Appendix A
This glossary defines the major theological, philosophical, and biblical-language terms used throughout this book. Because this book is written for a wide audience — including readers who may have no formal training in theology, philosophy, or biblical languages — every effort has been made to provide clear, accessible explanations. Technical precision is maintained, but jargon is always unpacked in plain language. Terms are arranged alphabetically. Greek and Hebrew words are transliterated and, where possible, the original script is provided in parentheses. Cross-references to the chapters where these concepts are discussed in depth are included for convenience.
How to Use This Glossary: If you encounter an unfamiliar term while reading any chapter, you can turn to this appendix for a quick, clear definition. Each entry also tells you where in the book the concept is treated at greater length. Think of this glossary as a friendly reference guide — a companion that walks beside you through the sometimes-dense terrain of theology and philosophy.
A way of understanding Christ's human nature in which the "nature" the Son of God assumed at the Incarnation is thought of as a set of properties or characteristics — an abstract collection of attributes like "being rational," "being embodied," "having a will," and so on — rather than as a concrete, individual thing. On this view, the Son did not assume a particular body-soul composite; He took on the property of "being human." This stands in contrast to the concrete nature view (see below), which holds that the Son assumed a real, particular, individual human nature — a specific body united to a specific soul. The abstract nature view has been defended by philosophers like Brian Leftow and, in a modified form, by William Alston and Michael Rea. However, many theologians and philosophers have raised concerns about this view. If Christ assumed only an abstract set of properties, it is harder to see how He is truly and fully human in the way that you and I are human. We are not bundles of abstract properties; we are concrete, embodied persons with real bodies and real inner lives. Oliver Crisp discusses the advantages and disadvantages of both views in Divinity and Humanity, exploring whether the abstract nature view can account for dyothelitism and a complete Christology. This book follows Timothy Pawl and Andrew Ter Ern Loke in preferring the concrete nature view. (See Chapters 14 and 19 for extended discussion.)
A Greek term (from an- meaning "not" or "without" and hypostasis, meaning "person" or "individual subsistence") used in Christology to express the idea that Christ's human nature never existed as an independent person on its own. In plain language, the human nature of Jesus — His human body and human soul — never had a separate personal identity before or apart from the Son of God. There was never a man named "Jesus" walking around who then got joined to the Second Person of the Trinity. Rather, from the very first moment that Jesus' human nature came into existence (at the virginal conception), it existed in the Person of the eternal Son. The human nature is "without its own hypostasis" — it has no independent personal existence. This is the negative side of the coin, and it is complemented by enhypostasia (see below), which is the positive side. Together, the anhypostasia-enhypostasia distinction explains how Christ can have a complete human nature (with everything that makes a human being a human being) without that human nature being a separate person. Karl Barth described the distinction this way: the human nature of Christ does not possess existence in and for itself, in the abstract — it is anhypostatos. But it does acquire existence in the Person of the Word — it is enhypostatos. Oliver Crisp provides detailed analysis of the distinction in Divinity and Humanity, noting that the two aspects are not simply negative and positive restatements of the same idea but carry distinct theological content. Timothy Pawl develops the concept with philosophical precision in In Defense of Conciliar Christology. The physicalist problem with anhypostasia is explored in Chapter 19: if a human nature is just a physical body, how exactly does an immaterial divine Person "give personal existence" to a purely physical organism? On dualism, the soul provides a more natural metaphysical interface for this union. (See Chapters 14 and 19 for extended treatment.)
A heresy — a belief that the early church officially rejected as false — named after Apollinaris of Laodicea (c. 310–390). Apollinaris taught that in Jesus Christ, the divine Logos (the Word, the Second Person of the Trinity) took the place of the human nous (mind/rational soul). In other words, Jesus had a human body and perhaps a lower "animal soul" (responsible for physical life and basic emotions), but He did not have a human rational mind. The divine Word served as His mind instead. Michael Wilkinson explains in Crowned with Glory and Honor that Apollinaris operated within a "Word-flesh" paradigm that collapsed the person-nature distinction into a single category, creating ontological confusion about both Christ and the Trinity. The early church fathers, especially Gregory of Nazianzus, recognized that this was devastating to the gospel. Gregory argued with his famous axiom: "What is not assumed is not healed" (to gar aproslepton, atherapeuton; τὸ γὰρ ἀπρόσληπτον, ἀθεράπευτον). If the Son of God did not assume a human mind — if He did not take on a full human nature, body and soul — then the human mind is not redeemed. The councils of Constantinople I (381) and Chalcedon (451) definitively rejected Apollinarianism and affirmed that Christ possesses a complete human nature, including a rational human soul. This book argues that physicalism about human nature creates a problem that is structurally parallel to Apollinarianism: on physicalism, Christ's human nature lacks an immaterial soul, just as on Apollinarianism it lacked a human rational mind. Both views leave Christ with an incomplete human nature, and both therefore threaten the coherence of salvation. (See Chapters 7, 12, 20, and 31 for extended discussion.)
An argument against naturalism and physicalism, developed most famously by C.S. Lewis in Miracles (1947) and later refined by Alvin Plantinga in his "evolutionary argument against naturalism." The basic idea is that if our minds are entirely the product of blind, unguided physical processes — if our thoughts are nothing more than chemical reactions in the brain — then we have no reason to trust that our thoughts are rational or that they correspond to truth. Chemical reactions do not aim at truth; they just happen. If naturalism and physicalism are true, our reasoning faculties were shaped by natural selection for survival, not for truth-tracking. But then we cannot trust our reasoning faculties — including the reasoning that led us to believe in naturalism and physicalism in the first place. The argument is self-defeating. Lewis put it memorably: if thought is the product of non-rational causes, then there is no reason to believe it is valid — including the thought that naturalism is true. This argument suggests that the existence of genuine rational thought requires something more than physics and chemistry — something like an immaterial mind or soul. (See Chapter 4 for extended discussion.)
The event described in Acts 1:9–11 and Luke 24:50–53, in which the risen Jesus was "taken up" into heaven in the sight of His disciples, forty days after His resurrection. The ascension is theologically significant for this book because it demonstrates that the Incarnation is permanent. Jesus did not shed His human nature when He returned to the Father. He ascended as a man — body and soul — and He remains God and man forever at the right hand of the Father. The Nicene Creed affirms that He "ascended into heaven and is seated at the right hand of the Father." On physicalism, the ascension means that a physical human organism is now in heaven. On substance dualism, the ascended Christ retains His full human nature — a glorified body united to a human soul — forever united to His divine nature in the one Person of the Son. (See Chapter 26 for extended treatment.)
The term used in Christian theology (especially in the Catholic and Reformed traditions) to describe the direct, unmediated knowledge or "sight" of God that the redeemed will enjoy in the life to come. The phrase comes from the Latin visio beatifica, meaning "blessed sight" or "the vision that makes one blessed." It is not a vision with physical eyes but an intellectual and spiritual apprehension of God — the soul "seeing" God face to face. The apostle Paul speaks of this in 1 Corinthians 13:12: "For now we see in a mirror dimly, but then face to face." Joshua Farris explains that the vision is traditionally understood to be "a vision of the immaterial God by way of the intellectual eyes of the soul," involving capacities for understanding, knowing, and willfully being disposed toward God. Many theologians in the tradition (including Thomas Aquinas, Francis Turretin, and Jonathan Edwards) have argued that Christ's human soul enjoyed the beatific vision during His earthly life — that His human mind had direct access to the knowledge of God the Father. On the kryptic model (Loke), this is related to the preconscious access to divine knowledge available to Christ's human soul. On physicalism, the beatific vision can only be a pattern of neural activity — a brain state — which seems to trivialize what the tradition has understood as a profound spiritual encounter with the living God. (See Chapter 29 for extended discussion.)
