lnternationalJournalJbr Philosophy ofReli~io, 39 (1): 1-14 (February 1996) �9 1996 Khtwer Academic Publishers. Printed in the Netherlands.

Christian materialism and the parity thesis

CLIFFORD WILLIAMS Trinity College, Deelfield, Illinois, USA

In his Essay concerning human understanding, John Locke writes, 'All the great ends of morality and religion are well enough secured, without philo- sophical proofs of the soul's immateriality', l This thesis and its variants, which I shall call the parity thesis, provoked a good deal of controversy in seventeenth and eighteenth century England. 2 A revival of that controversy has taken place in the last two decades among Christian philosophers, though it has generally been undertaken without reference to the earlier one. The phrase, 'Christian materialist', which may strike many as being like the phrase, 'Christian atheist', has come to designate a Christian who believes both that people are purely material and that their being so is not detrimen- tal to their moral and religious features. Christian dualists are now forced to defend themselves not only against atheistic materialists, but also against their fellow Christians.

In this essay I shall resurrect Locke's views with the aim of producing a clear statement of the parity thesis. I shall ask what force the parity thesis has against dualism, raising the question of what kind of evidence would settle the issue between dualism and materialism. In the bulk of the paper, I shall present considerations which I believe lend support to the parity thesis, though not to the further claim that people actually are purely material.

1. On Locke

The setting for Locke's remarks on mind-body parity is in a chapter enti- tled, 'Of the extent of human knowledge', in which he describes the extent of our sensitive, intuitive and rational (or demonstrative) knowledge. 3 Our rational knowledge does not, he states, extend further than our ideas, nor does it extend as far as our ideas. This second point is true, he says, because we are not able to know, either intuitively or demonstratively, all of the con- nections that exist among ideas. As an example, he considers the ideas of matter and thinking. Though we have these ideas, we may 'never be able to know whether any mere material being thinks or no'. The reason for this is

that we cannot tell just by contemplating these ideas whether some matter has the ability to perceive and think. It might be that God, being omnipo- tent, has 'superadded' a faculty of thinking to matter; this is as much a pos- sibility as it is that he has superadded the faculty of thinking, not to matter, but to a spiritual substance. The first of these states of affairs is possible for God to have brought into being, says Locke, because it is not a contradic- tion that the 'first Eternal thinking Being, or Omnipotent Spirit, should, if he pleased, give to certain systems of created senseless matter, put together as he thinks fit, some degrees of sense, perception, and thought' .

On the basis of these considerations, Locke makes the statement I quoted in the first sentence of this article. If God could, without contradiction, have made matter to perceive and think, then he could have made purely material beings to be moral and religious entities. All of the requirements of morality and religion can be met even if people are merely material. Mind-body parity is true of life after death as well, Locke adds, for even if we were purely material, God could 'restore u s . . . in another world' and give us our 'retribution' according to our 'doings in this life'.

Furthermore, Locke infers, there is no more mystery in the idea of a material entity thinking than there is in the idea of a nonmaterial entity thinking. We must not suppose that dualism is true just because it is impos- sible to fathom how a material being can think. Nor must we suppose that dualism, even if true, makes thinking less baffling ~han materialism, for, Locke says, 'I would fain know what substance exists, that has not some- thing in it which manifestly baffles our understanding'.

Finally, Locke states, it is not 'of such mighty necessity to determine one way or the other' whether dualism or materialism is true. If God could have made us to be moral and religious beings either by using only matter or by adding a nonmaterial substance to matter, then it is not important that we know which it is. Nothing of cosmic significance hangs on the issue.

The context of these ideas makes it clear that Locke is not arguing against dualism or for materialism. He is not trying to show that people actually are only material beings, but that we cannot know which it is by purely rational means. His idea of 'know' , he says, includes only what we can determine by an inspection of the contents of our ideas. His appeal to the noncontradictoriness of the idea of thinking matter indicates that he is concerned only with what we now call logical possibility. We cannot know whether our thinking is performed by matter or nonmatter in the sense that there is nothing logically prohibiting either. It is still open to Locke to believe that dualism is true.

