Quoted from the International Journal for Philosophy of Religion 55:135–153, 2004.


Taking consciousness seriously: A defense of Cartesian dualism


Department of Philosophy, University of Delaware, Newark, Delaware 19716, USA

Most western traditional (theistic) philosophers have argued that the existence of consciousness requires some form of substantial non-material soul or self. Both God and the self are non-material, but the self has a material component that God does not. There have been several varieties of non-material substantial souls among western philosophers past and present. Three prominent conceptions are the Platonic/Cartesian, the Aristotelian/Thomistic, and now “emergent” dualists. All three are thought to be dead by the majority of contemporary philosophers of mind.

My purpose in this paper is to defend what is standardly called Cartesian dualism, as it has been modified over time since Descartes. This view of the self is derived from the examination of consciousness as we are aware of it directly, but does have interesting relationships with western theism. It is often claimed that God is needed to explain the existence of souls, and, conversely, that the existence of souls provides important evidence to justify belief in a western theistic God.

Descartes was convinced that the present existence of a non-substantial self could not be contradicted, and found other reasons to support his view that this self was not material, persisted in time, was possibly immortal, and had a relation to its body which was merely contingent and with which it interacted frequently. Taking consciousness seriously requires a non-material self.

Briefly stated, modern Cartesians have defended the existence of a nonmaterial persisting conscious self, justifying its persistence in order to account for continuity of experience, character and memory, and justifying its non-materiality by the fact that its contents (qualia, feelings, thoughts, etc.) cannot be located in the physical world (inside or outside the self) and that its ways of responding (reasoning, free will, intentionality, etc.) are not ways that material bodies operate. So far I am merely stating the obvious about substance dualism.

It is my claim that if we are to take consciousness seriously, take it as we experience it ourselves, a substance view of the self is required. As I have said, there are currently three forms of substance dualism, and I cannot defend and analyze all three. What I have chosen to do is defend the Cartesian view, commenting on some of the reasons why emergent dualist views are not adequate, and ignoring for the present project Aristotelian/Thomistic views, though I think such views share deficiencies with emergent dualism.

It is important now to defend substance dualism because there are clear signs that some of the more important defenders of non-substance philosophies of mind have realized that their hopes for doing justice to consciousness and many of the traditional values embedded in our view of the self cannot be worked out short of substance dualism. Philosophy of mind is in crisis, as I shall show in a moment. Recent philosophers of mind have been dismissive of Cartesian dualism, but when one looks at the reasons for its supposed demise, those reasons look rather lame, and have often been refuted decisively, but apparently overlooked. Substance dualism is much more defensible than it has been given credit for being, so now is a propitious time for a resolute defense of substance dualism against shoddy rejection, and also a propitious time to clarify some of the aspects of substance dualism that have given cause for philosophical offense. I want to contribute to both efforts.

After noting what a number of the leading anti-Cartesians have been saying about the problem of consciousness, I will examine and rebut many of the standard objections against the Cartesian view, and then try to clarify some of the things that Cartesians could have said more clearly about the nature of the Cartesian soul and its interaction with and interdependence on the body it usually uses.

Consciousness and the physical conception of the world

The roster of the dissatisfied in contemporary philosophy of mind is impressive, as the following observations will show. Many of those I cite had hoped to find solutions more compatible with materialism, such as dual-aspect/panpsychist pictures of mind or as property dualism and new forms of epiphenomenalism, but they are unhappy with their results, as they tell us. A few have opted for theories of emergence, but I will argue that only substance dualism can do justice to consciousness as we know it.

Why has consciousness turned out to be such a problem? There are many problems about consciousness that materialism has been unable to solve, and those problems are deep ones. For example William Lycan says that “few theorists question the eventual truth of materialism in some form, but many see a deep principled difficulty for the materialist in giving a plausible account of ‘consciousness’.” He goes on to say that the problem is not just the problem of intentionality (mental aboutness) but “has to do with the internal or subjective character of experience, paradigmatically, sensory experience” and that the problem is not merely an empirical problem but a conceptual one.1 Similar quotations could be obtained from many others who say that there is what had often been called a “qualitative gap,” “an impassable chasm” between mental states and brain processes that no one knows how to bridge from the materialist side.2

There is widespread agreement, also, that much is at stake if Cartesian dualism is abandoned. If there is no Cartesian soul then there is no reason to believe in a self which unifies present experience or which persists over time, in the possibility of life beyond death, in rationality as we ordinarily conceive it, in libertarian free will, and in our ordinary notions of moral responsibility. Ted Honderich acknowledges that the acceptance of determinism requires abandoning all of the following: that we have the power of origination to make our own future; that the quest for knowledge is an open one rather than “a guided tour fixed by causation”; and that we are responsible and can credit ourselves and blame others for what they do.3 J. R. Lucas, himself a dualist, adds that when free will goes so also go rational judgment and rational action. “Rational judgment, like rational action, presupposes freedom. If there is no free will, we are not independent rational beings reaching reasoned conclusions on the basis of evidence and arguments.”4 A materialist, Steven Pinker, after explaining for nearly 600 pages how the mind supposedly works, admits that there are still six enigmas that continue to baffle cognitive scientists: consciousness, the self, free will, meaning, knowledge, and morality.5