The view, affirmed throughout this book, that a human being is made up of two essential components: a physical body and an immaterial soul. These two are deeply united — they are not simply "stacked" on top of each other like bricks, but intimately woven together to form one functioning human person. The soul is not trapped in the body like a prisoner (as some versions of Platonism suggested), nor is the body an unimportant shell. Both body and soul are essential to full human nature, and both are good. However, the soul can survive the death of the body (as Scripture teaches about the intermediate state), even though this is an abnormal and incomplete condition. The reunion of body and soul at the resurrection restores the full human person. John Cooper calls this position "holistic dualism" — holistic because it affirms the deep unity of body and soul, and dualism because it affirms that body and soul are two genuinely distinct realities. (See Chapters 2, 3, and 4 for extended discussion.)
The doctrinal statement produced by the Council of Chalcedon in AD 451. This is one of the most important documents in the entire history of Christian theology. It defines how the two natures of Christ — divine and human — are related in the one Person of the Son. The definition affirms that Christ is "truly God and truly man, of a rational soul (ek psychēs logikēs; ἐκ ψυχῆς λογικῆς) and a body," and that His two natures are united in one Person (prosōpon; πρόσωπον) and one subsistence (hypostasis; ὑπόστασις) "without confusion, without change, without division, without separation" (asynchytōs, atreptōs, adiairetōs, achōristōs; ἀσυγχύτως, ἀτρέπτως, ἀδιαιρέτως, ἀχωρίστως). Notice that Chalcedon explicitly says that Christ's human nature includes "a rational soul and a body." This is not an incidental detail — it was a deliberate rejection of Apollinarianism. The church fathers insisted that Christ has a complete human nature, and a complete human nature includes a soul. Michael Wilkinson argues in Crowned with Glory and Honor that this Chalcedonian definition should serve as the norm for all theological anthropology: if Christ's human nature — the paradigmatic human nature — includes a body and soul, then human nature as such includes a body and soul. This is one of the central arguments of this book: if Chalcedon is right, then physicalism about human nature is wrong, because a human nature without a soul is incomplete. (See Chapters 11, 14, and 31 for extended treatment.)
A Latin phrase meaning "the sharing of properties." This is the Christological principle that, because both the divine nature and the human nature belong to one and the same Person (the Son), the properties of each nature can be truthfully attributed to that Person. So we can say "God died on the cross" — not because the divine nature died (it cannot), but because the Person who died is God the Son, and He died according to His human nature. Likewise, we can say "this man created the universe" — not because Jesus' human nature created anything, but because the Person who has this human nature is the eternal Creator. The communicatio idiomatum depends on the fact that there is one Person who is the subject of both sets of attributes. The properties are not transferred from one nature to the other (that would be confusion of the natures, which Chalcedon forbids), but both sets of properties belong to the one Person. This principle requires that the human nature be a genuine, complete nature with its own real properties — including the soul-properties of consciousness, will, reason, and emotion. On physicalism, the human nature's properties are all physical — brain states and bodily processes. On dualism, the human nature has both physical properties (belonging to the body) and immaterial properties (belonging to the soul). (See Chapter 14 for extended treatment.)
The view — defended in this book, following Timothy Pawl and Andrew Ter Ern Loke — that the human nature assumed by the Son of God at the Incarnation is a concrete particular: a real, individual human nature composed of a specific body united to a specific soul. This is not an abstract collection of properties (see abstract nature view above) but a real, tangible, particular thing — as real and individual as your own human nature. On the concrete nature view, when we say "the Word became flesh," we mean that the eternal Son took to Himself a real human body and a real human soul, forming a complete, concrete, individual human nature that exists in and through the Person of the Son. Oliver Crisp discusses the concrete nature view in Divinity and Humanity, noting that it does not entail Nestorianism — the Son can assume a concrete human nature without that nature constituting a separate person — and that it is compatible with dyothelitism. (See Chapters 14 and 19 for extended discussion.)
The theological view that human beings are not inherently or naturally immortal. Instead, immortality is a gift that God gives to those who are saved through Christ. On this view, the unsaved do not live forever in conscious torment (as the traditional doctrine of hell holds) but instead are ultimately destroyed — they cease to exist. Proponents often cite passages like Matthew 10:28 ("Fear him who can destroy both soul and body in hell") and John 3:16 ("should not perish but have eternal life") as evidence. This book is not primarily about conditional immortality, but it engages with the movement because some prominent conditionalists have adopted physicalist views of human nature — denying the existence of an immaterial soul — as a way to support their position. This book argues that one can affirm conditional immortality without embracing physicalism: the soul is real, and it survives death, but its ultimate fate depends on God's gracious gift of immortality through Christ. (See Chapter 33 for extended treatment.)
A model of the Incarnation, influenced by the work of Lynne Rudder Baker on personal identity, which holds that the human nature of Christ is "constituted by" but not identical to a physical body. Just as a statue is constituted by a lump of bronze but is not identical to it (the lump can exist without being a statue), so Christ's human nature is constituted by a physical body but is not identical to that body. Some physicalist-leaning theologians have proposed this as a way to avoid the problems that physicalism creates for Christology — particularly the problem of the triduum mortis (what happens to Christ's human nature when His body dies). However, this book argues that constitution Christology does not actually solve the physicalist's problems. If the human nature is constituted by a physical body and there is no immaterial soul, then when the body dies and ceases to function, the human nature is still dissolved. The constitution relation does not provide an immaterial soul that can survive death. (See Chapter 35 for extended treatment.)
Not to be confused with creationism about the origin of the universe! In the context of theological anthropology, "creationism" is the view that God directly creates each human soul individually at (or around) the moment of conception. On this view, the soul does not arise from the physical processes of reproduction; it is a special act of divine creation for each new person. This stands in contrast to traducianism (see below), which holds that the soul is somehow generated from the parents along with the body. Soul creationism has been the dominant view in the Western church since at least the medieval period. Thomas Aquinas, for example, held that the soul is directly created by God. Joshua Farris discusses the debate between creationism and traducianism extensively in An Introduction to Theological Anthropology, arguing that any adequate account of soul origins must explain how the soul is a "fundamental immaterial part" that cannot be said to "emerge solely from the material stuff that precedes it." This book does not take a definitive stand between creationism and traducianism, but the author leans toward creationism. Either way, both positions affirm the reality and distinct existence of the immaterial soul — which is the central concern of this book. (See Chapters 2 and 25 for discussion.)
The belief, affirmed in the Apostles' Creed ("He descended into hell") and grounded in several biblical passages (1 Peter 3:18–20; 4:6; Ephesians 4:8–10; Acts 2:27, 31), that between His death on Good Friday and His resurrection on Easter Sunday, Jesus Christ descended to the realm of the dead. The precise nature and purpose of this descent has been debated throughout church history — was He proclaiming victory, offering salvation, liberating the Old Testament saints, or something else? — but the key point for this book is that the descent requires a subject who acts during the period when Christ's body lay dead in the tomb. On substance dualism, Christ's human soul descended to the dead while His body lay in the tomb. The Son remained united to both the soul (in the realm of the dead) and the body (in the tomb), preserving the hypostatic union. On physicalism, there is no soul to descend anywhere. If Christ is only a physical body, and the body is dead, then there is no Christ to act between death and resurrection. The descent becomes impossible. This is one of the most devastating arguments against physicalist Christology. (See Chapter 23 for extended treatment.)
