Introduction
You have a body, but you are a soul or self. Without your body, you could still exist. Your body could be and perhaps is outlasted by the immaterial substance which is your soul or self. Thus the substance dualist. Most substance dualists are Cartesians. The self, they suppose, is essentially conscious: it cannot exist unless it thinks or wills or has experiences. In this paper I sketch out a different form of substance dualism. I suggest that it is not consciousness but another immaterial feature which is essential to the self, a feature in one way analogous to a non-dispositional taste. Each self has moreover a different feature of this general kind. If this is right then simple and straightforward answers are available to some questions which prove troublesome to the Cartesian, consciousness-requiring type of substance dualist. I mean the questions, How can the self exist in dreamless sleep?, What distinguishes two simultaneously existing selves, and What makes a self the same self as a self which exists at some other time?
Why not just abandon substance dualism? Why suppose that the subject of consciousness is anything but corporeal? That is a question which I leave aside. I focus rather on the options that confront us if we do rightly or wrongly assume the subject not to be corporeal.
Someone will say that my very distinction between the subject and its consciousness betrays a mistaken view about how in general substances relate to properties, a failure to appreciate the truth that Kant enunciates when he maintains that ‘in their relation to substance, [accidents or properties] are not really subordinated to it, but are the mode of existence of the subject itself.’Footnote 1 In the Second Meditation, Descartes refers to ‘that I know not what of mine which cannot be pictured in the imagination.’Footnote 2 According to Galen Strawson, this shows that Descartes has relapsed into a ‘bad’, non-Kantian picture of objects and their properties, a picture ‘to which our minds keep defaulting’,Footnote 3 a picture, perhaps, in which bare particulars or propertyless substrata figure as the entities which must exist in order for properties to be instantiated. In another passage Descartes says that ‘thought must… be considered as nothing else than thinking substance itself’.Footnote 4 Here Strawson thinks that Descartes manifests a better attitude, shows that he has achieved a difficult insight out of which he was nevertheless sometimes hustled ‘by his critics’ insistence on the conventional metaphysical categories'.Footnote 5 We are to recognize that as Strawson puts it, ‘the subjectivity is just the subject’.Footnote 6 The speculations now to follow about the immaterial nature of what Descartes refers to as the I know not what of mine are in fact entirely compatible with Kant's doctrine about the relation between substances and properties. It is one thing to be a subject of consciousness, another to be a subject or substance in the sense just of something of which properties are predicated. Kant's is a doctrine of subjects in the latter sense. It does not licence us to deny the existence of that to which mental contents are presented. To deny it is to ignore the phenomenology. Suppose you seem to see a scarlet poppy and, straight afterwards, you are aware of having had this experience. Then you remember its content: it was an experience as of a scarlet poppy. But it may well be that you seem also to remember a something, distinct from this content, to which the content was presented. ‘…When I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe anything but the perception.’Footnote 7 Contrary to what Hume says, you may at least seem to catch something other than ‘the perception’, seem to discern the subject of this perception, and this even though you seem to discern it only with the perception. As with experiencing, so with thinking and with willing: as well as remembering the content of the episode, that which was thought or willed, you may seem to remember the subject of the episode, that which thought or willed.
Ipseities
What then are selves, according to the non-Cartesian substance dualist? They are immaterial, in the sense of not spatially extended. An alternative criterion of immateriality is supplied by the principle that a feature is material if and only if it is one to his possession of which the possessor has no privileged access.Footnote 8 I abjure that criterion because I want to leave open the possibility that selves have neither privileged nor unprivileged epistemic access to them as they are in themselves, and can but speculate about their noumenal nature. If they have no such epistemic access then on the alternative criterion of immateriality no selves would be immaterial.