Abandoning Cartesian dualism has serious consequences, so serious that Benjamin Libet and his co-editors make the plea that since so much is a stake, and the case for materialism is not yet proved, perhaps we should hold onto our folk psychological ideas, saying, “Seeing as our experience is one of agency and free will, and seeing as the entire religious, ethical, cultural and legal system of the western world is based on such an assumption, then it might be much better to assume that this is the position until science tells us, unequivocally, that this is not the case. That way we should all be “innocent until proven guilty”.”6

To jettison all these important values when the deep problem of consciousness has been acknowledged requires strong justification, but so many of the reasons that are given for abandoning dualism are so easily answered that it is reasonable to suspect that metaphysical bias is at work in the rejection of substance dualism. Colin McGinn admits that the belief that only the physical exists “is, I suppose, an article of metaphysical faith, though this phrase should be stripped of its pejorative connotations” and adds, in a footnote, that belief in things like a Cartesian mind “belong with incredulity over ghosts, telepathy, divine healing and the like,” referring to “a conviction of deep incoherence in the hypothesis in question.”7 No matter how strongly the data of consciousness call for a dualistic solution, dualism is simply unacceptable to many philosophers.

The problems of qualia, intentionality, rationality, free will, and the unity of the self have been with us for a long time. The dominant contemporary position in philosophy of mind has been to adapt to western science and to salvage only those parts of consciousness that can be reduced to physics, or to accept a minimal compromise with our inner awareness by admitting non-physical mental properties or states but making them non-causal. Property dualisms and epiphenomenalism have tried to accommodate mental properties but have failed to account for the unity of the self, rationality, intentionality and libertarian freedom. Substance dualism needs to again become a serious player in the discussion if our ordinary intuitions about the mind and mental causation are to be rescued.

Jaegwon Kim writes that recent philosophers of mind have tried to save mental causation through non-reductive materialism coupled with supervenience accounts of the relation between mental states and brain process, but concludes that mental causation cannot be saved that way since those same philosophers are committed to the closure of the physical world. For Kim the choices are eliminativism, retaining mental states but as epiphenomenal, or accepting what he calls substantival dualism. He frankly admits that philosophers in his circle know next to nothing about substantival dualism but thinks maybe there is something in it that needs to be explored.8

Tom Nagel recently decided that rationality must be postulated as a basic feature of reality and of the human mind in order to justify our ability to use reason in science, ethics, language and the like. He is passionately antagonistic to theism, but has decided that evolutionary naturalism cannot account for reason, and takes the presence of rational thinking and a rational universe to be just basic facts.9 This position would seem to be highly arbitrary. Most philosophers have joined rationality to theism and would see Nagel’s position as rather desperate. He just will not accept theism, but is there any other option really?

Some recent contributors to what has come to be called “consciousness studies” have been emphasizing evidence for mental causation by citing supporting psychological evidence. Max Velmans comments on the evidence for mental causation, both physical and psychological/clinical. It is his claim that “the extensive evidenceof mental causation within some clinical settings forms part of the database which any adequate theory or mind/consciousness-body/brain relationships needs to explain.”10

Many contemporary materialist philosophers of mind have admitted that the existence of parapsychological powers would overthrow materialist and epiphenomenal theories of mind, but there is little evidence that such philosophers have made much effort to examine the purported evidence for psi powers. Recent decades have been kind to parapsychologists. To take only one example, the recent Honorton-Utts exploration of remote viewing studies concluded with the skeptic Ray Hyman acknowledging that “the investigators seem to be getting significant results that do not appear to derive from the more obvious flaws of previous research” but maintaining that the case for parapsychological cognition has still not been demonstrated.11 Many parapsychologists are also excited about studies of remote viewing, Stevensonian cases suggesting reincarnation, and recent debates about the classical “cross-correspondence” literature from mediumship.

The case for an emergentist dualistic non-Humean self has been recently endorsed by John Searle and defended in a recent work by William Hasker. Hasker’s form is explicitly dualistic, while John Searle’s form is explicitly materialistic, but the views look substantially the same to me. Searle says that he now endorses an empirical non-Humean self with libertarian free will,12 and William Hasker sets forth the idea of an emergent unified self with free will which exists in space and exerts energy on the brain from which it has emerged.13

Panpsychism, ignored for decades by most philosophers of mind, has found support in some important places. Both Thomas Nagel14 and David Chalmers,15 while rejecting panpsychism as speculative, have seen it as a live option given the dual-aspect theories which both of them have been forced to defend by the non-materiality of mental states.

It should be noted that there are a number of philosophers who continue to advocate vigorously for substance selves, such as Richard Swinburne, John Foster (himself an idealist), Geoffrey Madell, and David Lund. They have not hesitated to claim that the consciousness problem cannot be taken seriously without non-physical substances.16

Replies to standard objections

My purpose in what follows is to reply to some of the weaker arguments against Cartesian dualism, then go on provide more adequate Cartesian responses to some of those that are thought to be especially strong. I will dwell at length on the criterion for personal identity and the problem of evidence for mental causation, the “pairing” problem, and the close dependence of mind on brain and of brain on mind. These are thought by Keith Campbell, William Hasker. Jaegwon Kim, Jerome Shaffer and others to justify rejecting Cartesian dualism.