The model of the Incarnation developed by Andrew Ter Ern Loke in A Kryptic Model of the Incarnation, and the model favored by the author of this book. On this model, the divine Son retains all of His divine attributes (omniscience, omnipotence, omnipresence) during the Incarnation, but these attributes are concealed or "hidden" (krypsis; see below) at a "preconscious" level — below the threshold of Christ's ordinary human awareness. Jesus, in His day-to-day human experience, thought and felt and perceived the world through His human mind. But the divine knowledge and power were always present, available at a deeper level, and could break through into His human consciousness when the Father willed it (for example, in miracles or in prophetic knowledge). This model avoids the problems of kenoticism (which requires God to give up divine attributes, which seems impossible) while also taking seriously the genuine limitations of Jesus' human experience. Think of it this way: imagine you have vast knowledge stored in a library, but you are reading one book at a time. The other books are all there — you have not lost them — but your conscious attention is focused on the one book in front of you. In a rough analogy, Christ's divine omniscience is always "in the library," but His human mind is reading "one book at a time." The model also requires a human soul, since the "preconscious" interface between divine and human operates at the level of the soul, not the brain. (See Chapter 17 for extended treatment.)
From the Greek dyo (δύο), meaning "two," and thelēma (θέλημα), meaning "will." Dyothelitism is the orthodox Christian doctrine that Christ has two wills — a divine will and a human will — corresponding to His two natures. This was defined as dogma at the Third Council of Constantinople (681), which rejected monothelitism (the view that Christ has only one will). The key biblical text is Jesus' prayer in Gethsemane: "Not my will, but yours, be done" (Luke 22:42). In this prayer, Jesus distinguishes His own human will (to thelēma mou; τὸ θέλημά μου) from the Father's will (to thelēma sou; τὸ θέλημά σου). The human will genuinely shrinks from suffering, but freely submits to the divine will. Maximus the Confessor was the great champion of dyothelitism, arguing that the will is a property of nature, not of person — therefore, two natures require two wills. On substance dualism, the human will is a faculty of the human soul — an immaterial capacity for choosing that belongs to Christ's complete human nature. On physicalism, the human "will" is just a neurological process — a pattern of brain activity. The question is whether a brain event can constitute a genuine "will" in the robust theological sense required by the councils. (See Chapters 13 and 14 for extended treatment.)
A view of human nature, associated primarily with philosopher William Hasker, which holds that the soul is a real, immaterial substance — but one that emerges from the physical brain once the brain reaches a certain level of complexity. On this view, the soul is not directly created by God (as on creationism of the soul) and is not present from the moment of conception. Instead, it arises naturally from the physical processes of brain development. Once it emerges, however, it is a genuinely distinct, immaterial substance that can (in principle) survive the death of the body. Emergent dualism occupies a middle position between physicalism (which denies the soul entirely) and traditional substance dualism (which holds that the soul is directly created by God). This book interacts with emergent dualism, especially in the context of the Incarnation: if Christ's soul emerged from His brain, then there was a period during the early stages of fetal development when the Son was united to a body but not yet to a soul — a kind of temporary Apollinarianism. This is the "Hasker problem." (See Chapters 2, 4, and 25 for discussion.)
The broader philosophical view that complex properties, structures, or substances can "emerge" from simpler components in a way that is genuinely novel — not merely the rearrangement of what was already there. In the philosophy of mind, emergentism holds that consciousness and mental properties arise from physical brain processes but are not reducible to them. Emergentism differs from reductive physicalism (which says mental properties just are physical properties) and from substance dualism (which says the mind/soul is a fundamentally different kind of thing from the body). Some emergentists (like Philip Clayton) hold that what emerges is still physical; others (like William Hasker) hold that what emerges is a genuinely immaterial substance. This book engages with emergentism as a middle position but argues that it does not resolve the fundamental Christological problems created by denying the immaterial soul. (See Chapters 2 and 4 for discussion.)
A Greek term (from en- meaning "in" and hypostasis meaning "person" or "individual subsistence") used in Christology to express the positive counterpart of anhypostasia. While anhypostasia says that Christ's human nature never existed as an independent person, enhypostasia says that Christ's human nature does have genuine personal existence — but it has that existence in the Person of the eternal Son. The human nature is "in-personalized" or "given its personal existence" by the Word. Karl Barth put it this way: in the act of the Incarnation, the human nature acquires existence in the mode of being of the Word. The human nature is not impersonal in the sense of lacking any personal reality — that would make Christ less than fully human. Rather, its personal reality is the personal reality of the Son of God. The Son gives His own personal existence to the human nature, making it His own. Oliver Crisp observes in Divinity and Humanity that the two aspects of the distinction carry different theological content and should not be treated as merely negative and positive restatements of the same idea. On dualism, the Son is personally united to a body-soul composite, with the human soul serving as the "point of union" between the divine Person and the physical body. On physicalism, the Son would be personally united to a physical organism alone, which raises the question of how an immaterial divine Person "personalizes" a purely material body. (See Chapter 19 for extended treatment.)
From the Greek eschatos (ἔσχατος), meaning "last" or "final." Eschatology is the branch of theology concerned with "last things" — death, the intermediate state, the return of Christ, the resurrection of the dead, the final judgment, and the eternal state. Eschatology is relevant to this book because a person's view of human nature has enormous consequences for what happens at death and beyond. On dualism, death is the separation of soul and body; the soul continues to exist consciously in God's presence (for the redeemed) while awaiting the resurrection. On physicalism, death is the end of the person's existence until God recreates them at the resurrection. The intermediate state, the descent to the dead, and the nature of the resurrection body are all deeply affected by one's anthropology. (See Chapters 3, 23, 24, and 33 for discussion.)
Key Distinction: Anhypostasia and enhypostasia work together as two sides of one coin. Anhypostasia is the negative statement: Christ's human nature is not an independent person. Enhypostasia is the positive statement: Christ's human nature does have personal existence — in the Person of the Son. Together they explain how Christ can have a complete human nature without being two persons.
The view that, while body and soul are two genuinely distinct realities (ontological dualism), they function together as a deeply integrated unity in normal human life. The body is not a prison for the soul, and the soul is not a ghost merely inhabiting a machine. Rather, body and soul are designed to work together — they form one complete, functioning human person. This is the position defended by John Cooper in Body, Soul, and Life Everlasting, who calls it "holistic dualism." Cooper argues that the Bible teaches both the deep integration of body and soul (holism) and the distinct existence and survival of the soul after death (dualism). The separation of body and soul at death is abnormal and temporary — it will be resolved at the resurrection, when the body is raised and reunited with the soul. (See Chapters 2 and 3 for extended discussion.)
The famous principle stated by Gregory of Nazianzus (c. 329–390) in his Epistle 101 against Apollinarianism: "What is not assumed is not healed" (Greek: to gar aproslepton, atherapeuton; τὸ γὰρ ἀπρόσληπτον, ἀθεράπευτον). Gregory's point is simple but profound: if the Son of God came to save the whole human person — body, soul, and mind — then He must have assumed the whole human person. If He did not take on a human mind (as Apollinaris claimed), then the human mind is left unredeemed. If He did not take on a human soul (as physicalism effectively implies, since it denies the soul exists), then the human soul is left unredeemed — or rather, on physicalism, there is no soul to be redeemed in the first place, which creates a different but equally serious problem. As Michael Wilkinson notes in Crowned with Glory and Honor, Gregory's critique effectively demonstrated that Apollinarianism "vitiates both the humanity of Christ and the salvation of humanity in Christ." This axiom is one of the most powerful theological arguments for the completeness of Christ's human nature, and it runs throughout this book. (See Chapter 12 for extended treatment.)
