By Marc Cortez
Soul and body, body and soul--how mysterious they were! There was animalism in the soul, and the body had its moments of spirituality. The senses could refine, and the intellect could degrade. Who could say where the fleshly impulse ceased, or the psychical impulse began?
~ Lord Henry Wotton, in The Picture of Dorian Gray by Oscar Wilde
As I sit in my chair typing this chapter, I am clearly an embodied, physical being. I have a spatio-temporal location (i.e., I am in my chair at this moment in time) and dimensions like height, weight, and volume. And yet, at the same time, there seems to be more to me that just my body. I have thoughts, feelings, and other 'inner' experiences that are difficult to equate simply with my physical body alone. Indeed, I even seem able to think of myself as something distinct from my body. I find myself talking about my body, as though it were something that I possessed and used rather than something that constitutes my own being. Sometimes, I even imagine scenarios in which I exist outside my body, or continue to exist after my body dies. What does this all mean? Is my physical body all that there is to me? Or, am I really some non-physical thing—call it a 'soul' or a 'mind'—inhabiting a body for a while? Possibly I am somehow both a body and a soul connected in some mysterious way? Or, maybe there is some other way of understanding all of this. These are the questions that will face us as we seek to understand more deeply the nature of human ontology.
How we understand human constitution has important implications for a range of issues including, among other things, personal identity, consciousness, free will, and the relationship of human persons to other animals, as well as such issues as the beginning and end of human life, the dignity of the human person, the nature and process of salvation, and, ultimately, the fundamental nature of what it means to be 'human'.
The questions surrounding the best way to understand the constitution of the human person, however, have proved remarkably difficult. The first and most obvious reason for this is the sheer number of proposals under consideration. According to one estimate, thinkers have offered no less that 130 different views of human ontology. We can alleviate this difficulty somewhat by restricting ourselves to the most influential theories, but this still leaves us with a substantial number to evaluate. Needless to say, this can prove a daunting task. A second challenge comes from the biblical data. As we will see, although the biblical authors had much to say about being human, they made no attempt to provide a philosophically precise account of human ontology that would generate a decisive answer to the questions proposed above. This presents the opportunity for significant diversity on our question, even among people appealing to the same biblical texts. The number of discrete disciplines that are involved in the discussion likewise complicates matters. Indeed, to do justice to our question, it would seem that we need to be well versed in (at least) the fields of exegesis, theology, philosophy, psychology, biology, physics, and the neurosciences. The impossibility of any individual gaining more than a basic familiarity with so many disparate disciplines leaves many with a feeling of irreparable inadequacy. This last challenge is complicated by the tremendous speed with which contemporary scientific developments are proceeding. The last three decades have witnessed incredible developments in our understanding of the human brain. Thus, although understanding human ontology is vitally important because of its broad range of implications, it remains one of the most challenging questions to address in a Christian anthropology.
The Mind/Body Debate: Consensus and Disagreement
a. Areas of General Consensus
As with many discussions, our best starting point for understanding this particular debate will be to consider the main areas of consensus among Christian scholars working in this area. We can identify four such areas of consensus.
1. Human persons are embodied beings. Nearly everyone affirms that human persons are physical, embodied beings and that this is an important feature of God's intended design for human life. Thus, most biblical scholars agree that although biblical terms like 'spirit', 'soul', 'body', 'flesh', and the like, appear at first glance to refer to 'parts' of the human person, they actually should be understood as referring to the human person as a whole, albeit from different perspectives. So, for example, 'soul' does not refer primarily to the immaterial essence of a human person, but to the whole human person as a living being. Similarly, 'flesh' denotes not simply the physical shell of the person, but the whole person as a creaturely being. Thus, although we will see that there are important differences in how scholars understand the nuances of these terms and the biblical ontology that underlies their use, both Old Testament and New Testament scholars agree that the biblical texts focus primarily on the human person as a whole, psychophysical being. Theologically, as we saw in the previous two chapters, the imago dei and the creation of human persons as gendered beings, both signify the importance of the body for understanding humanity. Similarly, the incarnation and the resurrection affirm the essential goodness of the physical creation and the centrality that physical embodiment has for true human life.
This affirmation of human embodiment means that at least two theories of human ontology are widely regarded as biblically and theologically inadequate. First, idealism, which views the human person as a purely 'spiritual' being, finds few supporters among contemporary thinkers. Second, classic, or 'Cartesian', dualism, which argues that the spiritual and the physical are two, fundamentally distinct, 'parts' of the human person, while not denying the physicality of the human, is widely criticized for its apparent denigration of the body and its overly sharp distinction between the material and immaterial dimensions of the human person. The contemporary consensus, then, maintains that any adequate anthropology must affirm human embodiment in ways that idealism and Cartesian dualism simply are not able to do.
2. Human persons have a real mental life that is important and efficacious. Most agree that we must affirm the reality and significance of humanity's vital spiritual, mental, and emotional life. Human persons have an 'inner' dimension that is just as important as its 'outer' embodiment. From this perspective, then, most Christian thinkers affirm that there are certain aspects of the human person that cannot be entirely explained in 'physical' terms alone. Instead, they affirm that human mental life is a distinguishable aspect of human existence that must be accounted for in understanding such things as mental causation, free will, personal identity, and conscious experiences.
Consequently, the current consensus rejects any reductive theory of human ontology. Such theories understand human persons as strictly physical beings—that is, 'mental' realities are actually identical and explainable as physical realities. The 'mental' language that we use (e.g., thought, feeling, decision, etc.) can either be reductively explained in terms of the underlying physical events that cause them, or should be eliminated from our language entirely as stemming from erroneous ways of thinking about the human person (i.e., the so-called “folk psychology). Neither of these approaches finds much support among contemporary Christian thinkers.
3. We should develop our understanding of the human person in dialogue with contemporary science. We will see that various thinkers differ in precisely how their theories interact with contemporary science, often disagreeing on the particular role that science should play in informing and/or evaluating the various proposals, but there is widespread agreement that our understanding of human ontology should be informed to some degree by modern science; no theory can simply ignore these findings and operate in a theological or philosophical vacuum. Thus, all of the theories attempt to engage and provide some perspective on recent developments in neuroanatomy, neurophysiology, and the cognitive sciences, among others. While not every theory agrees that it can be invalidated by this scientific data, its adequacy or inadequacy will be established at least partly on the basis of how convincingly it can articulate a way of dealing with this information.
4. We must be able to affirm an understanding of the human person that maintains personal identity through death and resurrection. Finally, most Christian theologians affirm that our understanding of human ontology must be sufficient to affirm an understanding of personal identity that can be sustained through such a radical transition as physical death and resurrection. This again suggests that any radical dualism, which might imply that the body is unimportant for true human life, or radical materialism, which would reject the whole discussion as yet another manifestation of folk-psychology, will be inadequate as a Christian anthropology. At the same time, this area of consensus raises some significant challenges as each theory tries to articulate an understanding of personal identity that is consistent with its ontological commitments, while at the same time explaining how this personal identity can be sustained through death and resurrection.
b. The Shape of the Debate
Within the space provided by these points of consensus, we still find Christian thinkers divided on how to understand human ontology. At its most basic level, the debate continues to be shaped primarily by whether one affirms some form of dualism, according to which humans are composed of two distinct substances (i.e.,) or physicalism, in which the human is viewed as an entirely physical entity. As we will see, though, there importantly different ways in which each of these can be formulated.
Although some forms of substance dualism have been largely rejected by contemporary thinkers, newer approaches have modified and clarified these earlier formulations in several important ways, and such modern dualisms continue to be prominent candidates for human ontology. As a theory of human ontology, substance dualism in any of its various forms makes three basic claims.
There are distinct mental realm and physical realms. Substance dualists view it as simply evident that the mental and the physical realms both exist and must be taken into account in any discussion of human constitution. If we look at the human person, we can see that he has 'mental' aspects (e.g., thoughts, intentions, volitions, experiences, etc.) and 'physical' aspects (i.e., a body), and that both of these are real. Dualists will present some formidable arguments in favor of their position, but they also contend that this is simply the 'commonsense' view that has been held by most people throughout history. And, indeed, many physicalists would agree.
The mental and physical realms are both fundamental. Furthermore, substance dualists contend that these realms are both fundamental and, therefore not reducible to anything more basic. That is, neither the mental nor the physical realm is derived from the other, but they both exist independently as fundamental constituents of the universe.
