

Metaphysics in the tradition of Aristotle offers a useful distinction to put us on the way toward fulfilling the tall order. This tradition distinguishes between essence and necessity in ways that are somewhat foreign to contemporary analytic metaphysics (but less and less foreign in recent years). Aristotelians say that what is necessary (to, or for, x) is not for that reason essential (to, or for, x), and vice versa. To fulfill the tall order, then, I'd like to employ this distinction between essence and necessity to claim that being a human being, while essential to things like you and me, is not necessary to things like you and me. I am essentially a human being—for now. But I'm not necessarily a human being, and someday I won't be. Things like you and me, things that are essentially but are not necessarily human beings, I will from now on call human persons. The label may be misleading, since it includes the term human! But persons alone would also be misleading since persons come in divine and angelic varieties (and possibly others). Just let human person be a term of art for this paper. The term human being, then, will be used in the familiar way: a human being is a rational animal, a composite of body and soul. And human person will be reserved for the things that are essentially but are not necessarily human beings. Being a human being is not a necessary condition for being a human person: Jesus Christ was a human being but not a human person, for example, and perhaps some of the angelic appearances in the Old Testament were made by human beings who were angelic or divine persons. But even though divine and perhaps angelic persons can be human beings, they are not essentially human beings. In fact, according to the way I've fixed the labels only human persons are essentially human beings, in the sense that something is a human person if and only if it is essentially a human being.

So why think that being necessary and being essential are distinct in the way I have asserted that Aristotelians say they are? According to Aristotelians, essences are the sorts of things capable of real definition, where a real definition is some linguistic formula that says what a thing is, as opposed to how it is characterized. Among all the many things we can say about Socrates, for example, we can say both what he is (a human being) and how he is characterized (he's short, snub-nosed, curly-haired, wily, courageous, Athenian, and so on). Aristotelians call these various ways in which Socrates is characterized his accidents. While it's common to introduce the concept of accident by saying something along these lines: an accident is the sort of property a thing could gain or lose and still be the very thing that it is—this isn't quite right. Aristotelians recognize a class of necessary accidents, properties that are accidental to but do not belong to the essence of the subject which has them. The classic example is the property of being risible, which means having the ability to laugh. Aristotelians say that this property is caused by or is derivative from the conjunction of a human being's rationality and animality: rationality, because in order to laugh you've got to be able to find things funny, and only rational beings can do that; animality, because in order to laugh you've got to be able to produce certain kinds of motions and/or sounds, and only bodily beings can do that. The relationship between risibility and rational animality is such that given the latter it is necessary that there be the former. So risibility is a necessary property of a rational animal. But it's not an essential property, because it is both dependent on and wholly explained in terms of rational animality. Other necessary accidents fail to be essential properties for other reasons. Kit Fine argues that the property of being such that there are infinitely many prime numbers, while a necessary property of Socrates (and of everything else), is not an essential property of Socrates because it has nothing to do with Socrates; it doesn't tell us anything about what Socrates is. So some necessary properties are not essential properties.Footnote ⁶

It's a little harder to show that some essential properties are not necessary properties, but this is actually the claim most crucial to what follows—since I'm arguing that being a human being is essential but not necessary to being a human person. To show this, we can think of an essence as something like an ideal or standard against which things having that essence are measured. Knowing the essence of some species of rose, for example by reading all about it in a horticultural book, lets us say whether some individual member of that species is doing well or poorly, is living up to its essence, as it were. If you go to medical school you learn about the essence of the human body, and this knowledge enables you to determine whether some individual human being is healthy or unhealthy and what he or she needs to get better, if unhealthy. In this sense of essence as standard or ideal, having two feet is an essential property of a human being. But of course it's not a necessary property of a human being. Producing roses of just such a shape and size and color is part of the essence of this rose bush, but if the rose bush is diseased or infested with bugs or is not receiving adequate water and other nutrients, it may fail to produce roses or produce subpar roses. But it doesn't for this reason cease to be the rose bush it is, or cease to belong to the kind of rose to which it belongs. So in general we can say that some essential properties are not necessary properties.

So let's take stock. Theologically motivated hylomorphists think that Socrates is essentially a human being, which means that he is essentially a composite of body and soul. They also think that he is immortal, in the sense that when he dies his body will be corrupted but his soul will live on. We want to say that Socrates ceases to be a human being and that Socrates continues to exist. The distinction between essence and necessity drawn here leaves it a possibility that something essential to Socrates—his being a human being—is not necessary to him. Cartesians will simply deny the essentiality of Socrates's being a human being, but it's not open to hylomorphists to do that. So we seem compelled to conclude that Socrates's humanity is not necessary to Socrates. When Socrates dies he ceases to be a human being but continues to exist. And since Socrates never ceases to exist, his resurrection, when it comes and whatever exactly it is, will not involve Socrates's coming into existence again after a period of his nonexistence. So we don't need to posit intermittent existence, we can say with Aquinas that the saints satisfy a necessary (yet perhaps insufficient) condition for intercession—namely that they actually exist—that departed souls can be justly judged (how could Socrates's soul justly be judged for Socrates's deeds if it wasn't identical with Socrates?), and take advantage of hylomorphism's rich anthropology for an account of pre-mortem human nature.