I am assuming, with William Hasker, that the standard conceptual objections to Cartesian dualism can be met. I will argue that there are no intractable conceptual problems in identifying or individuating Cartesian souls or with making mind-body interactions intelligible. I agree with Hasker who says of the claim that the interaction is unintelligible and impossible that “it may well hold the all-time record for overrated objections to major philosophical positions.” (Hasker, 151) Of the so-called intelligibility and identifiability problems, he notes that “once we have accepted epistemological fallibilism and given up our preoccupation with Cartesian demons, reasonable answers are not too difficult to find” (Hasker, 210).

For my list of standard objections to dualism, I have used chiefly Keith Campbell, supplemented at one point by Jerome Shaffer.17 The objections will be familiar to those knowledgeable in the field and could have come from a variety of sources.

Individuation and identification

Jerome Shaffer poses the individuation problem this way. Suppose that we find two sets of experiences which are exactly similar to each other, why say that there are two individuals instead of one? It “is perfectly intelligible to suppose that at some time we might have two distinct minds with exactly the same history of mental events.” If we suppose this, “then what would make them two distinct minds rather than one and the same mind?” (Shaffer, 38–39).

Campbell puts the objection this way. Atoms can be located and counted because they are different spatially, but “spirits cannot, of course, be individuated and counted in this way. But then, in what way can they be individuated and counted? If there really is no difference between one spirit and two spirits of exactly similar history and contents, then spirits are a very suspect sort of thing indeed” (Campbell, 44).

Both Campbell and Shaffer “helpfully” suggest that dualists could say that spirits are located in the same place where their brains are, but any good Cartesian must reject that suggestion. It is precisely because colors and thoughts cannot be reduced to physical properties or be found in physical space that makes dualism attractive. This point is made decisively by Colin McGinn, not himself a dualist, who points out of our conscious experience that “it is not located at any specific place; it is not made up of spatially distributed parts; it has no spatial dimensionality; it is not solid. Even to ask for its spatial properties is to commit some sort of category mistake, analogous to asking for the spatial properties of numbers.”18 It is precisely because colors and thoughts cannot be reduced to physical properties or be found in physical space that makes dualism attractive.

The Cartesian answer to individuation is to appeal to the subject, not the content, of consciousness. There are two persons rather than one if the sets are experienced by two separate subjects! Why think that there actually are separate individual spiritual substances? Minds never overlap, therefore there must be something separating souls. If it were the case that “two” minds had the same experience, they would not in fact be two but would instead be one. If each mind reports that it does not share any of the experiences of the other, isn’t that evidence enough that there are two?

I propose that if the circumstances Campbell and Shaffer imagine should ever arise, that we simply ask the person or persons involved how many there are. Let us suppose that we have found two relevantly similar bodies which have undergone relevantly similar histories. I propose that we pinch first one body and then the other to see what results. I pinch body A and ask B, did you feel it? If not, and body A says that it did feel it, then there are two persons involved. If body B answers that it felt the pinch of body A and also says that it felt the pinch of body B, then the two bodies are being used by a single soul. Two bodies being used by one soul is strange, but not impossible to a Cartesian, although admittedly I was hard to convince. Why not?

The important question is, what provides the criterion for personal identity? Campbell and Shaffer are assuming that souls are individuated by psychological states or by bodies, but as many Cartesian philosophers have pointed out, while identification of selves by bodies and by psychological states is usually correct, and thus bodies and psychological continuity normally count as valuable evidence for establishing personal identity, neither psychological continuity nor bodily continuity provide a criterion for personal identity.

A good Cartesian can imagine that there is a possible person in this or some possible world who has exactly similar psychological characteristics to hers and yet is someone else, and can imagine that a person who grew up differently in this world or some possible world could still be her. Had she become a plumber instead of a philosopher she would have been the same person, though, to borrow from John Gardner, under these circumstances it might be her pipes, not her theories that fail to hold water. For Cartesians, it is the subject of awareness, not the psychological states or body it has, that individuates and identifies the person.

As a Cartesian, how do I identifya soul? I judge from bodily responses

– what its body says and does and how it decides between options. I have to infer from bodily responses because souls cannot be observed directly. Inferences from behavior to minds is fallible, but we Cartesians now use best explanations to answer allquestions that take us beyond the present subjective data of consciousness. Under ordinary circumstances third-person identification should be unproblemmatic either in this life or in any life to come, in terms of character and personal memories. When it comes to identification of post-mortem persons, supposing that there is a some sort of body or bodysurrogate, it should be possible to identify the soul without much problem. Again I propose a simple experiment. Let us ask her who she is, and if she has mixed memories, ask her to use the internal consistency of memories to weed out false ones. Let us confirm her self-identification by using additional evidence such as her personality and check her memories as best we can.

Finally, though I have not yet put forward the justification for making this claim, whether a re-embodied soul could efficiently operate a body like her former one would be a further source of evidence. If dualism is true, souls have adapted their bodies to their use and presumably would have difficulty using bodies adapted by dissimilar souls, at least so I will argue.