A phrase coined by philosopher David Chalmers in The Conscious Mind (1996) to describe the central puzzle of consciousness: Why does physical processing in the brain give rise to subjective experience at all? Why is there "something it is like" to be a conscious being? We can explain the brain's functional activities — processing information, coordinating behavior, responding to stimuli — in purely physical terms (Chalmers calls these the "easy problems"). But explaining why any of this is accompanied by conscious experience — by qualia, by the felt quality of awareness — seems to go beyond what physics and neuroscience can currently explain, and perhaps beyond what they can ever explain. The hard problem is a major challenge for physicalism, because it suggests that consciousness is not fully explicable in physical terms. Substance dualists argue that consciousness belongs to the soul — an immaterial reality that is fundamentally different from physical matter — and that is why the hard problem is so "hard": you cannot derive the immaterial from the material. (See Chapter 4 for extended discussion.)
A Greek term meaning "of the same substance" or "of the same being." This word was enshrined in the Nicene Creed (AD 325) to express the relationship between the Son and the Father: the Son is homoousios with the Father — He shares the same divine substance or essence. The Son is not a lesser god, not a created being, not merely "similar" to the Father (homoiousios, ὁμοιούσιος, with an extra iota) — He is of the very same being as the Father. This was the key term in the defeat of Arianism (the heresy that the Son was a created being). At Chalcedon (451), the term is used in both directions: Christ is homoousios with the Father according to His divinity, and homoousios with us according to His humanity. He is of the same divine being as God the Father, and of the same human being as us — truly God and truly human. (See Chapters 6 and 11 for extended discussion.)
A view of human nature rooted in the philosophy of Aristotle and developed extensively by Thomas Aquinas. The term comes from the Greek hylē (ὕλη), meaning "matter," and morphē (μορφή), meaning "form." On this view, a human being is a composite of matter (the body) and form (the soul). The soul is the "form" of the body — it is what makes a lump of matter into a living human being. Unlike substance dualism, hylomorphism does not typically view the soul as a separate substance that can easily exist on its own apart from the body. Rather, the soul is the organizing principle that gives life, structure, and identity to the body. However, Aquinas (following Aristotle partially but going beyond him) argued that the human rational soul is a special kind of form — a "subsistent form" — that can survive the death of the body, even though it naturally belongs with a body. This creates an intermediate state in which the soul exists without the body, but in an incomplete and unnatural condition, awaiting the resurrection. Hylomorphism is sometimes considered a "middle position" between physicalism and substance dualism. This book treats it as a form of dualism (since it affirms the reality of an immaterial soul), though its metaphysical framework differs from that of substance dualism. Joshua Farris surveys the various forms of hylomorphism in An Introduction to Theological Anthropology, noting the important differences between Thomistic hylomorphism and other variations. (See Chapter 2 for extended discussion.)
One of the most important — and most debated — technical terms in all of Christian theology. In classical Greek, hypostasis had a wide range of meanings: foundation, substance, sediment, reality, confidence, and many others. As Norman Tanner observed, there were precious few things the term did not mean. In Christian theology, it came to have a very specific meaning: an individual, subsisting thing — a particular entity that exists in itself. In the context of the Trinity, hypostasis refers to each of the three Persons — the Father, the Son, and the Holy Spirit are three hypostaseis (the plural) sharing one ousia (essence or being). In the context of Christology, hypostasis refers to the one Person of the Son, who possesses both a divine nature and a human nature. The Chalcedonian Definition affirms that Christ's two natures are united in one prosōpon (πρόσωπον, "person" or "face") and one hypostasis. Timothy Pawl, following the medieval tradition and drawing on William of Ockham, defines a hypostasis (or supposit) as a complete being, incommunicable by identity, not apt to inhere in anything, and not sustained by anything. Thomas Aquinas defined it as an "individual substance" that is complete, subsisting of itself, and separate from all else. John of Damascus described the hypostasis as that which indicates who someone is, as distinct from what they are (which is the nature or ousia). (See Chapters 11 and 14 for extended treatment.)
The union of the divine nature and the human nature in the one Person (hypostasis) of the Son of God. This is the central mystery of the Incarnation and the heart of orthodox Christology. The Chalcedonian Definition establishes the parameters: the two natures are united in one Person "without confusion, without change, without division, without separation." The natures are not mixed together into a third thing (against Eutychianism); neither nature is changed into the other; the natures are not divided into two separate persons (against Nestorianism); and the natures are never separated from each other. On substance dualism, the Son's human nature is a body-soul composite, and the hypostatic union links the divine Person to this complete human nature — including an immaterial soul that can survive the death of the body. On physicalism, the Son's human nature is just a physical organism. When that organism dies, there is nothing left of the human nature — and the hypostatic union appears to be dissolved. This is the devastating triduum mortis problem that runs throughout Part V of this book. (See Chapters 14 and 21–22 for extended treatment.)
From the Latin incarnatio, meaning "becoming flesh" or "taking on flesh." The Incarnation is the central Christian doctrine that the eternal Son of God — the Second Person of the Trinity, the divine Logos — took on a complete human nature and became a human being, while remaining fully God. As John 1:14 says, "The Word became flesh and dwelt among us." The Incarnation does not mean that God stopped being God. It does not mean that the Son was transformed into a human. It means that the Son, without ceasing to be what He always was (fully divine), began to be what He had never been before (fully human). He added a human nature to His divine Person. This book's central argument is that the Incarnation — properly understood — requires that human nature include an immaterial soul. If human nature is only physical matter (as physicalism claims), then the Incarnation faces a host of devastating philosophical and theological problems. (See Chapter 1 and throughout the book.)
The condition of human persons between death and the final resurrection. On substance dualism, the intermediate state is a period in which the soul exists without the body — conscious, personal, and aware, but in an incomplete condition, awaiting the resurrection of the body. Key biblical texts include Luke 23:43 (Jesus telling the thief, "Today you will be with me in paradise"), Philippians 1:23 (Paul's desire "to depart and be with Christ"), 2 Corinthians 5:8 ("away from the body and at home with the Lord"), and Revelation 6:9–11 (the souls of the martyrs under the altar). John Cooper provides extensive biblical exegesis on this topic in Body, Soul, and Life Everlasting, arguing that the intermediate state is one of the strongest biblical arguments for dualism. On physicalism, there is no intermediate state in any traditional sense — when the body dies, the person ceases to exist until God recreates them at the resurrection. This creates serious problems for the many biblical texts that seem to describe conscious existence between death and resurrection. (See Chapters 3 and 23 for extended treatment.)
From the Greek kenōsis (κένωσις), meaning "emptying." The term is drawn from Philippians 2:7, where Paul says that Christ "emptied himself" (heauton ekenōsen; ἑαυτὸν ἐκένωσεν) by taking on the form of a servant and being born in human likeness. Kenotic Christology is a family of models of the Incarnation that propose that the Son of God gave up or set aside some or all of His divine attributes (such as omniscience, omnipotence, and omnipresence) in order to become human. On this view, the Son literally "emptied" Himself of divine powers. This book rejects kenoticism. The reason is theological and philosophical: God's essential attributes are what make God God. If the Son divests Himself of omniscience, He ceases to be omniscient — and a being who is not omniscient is not fully God. Kenoticism thus threatens the full deity of Christ. Oliver Crisp discusses various forms of krypsis and kenosis in Divinity and Humanity, clarifying the important differences between them. The kryptic model (see krypsis below) is presented as a superior alternative: the Son retains all divine attributes but conceals them, rather than surrendering them. (See Chapter 15 for extended treatment.)