Actually, it's not quite so easy as it sounds. In making humanity an essential but not necessary property of a human person, Socrates, we've committed ourselves to there being some subject, what I'm calling a human person, which has that property, being a human being, in its pre-mortem career, and loses that property post-mortem. So we need to say something about what it is that holds this subject place. Evidently it cannot be the soul of Socrates, since Socrates's soul was a part of a human being and in general parts can't plausibly be construed as the subjects that are the wholes of which they are parts. So if Socrates's soul is a part of a human being, then it can't be the subject of this essential but not necessary property, being a human being.

Or, if we feel the need to insist that Socrates's soul is the only thing that could possibly hold the subject place, then we need to reconstrue the relationship between body and soul. It wouldn't be the relationship of co-parts of the same whole, as the hylomorphists tell us; instead it would be something more like a subject-property relation: the soul has or wears the body, and at death it loses the body. But of course, this is no longer hylomorphism; it's just Cartesianism, and in this paper we're trying to avoid that anthropology.

So we're still in need of something to hold the subject place, and ex hypothesi we're saying this cannot be Socrates's soul. Now I'll make a suggestion about what this might be. It's a suggestion inspired by Dante but let me be up front and say that I'm not attributing this view to Dante.

I bid you to consider the butterfly.

In Purgatorio X, Virgil is guiding Dante through the circle of the Proud, where the suffering souls walk hunched over for their allotted time carrying heavy stones on their backs. Virgil, apparently exasperated by the stupidity of human pride, admonishes us:

The immediate point of the passage is to get us to see our present insignificance, that we are worms, larvae, grubs. But the whole force of the admonition consists in the contrast between our present lowly state and that state to which we are destined: angelic butterflies. At some point, post-mortem, we will be so transformed that that life compared to this is like a butterfly's to the caterpillar's.

Thus inspired, here's my basic idea and then I'll fill in some details: what I have been calling a human person is a certain kind of sempiternal life-form with at least three distinct phases, roughly corresponding to the life phases of a butterfly: caterpillar, chrysalis, adult. While we ordinarily think of a human being as a complete life-form which ends at death (and perhaps begins to exist again at resurrection), on my Dantean view we need to think of a human being rather as what a human person is in the first phase of its life, the merely human or caterpillar phase. Death is the transformation by which human persons enter their second phase of life, the interim or chrysalis phase, and resurrection is the transformation by which human persons enter their third phase of life, the glorified human or butterfly phase. Now I'm aware that this is the stuff of Hallmark card sentimentality. But there's more to it, I promise, so bear with me.

To avoid confusion of terms let me talk about a certain species of butterfly, the Monarch, and let me call the adult phase of the Monarch's life its butterfly phase. It is essential to the Monarch that it have lots of legs and a mandible jaw—in its caterpillar phase. It's essential to the Monarch that it produce and be wrapped in a green chrysalis—in its chrysalis phase. And it's essential to the Monarch that it have those wondrous orange and black wings—in its butterfly phase. The thing that has lots of legs and a green chrysalis and orange and black wings is one and the same life-form, the Monarch. Similarly, I want to say that it's essential to a human person to be a human being—in its merely human phase; and it's essential to a human person to be a disembodied soul—in its interim phase; and it's essential to a human person to be a glorified human being—in its glorified human phase. One and the same life-form, the human person, has all the properties associated with being a mere human being, being a disembodied soul, and being a glorified human being. It just has these properties at different phases.

We want to say that in no phase is a human person simply identical with its soul, even in the interim phase. In the merely human phase the human person has at least two parts, body and soul, and is therefore a merely human being. In the glorified human phase the human person also has at least two parts, glorified body and soul, and is therefore a glorified human being. And in the interim phase the human person has at least one part, the soul, and lacks a body, and is therefore at least a disembodied soul.

The relationship between a human person and its disembodied soul in the interim phase raises a mereological quandary. According to the highly plausible mereological principle of supplementation, if x is really and truly a part (a proper part in the language of mereology) of some whole, y, then y has some proper part, z, other than or disjoint from x. In other words, anything composed of parts has at least two of them. So if a thing fails to have at least two proper parts then the relation between it and its one “improper” part is simply identity, rather than composition or constitution.Footnote ⁸ From this it follows that if we're going to maintain that a human person never is identical with a soul, even in the interim phase, then we've got to supplement a human person in the interim phase with some part in addition to its soul. Ex hypothesi this can't be a body, so it's got to be something else.

What could it be, then? Really, the possibilities are nearly endless here. Parthood is a very democratic relation. Physical objects can be parts, but so can forms, both substantial and accidental, both absolute and relative. Or, if you don't like talking about forms, you could say that properties can be parts, including dispositions and capacities. So can more exotic things, to which I'll return after another Dantean interlude.