Locke, in fact, states elsewhere in the Essay that he believes dualism is true. He writes, 'We have as much reason to be satisfied with our notion of immaterial spirit as with our notion of body, and with the existence of the one as well as the other'. 4 Indicating why, he says that, not 'apprehending

how they ['the operations of mind, viz. thinking, reasoning, fearing, etc.'] can belong to body, or be produced by it, we are apt to think these the actions of some other substance, which we call spirit'. 5 The reader who has encountered Locke's parity thesis will wonder whether Locke means in this second passage to be saying that it is logically impossible for us to appre- hend how thinking can belong to matter. If he does mean this, he would be contradicting what we have already seen him unambiguously to say in enunciating the parity thesis. To make Locke consistent we must interpret him as saying that our inability to apprehend how thinking can belong to matter is not a logically inability, but a nonlogical one, deriving, perhaps, from our inability to imagine things being different from the way in which we are accustomed to encounter them in experience. Unfortunately, Locke does not address the issue. For the sake of consistency, however, I will suppose him to be referring to a nonlogical inability of some sort. Thus interpreted, his position would be that though dualism is true, it might not have been, since God might have adjoined thinking to matter instead of to spirit. We are warranted in believing dualism, even though we do not have rational, or demonstrative, knowledge of its truth.

2. The par i ty thesis

There are several claims that we can distill from Locke. The one on which the others rest involves God's omnipotence.

(1) God can make matter think. The reason for this is that

(2) There is no contradiction in the assertion that matter thinks. If we add to thinking such qualities as feeling and choosing, the qualities, namely, that are requisite for something to be a moral and a religious being, we get the claim that

(3) God can make a purely material being to be a moral and religious entity.

From these claims, it follows, Locke believes, that (4) There is no more mystery in the idea of matter thinking than there is

in the idea of spirit thinking. The word that explains why Locke makes these claims is 'superadd'. He writes, 'God can, if he pleases, superadd to matter a facul t 3' o f thinking'. What he appears to have had in mind is that the idea of matter is neutral with respect to thinking. God can make some matter not to think, which he certainly has, but he can also make some matter think by adding to it an ability which it would not otherwise possess. Thus, it is not a contradiction to say that matter thinks, and it is possible for God to use only matter in making a moral and religious creature, because the idea of matter does not

exclude the idea of thinking. We can add to this last thought something that Locke himself does not say, but which is required by what he says: the idea of matter does not contain the idea of thinking either. If it did, it would be a necessary truth that matter thinks, and there would be no point in Locke's asserting that God can make matter think.

It is important to notice now that in order for there to be parity between matter and spirit, we need a conception of spirit that also is neutral with respect to thinking. According to this conception (here I go beyond Locke), the idea of spirit neither contains nor excludes the idea of thinking. God can make spirit not to think, and he can also make spirit that thinks, in the same way he makes matter think - by adding an ability to it which it would not otherwise possess.

In order, therefore, for (1)-(4) to assert parity, they must be reformulated so as to include the same neutral conception of spirit that they contain about matter. To formulate these claims, though, a terminological matter must be resolved first. In ordinary parlance, 'spirit' and 'soul ' have the idea of think- ing associated with them. To say that spirits or souls do not think is tanta- mount to a conceptual absurdity in the minds of many users of the English language, so that to conceive of spirit neutrally, analogous to the way in which Locke suggests we may think of matter, is nearly impossible. In order to avoid begging any questions, therefore, we should use more neutral words, such as 'nonmatter ' and 'nonmaterial ' . These words are also appro- priate because they convey what is at stake in the dualism-material ism controversy: Does something material in us do the thinking or does some- thing nonmaterial do it? Using these words, then, (1)-(4) become

(5) God can make matter and nonmatter either to think or not to think. The reason God can do these things is that

(6) There is no contradiction in asserting either that matter and nonmat- ter think or that they do not think.

Adding moral and religious features to the domain, we get (7) God can make either a purely material being or a nonmaterial entity

to have moral and religious characteristics. From these we can infer that

(8) There is an equal amount of mystery in matter thinking as there is in nonmatter thinking.

I shall refer to these as the parity theses.