Next I suggest that each self has a property which is intrinsic, in the sense of non-relational and non-dispositional. If selves are immaterial, the intrinsic property will not be one which requires its possessor to be spatially extended. Examples of intrinsic properties are non-dispositional tastes and colours. An apple is sweet if it tastes sweet when tasted under normal conditions. ‘Sweet’ is here used twice: once in the phrase ‘is sweet’, and once in the phrase ‘tastes sweet’. In ‘is sweet’, ‘sweet’ stands for a dispositional property. But in ‘tastes sweet’, ‘sweet’ is used in a non-dispositional sense. It is indeed impossible to define a dispositional taste property except in terms of its non-dispositional counterpart. Only in terms of non-dispositional taste properties can we fully describe the contents of taste experiences. There are in the same way non-dispositional properties of colour. If something has a non-dispositional colour then it is spatially extended, and this remains true even on what may be the false assumption that only contents of experience have such properties. Even coloured sense data have spatial properties. But something can have a non-dispositional taste without being spatially extended, and the intrinsic properties of immaterial selves are I suggest analogous to non-dispositional tastes.
Finally, I suggest that the intrinsic property of each immaterial self is unshared: no two entities both have it. If by a property is meant a universal, something which if instantiated has many instances, is shared by many owners, then there are no unshared properties. But by a property I mean just a feature. A property is unshared if just one entity has it, either contingently, as the moon has the property of being a natural satellite of the earth, or necessarily, as 3 has the property of being an integer that equals 2 + 1. Each self's intrinsic property is, I conjecture, contingently unshared. Someone may object that if a self possesses an intrinsic property with which experience acquaints it then that self will share the property with the entity which is the content of the experience. Is ‘entity’ the right word? Why not? Experiences have objects. But they also have contents: their objects are presented to the subject in a certain way. Their objects may be non-existent but it is hard to deny existence to their contents. Let me then meet the objection by weakening the definition of being contingently unshared: a property is contingently unshared if is contingently true that it is possessed by one and only one entity which is not a mental content.
I need a label for these immaterial, intrinsic, taste-like, unshared properties. I will call them ipseities. And now we can speculate that there are substances of a kind for membership of which it is necessary and sufficient for a substance to have an ipseity. For as the non-Cartesian substance dualist speculates, selves are just such substances. They are substances to which ipseities are essential, and consciousness not essential. All subjects of consciousness will then be selves. But it is not necessary to suppose that all selves are subjects of consciousness. A self may often function as such a subject, may often think or will or have experiences. And sometimes, after it has thus functioned, it may seem to remember doing so. But it is not essential to a self that it is conscious. Nor is that essential even to a human self: a human self can be defined with maximum latitude as one which either has or has at some time had a human body and which either is or has at some time been conscious.
A further speculation. Though ipseities are unshared, it need not be denied that there are qualitative resemblances between them. Imagine a hue with just one instance. It has, in this one instance, a discernible degree of brightness and a discernible degree of saturation. Since the hue has just one instance, the degrees of brightness and of saturation are discernible only by comparison with instances of other hues. Though ipseities are more closely analogous to non-dispositional tastes than to non-dispositional colours, may not two or more ipseities agree or differ in a way analogous to that in which two uniquely instantiated hues may differ in point of brightness or saturation? That possibility is not excluded by our inability to discern such gradations by comparing different ipseities. It is possible then that John's ipseity is in some degree affected by what he has done and thought and experienced, and that Mary's different ipseity is similarly affected to the same or to a different degree. Two ipseities may, one might say, be equally or unequally stained or clarified by what their selves have done or undergone.
And there is another way in which ipseities can resemble each other. Imagine three hues, each with just one instance. Call these hues A, B, and C. A may resemble B more than it resembles C, as for example, in the case of ordinary shared hues, red resembles orange more than it resembles blue. In the same way, that ipseities are unshared features does not prevent my ipseity from resembling yours more than it resembles his, or prevent mine from being more like yours than either is to anyone else's. There can in this way be special affinities between different selves.Footnote 9
Acquaintance with ipseities
Selves have ipseities, but does any self have experience as of having a particular quality which is in fact its own ipseity, and which it can somehow know to be its own ipseity? Is it indeed possible for one self somehow to gain acquaintance with the ipseity of another self, and to know that it has gained this acquaintance?