From the Greek krypsis (κρύψις), meaning "hiding" or "concealment." Kryptic Christology, developed by Andrew Ter Ern Loke in A Kryptic Model of the Incarnation, proposes that the Son of God did not give up any divine attributes at the Incarnation (contra kenoticism) but instead concealed or hid them. Specifically, Loke's "Divine Preconscious Model" holds that the divine attributes (omniscience, omnipotence, omnipresence) were present at a "preconscious" level — below the threshold of Christ's ordinary human awareness. Jesus experienced the world through His human mind, with genuine human limitations (He could be tired, surprised, and ignorant of certain things at the conscious human level), while the divine attributes were always "there," hidden beneath the surface of His human consciousness, available when the Father willed them to be accessed. This model has deep roots in the Lutheran theological tradition (especially the concept of krypsis versus kenosis) and has parallels in the thought of Oliver Crisp, who also discusses krypsis in Divinity and Humanity. The kryptic model is the author's preferred Christological framework. It preserves the full deity of Christ (no divine attributes are surrendered), the full humanity of Christ (His human experience is genuine and limited), and the coherence of the hypostatic union. It also requires a human soul — the "preconscious" interface between divine and human operates at the level of the soul, not the brain. (See Chapter 17 for extended treatment.)
A Greek word with a rich range of meanings: word, reason, speech, account, principle. In Christian theology, the Logos refers specifically to the Second Person of the Trinity — the eternal Son of God. The term is used most famously in the opening of John's Gospel: "In the beginning was the Word (Logos), and the Word was with God, and the Word was God" (John 1:1). Andrew Ter Ern Loke, in The Origin of Divine Christology, traces the earliest Christian conviction that Jesus is identified with the YHWH of the Old Testament, showing how passages originally about YHWH were applied to Jesus by Paul and other New Testament writers. The Logos is the divine Person who becomes incarnate — who takes on human nature and becomes the man Jesus Christ. Throughout this book, "the Son," "the Word," and "the Logos" are used interchangeably to refer to the Second Person of the Trinity.
The ability of mental states — thoughts, beliefs, desires, intentions — to cause physical events. When you decide to raise your hand and your hand goes up, your mental decision caused a physical event. Mental causation is widely regarded as a serious problem for physicalism, especially nonreductive physicalism. If mental properties are not identical to physical properties (as nonreductivists claim) but are entirely dependent on them (as physicalists insist), then it is unclear how mental properties can do any causal work. The physical world seems "causally closed" — every physical event has a sufficient physical cause. If your brain state is a sufficient physical cause of your hand going up, what role does your conscious decision play? This is the "exclusion problem," and it threatens to make consciousness an epiphenomenon — a mere byproduct with no causal power. On substance dualism, mental causation is straightforward: the soul (an immaterial substance) causes physical events through its connection to the body. (See Chapter 4 for extended discussion.)
From the Greek monos (μόνος), meaning "one" or "single," and physis (φύσις), meaning "nature." Monophysitism is the heretical view that Christ has only one nature — a single, mixed divine-human nature — rather than two distinct natures (divine and human) united in one Person. The most extreme form of this heresy is associated with Eutyches (c. 380–456), who taught that Christ's human nature was absorbed into His divine nature like a drop of wine in the ocean. The Council of Chalcedon (451) rejected this view with the formula "without confusion, without change" — the two natures remain distinct; they are not blended into a third thing. (See Chapters 11 and 31 for extended discussion.)
From the Greek monos (μόνος), meaning "one," and thelēma (θέλημα), meaning "will." The heretical view that Christ has only one will — typically understood as a single divine will — rather than two wills (divine and human). Monothelitism was condemned at the Third Council of Constantinople (681), which affirmed dyothelitism — that Christ has two wills, corresponding to His two natures. The monothelite controversy was in many ways a continuation of the monophysite controversy: if Christ has only one nature, He would presumably have only one will; if He has two natures, each nature should have its own will. The will is a property of nature, not of person, as Maximus the Confessor argued. Therefore two natures require two wills. (See Chapter 13 for extended treatment.)
An experience reported by some individuals who have been clinically dead or very close to death and then revived. Common features include a sense of leaving the body, moving through a tunnel, encountering a brilliant light, meeting deceased relatives or a "being of light," experiencing a life review, and feeling profound peace. For the purposes of this book, the most significant category is the veridical NDE — cases in which the person accurately reports details about events occurring in their vicinity (or even at distant locations) while they were clinically dead, with no brain function detectable on EEG monitors. These cases are significant because they provide empirical evidence that consciousness can exist apart from the functioning brain — exactly what substance dualism predicts and what physicalism denies. Researchers such as Pim van Lommel, Bruce Greyson, Sam Parnia, Michael Sabom, Kenneth Ring, Jeffrey Long, and Raymond Moody have documented and studied NDEs extensively. (See Chapter 5 for extended treatment.)
A Hebrew word used extensively in the Old Testament, often translated as "soul," "life," "self," "person," or "living being." It has a wide semantic range. In Genesis 2:7, God breathes into Adam the "breath of life" and Adam becomes a nephesh chayyah (נֶפֶשׁ חַיָּה) — a "living being" or "living soul." Physicalists often argue that nephesh simply means "whole living person" and does not refer to a separable, immaterial component. Dualists respond that while nephesh can refer to the whole person, it can also refer to the inner self that survives death — as in Psalm 16:10 ("You will not abandon my nephesh to Sheol") and Genesis 35:18 ("As her nephesh was departing — for she was dying"). John Cooper discusses the semantic range of nephesh carefully in Body, Soul, and Life Everlasting, arguing that the word is flexible and context-dependent, but that several key passages strongly imply a separable immaterial dimension. The Greek equivalent in the New Testament is psychē (ψυχή). (See Chapter 3 for extended treatment.)
A heresy named after Nestorius, Patriarch of Constantinople (c. 386–451), who was perceived to have taught that Christ is two persons — a divine person (the eternal Son) and a human person (the man Jesus) — who are morally and relationally united but not united in one Person. In short, Nestorianism divides Christ into two subjects, two "whos." The Council of Ephesus (431) condemned Nestorius, and the Council of Chalcedon (451) further clarified that Christ is one Person in two natures — not two persons side by side. The charge of Nestorianism is relevant to the physicalist debate because some theologians (such as those in Christian Physicalism?) have argued that physicalism actually avoids Nestorianism better than dualism. This book argues the opposite: that physicalism, by failing to account for the anhypostasia-enhypostasia distinction properly, actually risks Nestorianism or creates other equally serious problems. (See Chapters 11, 19, and 22 for discussion.)
A view of human nature that holds that a human person is entirely physical — there is no immaterial soul — but that mental properties (consciousness, thought, emotion, will) are not reducible to physical properties. In other words, while everything about you is physical, your mental life is not just brain chemistry; it is a higher-level description of what the brain does that cannot be fully captured in the language of neurons and synapses. Nonreductive physicalism has been defended by Christian thinkers such as Nancey Murphy and Warren Brown. This book argues that nonreductive physicalism, despite being more sophisticated than reductive physicalism, still fails to account for the Incarnation. Even if mental properties are "non-reducible," they are still entirely dependent on the brain. When the brain dies, the mental properties cease. This means that at Christ's death, everything about His human nature — including all human mental properties — ceased to exist, dissolving the hypostatic union. (See Chapters 2, 4, and 20 for extended discussion.)