Dante's descriptions of human transformation in the afterlife soar far loftier than comparisons to butterflies. The most dramatic I know of occurs in Paradiso I. Dante has just arrived in Paradise, guided now by his beloved Beatrice. At first he tries with Beatrice to gaze on the heavenly spheres, but his eyes are burned and he's forced to turn away. Then, turning his attention to Beatrice, the best thing around that his as yet unchanged eyes can actually look upon, he undergoes his great change:

First, Dante gives us a simile: what he went through was like changing from a man to a god. Then the neologism: trasumanar. Dante describes his experience as transforming into something beyond the human. The transformation endows Dante with the power to gaze upon the heavenly realm, and these powers will be periodically boosted throughout the poem until he wins through to the beatific vision.

A word about the timing of this transformation. It's plausible to think that all souls in Paradise have already experienced a similar sort of transhumanization, because they all possess the power of clear sight. And it seems to be a transformation only given to those who've made it all the way to Paradise—we have no reason from the poem to think that the souls in Purgatory have yet to receive it, and of course those in Hell have not and will not. But this transformation occurs prior to the resurrection, as all the events of the poem do. So whatever else we can say about transhumanization, it occurs in the interim phase.

Now what we're looking for is a part to supplement a human person's soul in the interim phase, such that we can say that the disembodied soul is a part of a human person in that phase and is not identical with a human person in that, or any, phase. Dante of course doesn't mention any part acquired during his transhumanization. But we're free to speculate.

Rosetta Migliorini Fissi has argued for a close association between Dante's concept of trasumanar and St. Bernard of Clairvaux's understanding of deificatio, the goal of the mystical life whereby the mystic is, in some sense, deified.Footnote ¹⁰ Her argument need not concern us here, but remember that it is Bernard who takes over Beatrice's role as guide as Dante reaches the climax of Paradiso; so Dante clearly holds him in high esteem. Expounding his concept of deification, St. Bernard writes,

So according to Bernard when we're deified we remain human, we are still ourselves, but we have another form, glory, power. And this other form/glory/power is God himself or some aspect of God (his will, his love). At this point it might seem sacrilegious to go on doing metaphysics, but here I go. I mentioned earlier that some rather exotic things might be able to be parts, and here we have one: Bernard's concept of deification let's us say that the human person in the interim phase might be constituted by its disembodied soul together with God Himself. The whole human person in the interim phase, then, has its disembodied soul and God as parts. Supplementation satisfied.

Now God is a very exotic thing indeed to make shift as a part of a human person. Western metaphysical scruples will hardly allow it. So we could take the easy way out and say that not God himself but something specially created by God—a grace—transhumanizes, deifies the human person and also composes, with the disembodied soul, the human person in the interim phase. Alternately, we can look East and claim that not God's essence but some divine energy—God's uncreated activity—is what partially composes the soul beginning in the interim phase.Footnote ¹²

I've said that the human person in its third, resurrected, phase has at least two parts: soul and glorified body. Of course, it might have more. There's no reason to think that God or his grace or his energy ceases to partially constitute the human person at the resurrection. After all, the benefit of deificatio is not merely to supply a part. So we could say that the third-phase human person has in fact three parts: soul, glorified body, and God or God's grace or God's energy. (And for that matter, it may be that for some human persons, this special union with God begins to occur in the first, mere-human-being phase of life.)

But Dante only transhumanizes once he's reached Paradise. What of those souls in Purgatory and Hell? Whatever else their troubles, they too are in the interim phase and are therefore in need of a supplemental part if they are not to be identified with their disembodied souls. Let's take the souls in Purgatory first. We could just say that they receive some special person-constituting grace or energy that is somewhat less ennobling than transhumanization. This would do the trick.Footnote ¹³ And we could say something similar even for the souls in Hell. The basic metaphysical move here is to posit God as supplying something sufficient, along with a soul, to constitute an interim-phase human person. Maybe it's not appropriate to describe those in Hell as partially constituted by God or God's grace—but surely God could come up with something. If ascending to Paradise involves transhumanization, descending to Hell may involve dehumanization—taking on some part (like horns or tails or nasty teeth) that makes one less than a human being but still metaphysically complex enough to be a human person.

And now let me close the paper. I have sought to preserve a robust Thomistic hylomorphic conception of human beings in the face of some challenges arising from the Christian doctrine of the afterlife. A soul all by itself is not a person, according to hylomorphism, so the existence of the soul after death is not enough to secure personal immortality. In order to secure personal immortality for the hylomorphist, I argued that being a human being is an essential but not necessary property of a human person and that a human person is a sempiternal life form whose life has at least three distinct phases: being merely human, being a disembodied soul, and being a glorified human. In order not to fall afoul of the mereological principle of supplementation, and to avoid a lapse into Cartesianism, I argued that we ought to avoid identifying the disembodied soul with the human person in its second-phase interim state and hold instead that the disembodied soul is one part of a composite object that is that human person in the interim phase. Drawing on Dante's idea of transhumanization, enriched by St. Bernard's elaboration of the concept of deification, I argued that God or God's grace could supply that extra part needed in order to keep the human person distinct from its soul. I then offered a couple other ways in which we might obtain the needed supplementation, ways which could also apply to the souls in Purgatory. I conclude that while mystical theology was certainly not designed to solve metaphysical problems, this is nevertheless one of its lesser benefits.