3. Force of the parity theses

Would the parity theses, if true, refute Christian dualism? The answer is that they would if Christian dualism is conceived to be necessarily true, but that

they would not if Christian dualism is conceived only to be contingently

true. The parity theses assert (a) that the idea of nonmatter does not necessar-

ily include the idea of thinking, and (b) that the idea of matter does not nec- essarily exclude the idea of thinking. Thus, dualists who assert that there is such a necessary inclusion and such a necessary exclusion would be mis- taken if the parity theses are true. However, if dualists assert that it is a con- tingent fact that the thing in us that thinks is nonmaterial, then the parity theses would not refute their position, for the parity theses have nothing to say about what contingent facts exist. They only say something about possi- bilities, namely, that it is possible for thinking to be conjoined either to matter or to nonmatter.

Do Christian dualists conceive of their position as being necessarily true? That is, do they believe that it is a necessary truth that the thing in us that thinks is nonmaterial, and that it is a contradiction to say that matter thinks? The answer to this question is not so easy to determine. Little in what Christian dualists say addresses the logical and evidential status of their claims. This fact is not surprising, though, for most of us, most of the time, practice philosophy without asking whether there are conditions which, if they were to exist, would refute our philosophical claims. Moreover, it is notoriously difficult to determine what these conditions would be and whether they actually exist. Philosophy works in the nebulous realm of broadly conceptual and broadly empirical, but not clearly either.

Nevertheless, there is evidence that indicates that many Christian dualists would say, if asked, that their position is not merely contingently true. Some of the evidence is merely circumstantial, but some is fairly direct. The cir- cumstantial evidence is that Christian dualists have reacted to parity theses negatively, and they have done so vigorously. They have been 'enthusias- tic', to use Locke's word, in supporting their position. If they agreed with Locke that it is possible for matter to think, they would not be so bothered when someone asserts that it does. They would say, 'Although it might be that God has made us purely material, I do not believe he has actually done so'. Christian dualists do not say this. They respond to the parity theses by trying to refute them.

Moreover, the arguments that Christian dualists use in support of their position appear to require the necessity of mind being different from matter and not just its contingency. The different properties argument, for example, states that thoughts are not identical to electrical-chemical occurrences in the brain because the former possess certain features, such as being inten- tional and being indivisible, that the latter do not. This argument is put forward, not as the result of empirical investigation, but as a conceptual consideration - brain events cannot be conceived to be intentional. The

same is true of the privacy argument. Thoughts in principle are private, it is said, and brain events are in principle public, so it is impossible for the two to be the same.

In addition, the language Christian dualists sometimes use is indicative of necessity rather than of contingency. Phrases such as 'cannot be the same' are often used instead of 'are not the same'. This is not always the case, though. Richard Swinburne, for example, after putting forward a different properties argument for dualism, concludes that mental events and brain events 'are different'. 6 In the same paragraph in which this 'are' appears, however, Swinburne writes that the two kinds of events 'cannot be the same'. Pascal uses even stronger words: 'There is nothing so inconceivable as the idea that matter knows itself'. 7 'Cannot' and 'inconceivable', of course, are ambiguous. They could be used by a physicist to mean 'physi- cally unable' or 'empirically unimaginable'. So dualists could mean that we are not empirically able to account for mental and physical events possess- ing different properties or abilities. But this interpretation is unlikely, since dualists present us with no assessment of alternative empirical hypothesis. And their words, such as Pascal's 'nothing so inconceivable', possess an intensity that jars with mere empirical unimaginability. What Swinburne appears to be ruling out is not just the actuality but the possibility of alter- native empirical accounts. And what Pascal most likely meant is that it is a contradiction for matter to know itself, and that this contradiction is the most evident of contradictions. 8

A fair reading of most other Christian dualists will reveal, I believe, that they mean to be asserting that the idea of matter thinking is logically impos- sible. The parity theses are, therefore, pertinent to claims actually made by Christian dualists. It does not follow that Christian dualism is false if the parity theses are true, for Christian dualism might be conceived to be con- tingently true. In fact, if the parity theses are true, then Christian dualism would be a contingent thesis. So also would Christian materialism. Since (I believe) the parity theses are true, it follows that the controversy between Christian dualists and Christian materialists is not resolvable by conceptual analysis alone. It is resolvable, if it is, by nonconceptual considerations, perhaps empirical ones or revelational ones or metaphysical ones.

4. Support for the parity theses

What would show the parity theses to be true? I shall begin with God's omnipotence, since that is where Locke begins. Parity thesis (5) states that God can make both matter and nonmatter either to think or not to think. If we conceive of God's omnipotence as the ability to do anything, then (5) is certainly true. To the Christian dualist, however, this will be a cheap victory.