A Greek word meaning "mind," "intellect," or "rational soul." In the philosophy of Plato and Aristotle, the nous is the highest faculty of the soul — the capacity for reason, understanding, and contemplation of truth. In early Christian theology, the nous became a critical term in the Apollinarian controversy. Apollinaris argued that in Christ, the divine Logos replaced the human nous, so that Christ did not have a human mind. The church fathers rejected this and insisted that Christ possesses a complete human nature, including a human nous. Gregory of Nazianzus argued that if Christ did not assume a human nous, then the human nous — the seat of rational thought and the very faculty most corrupted by sin — is left unredeemed. (See Chapters 12 and 30 for discussion.)
The doctrine that the sin of Adam (the first human being) has affected all of his descendants, so that every human being is born in a state of sinfulness and spiritual corruption. The precise mechanism of this transmission has been debated: traducianists argue that it is transmitted through the soul (since the soul comes from the parents); creationists argue that it is transmitted through human nature broadly or through some other means. On physicalism, original sin must be transmitted entirely through physical processes — perhaps through genetics or epigenetics. But this creates the uncomfortable implication that sin is essentially a biological condition, which seems to reduce moral and spiritual corruption to a medical problem. On dualism, original sin affects the whole person — body and soul — and its transmission involves the spiritual as well as the physical. This distinction matters for Christology: if Christ assumed a human nature without original sin, the question is how this was accomplished. On dualism, the direct creation of Christ's human soul by God (ensoulment at the virginal conception) provides a natural explanation. On physicalism, Christ's freedom from original sin must be explained entirely in terms of His physical constitution, which risks the Pelagian implications discussed under that entry. (See Chapters 25 and 27 for discussion.)
A Greek word meaning "essence," "substance," or "being." In Christian theology, ousia refers to what something is — its essential nature or being. In the doctrine of the Trinity, the Father, Son, and Holy Spirit share one ousia (one divine being or essence) while being three distinct hypostaseis (three Persons). In Christology, Christ has two ousiai — a divine essence and a human essence — united in one Person. As Michael Wilkinson explains in Crowned with Glory and Honor, the Trinitarian distinction between hypostasis (who God is) and ousia (what God is) was essential to the development of orthodox Christology. The Cappadocian Fathers (Basil the Great, Gregory of Nazianzus, Gregory of Nyssa) clarified the distinction: ousia is what is shared (the common essence), while hypostasis is what is individual (the particular person). (See Chapters 6 and 11 for discussion.)
A heresy named after the British monk Pelagius (c. 354–420), who taught that human beings can, by the exercise of their own free will and natural abilities, live sinless lives and merit salvation without the need for divine grace. The church condemned Pelagianism and affirmed the necessity of grace for salvation. This heresy is relevant to this book's argument because physicalism creates what we might call the "sinlessness-Pelagian dilemma" for Christology: if Christ's human nature is purely physical, and His sinlessness is explained by His physical constitution (perhaps a uniquely configured brain that is incapable of sinning), then His sinlessness is not a moral achievement but a biological inevitability — which makes it meaningless. But if His brain is capable of sinning and He simply chose not to, then on physicalism, the explanation must be entirely in terms of brain chemistry and neural wiring — which makes His moral perfection a matter of lucky genetics rather than genuine virtue and the work of the Holy Spirit. On dualism, Christ's sinlessness is rooted in the orientation of His human soul toward the Father, empowered by the Holy Spirit. (See Chapter 27 for extended treatment.)
A Greek word (περιχώρησις) meaning "mutual indwelling" or "interpenetration." In Trinitarian theology, perichoresis describes the way in which the three Persons of the Trinity dwell in and through one another — each Person fully contains and is fully contained by the other two. In Christology, perichoresis sometimes describes the intimate mutual relationship between the divine and human natures in Christ — each nature interpenetrating the other (without confusion). Oliver Crisp discusses Christological perichoresis in Divinity and Humanity. The concept underscores the depth and intimacy of the union between Christ's two natures — it is not a loose association but a profound mutual indwelling. (See Chapter 14 for discussion.)
The Latin word for "person." In Christian theology, persona is the standard Latin translation of the Greek hypostasis (and prosōpon). God is one substantia (substance or essence) in three personae (persons). Christ is one persona in two naturae (natures). The term was famously used by Tertullian in the early third century and became standard in Western theology.
The philosophical question of what makes you the same person over time and through change. What makes the "you" who existed yesterday the same person as the "you" who exists today? This question becomes critical in the context of death and resurrection. On substance dualism, personal identity is grounded in the continuity of the soul — the same soul that existed before death continues to exist after death and is reunited with a body at the resurrection. On physicalism, personal identity is grounded in physical continuity — the same body (or brain) persists over time. But at death, the body disintegrates. If God recreates a new body at the resurrection, is it the same person or merely a copy? This is the replica problem (see below). For Christology, the personal identity question is acute during the triduum mortis: if there is no soul, what ensures that the risen Jesus is the same person as the crucified Jesus? (See Chapter 24 for extended treatment.)
The philosophical view that everything that exists is physical — made up of matter, energy, and the physical forces that govern them. In the context of this book, physicalism about human nature is the view that a human person is entirely physical, with no immaterial soul, spirit, or mind. On this view, you are your body — specifically, you are your brain and nervous system. Your thoughts, emotions, decisions, and consciousness are all products of physical brain processes. When your brain dies, you cease to exist — there is no "you" that survives the death of your body. Richard Swinburne, whose work is engaged extensively in this book, defines a person on substance dualism as identical to an immaterial substance — a soul — that has the capacity to think and perform free actions. This contrasts sharply with the physicalist identification of persons with brains or bodies. This book argues that physicalism about human nature is incompatible with orthodox Christology. (See throughout the book, especially Chapters 2, 4, 20–29, and 33–35.)
See Nonreductive Physicalism above.
See Reductive Physicalism below.
The Greek word for "nature." In Christology, physis refers to each of Christ's two natures — divine and human. The Chalcedonian Definition speaks of Christ being known "in two natures" (en dyo physesin; ἐν δύο φύσεσιν). The earlier formula of Cyril of Alexandria spoke of "one nature (mia physis) of the incarnate Word," which the monophysites seized upon but which Cyril himself understood in a way compatible with the later Chalcedonian two-natures language. In the Apollinarian controversy, the question was whether Christ's human physis was complete — including a rational soul — or incomplete, lacking a human mind. The church insisted it was complete. (See Chapters 11 and 12 for discussion.)
A Greek word meaning "spirit," "breath," or "wind." In the New Testament, pneuma has several uses: it can refer to the Holy Spirit (to Pneuma to Hagion; τὸ Πνεῦμα τὸ Ἅγιον), to the human spirit, or to the breath of life. When Jesus died on the cross, He "gave up his spirit" (paredōken to pneuma; παρέδωκεν τὸ πνεῦμα, John 19:30). This language implies that something — the spirit or soul — departed from the body at death. In Luke 23:46, Jesus says, "Father, into your hands I commit my spirit (pneuma)!" — indicating that His spirit continued to exist after His body died. Paul uses pneuma to refer to the immaterial dimension of the human person in passages like Romans 8:16 ("The Spirit himself bears witness with our spirit") and 1 Corinthians 2:11 ("Who knows a person's thoughts except the spirit of that person, which is in him?"). The relationship between pneuma (spirit) and psychē (soul) is debated: trichotomists believe they refer to two distinct immaterial components, while most dualists treat them as different words for the same immaterial reality, with pneuma emphasizing the person's relationship to God and psychē emphasizing the person's inner life. (See Chapters 3 and 7 for extended discussion.)