The mental and physical realms are ontologically distinct. Consequently, substance dualists affirm that these two realms are ontologically distinct—i.e., they can (at least) conceivably exist separate from the other. Indeed, the notion of separability is so strongly linked to substance dualism that many identify this as its defining characteristic. And, as ontologically distinct entities, the mental and physical substances are capable of entering into causal relationships with one another. The soul possesses a peculiar causal relation with its body such that it is able to act directly upon the body and be acted upon by the body.
Cartesian dualism construed these two substances in such a way that their fundamental differences made it difficult to understand what relationship they could possibly have with one another. Most contemporary dualists, though, affirm a form of dualism that presents a more 'holistic' understanding of human persons. These thinkers seek an ontology that maintains the basic commitments of substance dualism (i.e., two ontologically distinct substances that are conceivably separable), while still affirming the functional interdependence of the entire person. We can identify at least three prominent forms of this modern substance dualism.
Holistic Dualism. Holistic dualism 'affirms the functional unity of some entity in its totality, the integration and interrelation of all the parts in the existence and proper operation of the whole'. Thus, the human person comprises two distinct 'parts', but these two parts are fully integrated and interdependent such that the organism as a whole only functions properly when both are working in intimate union. Although it remains conceivable that soul and body could be separated at death, and that the person could thus survive physical death in the continuity of the soul, it would be a truncated existence limited by the loss of the psychophysical union.
Emergent Dualism. Another approach that has recently received significant attention is the idea that minds and bodies are integrally related because minds are emergent entities—i.e., mental substances emerge from properly configured physical systems. Thus, William Hasker argues that we should view the human mind as something that is 'produced by the human brain and is not a separate element ‘added to’ the brain from outside.' Such properties are emergent in that
they manifest themselves when the appropriate material constituents are placed in special, highly complex relationships, but these properties are not observable in simpler configurations nor are they derivable from the laws which describe the properties of matter as it behaves in these simpler configurations.
While we will see that there is a form of emergentism that is broadly compatible with physicalist commitments, emergent dualism transcends this approach by arguing that what emerges from the physical substrate are not merely emergent properties, but emergent substances. Thus, although emergent dualists argue for on ontologically deep relation between the mental and physical substances, once the mental substance emerges, it is a distinct substance that is at least conceivably separable from its physical counterpart.
Thomistic Dualism. Finally, a renewed interest in Aristotelian and Thomistic ontologies has generated a number of proposals for understanding substance dualism in terms of the soul as the form of the body. For thomistic ontologies, all material objects comprise a material composite (i.e., the matter from which the person derives) and a substantial form, which determines the essential nature of the object. In the human person, the soul is 'the substantial form…in virtue of which the matter informed by it…constitutes a living human body'. Thomists thus view the soul as 'an individuated essence that makes the body a human body and that diffuses, informs, animates, develops, unifies and grounds the biological functions of its body'. Additionally, thomists generally agree that it is (at least) conceivable that the soul could survive the death of the body, though its existence would be sharply limited.
Substance dualism has long been the subject of stringent criticism. Unfortunately, many criticisms of substance dualism focus almost exclusively on Cartesian dualism, failing to recognize that ways in which modern dualists have moved beyond Cartesian dualism in emphasizing the embodied nature of human life. Frustrated by this, Charles Taliaferro calls for critics of modern dualism to present 'a fairmined, reasoned case against dualism' that takes seriously 'the ways in which a version of dualism may do justice to the unified nature of embodied life'. In this section, we will consider whether these newer forms are as successful against key criticisms as this claim suggests.
The Dissimilarity Argument. Since psychophysical causal interaction is part of the very definition of this type of dualism, questions related to the coherence of its account of mental causation are critical for determining its overall adequacy. The problem of providing an adequate account of the causal relationship between the mental and the physical, however, has long plagued substance dualism, especially in its Cartesian forms. How is it that when I formulate a volition in my non-physical soul (e.g., 'I am going to move my arm now'), this non-physical volition causes a corresponding effect in my physical body (e.g., my arm moves)? Descartes infamously attempted to resolve this problem by locating such causal transaction in the pineal gland. This answer failed to convince anyone, however, and many have concluded that substance dualism is simply unable to provide any kind of adequate resolution to this problem.
The problem of mental causation, however, actually stems from a number of related arguments. Among the oldest and most frequently cited of these objections contends that dualism's account of the two substances renders them so fundamentally different as to disallow any possibility of causal interaction. Causality in the physical world seems to involve things like proximity, energy exchange, etc. And yet these are precisely the kinds of things that non-physical entities do not do—they have no physical location and they do not engage in energy transactions with physical entities (at least on most accounts). They are simply 'different' and, consequently, they cannot engage in causal transactions with physical entities.
Dualists reject this argument for at least two reasons. First they are quick to point out that the differences in view could include fundamentally different kinds of causation—i.e., 'physical' and 'mental' causation. As completely different kinds of causations, we should not expect mental causation to meet the criteria and expectations of physical causation. They are just different. Indeed, some will argue that mental causation is so different as to be ultimately mysterious. This should not trouble us too much, however, according to these thinkers, because physical causation is basically mysterious as well. As we will see in the next section, physicalists have their own problems accounting for mental causation. Dualists, then, contend that all causal relations are inherently opaque and that their position is no more fundamentally mysterious than that offered by the physicalists.
Dualists also feel justified in rejecting this argument in that it fails to provide any defense for its basic intuition. As Jaegwon Kim, himself a physicalist, points out, 'As it stands, it is not much of an argument—it hardly gets started; rather, it only expresses a vague dissatisfaction of the sort that ought to prompt us to look for a real argument. Why is it incoherent to think that there can be causal relations between ‘diverse substances’? The other arguments that we will consider, then, seek to provide exactly such an explanation for why dualistic causation is either incoherent or, at least, improbable.
The Causal Pairing Argument. The causal-pairing argument contends that dualistic causation is incoherent because it cannot provide any explanation for the causal relation that obtains between souls and the bodies. In other words, what makes it the case that my soul interacts causally with my body and not the body of the person next to me? Causal relations in physical systems are typically established by 'non-causal' properties like spatial location, movement, and physical laws. Yet many thinkers contend that there are not any non-causal properties of a non-physical, non-spatial soul that could account for its causal transaction with a particular body—it cannot be located near or within the body, and dualists cannot provide an account of the relevant nomological relationships that might govern such a causal transaction.
Once again, though, the modern dualist has a couple of responses. First, many modern dualists will repeat that mental causation is simply different from physical causation. Consequently, these will contend that mental causation does not need an explanation for this causal pairing—the body-soul causal relation is a brute relation and cannot be established or explained on any other grounds. Another response, however, recognizes the legitimacy of the objection for Cartesian dualism, but denies that it is a problem for modern dualisms. The causal pairing problem seems to be a problem only if dualism entails that 'we do not have the slightest hint of any relation holding' between souls and bodies. But, many modern substance dualists affirm that the soul has precisely such a spatio-causal relation to a particular body and (e.g., it 'emerges' from the body, it is the 'form' of the body, etc.). Consequently, they avoid much of the force of this objection.
The Principles of Science Argument. Many who object to dualist interactionism do so because of a conviction that modern science simply leaves no room for non-physical causes of physical effects. These concerns stem primarily from a commitment to three basic principles:
Causal Completeness of the Physical (CCP): every physical event that has a cause at t has a physical cause at t.
Explanatory Exclusion (EE): ' two or more complete and independent explanations of the same event or phenomenon cannot coexist'.
Conservation of Energy (COE): the total energy of an isolated system remains constant regardless of any changes within that system.
These three principles constitute a significant challenge for substance dualism. CCP proposes that all physical events have physical causes. Thus, a physical event, like my arm rising, must have a physical cause, like the chain of neurons firing that cause the muscles to contract and my arm to rise. According to EE, though, if a physical event has a physical cause and, consequently, can be fully explained as a result of that physical cause, no other explanation is necessary; indeed, all other possible explanations are excluded. Thus, if I can explain the physical event of my arm rising by looking to the sequence of physical causes taking place in my physical body, I cannot also appeal to some non-physical entity as an 'additional' explanation of that event. Taken together, then, CCP and EE entail that all physical events have physical causes and that all physical events, therefore, can be fully explained in terms of their physical causes.