The traditional criterion of omnipotence is logical possibility, so in order for (5) to be true, it must be shown that it is logically possible for matter and nonmatter to think or not to think. The truth of parity thesis (6) must be demonstrated in order to establish the truth of (5). And this, says the Christian dualist (who asserts that dualism is true of necessity and not con- tingently), cannot be done. The Christian dualist of this sort is, therefore, committed to saying that there is something God cannot do, namely, make matter think, because doing so is contradictory. This would not impugn God's omnipotence, however, since omnipotence means the ability to do anything that is logically possible.

What would show that the idea of matter's thinking is logically possible? It is tempting to answer this question with a simple declaration. The Christian dualist might declare that nothing could show that it is possible for matter to think because it is self-evident to anyone who considers the idea of matter that it cannot think. The Christian materialist might respond with the assertion that an inspection of the idea of matter does not reveal the inability to think. Actually existing inorganic matter does not think, to be sure, but this is not due to the nature of matter as such. It is not only tempt- ing for each side to answer the question in these ways, but it is often done. There seems to be little more that one can say about logically possibility than 'It is' or 'It is not'. Nevertheless, I want to move beyond simple decla- rations. The following considerations are designed to support parity between matter and nonmatter by loosening the necessary inclusion and exclusion dualists have thought they have seen, that is, by supporting (a) and (b) above (p. 5).

(a) The Adam and Eve experiment. In his Enquiry concerning human under- standing, David Hume imagines that Adam has just been created with his intellectual capabilities at their fullest and with the following situation pre- sented to him: two billiard balls are traveling toward each other. The ques- tion Hume poses is, 'Can Adam predict what will happen when the two balls meet?' His answer is that he cannot. In order to do so, Adam must have had previous experience of billiard balls or other objects hitting each other. Without such experience, Adam cannot tell whether the balls will crumple, explode into pieces, rebound, stop entirely or fly into the air. Hume uses this imaginative experiment to show that we do not have a priori knowledge of causal relations. A similar experiment shows that we do not have a priori knowledge of matter's inability to think, and therefore that it is not contradictory to say that matter thinks. (It also shows that 'matter does not think' is not a synthetic a priori truth).

Imagine that God has just created Adam and Eve and that he is present- ing each to the other. His presentation takes longer than the usual, 'Eve, I would like for you to meet Adam', and 'Adam, this is Eve', because he is

explaining to each, before they see each other, the workings of the other's brain. He is using a cerebroscope to do this. Its screen displays the activities in various regions of the brain, it follows the motions of neurons, it catches the firing of synapses, enlarges the pulsations in cells, and replays particu- larly striking occurrences. Adam and Eve are awestruck by the magnificent array of complexly interrelated parts.

Our question is 'Can Adam and Eve determine that the brain of the being they are about to see is not able to think?' The answer, I believe, is that they cannot. They are unable to say that an additional, nonbrain entity that is incapable of being observed on a cerebroscope must be present in order for the being possessing the brain to be able to think. So far as they can tell, the intricate object they have observed might be able to do the very sorts of things they are acquainted with from their own experience. It might be able to have thoughts and feelings, or it might not. It might be the sort of thing that can act on its own, with the motions they have seen represented on the cerebroscope being those of self-moving entities. It might even be the kind of thing that can have knowledge, not only of other material things but of the immaterial one who made it. Adam and Eve cannot tell a priori what capabilities the brain has or does not have.

This experiment shows that our concept of matter does not include the concept of the inability to think or feel or be a self-mover or have knowl- edge of immaterial entities such as God. It is not an a priori truth that matter cannot think. Adam and Eve can imagine a purely material being with the right sort of composition possessing the same person-characteris- tics they themselves possess. It is not contradictory for them to think of brain-like matter being responsible for the intellectual, emotional, active, moral and religious features of a creature. If we have trouble thinking this, it is not on a priori grounds or for purely logical reasons.

(b) The possibility of an immaterial substance not thinking. There are two considerations which support this possibility. The first is that Adam and Eve are not able to tell a priori that nonmaterial entities think, and the second is that philosophers have postulated the existence of nonmaterial entities that do not have the ability to think.