A Greek word meaning "face," "appearance," or "person." In Christology, the Chalcedonian Definition uses prosōpon alongside hypostasis to refer to the one Person of Christ. The two terms are used together in the Definition to ensure clarity: Christ's two natures are united in "one person (prosōpon) and one subsistence (hypostasis)." In earlier usage, prosōpon could refer merely to an outward appearance or role (as in a theatrical mask), which is why the Chalcedonian fathers also used the more metaphysically robust term hypostasis to make clear they meant a genuine, subsisting person — not just an outward appearance. (See Chapters 11 and 14 for discussion.)
The Greek word for "soul" or "life." It is the standard Greek equivalent of the Hebrew nephesh. Like nephesh, psychē has a range of meanings: it can refer to the whole living person, to physical life, or to the immaterial soul that survives death. In Matthew 10:28, Jesus says, "Do not fear those who kill the body but cannot kill the soul (psychē). Rather fear him who can destroy both soul (psychē) and body in hell (Gehenna)." This verse makes a clear distinction between the body (which humans can kill) and the soul (which they cannot), strongly implying that the soul is a distinct reality that survives bodily death. In Matthew 26:38, Jesus says, "My soul (psychē) is very sorrowful, even to death," using the term to refer to His own inner life — His human experience of anguish. The Chalcedonian Definition explicitly states that Christ's human nature is composed "of a rational soul (psychē logikē; ψυχῆς λογικῆς) and a body." (See Chapters 3, 7, and 8 for extended discussion.)
A philosophical term (the singular is quale) referring to the subjective, first-person qualities of conscious experience — what it feels like to have a particular experience. The redness of red, the taste of chocolate, the pain of a headache, the sound of a violin — these are all qualia. They are the "raw feels" of consciousness. Qualia pose a major problem for physicalism because they seem to resist any purely physical description. You can describe every physical fact about light wavelengths and neural processing that occurs when someone sees the color red, but no amount of physical description captures what it is like to see red. The philosopher David Chalmers calls this "the hard problem of consciousness." Frank Jackson's famous "Mary's Room" thought experiment illustrates the point: Mary is a brilliant scientist who knows every physical fact about color vision but has lived her entire life in a black-and-white room. When she finally sees something red for the first time, she learns something new — what red looks like. This means there is something about conscious experience that is not captured by physical facts alone — which is exactly what substance dualism predicts. (See Chapter 4 for extended discussion.)
The view that mental properties — consciousness, thought, emotion, will — are identical to physical properties. On this view, your experience of pain just is a particular pattern of neural firing. Your thought "I should call my mother" just is a specific brain state. There is no separate "mental" reality — mental terms are just a convenient way of describing physical events at a higher level of description. Reductive physicalism is the most radical form of physicalism about the mind. Most Christian physicalists do not hold this view, since it seems to eliminate genuine mental causation and first-person experience. Instead, most Christian physicalists prefer nonreductive physicalism (see above), which tries to preserve the reality of mental properties while denying the existence of an immaterial soul. (See Chapters 2 and 4 for discussion.)
A philosophical problem for physicalist accounts of the resurrection. If a person is entirely physical and ceases to exist at death, then the resurrection would involve God recreating that person — producing a new physical body with the same structure and memories as the one that died. But is this recreated person the same person as the one who died, or merely a copy — a "replica" that has the same properties but is not numerically identical to the original? It is as if God made a perfect photocopy of a painting after the original was destroyed. The copy may be indistinguishable from the original, but it is not the same painting. On substance dualism, this problem does not arise, because the immaterial soul provides continuity of personal identity through death: the same soul that existed before death continues to exist after death and is reunited with a resurrection body. The identity of the person is guaranteed by the persistence of the soul. Philosopher Dean Zimmerman has worked extensively on this problem from the perspective of materialist metaphysics. (See Chapter 24 for extended treatment.)
A Hebrew word meaning "spirit," "breath," or "wind." It is the Old Testament counterpart of the Greek pneuma. In the Old Testament, ruach is used in several ways: it can refer to the Spirit of God (Ruach Elohim; רוּחַ אֱלֹהִים), to the wind, to the breath of life, or to the human spirit. In Ecclesiastes 12:7, the ruach "returns to God who gave it" at death, while the body returns to dust — suggesting a distinction between the physical body and the immaterial spirit. In Isaiah 26:9, the speaker says, "My soul (nephesh) yearns for you in the night; my spirit (ruach) within me earnestly seeks you" — using nephesh and ruach in parallel as terms for the inner, immaterial dimension of the person. (See Chapter 3 for extended discussion.)
The philosophical and theological view that a human being is composed of two fundamentally different kinds of substance: an immaterial substance (the soul or mind) and a physical substance (the body). On this view, the soul is not merely a property or function of the body — it is a distinct, real thing in its own right. You are not just your body, and you are not just your soul — you are both, deeply united. But the soul is the essential "you" — the center of consciousness, the subject of experiences, the bearer of personal identity — and it can survive the death of the body (though this disembodied state is incomplete and awaits the resurrection). Substance dualism has been the dominant view in the Christian tradition for most of church history. It is defended by philosophers such as Richard Swinburne, J.P. Moreland, Charles Taliaferro, and William Hasker (in a modified form), and by theologians such as John Cooper, Joshua Farris, and Michael Wilkinson. This is the position defended throughout this book. (See Chapters 2, 3, 4, and throughout.)
A technical philosophical concept used in discussions of the relationship between mental properties and physical properties. To say that mental properties "supervene" on physical properties means that there can be no change in mental properties without a corresponding change in physical properties. In plain language: if two brains are physically identical in every respect, they must also be mentally identical — you cannot change what someone thinks or feels without changing something about their brain. Nonreductive physicalists often use supervenience to explain the relationship between mind and brain: mental properties are determined by physical properties (supervenience), but they are not identical to or reducible to physical properties (nonreduction). Critics (including substance dualists) argue that supervenience alone does not explain how or why physical processes give rise to conscious experience — it merely describes a correlation without explaining the mechanism. (See Chapter 4 for discussion.)
A Latin term used in medieval philosophy and theology, roughly synonymous with hypostasis. A supposit is an individual, complete, subsisting entity — a thing that exists in its own right and is the ultimate subject of predication (the "who" or "what" to which properties are attributed). Timothy Pawl, drawing on William of Ockham, defines a supposit as a complete being, incommunicable by identity, not apt to inhere in anything, and not sustained by anything. All persons are supposits (since a person is a supposit with a rational nature), but not all supposits are persons — a non-rational animal, for example, is a supposit but not a person. In Christology, Christ's human nature is not a supposit, because it does not exist independently — it is sustained by the Word and exists in the Person of the Son (enhypostasia). (See Chapters 14 and 19 for discussion.)
The process by which human beings are transformed to share in the divine life — to "become partakers of the divine nature," as 2 Peter 1:4 says. Theosis is especially prominent in Eastern Orthodox theology but has parallels in Catholic and some Protestant traditions. The classic statement is attributed to Athanasius of Alexandria: "God became man so that man might become God" — meaning not that humans become God in essence, but that through the Incarnation and the work of the Holy Spirit, human beings are elevated, transformed, and brought into the closest possible union with God. Joshua Farris describes theosis as the process by which "saints become like God in that they exhibit attributes and characteristics that resemble their redeemer," and notes its intimate connection with the beatific vision. The Incarnation is the foundation of theosis: because God took on human nature, human nature can be elevated to participate in divine life. On dualism, the soul is the primary locus of this transformation — the inner person is being renewed and sanctified. On physicalism, theosis would have to be entirely a physical process — the "divinization" of a physical organism. Whether a purely physical being can "participate in the divine nature" in any meaningful sense is a question this book raises. (See Chapter 29 for extended treatment.)