Interaction objections

What about the oft-repeated objections to souls interacting with physical bodies? Again it is frequently admitted even by philosophers who are not Cartesians that Cartesians have given perfectly reasonable answers to these objections. The answers may be false, but are not incoherent. The basic lines of dualist replies to many of these objections depend upon those provided by  C. D. Broad in 1925.19

Dualists point out that causal connections are learned from experience, not known a priori. As many dualists have claimed, mind-brain interactions may be “anomalous.” It may be true that physical causes and effects are linked by spatio-temporal continuity, but that is surely not true of mental causes and effects. Mental causes, unlike physical causes, may be linked by semantic content or by association, but not by spatial links. Links between mind and brain are causal, not spatial. If psychokinesis is possible, mind does not move from the vicinity of its body and go to the area of the body it affects, it just directly works on that object.

Moreover, if mental causes merely change the distribution of energy in the physical world, then conservation of energy causes no problem. I differ from some Cartesians in thinking that any actions of mind on brain should in principle be capable of scientific investigation. It is true that my mind itself cannot be examined by physical science, but if my mind acts on my brain by changing the resistance of synapses, or if my mind can act on “remote” matter and directly affect other brains, then a developed physical science should provide evidence of mental causation. Some parapsychologists think that parapsychological science has established such influences.  

Lack of physical evidence

Campbell’s major reason for rejecting Cartesian dualism in favor of epiphenomenalism is that the increasing success of physiological explanation justifies believing that someday scientists will be able to explain everything. There is no (or little) evidence that the physical order is open to mental causes (Campbell, 51–55). As a Cartesian I have three things to say.

In the first place, it should be possible to provide experimental evidence given proper experiments and the capacity of physical science to detect changes of the order that would be required if dualism is true. If mental actions on brain fall within quantum limits, such actions might never be directly detectable, but there are other ways to show mental causation. Campbell himself suggests that evidence might be provided by showing that total brain activity deviates in a non-random way from expected probabilities. (Campbell, 54). Sir John Eccles, as is well known, claims that there is already some physical evidence that suggests mental causation.17 Libet et al. suggest parallel tracking of phenomenal experience, brain events and volitional acts (Libet et al., xxi), and Velmans, as I have noted, provides a convenient summary of evidence of mental causation from both physical and clinical sources.

Secondly, commentators have largely ignored the fact that if the mind works in the way dualists think it works, there would be no, or little, physical evidence of mind’s working on body given the present resources of science for measuring what happens in the brain. If mind is not an energy system, and mind does not work on the physical world by exerting energy on it but works by influencing the distribution of energy within the physical world, then observing mind’s actions would be beyond the capacity of present physical science. The paucity of physical evidence at present should not embarrass a Cartesian. It is only to be expected if dualism were true.

Thirdly, there are many kinds of non-physical evidence for Cartesian souls and for mental action on the physical world. Many of the things that materialism cannot yet explain would provide evidence for mental causation. Cartesians have claimed that evidence from the field of parapsychology, libertarian free will, plus rationality and intentionality all count as evidence.

Dualists should not be troubled by the fact that there is little evidence of a physical sort given the present level of brain science. They should be troubled if it turns out that all of the suggestions for finding relevant evidence listed above should be negative, and would have to come up with some explanation of that fact. Their main resource for evidence is not physical, it is the experience of mental causation and the ways mental activities differ from physical ones.

Apparent self-splitting

Hasker mentions in passing that the apparent self-splitting that results from brain splitting, the operation known as commissurotomy, causes problems for substance dualism, though not for his own view, although he provides no details about what he would say about various thought-experiments (Hasker, 193). Of the dualist responses he discusses only Swinburne and Eccles.

Many Cartesian dualists have dealt with this problem. Geoffrey Madell admits that dualism cannot allow self-splitting, but it can accommodate branching (Madell, 131–133). The branches might be dissociated from each other. What would make them branches of one self would be that they are each experienced by the same self. John Foster (Foster, 258–261) makes a distinction between what he calls consubjectivity and serial co-consciousness. Serial co-consciousness is the psychological relation between successive states of consciousness and consubjectivity is the occurrence of psychological states to the same subject at the same time. Foster’s view of fission is that psychological states might be separated into two streams each of which is serially co-conscious but the two streams would not be consubjective.

It is important to remember that modern Cartesian dualism concedes states of the self which are ordinarily not accessible to waking consciousness (dreams, unconscious states) and that such things as webs of desires, memories, beliefs, and dispositions to react in particular ways, are not present in their totality to waking consciousness. I would defend the view that split personalities provide a good model for brain fission, and note that there are dualists such as Steven Braude who defend the view that multiple personalities should be seen as aspects of a single self.21

Critics have sometimes supposed that duplicating bodies would cause a problem for dualists, the problem of finding another soul to used the duplicate body which would otherwise be a zombie. But why not consider that the one soul might use both bodies? Why not two bodies each contributing to the awareness of the same self? A self might not choose to relate to multiple bodies to avoid confusion, or it might welcome the opportunity to follow multiple careers, or whatever it is two post-mortem bodies are thought to do.  