Imagine that God is making Eve, but that instead of putting Adam to sleep while he does so, he shows Adam what he is doing and explains as he proceeds. 'I am making her right arm now', God says, 'first by making these stiff things called bones and then by putting muscles and skin around the bones'. 'How do you make it so it can bend?' Adam asks. 'I shape the bones at the elbow like this', God replies, putting the fist of one of his hands into the cupped palm of the other. After numerous shapings and explana- tions, God finally says, 'I am going to put something entirely different in

her now, which neither you nor I will be able to see - an immaterial sub- stance, as some people will later call it'. Adam asks, 'What is that for?' God explains, 'It makes her like you - alive and able to move, feel and think'.

Adam's question reveals his inability to tell a priori that nonmatter thinks and feels. This same inability is also revealed by the fact that philosophers have claimed existence for various nonmaterial entities that do not have the ability to think or feel: unexemplified possibilities, Forms, numbers, possi- ble worlds, objectively existing values, objectively existing logical rela- tions, such as disjunction and negation, and meanings. This fact shows that nonmatter is neutral with respect to thinking and feeling; it might do these but it also might not.

(c) The inability of nonmatter to e.~plain thinking. Christian dualists suppose that the presence of nonmatter in people explains the ability to think. If they did not make this supposition, there would be no reason for them to be dual- ists. They also appear to assume, though this has never been overtly stated, that if the idea of immaterial substance necessarily includes the idea of thinking, then the existence of such a substance in people explains the exis- tence of thinking in them. I shall not challenge this assumption, but shall note that if it is possible for an immaterial substance not to think, as the above considerations show, then the presence of nonmatter in people does not explain their thinking. What explains it is that God has endowed the nonmatter with the ability to think.

This point should not be misunderstood as asserting or entailing that matter does explain the presence of mental characteristics. It has no explanatory power either. To the Christian dualist who says that the materi- alist ends up with mystery, the materialist responds, 'Yes, that is right. We do not know how matter can think, but neither do we know how nonmatter can think. Christian dualism contains just as much mystery as Christian materialism.'

Consider a few mental and spiritual features. It is often said against mate- rialism that it cannot account for intentionality, because it is impossible to imagine chemicals intending. But it is equally impossible to imagine imma- terial substances intending. The mystery is how anything can intend, and it is not solved by claiming that nonmatter does the intending instead of matter. The same is true of having preferences. How can a conglomeration of cells have a preference for hammered dulcimer music instead of for Beethoven? We do not know. But it does not add to our knowledge to say that something nonmaterial has the preference.

Can something that is grey and squishy be guilty? Can it repent and then be forgiven? The mere posing of these questions is designed to reduce materialism to absurdity. The same absurdity results, however, when we ask

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how an immaterial entity can be guilty and forgiven, for nonmatter no more possesses the ability to be these than does matter. The absurdity comes from attributing the guilt and forgiveness to the stuff or substance which per- forms the guilty actions. It is a category mistake, though, to attribute the guilt to this stuff, just as it is a category mistake to say that hydrogen and oxygen molecules are slippery because water is slippery. Dualism, there- fore, does not give us any more explanation of the presence of guilt and for- giveness than does materialism.

The same is true of becoming a 'new creature in Christ' and of having the 'Holy Spirit dwell in us' - two of the Apostle Paul's favorite phrases. The nonmateriality of the entity that undergoes a spiritual rebirth does not explain the existence of the rebirth. What explains that are psychological and spiritual processes - thoughts, feelings, choices, inclinations, and the like, which either matter or nonmatter may possess. Or we may invoke a supernatural explanation, that God works in people to regenerate them. But it is no less conceivable that God works on matter than that he works on nonmatter to do this. Nor does dualism enlighten us with respect to the presence of the Holy Spirit in people (if this is interpreted ontologically instead of functionally), for it is just as possible for a divine immaterial being to reside in matter as it is for it to reside in nonmatter. After all, dualism asserts that an immaterial substance resides in matter.

5. Objections

My aim in presenting these three considerations has been to show, not that matter actually does think and feel, but that we can conceive it doing so no less than we can conceive nonmatter doing so. From one perspective, adopt- ing this position requires a major conceptual shift in Christian thought. It has seemed evident to most Christian theologians and philosophers that minds must be nonmaterial. Dualism has, in fact, been a lynchpin of Christian interpretations of human existence and of much Christian apolo- getics. From another perspective, very little conceptual shift is required by adopting the parity theses, because the important features of Christianity are retained. They are present without nonmaterial substances residing in us. I want now to secure more certainly the possibility of this being so by reply- ing to several objections.