A Greek title meaning "God-bearer" or, more loosely, "Mother of God." This title was officially affirmed for the Virgin Mary at the Council of Ephesus (431). It does not mean that Mary is the origin or source of the divine nature — the Son of God is eternal and existed before Mary. Rather, it means that the person Mary bore in her womb was God the Son incarnate. The child she carried, gave birth to, nursed, and raised was not merely a human being to whom God was later joined — He was, from the first moment of His conception, God the Son in human flesh. The title Theotokos is therefore not primarily a statement about Mary but a statement about Christ: it affirms the unity of His Person. The alternative title Christotokos ("Christ-bearer"), proposed by Nestorius, was rejected because it seemed to imply that Mary bore only the human nature — not the divine Person — which would divide Christ into two persons. (See Chapter 11 for discussion.)
The view that the human soul is not directly created by God at each conception (as creationism holds) but is instead generated or transmitted from the parents along with the body through the process of natural reproduction. Just as the body comes from the parents, so does the soul. Traducianism was favored by some church fathers, including Tertullian, and has the advantage of offering a straightforward explanation for the transmission of original sin from parents to children: if the soul comes from the parents, the corruption of sin can be passed along with it. However, traducianism raises its own difficulties — for instance, how can an immaterial substance be "divided" or "generated" through physical reproduction? Most theologians in the Western tradition have preferred creationism of the soul, though the question remains open. (See Chapter 2 for discussion.)
The view that a human being is composed of three parts: body (sōma; σῶμα), soul (psychē; ψυχή), and spirit (pneuma; πνεῦμα). Trichotomists appeal to passages like 1 Thessalonians 5:23 ("May your whole spirit and soul and body be kept blameless") and Hebrews 4:12 ("piercing to the division of soul and of spirit") as evidence. Most theologians in the Christian tradition, however, have preferred dichotomy — the view that a human being is composed of two parts: body and soul/spirit (with "soul" and "spirit" being different words for the same immaterial reality). This book does not take a strong stand on trichotomy versus dichotomy but operates within a broadly dichotomist framework. The essential point is that humans have an immaterial dimension — whether we call it "soul," "spirit," or both — that is distinct from the body and can survive death. (See Chapter 3 for brief discussion.)
A Latin phrase meaning "the three days of death" — referring to the period between Christ's death on Good Friday and His resurrection on Easter Sunday (Friday, Saturday, Sunday — counted inclusively, as was the Jewish custom). During this period, Christ's body lay dead in the tomb. The triduum mortis is the single most important testing ground for physicalist Christology, and Chapter 21 argues it is the most devastating argument against physicalism about human nature. The question is simple but powerful: What happened to the Incarnation during these three days? On substance dualism, Christ's human soul continued to exist — it departed from the body (as Luke 23:46 and 1 Peter 3:18–19 indicate) and went to the realm of the dead. The Son remained united to both the soul (in the realm of the dead) and the body (in the tomb). The hypostatic union was not dissolved — it was distributed, so to speak, across two locations. On physicalism, there is no soul. When the body died, nothing of the human nature survived. The Son was no longer united to a human nature. The Incarnation was interrupted. The hypostatic union was dissolved. Christ was no longer "true God and true man." This is a Christological catastrophe — a direct contradiction of the Chalcedonian affirmation that the two natures are united "without separation." (See Chapters 21 and 22 for extended treatment.)
A model of the Incarnation developed by philosopher Thomas V. Morris in The Logic of God Incarnate (1986). On this view, the incarnate Christ has two distinct minds — a divine mind and a human mind — operating simultaneously. The divine mind is omniscient and has full awareness of all divine knowledge. The human mind is limited and experiences the world as any ordinary human mind would. The relationship between the two minds is asymmetric: the divine mind has access to everything in the human mind, but the human mind does not have access to the divine mind (except when the divine mind allows it). Morris compared this to the relationship between the conscious mind and a broader, deeper awareness. The two-minds view takes seriously the genuine human limitations of Jesus (He was tired, hungry, surprised, and ignorant of certain things) while preserving His full divinity. This book respects the two-minds view but prefers the kryptic model (Loke), which shares many features with Morris's model but develops the idea of "preconscious" divine attributes more fully and avoids some of the criticisms leveled at the two-minds view — particularly the concern that two complete minds seem to imply two persons. (See Chapter 16 for extended treatment.)
Summary of Key Models: The five major models of the Incarnation discussed in this book are: (1) Kenotic Christology — the Son empties Himself of divine attributes (rejected); (2) Two-Minds View (Morris) — the Son has two distinct minds, divine and human; (3) Kryptic Model (Loke) — the Son retains all divine attributes but conceals them at a preconscious level (the author's preferred model); (4) Conciliar Christology (Pawl) — a rigorous philosophical defense of the councils' formulations; (5) Compositional Christology (Leftow) — Christ is "composed" of the divine nature and a human nature. See Appendix B for a detailed comparison chart.
See Hypostatic Union above.
A near-death experience in which the person reports verifiable information that they could not have known through normal sensory means while they were clinically dead. For example, a patient who accurately describes conversations occurring in another room of the hospital, or objects placed in locations invisible from the operating table, while their heart was stopped and their brain showed no electrical activity. These cases are especially significant for the debate between physicalism and dualism because they suggest that consciousness can operate independently of the brain — which is exactly what one would expect if there is an immaterial soul. If the mind is just the brain, then no perception or awareness should be possible when the brain has shut down. Yet veridical NDEs document exactly such perception. Researchers like Sam Parnia (the AWARE study), Pim van Lommel (the Dutch prospective study), and Michael Sabom (the Atlanta study) have documented such cases with careful controls. (See Chapter 5 for extended treatment.)
The doctrine, affirmed in the Apostles' and Nicene Creeds and grounded in Matthew 1:18–25 and Luke 1:26–38, that Jesus was conceived in the womb of the Virgin Mary by the power of the Holy Spirit, without a human father. The virgin birth is theologically significant for Christology because it is the means by which the eternal Son took on human nature. The Son did not begin to exist at the virgin birth — He is eternal. But His human nature began at that moment. On substance dualism, the virgin birth involves the creation of both a human body and a human soul, united from the first moment of conception to the Person of the Son. On physicalism, the virgin birth produces only a physical organism — a body — without a soul, since physicalism denies the soul's existence. The question of how Christ's human nature was formed at the virginal conception, and whether emergent dualism creates a "Hasker problem" (a temporary Apollinarianism during early fetal development), is discussed at length. (See Chapter 25 for extended treatment.)
A Note on Greek and Hebrew Terms: Throughout this book, Greek and Hebrew terms are transliterated into English letters for ease of reading. Where possible, the original script is also provided in parentheses — for example, psychē (ψυχή) or nephesh (נֶפֶשׁ). You do not need to know Greek or Hebrew to understand this book. Every foreign term is always explained in plain English. The original languages are provided for precision and for readers who want to explore further.
See Logos above.
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This glossary is intended as a working reference, not an exhaustive dictionary. For more detailed treatment of any term, consult the chapter indicated in parentheses. The goal is to ensure that every reader — whether a seasoned theologian or someone encountering these ideas for the first time — can follow the argument of this book with clarity and confidence. If a term appears in the text that is not covered here, a brief definition is typically provided in the chapter where it first appears.