The continuity problem

About the continuity problem (Campbell, 48–50; Hasker, 151–153), a Cartesian has problems knowing exactly what to say, but may claim this as a virtue, not a defect. No one has very clear views on when selves emerge in the course of evolution or in the progress from the uniting of sperm with egg, but a Cartesian has an additional reason for not knowing.

It is one of the virtues of Cartesianism that since souls are not observable, decisive answers to such questions, other than those obtained by asking, cannot be given. If answers cannot be obtained from asking, best guesses from observable behavior are in order, and those best guesses are probably not too different from the guesses of emergentists who have to face these very same questions. Modern Cartesians are open to the possibility that minds may exist in animals and may even exist in all things, as in panpsychist versions of dualism. In many cases, we are rather confident that there is a mind behind the behavior, and in some cases we are rather confident that there is not, but these are just best guesses. Some day zombies may fool us, and some day cats and dogs may acquire comprehensive ways to speak and will confirm pet owners’ guesses that they have minds after all, but there is no reason to suppose, with Andy Clark, that “we would never have cause to even suspect someone of being a Zombie, since their responses and inner structure are, by definition, the same as those of the non-Zombie.”22 Why not? Because zombies, lacking minds, can not do many of the sorts of things that beings with minds can do.

The problems faced by dualists on such matters also have to be faced by non dualists who admit the existence of non-physical mental states, whether they be property dualists or emergent dualists or panpsychists of either the dualist or dual-aspect variety. What we are asking about is the problem of other minds in one of its familiar forms.

You might ask, can’t you examine your own inner states and determine when you acquired your connection to the body you now use? Once we admit that there may be mental states which are not presently accessible to consciousness, definite answers seem impossible. I can say with confidence that sometime I became aware that my conscious awareness was, as a matter of contingent fact, connected with a particular physical body and only with that body. I surely existed prior to that moment, but how long before I cannot tell. I cannot even rule out existing for long periods prior to my interaction with this body or having had multiple lives. Many answers are compatible with the facts about selves as Cartesians know them.

The mind’s close pairing with brain

Now let us turn to the other major objection that Hasker and others think Cartesians must face, what is called the pairing problem and mind’s apparent dependence on brains. A Cartesian soul is non-material and has no location in space but regularly interacts with one and only one body, what exactly is responsible for this linkage? Once the linkage is established, why does it seem to be so firm? Why can’t souls interact with any bits of matter? Why is its influence normally confined to just its own body, and why does the mind seem to be dependent for its active functioning on the brain? This is a complex set of questions. What I want to suggest is that Cartesians have resources which can be developed in such a way as to help solve some of these problems and speak to the ones that remain.

The ultimate solution to the original attaching of souls to bodies precedes any awareness on my part, but a solution which appeals to God is in order for most theists, since it is rare to find a dualist who is not a theist. Souls need bodies in order to gather information and to interact with other souls, and it may well be that bodies are needed for souls to develop. Many theists from Plato onward have developed “soul-building” explanations for the soul’s attachment to and even restriction to one body at a time.

Once a soul has been attached to a body, there are quite ordinary explanations for why soul and body become increasingly interdependent. Hasker claims, I think mistakenly, that the mutual interdependence of bodies and minds causes difficulty for Cartesians (Hasker, 153–170). First off I will grant that sometimes Cartesians have talked about the mind-body relation in problematic ways, such as by being far too ready to accept implausible thought experiments like cobbler-prince exchanges, or souls using trees as vehicles for thought and action. The reason why such thought experiments are implausible is that though they are conceivable, the actual mutual dependence of developed souls and developed bodies is such as to make such exchanges very difficult to conceive, and make using trees to express thoughts virtually impossible. Although there are no logical limits on the number of kinds of bodies with which a single soul could interact, there seem to be severe limitations on what a soul could do with untrained bodies.

Dualists have always admitted that the mind is dependent on its body for information about the world and for interacting with other persons, but Hasker claims that as evidence increases that the brain performs such complex tasks as information processing, problems arise for Cartesian dualists (Hasker, 155). The mind uses eyes and brains to gather information about the existence and character of things outside itself, trains bodies to perform the complex tasks needed for communication, trains the brain to work multiplication problems, creates mechanical brains to work out complicated equivalences in mathematics and logic, why should the fact that it uses the brain to process information be taken as an especially difficult problem for Cartesians?

It may be that once there were Cartesians who thought that there were activities of the mind that were not accompanied by activities in the brain, but present day Cartesians are not obliged to think this. Why not concede, for the sake of argument, that every activity of the mind has its corresponding brain state? Would continuous strict correlation cause difficulties for Cartesian dualists? I think not. Exploring this question may prove very helpful for analyzing the close coordination of minds and bodies.

Let us suppose that the correlation is tight, and it is true that as brain science advances, some future scientist will be able to infer what experiences a self is having from the state of its brain. Dualists will not find that at all disturbing. A dualist will point to the limits in the knowledge that the scientist has acquired. She can infer from what is going on in someone’s brain what mental state that person is experiencing, but she cannot thereby capture that mental state itself. She could infer from the state of the brain that someone is feeling pain, but she will not thereby know what it is like for that person to feel pain. A dualist cannot even experience her own mental states by observing her brain. Of course, many dualists deny that correlations are in fact this tight, my point is simply that the dualist can concede it and not be distressed.