Once again, of course, the dualist could contend that mental causation is just different and does not need to adhere to these principles. Although CCP and EE might be valid methodological commitments for the physical sciences, we should not try to make them metaphysical theses. Some have argued in rejoinder, however, that this counter-argument misses the point of the physicalist objection. Physicalists do not merely criticize dualists for failing to maintain the physicalist framework, but primarily for positing a theory than has little or no support from the physical sciences. Given science’s superior explanatory track record, physicalists argue, we should assume a scientific framework unless and until it is proven wrong. A dualist might fairly ask, however, what would qualify as proof in this argument? Since the framework of the objection rejects the possibility of non-physical causes by definition, it seems unlikely that they would accept anything that transcended this framework. But this predetermines the outcome. Thus, many dualists contend that the problem lies with the limited scope of these physicalist laws, rather than with dualism itself. This does not mean that modern dualists reject science; indeed, many of them rely heavily on the sciences for informing their understanding of how the psychophysical relationship works. But, unlike thinkers who affirm that science is 'all-competent', dualists often contend that science is inherently limited in its ability to speak to the existence and nature of the soul.
A second response, however, notes that the physicalist solution is itself untenable. As we will see, both reductive and nonreductive forms of physicalism struggle to explain mental causation in a way that maintains its commitment to these basic principles while, at the same time, affirming the causal significance of the mental. Many dualists simply contend that given a choice between the two, the dualist framework is superior in terms of its ability to affirm the causal efficacy of the mental and the free agency of the human person.
The third principle, COE, likewise raises some problems for many thinkers. Dualist interaction entails that mental substances are able to cause changes in physical systems. But, since physical causation requires energy transaction, any such change seems to entail a change in the total energy of the physical system, thus apparently violating COE, a fundamental law of modern science. Dualists have offered two kinds of response to this concern. The first is to contend that COE should be understood as a statistical principle and that mental causation would not constitute a violation of COE so long as mental acts only involved small amounts of energy. Thus, as long as the total energy of the physical system remains largely unchanged, COE does not constitute a problem. However, even if individual mental acts only involve small amounts of energy, the tremendous number of mental acts occurring on a regular basis would certainly constitute a statistically significant contribution to the overall state of the system. A second response argues that science only entails a weak form of COE, one that holds only for closed systems. Psychophysical causation, therefore, does not violate COE since mental substances lie outside the physical system. While it is certainly correct that psychophysical causation would not violate a weak form of COE, this approach does not take into account the physicalist’s most likely rejoinder—i.e., (1) the lack of evidence for any mental substances outside the physical system and (2) the weight of evidence that the total state of energy of the physical system does not change both support the conclusion that a strong form of COE is justified even if not logically required.
It would seem, then, that once again the dualist’s best response is to argue that psychophysical causation is simply different than physical causation. In other words, since mental causation differs from physical causation, there is no reason to suppose that mental causation requires the transfer of energy. Even though physical-to-physical causation always requires the transfer of energy, it is not necessary to conclude the same for mental-to-mental or mental-to-physical causation. While the physicalist will certainly not be convinced by this argument, it is logically consistent with the dualist’s own framework.
The Individuation and 'Other Minds' Arguments. Two other problems often raised against Cartesian dualism do not seem to be as difficult for modern forms of dualism. One classic argument contends that dualism has no way of individuating one soul from another. Since Cartesian souls are understood to be non-physical, they cannot be individuated like physical entities on the basis of spatial location. Contemporary dualists, however, insofar as they argue that souls do have spatio-causal relations to particular bodies, should be able to utilize that as the basis for individuating between particular souls as well.
Finally, since dualism affirms a non-physical substance that is unavailable to empirical observation, many contend that dualism entails that human persons can only be confident in their own mentality and must remain agnostic with respect to the existence of other minds. In other words, whether the person across the table is actually a zombie with no mental life at all is something we can never know confidently. This argument, though, is routinely dismissed by dualists, who argue that even though dualism entails that we cannot have indubitable knowledge of other people’s mental states, this does not entail that we must, therefore, be skeptical about their existence.
Physicalism comprises an entirely different approach to understanding human persons, viewing them as completely physical beings (i.e., comprising no additional non-physical or spiritual substance) whose ‘inner’ dimensions (e.g., beliefs, desires, intentions, feelings, etc.) must be understood in terms of their physical bases. Thus, although Christian physicalists reject any form of physicalism that dismisses mental realities entirely or views them as reductively identical with physical realities (i.e., 'strong' physicalism), they are actively exploring physicalist ontologies that maintain a commitment to the reality and significance of the human person's 'inner' life (i.e., 'weak' physicalism).
Weak physicalism can be developed in a number of different ways. Each of them, however, tends to affirm five basic concepts:
The universe comprises a hierarchy of distinguishable 'levels'. According to many philosophers, the various entities in the universe, and the sciences that study them, are best understood hierarchically. Thus, Kim describes the world as
a hierarchically stratified structure of 'levels' or 'orders' of entities and their characteristic properties. It is generally thought that there is a bottom level, one consisting of whatever micro-physics is going to tell us are the most basic physical particles out of which all matter is composed (electrons, neutrons, quarks, or whatever). And these objects, whatever they are, are characterized by certain fundamental physical properties and relations (mass, spin, charm, or whatever). As we ascend to higher levels, we find structures that are made up of entities belonging to the lower levels, and, moreover, the entities at any given level are thought to be characterized by a set of properties distinctive of that level.
We have a picture, then, of the world built up of multiple layers, each of which is ontologically dependent on the layer below it.
The 'mental' cannot be reductively understood in non-mental terms. This construal of the 'levels' of reality, means that higher levels can never be exhaustively understood or explained on the basis of lower-level concepts and theories alone. Unlike strong physicalism, weak physicalism contends that it is not only impracticable to talk about higher-level realities in lower-level terms, but that something significantly new actually takes place on each level that makes it simply impossible to reductively describe these new levels of reality solely on the basis of the lower levels. Thus, although each higher level continues to be ontologically dependent upon lower-level realities, they must be understood on their own terms.
Human persons are fundamentally material beings. As a physicalist theory of ontology, weak physicalism continues to maintain a commitment to ontological monism. Consequently, it rejects any appeal to non-physical substances as an explanation of human ontology. To flesh this out a little further, we can define physicalism as the theory that (a) human persons are either themselves physical entities or are exhaustively composed of physical entities; (b) that all the properties of human persons are either themselves physical properties or are properly related (whatever that proper relation turns out to be) to physical properties; and (c) that all causal processes are either physical processes or are causally dependent on physical processes.
The 'mental' is casually involved in producing physical events. Weak physicalists agree that mental processes, though they are ontologically dependent on lower-level realities, can exercise causal influence over lower-level realities (i.e., downward causation). Weak physicalists thus reject epiphenomenalism—the idea that mental properties are real but causally irrelevant—and dualism—with its affirmation of distinct substances. We will see that maintaining this tension between epiphenomenalism and substance dualism comprises a significant challenge for weak physicalism.
The Asymmetric Dependency of the Mental on the Physical. The hierarchical picture of reality drawn by weak physicalists along with their commitment to downward causation entails the concept of asymmetric dependency. That is, the levels of reality are somewhat interdependent, but since the lower levels are more ontologically fundamental, there is some element of asymmetry in the relationship. In this way the physical is accorded epistemological and ontological primacy, but not ultimacy.
Weak physicalists often explain this asymmetric dependency using one of three different concepts. The first, supervenience, affirms that 'mental properties or states of something are dependent on its physical, or bodily, properties, in the sense that once its physical properties are fixed, its mental properties are thereby fixed'. Thus, supervenience entails that higher-level properties or states (A facts) supervene on lower-level properties or states (B facts) if and only if (1) A facts are real (i.e., they are not merely conceptual); (2) A and B facts are distinct (i.e., they are not simply different ways of referring to the same properties or states); and (3) there is some objective dependency relationship between A and B facts such that A facts cannot change without a corresponding change with respect to B facts.
Though once quite popular, most philosophers now agree that supervenience ultimately fails to ground the asymmetrical dependency that it seeks to affirm. The concern is that supervenience merely establishes the necessary covariation of A and B facts without establishing either how or why this covariation takes place. But covariation by itself is insufficient to ground a properly physical mind-body theory. What is needed is 'a metaphysically deep, explanatory relationship' establishing the asymmetric dependency of mental properties on the physical. Thus, while helpful, supervenience is insufficient by itself.
Consequently, weak physicalists, like some dualists, often appeal to the idea of emergence. In a physicalist system, emergence refers to the conviction that higher-level entities exhibit novel properties that could not have been predicted and cannot be exhaustively explained by lower-level theories alone. This physicalist conception of emergence, then, is distinct from emergent dualism in that it does not affirm the emergence of a new substance. But it does affirm that new properties emerge at each level of reality and that they cannot be epistemologically reduced. Two distinct types of physicalist emergence arise, however, with respect the causal efficacy of these emergent properties and the causal completeness of the physical (CCP). Emergent1 affirms CCP and maintains that the causal efficacy of the mental must be affirmed in such as way as to be consistent with this principle. Emergent2, on the other hand, argues that once higher-levels entities emerge from their lower-level substrate, they exercise autonomous causal powers that are not fully determined by the physical causal framework.