One of the charges commonly made against materialism is that it is reductionist. In identifying mind with matter, it is said, the materialist elimi- nates the distinctive features of mind. And if this is the case, people would be nothing more than complex animals or sophisticated machines and thus would have lost their humanness. They would be nothing but parts of nature, without anything to suggest that they were made in God's image.

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The proper Lockean response to this objection is to say that if the parity theses are true, nothing would be lost if we were purely material. The matter of which we would be made would have all the abilities that Christian dual- ists say immaterial substances have. It would have the ability to move itself, feel, think, sin, love, and know God. For God would have given it these capabilities. They would be what made us different from other material entities that do not possess them and they also would be what constituted God's image in us. We bear God's image because we possess certain abili- ties, not because we are made of a certain kind of substance. Simply adding nonmatter to matter would not make something be like God. What makes something like God is the abilities it has. So if God can make a material being do all the things Christianity says people can do, as the parity theses assert, then people would not have been 'reduced' to 'mere matter'.

There is, of course, an obvious sense in which Christian materialism says that mind is reduced to matter, namely, the sense in which one states what something is made of. But this is an innocuous sense of 'reduce', for accord- ing to it science reduces clouds to masses of water droplets and dualism reduces mind to nonmatter. In this sense of 'reduce', the reduction of think- ing to matter would be no more inimical to Christianity than the 'reduction' of thinking to nonmatter, since in neither case would the reduction require the loss of anything incompatible with Christianity. Christian materialism is. in short, a nonreductionist materialism.

There is also in Christian materialism a conception of matter that differs markedly from the conception that Christian dualists have of it. Dualists think of matter - all matter - as inert, unable to move itself, and incapable of feeling, thinking, or loving. Christian materialists, however, say that only some matter is like this, whereas other matter is active, self-moving, and capable of feeling, thinking, and loving. To dualists, the very idea of matter being active and self-moving is unimaginable, for they think that matter is essentially passive and unfeeling, and what has passivity and unfeeling as part of its essence cannot be made active and feeling, not even by God. It would be like saying that God could make something to be both cylindrical and spherical at once.

The appealing feature of this objection is that most (perhaps all) people's everyday or precritical conception of matter is of something inert and unfeeling, just as dualists say it is. We must ask, however, what the source of this conception is. Is it derived solely from the meaning of the word 'matter?' Does it come from the fact that most of the matter we observe is inert and unfeeling? That it is the latter is shown, I believe, by the following scenario. Imagine a world in which there is no inorganic matter - no dirt, rocks, or metal - and also no plants or animals. Imagine, too, that there are people like ourselves in this world and that they are sustained somehow (we needn't imagine how) without the need of inorganic substances, plants, or

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animals. In such a world, the conception people would have of matter would be of something active and feeling, because they would never encounter any other kind. They would have no trouble being Christian materialists because the paradigm of a material thing for them would not be inorganic sub- stances. That, though, is our paradigm. And this is what makes it difficult for us to imagine matter that feels and thinks. We are, in fact, liable to think that no matter feels or thinks, and even more strongly, that none can feel or think. It would be a mistake, though, to infer either of these from our wide- spread acquaintance with matter that does not feel or think, as we are inclined to do.

The proper way for us to interpret Locke's parity thesis, consequently, is to say that neither matter nor nonmatter has mental capabilities as part of its essence. Each is neutral with respect to thinking and feeling. What God is able to do is to give mental abilities to each of these neutral substances. The wrong way to interpret Locke's parity thesis is to say that God can make something that is essentially unthinking to think. This would, indeed, be impossible, in the same way it is impossible for God to make a cylinder noncylindrical.

This neutrality undercuts another objection that is sometimes raised against materialism. Simply adding matter to matter won't produce think- ing, it is said. That is, you won't get thought by making aggregates of non- thinking elements. You need thought to begin with.