That something is going on in the brain when a person is thinking does not, of course, mean that a Cartesian is committed to claiming that the brain can think or deliberate. The brain can calculate, can even do operations in modern logic (manipulate symbols in accordance with syntactical rules without relation to the content of those symbols and rules), but such semantic activities as understanding the meaning of symbols, and thinking in the sense of reasoning from the content of one symbol to the content of another are mental activities.

Also, no Cartesian is required to hold “that in a disembodied state, without the brain’s assistance, the mind is unable to think.” (Hasker, 156) Why should the fact that the brain is working when the mind is causally connected with a body, imply that the mind cannot work in its absence? After all, the contents of thoughts and thinking activities as well as memories, beliefs, desires are mental for the Cartesian, however much they be correlated with brain processes.

In my opinion a good dualist admits that some functions of the soul depend on the operation of the brain (or a brain surrogate). Such operations are communicating with other minds, gaining information about the material world, and developing the structure of the soul by engaging in interactions with material bodies and through bodies with other souls. However a good dualist should also say that activities as thinking, feeling, remembering, and willing do not depend for their functioning on bodies or body surrogates. They often suggest that once the soul is unencumbered by the body, those activities might even gain strength.

On the other hand, it must be remembered, souls without bodies or body surrogates would have drastic limitations, cut off from any interactions with beings outside of itself. The privacy of souls is not like the proverbial hired cab, used only until it gets to its destination. The privacy of souls is a permanent limitation unless or until it acquires a body or its equivalent.


The structured soul, the structured body and the pairing problem

Cartesian philosophers have no problem in recognizing that the body/brain has a structure, and that changing of that structure is an ongoing process. What is not discussed so frequently is that the soul or mind must also have a structure. What we Cartesians should say about the soul is that it is not at present a blank slate but that our minds are slates that have been well written on. We should say that our present experience discloses to us that our souls are structured. Now, to talk about the soul as structured is not typical Cartesian talk, but I want to argue that it should be and to use the fact that the soul has a structure to help to minimize the “pairing” problem in the way it is usually raised. Why a particular existing soul continues to be paired with a particular existing body with which it mutually interacts has a relatively simple solution.

Let us assume that Cartesian dualism is true. Let us grant that I have a mind, that my mind cannot be reduced to the brain or its products, that my mind interacts causally with the brain and body that I call mine, that my mind is contracausally free, and that my mind has unity and persists through time. What else should I think about the mind? I propose that we need to add that my mind or soul has a definite structure which it has acquired over time.

What does my experience suggest? Am I pure subject? No, I find that my mind has certain definite features. My mind brings with it more or less integrated sets of memories, desires and beliefs, all of which are, like my body, contingently related to my mind in the sense that I would be the person that I am even if my memories, desires and beliefs were quite different than the ones they in fact are, but which nevertheless are part of this me that exists now. The subject faces an internal given, in other words.

How should we talk about these more or less integrated sets of memories, desires and beliefs that we each bring to the present moment? Swinburne offers the suggestion that we think of the soul as having a structure. What “I mean by claiming that the soul has a structure is very roughly that the determinants of change of belief and desire are in part soul-states, not mere brain-states; and that if body and soul were separated, some character would remain with the soul” (Swinburne, 262). He broadens his discussion of soul states to include perceptions, knowledge, memory, emotions and other mental states such as pleasures and pains (Swinburne, 236–241).

What sort of thing is a structured non-material thing? Given the privacy of the mental subject and of its states, no external description of mental structures is available. To say that the self has a structure is simply to say that at any present moment there is a set of memories, beliefs, desires, perceptions and other mental states present to the self which affect the set of memories, beliefs and desires which develop in the future and which, to a great extent, influence what these future sets will be, but without determining them.

It is helpful to look at C. A. Campbell’s description of free will as contra-causal, the power to act against the causes that constitute one’s formed character.23 Our experience tells us that we have developed a set of desires and beliefs which constitute what we call our character, and that we are free in that we can choose to act against our strongest desire, we can override our character as thus far formed. That the exercise of contra-causal freedom requires effort suggests that there is something in the soul that resists change. I would add that to correct memories requires mental effort as does changing our beliefs, which implies that memories and beliefs constitute a structured part of the soul. In all three cases, the effort required seems to be proportional to the place the changed item has in our webs of desires, memories and beliefs, and there may be times, as in cases of addiction or in resisting the adopting of contradictory beliefs, that I am unable to change because the item is central to the way we think about ourselves.

To think that the mind can change beliefs, memories or actions simply by willing them does not account for the mental difficulty involved. Thinking of the soul as structured, and of change as actually overcoming that structure, seems truer to inner experience. But it is not only the structure of the soul that has to be changed, the structure of the brain has to be changed as well, because the brain has a well-developed structure also. Because of continuous mutual interactions, there is a structured brain which would offer additional resistance, given brain’s causal relation to mind. The cobbler’s brain would not integrate well with the soul of the prince, which is why some thought experiments have been naive.