The third term, constitution, asserts that higher-level entities and properties are constituted by but not identical to the lower-level entities and properties that constitute them. For example, they argue that macro-entities—e.g., statues, dollar bills, and persons—are constituted by but are distinct from their copper, paper, and biological constituents. That this should not be understood as an identity relationship, according to constitution theorists, is established by the fact such macro-entities have different properties than their constituent elements. If you melted down a bronze statue and recast it in a new form, the statue would cease to exist, but the bronze would not. Thus, it would seem that although the bronze constitutes the statue, it is not simply identical with the statue. In the same way, persons are constituted by, but are not identical to, their physical bodies.
As a theory of human ontology, physicalism faces its own important criticisms. As we noted earlier, many thinkers affirm that substance dualism is the 'commonsense' understanding of the human person. This, of course, does not actually constitute an argument in favor of dualism since our commonsense notions might well be wrong. Many thinkers, including non-dualist philosophers, however, agree that this commonsense intuition does place the burden of proof on physicalism. In addition, non-physicalist philosophers utilize a number of key arguments against the coherence of weak physicalism.
The Consciousness Argument. Probably the most common argument against physicalism is that mental entities involve certain properties that simply cannot be coherently explained in a physicalist system. Most commonly, critics contend that human mentality is characterized by phenomenal consciousness—i.e., the qualitative feel that we associate with certain mental experiences. In other words, there is something that it is like to experience the taste of an orange, the sight of a sunset, or the feeling of a headache. Although fruits, sunsets, and pains are all physical things, my experience of them does not seem to be. Accounting for these qualia (i.e., properties of phenomenal experiences), has long been regarded as one of the most significant problems for any physicalist ontology. How is it that 'brain processes, which are objective, third person biological, chemical and electrical processes produce subjective states of feeling and thinking'? It does not seem conceivable that there is anything it is like to be an atom or a chemical process, so how does it come about that organisms solely constituted by atoms and chemical processes are characterized by vital subjective lives? There seems to be an 'explanatory gap' between our subjective experiences and our ability to explain them. For many thinkers, this is the 'hard problem' in philosophy of mind. Can we explain how a physical universe can give rise to subjective qualities?
Consistent with their framework, weak physicalists generally affirm the reality of such properties. They contend that humans have a real mental life, that it is characterized by such properties as intentionality and phenomenal consciousness, and that these properties cannot be reductively explained on the basis of non-phenomenal properties alone (contra strong physicalism). Nevertheless, they contend that we do not need to appeal to distinct, non-physical substances to explain the existence of these properties (contra dualism). One way in which the weak physicalist might do this would be to contend that the physical universe actually does have a phenomenological character at its core. The very building blocks of the universe (whatever those might be) have within them at least the potentiality for phenomenal experiences. This kind of 'naturalistic dualism' has received little support, however, given the lack of evidence for this theory and the apparent oddity of affirming that an atom can (even potentially) 'feel' in any way.
A more common approach appeals to the principle of emergence to contend that phenomenal properties are exactly the kinds of unique properties that we should expect to find as we move up to the higher levels of the universe. Many will argue that this is similar to what we see in the concept of 'life' itself. There is nothing that about the non-living matter of the physical universe that would lead us to believe that it could produce living beings. Yet, everyone now concurs that life is the direct result of combining non-living elements in certain ways. Similarly, these theorists argue, phenomenal properties are emergent properties derived from non-phenomenal matter.
Finally, taking a page out of the dualist playbook, a number of physicalists simply contend that phenomenological consciousness lies beyond our ability to explain. Thus, although our commitment to physicalism entails that we must affirm the ultimate physicality of phenomenological consciousness, we may never be able to provide a satisfying physical explanation of it.
The Conceivability Argument. Another classic arguments used to refute physicalism is based on the contention that if it is possible to think about the separation of the body and the soul, then they are conceptually distinct and, consequentially, non-identical. This 'modal' argument, moves from conceivability to metaphysical possibility and can be summarized roughly as follows:
Let 'A' refer to me and 'B' to my body.
1. A is B
2. Given the indiscernibility of identicals, t is not conceivable that A can exist without B or that B can exist without A.
3. But it is conceivable that A can exist without B and B can exist without A.
4. Therefore (1) is false; it is not the case that A is B.
The first premise is established on the basic ontological commitments of physicalism. The validity of the second premise is based on the principle of the indiscernibility of identicals; since the two are identical, it is not conceivable that one could exist without the other. The third premise, though, contends it is conceivable that I can exist independently of my body. This is usually established on the basis of thought experiments like mind-transfers, life after death, and out of body experiences. If it is conceivable that I could exist without my body, however, then it is conceivable that A is not B. Again, given the indiscernibility of identicals, if it is conceivable that A is not B, then A is not B.
The literature on modal arguments in general and this form in particular is quite extensive and lies beyond the scope of this chapter. We will have to content ourselves with noting that the primary physicalist response is to deny the validity of (3). Physicalists will often contend that (3) is either untrue—it is not really possible to conceive of a person without a body—or it is based on faulty ways of thinking—we can only conceive of A and B being separated because we have misunderstood what A is. Either way, the success of the modal argument is based on faulty convictions about what it means to be human. Ultimately, then, the modal argument does a better job of identifying ways in which dualists and physicalists differ in their basic convictions and intuitions than of providing the indubitable logical critique of physicalism that it claims.
The Mental Causation Argument. Given the objections to dualist mental causation in the previous section, it is perhaps ironic that mental causation also constitutes a primary objection to physicalism. Unlike the dualist problem of accounting for the causal interaction of two disparate substances, weak physicalism bears the burden of establishing the causal relevance of mental properties in a physical universe. This becomes critical when we realize that some account of such causal relevance seems necessary for grounding personal agency, moral responsibility, and rational mental processes (more on this in chapter 5).
One key form of this argument contends that weak physicalism is unable to provide an account of mental causation without violating its own ontological commitments. Carsten Hansen helpfully summarizes the main steps in this argument as follows:
(1) Suppose that a mental property instantiation M causes P*.
(2) M has a physical supervenience base P.
(3) On the standard accounts of causation, P qualifies as a cause of P*.
(4) Mental properties are not reducible to physical properties.
(5) M and P are distinct (simultaneous) sufficient causes of P*.
(6) Overdetermination is unintelligible.
Conclusion: Mental-to-physical causation is unintelligible given non-reductive physicalism.
To understand this argument, suppose that I am a weak physicalist and I contend that my mind formulates a volition that causes my arm to move. Of course, as a physicalist, I also affirm that this volition itself has its own physical base. Combine this with a commitment to the causal completeness of the physical (CCP) and it would seem that the physical base of that volition itself qualifies as the cause of my arm moving. Since I am a weak physicalist, the volition is not reducible to its physical base. It would seem, then, that I am affirming that the volition and its physical base both cause my arm to move. The idea that there can be two simultaneous and sufficient causes of the same event, however, is either incoherent or, at best, unnecessary. Thus Jaegwon Kim, the most prominent proponent of this argument, concludes that best way to account for mental causation in a physical world is either to affirm that the volition and the physical state are simply identical (reductionism) or that the volition is not causally relevant (epiphenomenalism).
Weak physicalists have offered three general responses to this argument. The first approach contends that the entire argument is invalid because it would ultimately undermine all higher-level properties and invalidate the sciences that study such higher-level realities (e.g., psychology, sociology, etc.). Consistently applied, then, the argument reduces everything to physics. This argument, though, simply points out the implications of the exclusion argument, without really providing a decisive argument for rejecting it.
Theists will often contend that if we affirm the possibility of divine action in the physical universe, then we have grounds for affirming that not all physical events have sufficient physical causes. This argument does not seem to be of much assistance to the physicalist, however, insofar as she does not want to portray the mental as a substance distinct from the physical realm, as would seem required by the analogy with divine agency.
Another set of arguments tries to construe mental causation in such a way as to avoid the implications of Kim's argument. One common approach has been to argue that when you are dealing with complex systems, like the human person, the entire system exercises causal influence on the behavior of its constituent elements. Although higher-level properties are ontologically dependent on their lower-level constituents, when they are combined into complex systems, they begin to exercise top-down causal efficacy with respect to these lower-level realities. Thus, the complex system that comprises human mentality can exercise top-down control of the lower-level physical system that comprises it. At the same time, the mental life of the human person is itself subject to top-down influence from higher-level social and contextual realities. It is, therefore, impossible to account for the behavior of any complex system in terms of its constituent elements alone; the system itself must be brought into the discussion as having an important causal role to play. Consequently, mental causes are not in competition with physical causes. Rather, they play a different role in the total causal process.