If Locke's parity thesis is true, however, the Christian materialist is not committed to the anomalous appearing claim that mind is formed by aggre- gating nonmental bits of matter. God can give the ability to think to the merest bit of matter, and he can also give the ability to think to the interac- tions of matter or to certain kinds of matter but not to other kinds. More- over, it is just as easy to conceive of God doing these as it is to conceive of his giving the ability to think to nonmatter. Yet how he can do this latter is as opaque to us as how he can do any of the forrner. 9 The neutrality of matter and nonmatter with respect to thinking puts them on a par with each other.

Dualists commonly use the different properties argument to deny parity. This argument says that thoughts cannot be identical to brain states because the two have different properties, and whatever has different properties must be different entities. Thoughts, for instance, are profound, superficial, relevant, irrelevant, and not located at any place. Love is satisfying, sacrifical, and imaginative. Brain states, however, are none of these. They are neither profound nor superficial, relevant nor irrelevant. They are located at particular places. It makes no sense to say of them that they are satisfying or unsatisfying. There must, therefore, be something nonmaterial to which we can attribute these characteristics, concludes the dualist.

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If this reasoning is sound, however, it also shows that thoughts cannot be identical to nonmaterial states, for nonmatter, too, is neither profound or superficial, satisfying or unsatisfying. Being imaginative is no more part of the idea of nonmatter than it is part of the idea of matter. What dualists must do, consequently, is to account for minds being nonmaterial even though we describe minds and nonmatter in different ways. They might say that our mental descriptions, though embodying a different conceptual framework from that embodied in our descriptions of nonmatter, nevertheless are used to refer to nonmaterial states. Or they might disavow the identity of mental states and nonmatter and assert some other connection between the two, for example, that nonmatter possesses mental capabilities, i.e., that nonmatter can do mental things. Both of these strategies can be, and have been, used by materialists, the first by identity materialists and the second by other kinds of materialists. The metaphysics of the exemplification of thinking in some substance is the same whether that substance is material or nonmater- ial. It is, indeed, a puzzle how the mental characteristics of profundity and irrelevance get exemplified, but this puzzle is not solved simply by postulat- ing nonmaterial souls.

Conclusion

If the parity theses are true, as I believe they are, then Locke's Irrelevancy Thesis is true. This thesis says that it is irrelevant whether people are purely material or whether they possess nonmaterial minds. God could have made us as we are either way. Moreover, if the parity theses are true, then the issue of dualism versus materialism cannot be settled by appealing only to conceptual arguments, as seems often to be done. Other considerations are relevant as well, especially empirical ones. Finally, if the parity theses are true, then we must be ready, if needed, to adopt a Sceptical Thesis as well. It might turn out that we will not be able to obtain the requisite evidence to determine whether or not we possess immaterial minds. But if the Irrelevancy Thesis is true, this scepticism would not be detrimental to Christianity. ~0

Notes

1. John Locke, An essay concerning human understanding (Dover, 1959), Book IV, Chapter III, Section 6, p. 195.

2. For an excellent treatment of Locke's position and of the reactions to it. see John W. Yolton, Thinking matter: Materialism in eighteenth-centu O, Britain (University of Minnesota Press, 1983).

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3. Book IV, Chapter III. The following quotes come from Section 6. 4. Book II, Chapter XXIII, Section 32. 5. Book II, Chapter XXIII, Section 5. 6. Richard Swinburne, The evolution of the soul (Clarendon Press, 1986), p. 54. 7. Pascal, Pens~es, trans. A. J. Krailsheimer (Penguin Books, 1966), p. 94 (#199). 8. The absence of alternative accounts is not so telling a consideration for Pascal as it is for

other dualists, since Pascal was not able to finish Perishes. 9. Locke supports this 'parity of opacity' in a different way when discussing the origin of

our ideas of substance in Book II, Chapter XXIII, Sections 22-32. ' If anyone. . , says he knows not how he thinks, I answer, Neither knows he how he is extended, how the solid parts of body are united, or cohere together to make extension' (Section 23). And, '[We] can as little understand how the parts of body cohere, as how we ourselves perceive or move' (Section 25).

10. Nothing I have said shows that dualism and materialism are on a par with respect to life after death. Showing this would introduce considerations that go beyond Locke's parity theses, and it has been my purpose to focus on these theses. Their domain is limited to thinking, feeling, loving, choosing, and the like.

Address for correspondence: Professor Clifford Williams, Department of Philosophy, Trinity College, Deerfield, IL 60015, USA Phone: (847) 317 7164