As a baby learns to drink from a cup its body makes many mistakes. Gradually the soul shapes the responses of its brain so that drinking becomes something automatic and the soul’s goal of satisfying its thirst without spilling the water is accomplished slowly over time. Drinking without spilling becomes a habit for that body, its soul no longer has to think about it. Match the soul with a body that has not been suitably trained, and the water spills once more. Soul-body coordination could not be instantaneous.

Suppose a soul is attached to a body raised in China, which has slowly developed a brain and vocal cords conditioned to conversing in Chinese. This conditioning makes communication easy with other souls who use bodies that have been similarly conditioned. Now imagine that soul linked causally with a French soul’s body. That soul would be handicapped, its body would make nasal sounds and not the right set of tones. Extensive reconditioning would be needed before that soul could communicate with other souls in its old Chinese environment. Instantaneous coordination would not be possible.

Let us consider memories and their impact on coordination. I am assuming that memories are not only contained in the structure of the soul but that physical correlates to memories are laid down as modifications of brain substance. A soul that used my body would be flooded with memories of early life in southeastern Ohio. These would conflict with the memories structured into its soul. Presumably would take time for the old memory traces to be erased and the right memory patterns to be laid down in the new brain.

All of these factors speak to the pairing problem and make it obvious that, as a practical matter, a soul needs a body which it has trained to accomplish its purposes in acting on and communicating with other souls. A particular soul and its particular body have adapted to each other over whatever length of time they have been paired, and for a soul to think or communicate or act efficiently it must use the body which it has shaped. Bodies which are different would be to varying degrees intractable to that soul’s use. Of course we would have to imagine that there are degrees of intractability ranging from the bodies of identical twins raised in similar environments to bodies raised in cultures speaking a different language, utilizing different tools for realizing purposes, valuing different behavior more highly, and fostering quite different value choices. Bodies would need to closely resemble the one with which the soul was used to interacting for efficiency of operation.

The soul is both independent of and related to the life of its body. What it does causes modifications in the structure of the brain, and what the brain does affects the soul’s structure, but the soul could continue to exist independently of its body, and could carry its structure into its disembodied state. In a disembodied state, it would not be encumbered by the existence of a body that distracts it, but the body has its uses as well. Plato did say that the body was a prison house, but he also recognized that in its relationship to its body, the soul works out its character. I do not know what Plato thought about communication between spirits, but I do know that I think that communication between spirits requires a medium of communication, a body or body surrogate. If so, a disembodied soul would be prevented from communicating with other souls, gaining new information about its environment, or working with other souls.

Bodies that duplicate in relevant respects the body that has died would make post-mortem communication between and interactions with other souls feasible in the same way that physical bodies make it possible now. Unless souls have some vehicle to use for communication and interaction, the life of the soul would be far less rich. Communication by disembodied souls could of course involve body substitutes. It might be that a disembodied soul can communicate with living persons by influencing their brains, or by taking control of the vocal apparatus of mediums. To my way of thinking, this is how telepathy works. It is an extended form of mind-brain interaction, not mind-mind.24 In the realm of post-mortem existence, communication among disembodied souls would be possible if souls had new bodies or if it were possible for souls to experience and manipulate mental objects, which is how

H. H. Price thought of afterlife.25

Hasker’s verdict with relation to evolutionary continuity and the close dependence of mind on brain is that “It’s not that these phenomena are logically inconsistent with Cartesianism; no doubt they can be accommodated, but there is a price to be paid for doing so. If Cartesian dualism is to be taken seriously as the truth about minds and their bodies, then both the problem of dependence and the problem of continuity need to be addressed in a way that exhibits the known facts as plausible consequences of the underlying metaphysical view. A string of ad hoc conjectures will not suffice” (Hasker, 157). I agree, but lack the expertise to contribute to the analysis of the particular abnormal conditions he mentions. All I can do is to suggest that considering the soul as structured and noticing the close correlation between the structures of bodies and the structures of souls should make a considerable contribution to understanding their close interdependence.

Summing up

What I have claimed in this paper is that the reasons for rejecting Cartesian dualism are not strong ones, and that what is at stake in rejecting Cartesian dualism is admitted by all to be enormous. I have tried to present Cartesian answers to typical objections, and to make some contribution by replying to some of the more nagging problems, namely the problem of a criterion for personal identity, the lack of physical evidence problem, and the problems of continuity, of pairing and the dependence of the developed soul on its structured body.

Considering that modern western science admittedly cannot explain consciousness, and has not been able to come up with any way of even imagining what a physical explanation of consciousness would be like, and the impact that the attempt to eliminate mental causation has on the folk-psychological ways of thinking about ourselves by which we live, my plea is that we hold ourselves innocent until we are proved guilty or until the progress of science proves dualism correct.


  1. William G. Lycan, Consciousness and Experience (MIT Press, 1996), p. 1.

  2. Typical discussions can be found in David C. Chalmers, The Conscious Mind (Oxford, 1996), part two; Thomas Metzinger, ed., Conscious Experience (Shoningh, 1995), Editor’s Introduction; Thomas Nagel, The View from Nowhere (Oxford, 1986), chapters one to four; and Georges Rey, Contemporary Philosophy of Mind (Blackwell, 1997) chapter two.
    The earliest reference I could find on this matter was in John Tyndall’s Presidential Address to the Mathematical and Physical Section of the British Association in 1868, almost a century and a half ago. He remarked that even if we were able to see the molecules of the brain, “the chasm between the two classes of phenomena would still remain intellectually impassible” and the most that a materialist can do is to “affirm the association of two classes of phenomena, of whose real body of union he is in absolute ignorance.” John Tyndall, Fragments of Science, Vol. 2 (P. F. Collier and Son, 1901), p. 95. He did think that science would solve this problem eventually. 