This argument, however, runs into at least one important problem. It is important to realize that, for the weak physicalist, no matter how high up in the system you go, higher-level entities are always asymmetrically dependent on their microphysical bases. If that is the case, any systemic influence these mental properties have is simply a larger part of the whole microphysical causal process. For example, suppose that some lower-level system has the potential to produce effects X, Y, and Z. Then, suppose that some higher-level system, s, acts on that lower-level system and causes it to activate Z from among those options. But, s is itself asymmetrically dependent on its own lower-level base, b. As such, we can say that b causes s. Thus, even if we say that s causes Z, it does so only insofar as it is caused by b. At this point, we are left with the conclusion that even if it is helpful to appeal to s in our causal account of Z, we are simply putting a higher-level 'label' on what is essentially a reductively deterministic process. If this is the case, mental causation is simply physical causation in disguise.
The Personal Identity Argument. One final issue that has often been raised as a problem for any physicalist ontology deals with the continuity of personal identity. In a theological context, the question usually arises around the need to explain the continuity of personal identity through physical death and resurrection. Since the physicalist views the human person as identical to her body (or, nearly so, according to the constitution view), the human person cannot continue to exist separate from her body. If this is so, when my body dies, I will no longer exist. If God brings a bodily organism to life 2,000 years later, what makes it the case that this bodily organism is me and not a mere replica of me? The question that emerges, then, is, 'Under what circumstances is some person who exists at one time, a, numerically identical with something that exists at another time, b?'
Physicalists offer three general ways of understanding the continuity of the human person through time. The first response looks to biological continuity as the criterion for continuous personal identity. Thus, the body itself grounds personal identity. For these thinkers, though, ‘body’ means more than a mere collection of physical parts, the persistent identity of which is notoriously difficult to establish. Instead, these philosophers assert material continuity in virtue of their understanding of the human body as a self-sustaining living organism. On this view, two entities, a and b, are identical just in case b is simply a later temporal stage in a continuous biological organism of which a was an earlier stage.
A problem arises for such an account, however, when we consider the resurrection. If continuous personal identity requires the continuity of a living organism, how can you have any continuous personal identity after the death of the biological organism? One possibility would be to argue that the causal connections necessary for such biological continuity are able to cross temporal gaps such that b could be part of the same biological organism as a even though there was a time when the biological organism, of which they are temporal stages, did not exist. The possibility of such a temporally ‘gappy’ existence, however, has been rejected by most philosophers as being incoherent within a physicalist framework. The primary alternative to such an account has been to suggest that although there can be no biological continuity beyond the death of the biological organism, it is at least conceivable that God could intervene at the death of the person so at to miraculously continue biological life despite the appearance of death. At least two different ways have been suggested for how God might accomplish this. According to Peter van Inwagen, God could create a simulacrum in place of the person’s corpse, which God whisks away to be miraculously preserved until the resurrection. Kevin Corcoran, on the other hand, suggests that a better, and less theologically disturbing, proposal would be to imagine that God copies a person’s 'simples' (i.e., the basic microphysical components of the human body) such that one set becomes a corpse and the second set continues the biological life of the person. Either way, the basic premise remains the same. Despite the difficulties of establishing biological continuity, these thinkers argue that it is conceivably within God’s power to intervene and sustain biological identity.
One could object, of course, that such proposals are highly sensational and speculative and that they have no ground in biblical texts or theological traditions. And this objection certainly has some validity. At the same time, we must acknowledge that the resurrection is an essentially mysterious event. Consequently, we cannot expect any theory to do more than posit hypothetical examples of how an identity theory might be constructed. Thus, difficulties raised regarding the believability of a particular identity theory must be set aside in the face of something as inscrutable as the resurrection. We will focus instead on questions of coherence and adequacy. Additionally, while we should be cautious with appealing to deus ex machina solutions to challenging problems, since the resurrection necessarily entails divine agency, we should assume that it is appropriate to invoke divine involvement to a certain extent.
Other physicalists argue that what really matters is psychological continuity. Using thought experiments like transferring a mind from one body to another or gradually replacing a human person’s biological parts with entirely synthetic parts, these thinkers argue that the identity of the human person is most closely associated with her mental states, and that even a total lack material continuity would not preclude continuity of identity. From this perspective a and b are identical just in case there is mental continuity between them that is appropriately connected. On this view a theory of the resurrection could simply be constructed around the conceivability of God transferring the relevant mental states from one body to another.
A key objection to the psychological continuity criterion is the problem of duplication. In other words, suppose that at the resurrection God decided to copy my relevant mental states twice and place these mental states in two different bodies. If psychological continuity is all that is necessary to ground personal identity, it would seem that both of these future versions of me would have equal claim to being me. And, of course, the problem could be multiplied by supposing that God were to create thousands of different versions of me (a truly terrible prospect!) all with an equal claim to being me. There would seem to be no way of discerning which one was 'actually' me.
The physicalist has a few options for responding to this concern. First, she could contend that identity is only sustained in cases where there is no such duplication. Any such duplication necessarily results in the loss of continuous identity. But why should this be the case? Surely if mental continuity is sufficient for personal identity, it should still be sufficient even if the mental state is copied? There does not seem to be anything necessary to the simple fact of duplication that would render the identity relationship void. Second, our physicalist could argue that all we need to affirm is that there is significant continuity between the present me and the future me, strict identity is unnecessary. The Christian doctrine of the resurrection, however, requires a much stronger view of continuous personal identity. Surely it is important that I will be resurrected and not merely some being that has a lot in common with me. It is not at all clear, then, that psychological continuity alone will suffice to ground a theological perspective on personal identity.
Finally, some argue that there are no necessary criteria that ground personal identity. This does not mean, however, that it is never possible to explain how a could be identical with b, it may in fact be possible to do this in many cases, but the no-criteria solution rejects the possibility that we could devise metaphysical criteria that would establish the identity of a and b in every case. Though we can affirm that identity persists, we will, not always be able to explain it.
This approach can be fleshed out in two different directions. One would be to concede that there are no strong criteria of identity, and argue instead that identity is grounded in a person's first-person self-representation of a coherent narrative. Thus, present-me and future-me are identical so long as I understand myself in both cases to be the single subject of a continuous narrative. I would never be able to establish to a third party that future-me is the same person as present-me, there are no criteria that could do this, but I can be confident in my own continuous identity as the subject of the same story. Such an approach, however, leaves itself open to concerns about manipulation. Suppose that some evil scientist figures out how to completely wipe a person's memory and replace them with my memories. That person would now understand himself to be the continuous subject of my narrative. Since this approach maintains that there are no objective grounds for establishing personal identity, it would seem that he has an equal claim to being me simply in virtue of the fact that he believes it to be the case. This will not do.
A second way to approach the no-criterion solution, argues that although no single criterion is sufficient to ground personal identity, there may be some set of criteria that are jointly sufficient for that purpose. Physicalists opting for this approach contend that most people think of personal identity as comprising multiple aspects—including physical, psychological, and relational factors. Thus, my wife can have confidence that I am the same person at the end of the day as I was at the beginning of the day because of my bodily continuity (I did not change bodies during the day), psychological continuity (I have the same knowledge and memories as earlier), narratival continuity (I still understand myself to be the same person I was before), and even relational continuity (we stand in the same relationship to one another). Though none of them suffice on their own—I could be the same person even if I suddenly thought I was someone else—together they present a compelling case for continuous personal identity. A problem with this approach, though, is that if each of these elements can be individually challenged as providing an adequate account of personal identity, it is not clear that combining them really helps strengthen the case. In other words, if I have been convinced by the arguments above that the individual criteria all fail to establish personal identity, then it would seem that combining them would similarly fail—e.g., God could create multiple beings who are biologically, psychologically, and narrativally continuous with present-me. A combination of criteria might incline me to believe more strongly in someone's personal identity (epistemology) but it is no more likely to actually establish that identity (ontology).
c. The Current State of the Debate
Many contemporary philosophers believe that developments in the modern sciences have rendered substance dualism obsolete, such that dualism is no longer ‘a serious view to contend with’. The ontological debate, however, is not so easily resolved. First, as we have seen, modern forms of dualism have been developed that offer new ways of interacting with the results of the modern sciences and responded to classic criticisms. Thus, instead of being eliminated by modern science, the vibrancy of modern dualism can be seen in the fact that the last several decades have witnessed a proliferation of non-physicalist ontologies—e.g., emergent dualism (Hasker), holistic dualism (Cooper), naturalistic dualism (Chalmers), integrative dualism (Taliaferro), and Thomistic dualism (Moreland), as well as other ontologies that do not fit easily into the physicalism/dualism framework like idealism (Foster), pluralism (Cartwright), and Aristotelian hylomorphism (Nussbaum).
At the same time, there is a growing realization that although we now know more than ever about the nature and function of the human brain, we are still struggling to understand its relationship to human mentality. Thus, despite the progress of philosophy of mind and the cognitive sciences throughout the twentieth century, we remain limited in our ability to provide a theoretical framework for interpretation that information. As Steven Rose notes, ‘we are still data-rich and theory-poor’. We can see this theoretical limitation at work in the variety of ontological theories claiming the moniker ‘physicalism’ and yet differing substantially in how human ontology should be understood—e.g., nonreductive physicalism (Van Gulick), dual-aspect monism (Jeeves), constitutional materialism (Corcoran), and emergent monism (O’Conner), as well as the more reductive forms that continue to have significant supporters (e.g., Dennett, Churchland, etc.).
Thus, the debate about human ontology is still very much alive and well, with a number of important theories being offered on both sides. As Kevin Corcoran states, 'the mind-body problem remains wide open'.
A Way Forward: Thinking Theologically about Human Ontology
The mind/body debate is an argument about the best theory for understanding human ontology; and, as we have seen, it is a debate with significant implications for a range of issues. Yet, the Bible does not provide an indisputably clear perspective on this issue. Quite a number of studies have focused on the biblical material related to human ontology. Unfortunately, the same physicalist/dualist debate that we find in philosophy and theology rages among biblical scholars as well. Although the majority of recent biblical scholars have argued in favor of a physicalist depiction of the person in the Bible, there is no shortage of scholars contending for a more dualistic conception. It seems unlikely, then, that the debate will be resolved at the level of biblical interpretation alone because the Bible just does not seem concerned with presenting a theoretically rigorous account of human ontology. Instead, it provides a theological framework, a way of thinking theologically about the human person, which has implications for what qualifies as an adequately Christian mind/body theory.
As we discussed in the opening chapter, any adequately Christian anthropology needs to begin with an understanding of human persons as imago dei beings. And, orienting anthropology in this way has significant anthropological implications. We identified seven things that Christian anthropology needs to affirm about the nature of human persons: christocentrism, relative uniqueness, mystery, relationality, responsibility, embodiment, and brokenness. These imago dei affirmations, if they truly are central affirmations of a Christian anthropology, should be able to serve as key points in a biblical framework for understanding human ontology. In other words, any adequately Christian anthropology must be able to affirm each of these coherently (i.e., in a way that is consistent with its own ontological commitments). To the extent that any theory of human ontology is unable to do so, that theory must be viewed as less than adequate and, at least, in need of serious revision before it can serve as an aspect of a theological anthropology. On the other hand, any theory capable of coherently affirming these assertions, should be viewed as theologically adequate and worth pursuing more fully.
So, what happens when we apply this theological framework to the particular dualist and physicalist theories that we have discussed in this chapter? At least some of the affirmations seem entirely consistent (or, at least, potentially consistent) with both approaches. As we have seen, many dualists openly espouse the mystery of the human person, affirming that there is something about humanity that will always escape understanding. Physicalists, on the other hand, might seem more susceptible to criticism on this point since they view the human person as an entirely material being and, consequently, at least theoretically open to scientific explanation at every turn. As we have seen, though, weak physicalism affirms the emergence of higher level properties and complex systems with novel properties that cannot be comprehensively understood on lower-level terms alone. At the very least, the weak physicalist can affirm significant mystery at these higher levels. Indeed, given the complexities involved in understanding the universe at its most fundamental levels (e.g., quantum mechanics, string theory, etc.), many physicalists are willing to affirm mystery here as well.
Similarly, it might seem that each approach struggles somewhat with the relative uniqueness of the human person. Physicalist theories occasionally sound as though they have lost sight of the uniqueness of the human person, portraying humans as virtually inseparable from the rest of creation. While this might be a necessary implication of strong physicalism, however, weak physicalism has no difficulty affirming that human properties are 'emergent' in ways that set them apart form other animals. Thus, although there is nothing that separates humans from animals ontologically—we are all physical creatures—humans still exhibit 'higher level' properties, capacities, and behaviors that are unique in creation. Dualists, on the other hand, are often critiqued for losing sight of the relativity of human uniqueness, portraying the human 'soul' and its capacities as completely without parallel in creation. Thus, many dualists have argued that only human persons have souls, sometimes going so far as to contend that other animals are merely biological machines. Nonetheless, modern dualists present a much different picture of human uniqueness. Many of these thinkers explicitly incorporate animal 'soulishness' into their ontologies, with some affirming an evolutionary account of the human soul.  Both approaches, then, are able to affirm the relative uniqueness of the human person in creation, even if some forms of each press too far toward either extreme.
A second point, christocentrism, raises more pressing questions. All of the theories that we have discussed are quite able to affirm that Jesus Christ should be the starting point for any adequate understanding of the human person. However, some have questioned the adequacy of a physicalist ontology at precisely this point. First, some have claimed that only a dualist ontology is capable of supporting an orthodox understanding of the incarnation. It is not entirely clear, though, why this should be so. Surely the mystery of the incarnation is sufficiently broad and deep to encompass either set of theories. As we have seen, though, a more significant challenge arises with the resurrection. The biblical narratives clearly portray Jesus as the same person both before and after the resurrection. Indeed, the soteriological significance of Jesus' death, resurrection, and ascension would seem to require that he be the same human person throughout. Yet, we have seen that significant questions remain as to whether a physicalist ontology is capable of coherently affirming any such notion of personal identity.
Additionally, despite the fact that many theologians from each perspective would affirm the significance of Christology for understanding the human person, neither approach has really engaged Christology in their own understanding of human ontology. Indeed, many seem more concern about the implications that a particular theory might have for our understanding of Jesus, than exploring how the person and work of Jesus should inform our understanding of human ontology. Unquestionably, more work needs to be done here.
Finally, each approach faces some important challenges with respect to responsibility. As we have seen, some account of responsibility is necessary to ground human relationality, moral accountability, and their role as imago dei beings in creation. On most accounts, however, responsibility requires that human persons be able to formulate thoughts and volitions that are causally efficacious in the production of their actions. In other words, responsibility requires mental causation. Both dualism and physicalism, though, face serious questions with respect to their understanding of mental causation. The physicalist account of mental causation seems trapped between its commitment to the causal completeness of the physical world and its claim that mental entities are real and causally efficacious. Thus, weak physicalist seems forced either to deny of one of these core convictions or to appeal to the existence of multiple sufficient causes for the same event (overdetermination). Since neither of these options is palatable to most weak physicalists, more work is needed to explain how weak physicalism can offer a coherent account of mental causation and moral responsibility.
Dualists, however, have problems of their own. Although modern dualists strongly affirm the integral relationship between the mind and the body in human life, in their account of mental causation, dualists frequently accentuate the fundamental differences between the mental and physical substances. Mental causation is often portrayed as ultimately mysterious and its connection with physical events as simply inexplicable. To the extent that they do this, however, dualists begin to undermine their own commitment to the psychophysical nature of embodied human life. If the connection between the mind and the body is entirely opaque and mysterious, how can we truly affirm that they are as tightly interrelated as the contemporary dualist claims? Here as well, more reflection is needed.
Thus, mental causation remains a problem for both accounts. Since it is a problem for both, however, it can hardly constitute a decisive objection against either. Indeed, given the inherent difficulties in trying to provide an adequate account of causation in general, let alone mental causation, we should not be too surprised by these struggles.
This leads us to a final area, that of embodiment. Physicalism affirms the embodied nature of human life in very clear ways, sometimes to the extent that their account of personal identity becomes problematic. Dualists, however, have long been criticized for denigrating or, at least, devaluing the nature of the body. Although contemporary dualism goes a long way toward alleviating some of these concerns, more work needs to be done. We have just seen that the dualist account of mental causation seems to undermine their emphasis on embodiment. The dualist description of the state of the human person between death and resurrection is often problematic as well. All dualists affirm the conceivability that the mind (and, typically, the person) can continue to function, to some extent, independently of the body. Although most contemporary dualists contend that this would be a truncated existence, severely limited by the loss of the body, thus emphasizing the integrated nature of humanity's psychophysical constitution, their descriptions often suggest otherwise. On one account, 'human persons in the interim state can be spoken of as having experiences, beliefs, wishes, knowledge, memory, inner (rather than bodily) feelings, thoughts, language (assuming memory or earthly existence) - in short, just about everything that makes up what we call personality'. If all of these things can function independently of the body, we must raise real questions about how seriously the embodied nature of human life is really being taken.