  3. Ted Honderich, How Free Are You? (Oxford, 1993), pp. 84, 91.

  4. J. R. Lucas, Responsibility (Clarendon Press, 1995), pp. 29–30.

  5. Steven Pinker, How the Mind Works (W.W. Norton, 1997), pp. 558–559.

  6. Benjamin Libet, Anthony Freeman and Keith Sutherland, “Editor’s Introduction,” The Volitional Brain (Journal of Consciousnss Studies, 6, No. 8/9, 1999) xxi. Further statements of the importance of our beliefs in the self, this time from persons who deny that such beliefs are justified, can be found in Saul Smilansky, Free Will and Illusion (Clarendon, 2000), chapter 12, and in Georges Rey, Contemporary Philosophy of Mind (Blackwell, 1997), pp. 313–315.

  7. Colin McGinn, The Problem of Consciousness (Basil Blackwell, 1991), p. 87. John Searle, Tom Nagel and David Chambers have all been saying that a revolution in science is needed to provide a materialist solution, but McGinn thinks the problem can never be solved. His most recent book, Mysterious Flame: Conscious Minds in a Material World (Basic Books, 1999) is an extended attempt to provide reasons for thinking that the human brain, developed to provide solutions to practical problem, is incapable of ever providing a correct, i.e., a materialist, solution.

  8. Jaegwon Kim, Mind and the Physical World (MIT, 1998), p. 119. It is ironic that he only had to look at the work of his distinguished predecessor, C. J. Ducasse, to find defences of such dualism.

  9. Tom Nagel, The Last Word (Oxford, 1997), pp. 138–139.

  10. Max Velmans, ed., The Science of Consciousness (Routledge, 1996), p. 16.

  11. Ray Hyman, “Evaluation of a Program on Anomalous Mental Phenomena,” Journal of Scientific Exploration 10 (1)  (1996), p. 55.

  12. John Searle, “Consciousness, Free Action and the Brain,” Journal of Consciousness Studies 7 (10)  (2000), pp. 9, 16.

  13. William Hasker, The Emergent Self  (Cornell, 1999), Chapter Seven. My critique of Hasker appeared in Faith and Philosophy (Jan, 2003), pp. 37–49.

  14. Thomas Nagel,  View From Nowhere (Oxford, 1986), pp. 49–50, defends dual-aspect theory because it combines the radically disparate elements that give rise to the mind-body problem, though it has “the faintly sickening odor of something put together in the metaphysical laboratory.” Its drawbacks? It leads to panpsychism and offers no way of providing for the experienced unity of subjective experience.

  15. David Chalmers, op cit., pp. 293–301.

  16. John Foster, The Immaterial Self (Routledge, 1991); David H. Lund, Perception, Mind and Personal Identity (University Press of America, 1994); Geoffrey Madell, The Identity of the Self (Edinburgh University Press, 1981); and Richard Swinburne, The Evolution of the Soul (Clarendon Press, 1986). Readers of an older generation will be reminded of A. C. Ewing, Value and Reality (Allen & Unwin, 1973); C. A. Campbell, On Selfhood and Godhood (Allen & Unwin, 1957); and Hywel D. Lewis, The Elusive Mind (Allen & Unwin, 1969) or The Self and Immortality (Seabury Press, 1973).

  17. Keith Campbell, Body and Mind. Second Edition (Notre Dame, 1984) and Jerome A Shaffer, Philosophy of Mind (Prentice Hall, 1968).

  18. Colin McGinn, “Consciousness and Space,” Journal of Consciousness Studies 2(3) (1995), p. 220. A more elaborate statement appears in The Mysterious Flame (Basic Books, 1999) as Chapter Four.

  19. C. D. Broad, The Mind and Its Place In Nature (Routledge & Kegan Paul, 1925), pp. 97– 113.

  20. John C. Eccles, The Human Mystery (Springer, 1979), Lecture Ten.

  21. Stephen E. Braude, First Person Plural (Rowman & Littlefield, 1995).

  22. Andy Clark, Mindware (Oxford, 2001), p. 182.

  23. C.A. Campbell, In Defence of Free Will (Allen & Unwin, 1967), pp. 56–77.

  24. Frank B. Dilley, “Telepathy and Mind-Brain Dualism,” Journal of the Society for Psychical Research (April, 1990) pp. 129–137. See also C. D. Broad, Religion,  Philosophy and Psychical Research (Routledge & Kegan Paul, 1953), pp. 26–27.

  25. H. H. Price, “Survival and the Idea of “Another World”,” Proceedings of the Society for Psychical Research 50 (182) (January 1953), pp. 1–25. This has been reprinted many times, for example in Frank B. Dilley, ed., Philosophical Interactions with Parapsychology (St. Martin’s Press, 1995), pp. 237–262.