What am I? Am I a physical thing? Am I a spiritual thing? Am I some combination of the two? Am I something else entirely? These questions continue to generate heated debate among Christian thinkers and are unlikely to be resolved in the near future. Indeed, at this point in the conversation, it is difficult to picture what a resolution to this issue would even look like. Our approach in this chapter, consequently, has been to find a way of thinking through the issues, rather than trying to resolve the debate itself. Thus, I have argued that what is most important in this discussion, is that we make sure that our understanding of human ontology, whatever it might be, is capable of sustaining the core affirmations that we need to make about the human person is order to have a theologically adequate understanding of humanity. An ontology that rejects any of these affirmations must be rejected as a viable option for an adequate anthropology.
Ideally, we are seeking an ontology that can affirm all of these things about the human person and do so in a way that is entirely consistent with its own ontological commitments. As we have seen, though, most of the options on the table struggle to provide coherent explanations of at least a few of these affirmations. As long as this remains the case, it would seem that our best course of action would be to hold any ontology on a tentative and provisional basis.
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Rose, Steven P. R., 'Introduction: The New Brain Sciences', in David A. Rees and Steven P. R. Rose (eds), The New Brain Sciences: Perils and Prospects, pp. 3-14.
Searle, John R., The Rediscovery of Mind (Cambridge, Mass: MIT Press, 1992).
Stump, Eleanore, 'Non-Cartesian Substance Dualism and Materialism without Reductionism', Faith and Philosophy 12 (1995), pp. 505-31.
Taliaferro, Charles, Consciousness and the Mind of God (Cambridge: CUP, 1994).
van Cleve, James, 'Mind-Dust or Magic? Panpsychism Versus Emergence', Philosophical Perspectives 4, Action Theory and (1990), pp. 215-26.
Van Inwagen, Peter, Ontology, Identity, and Modality (Cambridge: CUP, 2001).
———, 'Possibility of Resurrection', International Journal for Philosophy of Religion 9.2 (1978), pp. 114-21.
Wolff, Hans Walter, Anthropology of the Old Testament (trans. Margaret Kohl, London: SCM, 1974).
Zimmerman, Dean, 'Materialism and Survival', in Eleanore Stump and Michael J. Murray (eds), Philosophy of Religion: The Big Questions, pp. 379-86.
 For the purposes of this study, I will use the terms 'mind' and 'soul' interchangeably.
 Graham McFarlane, 'Review of Niels Henrik Gregersen, The Human Person in Science and Theology (London: T. & T. Clark, 2000), Science and Christian Belief 14 (2002), pp. 94-95.
 Cf. Robert Jewett, Paul's Anthropological Terms (Leiden: Brill, 1971); Hans Walter Wolff, Anthropology of the Old Testament, trans. Margaret Kohl (London: SCM, 1974).
 e.g., Jaegwon Kim, Supervenience and Mind: Selected Philosophical Essays (Cambridge: CUP, 1993).
 e.g.,Paul M. Churchland, 'Eliminative Materialism and Propositional Attitudes', Journal of Philosophy 78 (1981), pp. 67-90.
 For useful summaries of some of these developments see Malcolm Jeeves, 'Mind Reading and Soul Searching in the Twenty-First Century: The Scientific Evidence', in Joel B. Green (ed.), What About the Soul? Neuroscience and Christian Anthropology (Nashville: Abingdon, 2004), pp. 13-30.
 In philosophy of mind, ‘dualism’ can be used with reference to a duality of substances (as here), properties (i.e., distinct mental and physical properties of a single substance), or predicates (i.e., semantic duality that is not reflected ontologically). In this chapter, we will use the term ‘dualism’ to refer to a dualism of substances in the human person.
 E.g., Moreland and Rae, Body & Soul, p. 17.
 We must emphasize, though, that dualism need only affirm the conceivability of such ontological separation and not necessarily its actuality.
 John W. Cooper, Body, Soul, and Life Everlasting (Grand Rapids: Eerdmans, 2000), p. 45.
 E.g., Karl Popper, Knowledge and the Body-Mind Problem: In Defense of Interaction (London: Routledge, 1994); William Hasker, The Emergent Self (Ithaca: Cornell University Press, 1999).
 Hasker, The Emergent Self, p. 189.
 William Hasker, The Emergent Self (Ithaca: Cornell University Press, 1999), pp. 189-90.
 E.g., David Braine, The Human Person: Animal and Spirit (Notre Dame: University of Notre Dame Press, 1992); Eleanore Stump, 'Non-Cartesian Substance Dualism and Materialism without Reductionism', Faith and Philosophy 12 (1995), pp. 505-31.
 Eleanore Stump, 'Non-Cartesian Substance Dualism and Materialism without Reductionism', Faith and Philosophy 12 (1995), pp. 505-31 (508) (cf. Summa Theologica Ia.76.1). It is important, then, not to confuse form with shape. The form is that which determines the essential nature of the entity, which certainly has a bearing on its shape, while the shape is a function of its material elements.
 J. P. Moreland and Scott B. Rae, Body & Soul: Human Nature and the Crisis in Ethics (Downers Grove, IL: InterVarstiy, 2000), p. 202.
 Charles Taliaferro, Consciousness and the Mind of God (Cambridge: CUP, 1994), p. 568.
 Jaegwon Kim, 'Lonely Souls: Causality and Substance Dualism', in Kevin Corcoran (ed.), Soul, Body, and Survival: Essays on the Metaphysics of Human Persons (Ithaca: Cornell University Press, 2001), pp. 30-43 (32).
 Cf. esp. John Foster, 'Psychophysical Causal Relations', American Philosophical Quarterly 5.1 (1968), pp. 64-70.
 Joshua Hoffman and Gary S. Rosenkrantz, Substance: Its Nature and Existence (London New York: Routledge, 1997), p. 197.
 Jaegwon Kim, 'Supervenience', in Hans Burkhardt and Barry Smith (eds.), Handbook of Metaphysics and Ontology (Munich Philadelphia: Philosophia Verlag, 1991), pp. 119-38 (250).
 Peter Atkins, 'Purposeless People', in edited by Arthur Peacocke and Grant Gillett (eds.), Persons and Personality: A Contemporary Inquiry (Oxford: Basil Blackwell, 1987), pp. 12-32 (13).
 Apparently this objection was first formulated by Leibniz (Edward Averill and B. F. Keating, 'Does Interactionism Violate a Law of Classical Physics?' Mind 90.357 (1981), pp. 102-07).
 Robert Larmer, 'Mind-Body Interaction and the Conservation of Energy', International Philosophical Quarterly 26 (1986), pp. 277-85 (277).
 Karl R. Popper and John Carew Eccles, The Self and Its Brain: An Argument for Interactionism (New York: Springer International, 1977).
 E.g., Averill and Keating, 'Does Interactionism Violate a Law of Classical Physics?'
 Some have argued that quantum science provides support for the idea that physical systems are not 'hermetically sealed off from "outside" forces' (Taliaferro, Consciousness and the Mind of God, p. 221). Whether such appeals to quantum mechanics can provide the necessary support for dualist causation, though, would require a far more extensive understanding and analysis of quantum theory than is possible in this chapter and, indeed, than is normally offered by dualists appealing to it (though cf. Roger Penrose, The Emperor's New Mind (Oxford: OUP, 1989)).
 Although the Cartesian dualist could posit some non-spatial relation to individuate souls or some other metaphysically deep, but epistemologically unavailable principle of individuation (e.g., haecceity), but they have yet to provide a meaningful explanation of what such an account might be.
 Jaegwon Kim, 'The Non-Reductivist's Troubles with Mental Causation', in John Heil and Alfred R. Mele (eds.), Mental Causation (Oxford: Clarendon, 1993), pp. 189-210 (190).
 Jaegwon Kim, 'The Mind-Body Problem after Fifty Years', Royal Institute of Philosophy Supplement 43 (1998), pp. 3-21 (7).
 Kim, 'The Mind-Body Problem after Fifty Years', p. 10.
 For a good overview of emergence and its historical development see Ansgar Beckermann, H. Flohr, and Jaegwon Kim, Emergence or Reduction? Prospects of Nonreductive Physicalism (Berlin: Walter de Gruyter, 1992).
 These labels come from John R. Searle, The Rediscovery of Mind (Cambridge, Mass: MIT Press, 1992). Since many question whether emergent2 qualifies as a truly physicalist ontology, suspecting that it is actually a form of dualism in disguise, we will focus in this chapter on emergent1.
 Lynne Rudder Baker, 'Why Constitution Is Not Identity', Journal of Philosophy 94.1 (1997), pp. 599-621.
 E.g., Michael E. Levin, Metaphysics and the Mind-Body Problem (Oxford: Clarendon, 1979); There are some, though, who argue that physicalism is actually the more intuitive approach (e.g., Peter van Inwagen, 'Dualism and Materialism: Athens and Jerusalem?' Faith and Philosophy 12.4 (1995), pp. 475-88). In some ways, then, we are dealing with a conflict of basic intuitions that makes negotiating the various arguments quite difficult.
 John R. Searle, 'Consciousness' (accessed 8 Oct 2005) http://humanities.ucsc.edu/NEH/searle1.htm.
 Joesph Levine, 'Materialism and Qualia: The Explanatory Gap', Pacific Philosophical Quarterly 64 (1983), pp. 354-415.
 This could be construed in terms of (1) ‘panpsychism’, or the theory that all physical entities have intrinsic phenomenal properties, (2) ‘protophenomenal properties’, the theory that all physical entities have properties that are disposed toward the production of phenomenal properties, or (3) ‘neutral monism’, that is, the idea that physical and mental properties are properties of some fundamental substance that is itself neither mental nor physical.
 E.g., Daniel Stoljar, 'Physicalism and Phenomenal Concepts', Mind & Language 20.5 (2005), pp. 469-94.
 This is a modified form of the argument presented in Taliaferro, Consciousness and the Mind of God, p. 175.
 Constitution theorists, though, would differ on this point and would respond differently to this argument. Nonetheless, most physicalists affirm some kind of identity relationship between mind and body.
 see William Hasker, 'Swinburne's Modal Argument for Dualism: Epistemically Circular', Faith and Philosophy 15.3 (1998), pp. 366-70; Stewart Goetz, 'Modal Dualism: A Critique', in Kevin Corcoran (ed.), Soul, Body, and Survival: Essays on the Metaphysics of Human Persons (Ithaca: Cornell University Press, 2001), pp. 89-104.
 Carsten Martin Hansen, 'Between a Rock and a Hard Place: Mental Causation and the Mind-Body Problem', Inquiry 43.4 (2000), pp. 451-92 (470).
 By rejecting the possibility that the body as a materially composite entity could be the ground of personal identity, these thinkers all reject the classic 'reassembly' version of the resurrection.
 Peter Van Inwagen, 'Possibility of Resurrection', International Journal for Philosophy of Religion 9.2 (1978), pp. 114-21.
 Kevin Corcoran, 'Physical Persons and Postmortem Survival', in Kevin Corcoran (ed.), Soul, Body, and Survival: Essays on the Metaphysics of Human Persons (Ithaca: Cornell University Press, 2001), pp. 201-17. Corcoran also has to respond to the objection that that God could create multiple biological organisms who are all biologically continuous with the same person, since such an account would render Corcoran’s identity theory untenable. He responds by simply stating that God would not participate in such an action (Corcoran, 'Physical Persons'). Though this certainly seems reasonable, it is not clear that he has sufficiently addressed the problem that his solution raises for Kripke's notion of strict identity (cf. Saul A. Kripke, 'Identity and Necessity', in John Heil (ed.), Philosophy of Mind: A Guide and Anthology (Oxford: Oxford University Press, 2004), pp. 128-33). Van Inwagen’s solution, though problematic as well, at least avoids this problem.
 Although the intermediate state often factors into the discussion at this point, Lynn Baker rightly argues that an intermediate state by itself does not raise any issues for physicalist ontologies that do not already arise with respect to resurrection in general (Lynne Rudder Baker, 'Need a Christian Be a Mind/Body Dualist?' Faith and Philosophy 12.4 (1995), pp. 489-504).
 Cf. Trenton Merricks, 'Endurance, Psychological Continuity, and the Importance of Personal Identity', Philosophy and Phenomenological Research 59 (1999), pp. 983-97.
 Van Inwagen goes even further and argues that the very nature of the psychological-continuity theory is fundamentally incompatible with a physicalist ontology (Peter Van Inwagen, Ontology, Identity, and Modality (Cambridge: CUP, 2001), pp. 144-61).
 E.g., Trenton Merricks, 'There Are No Criteria of Identity over Time', Nous 32 (1998), pp. 106-24; Nancey Murphy, 'The Resurrection Body and Personal Identity: Possibilities and Limits of Eschatological Knowledge', in Ted Peters, Robert J. Russell, and Michael Welker (eds.), Resurrection: Theological & Scientific Assessments (Grand Rapids: Eerdmans, 2002), pp. 202-18.
 Daniel Dennett, Brainstorms: Philosophical Essays on Mind & Psychology (Montgomery, Vt.: Bradford, 1978).
 Steven P. R. Rose, 'Introduction: The New Brain Sciences', in David A. Rees and Steven P. R. Rose (eds.), The New Brain Sciences: Perils and Prospects (New York: CUP, 2004), pp. 3-14 (5).
 Kevin Corcoran, 'Introduction', in Kevin Corcoran (ed.), Soul, Body, and Survival: Essays on the Metaphysics of Human Persons (Ithaca: Cornell University Press, 2001), pp. 1-11 (11).
 Among the classic older studies are Walther Eichrodt, Man in the Old Testament, trans. R. Gregor Smith (London: SCM, 1951); John A. T. Robinson, The Body: A Study in Pauline Theology (Chicago: Regnery, 1952); Rudolf Karl Bultmann, Theology of the New Testament, vol. 2 (New York: Scribner, 1951); Werner Georg Kümmel, Man in the New Testament, trans. John J. Vincent (London: Epworth 1963); Jewett, Paul's Anthropological Terms; Hans Walter Wolff, Anthropology of the Old Testament, trans. Margaret Kohl (London: SCM, 1974); and Robert H. Gundry, Soma in Biblical Theology, with Emphasis on Pauline Anthropology (Cambridge: CUP, 1976).
 In a number of recent articles, Joel Green convincingly demonstrates and exemplifies the predominantly physicalist orientation of most contemporary biblical scholars (e.g., Joel B. Green, 'Eschatology and the Nature of Humans: A Reconsideration of Pertinent Biblical Evidence', Science & Christian Belief 14.1 (2002), p. 33; Joel B. Green, 'Restoring the Human Person: New Testament Voices for a Wholistic and Social Anthropology', in Robert J. Russell, et al. (eds.), Neuroscience and the Person: Scientific Perspectives on Divine Action (Vatican City: Vatican Observatory, 2002), pp. 3-22); a point that is not disputed by dualist biblical scholars (c.f., John W. Cooper, 'The Identity of Resurrected Persons: Fatal Flaw of Monistic Anthropology', Calvin Theological Journal 23 (1988), pp. 19-36).
 Among the more recent relevant studies are Joseph Osei-Bonsu, 'Anthropological Dualism in the New Testament', Scottish Journal of Theology 40.4 (1987), pp. 571-90; John W. Cooper, Body, Soul, and Life Everlasting (Grand Rapids: Eerdmans, 2000); John Cooper, 'The Bible and Dualism Once Again', Philosophia Christi 9.2 (2007), pp. 459-72; and N. T. Wright, The Resurrection of the Son of God (London: SPCK, 2003).
 E.g., Popper and Eccles, The Self and Its Brain; Richard Swinburne, The Evolution of the Soul (Oxford: Clarendon 1986); Taliaferro, Consciousness and the Mind of God; Hasker, The Emergent Self; though cf. Moreland and Rae, Body & Soul; Goetz, 'Substance Dualism'.
 Stephen T. Davis, 'The Resurrection of the Dead', in Stephen T. Davis (ed.), Death and Afterlife (Basingstoke: Macmillan, 1989), pp. 119-44 (121).
 One promising possibility here would be to appeal to the possibility that God could miraculously sustain some level of functionality for the mind during the intermediate state (cf. William Hasker, The Emergent Self (Ithaca: Cornell University Press, 1999)). Thus, the person continues to exist independently of the body, not because the mind is basically immortal and capable of functioning in a disembodied state, but because God chooses to mercifully sustain its existence until its eventual re-embodiment.