The first question is phenomenological. Go back to the scarlet poppy. You seem to see it and, straight afterwards, you are aware of having had this experience. You remember the content of the experience: it was an experience as of a scarlet poppy. But you seem also to remember a something, distinct from this content, to which the content was presented. How does this something present itself? Just as an indeterminate or hazy object? Or as something with a definite particular intrinsic quality? Only in the latter case could experience acquaint you with a quality which was in fact also the particular ipseity which belongs to you as you are in yourself. But even in the latter case it would be a further step to claim that you know, directly or otherwise, that the experienced quality is an unshared quality which belongs to you as you are in yourself. I see no reason to think that you could gain such knowledge.
However we answer the first question, the second question must I think be answered in the negative. A divine self would doubtless have knowledge of the ipseities of all selves. A mystic might glimpse the ipseity of a divine self. But human selves are not thus open to each other, at least this side of the grave. A human self could not in the natural way of things even gain acquaintance with a quality which is experienced by another self and which may for all that other self knows be its own ipseity.
Has anyone thought that experience acquaints each self with the particular quality which is in fact the ipseity of that self? Gerard Manley Hopkins seems to have believed as much. Of his ‘selfbeing’ Hopkins wrote that it had a taste ‘more distinctive than the taste of ale or alum, more distinctive than the smell of walnut-leaf or camphor’. This taste was ‘incommunicable by any means to any other man (as when I was a child I used to ask myself What must it be like to be someone else?) Nothing else in nature comes near this unspeakable stress of pitch, distinctiveness, and selving, this selfbeing of my own. Nothing explains or resembles it, except so far as this, that other men to themselves have the same feeling.’Footnote 10 Perhaps, if we are inclined to think that the subject presents itself to memory just as a hazy or indeterminate something, we should reflect that the seeming indeterminacy may be a product just of overfamiliarity. Or perhaps it is a product of the fact that, as Hopkins put it, ‘searching nature I taste self but at one tankard, that of my own being.’Footnote 11 We are unable, in the case of the experienced qualities which could be our ipseities, to experience contrasts between different qualities of that general kind. The taste of ale is salient just because I can contrast it with the taste of alum; scarlet is salient because I can contrast it with dark blue. If no self can in the natural way of things experience the putatively ipseical quality which another self experiences, then no self can experience a contrast between the two qualities. But even if Hopkins is right about the determinacy of the quality you experience when you seem to experience yourself as a subject, he does nothing to show that this quality is an ipseity possessed by yourself as you are in yourself. Whatever its theoretical advantages and pragmatic attractions the ipseical form of substance dualism remains a speculation.
Consciousness and Identity
What theoretical advantages? On the Cartesian version of substance dualism, a self must think or will or have experiences: it is an essentially conscious substance. From this it follows that selves are conscious whenever they exist. How then can a self enjoy dreamless sleep? To meet this difficulty, you might follow Descartes and deny that there is any such thing as dreamless sleep: during sleep we always dream, even if we cannot always subsequently remember doing so.Footnote 12 Another possibility would be to say that selves ‘… exist in a time-order different from that in which they are deemed to have periods of unconsciousness’, and that ‘although they may be said to undergo periods of unconsciousness by virtue of intermittently participating in physical time, they are, in their own time-order, essentially conscious’.Footnote 13 Or you might insist that, though persistent and conscious whenever they exist, selves have an existence which is intermittent: sometimes they stop existing and then start again.Footnote 14 Suppose however that selves are taken not as substances which are essentially conscious, but rather as substances to which ipseities are essential. Then the difficulty does not arise. The self continues to exist, with its own ipseity, even when it is not conscious. And so long as it has at some time been conscious and has at some time had a human body, it continues to exist as a human self: if there are selves which will have but do not yet have bodies and which will be but are not yet conscious then these selves will be but are not yet human.
What distinguishes two simultaneously existing selves? What makes an earlier self the same self as a later self? These questions are troublesome to the Cartesian kind of substance dualist. Is it not possible for two simultaneously existing selves to have thoughts or volitions or experiences with intrinsically indistinguishable contents, and for the same body to be shared by two simultaneously existing selves or by an earlier and a later self? It may be suggested that an earlier self is the same self as a later self if and only if all the mental episodes of which the earlier self is the subject belong to the same set of conscious episodes as those of which the later self is the subject. But what makes for a single set of conscious episodes? Causal relations between the episodes? Resemblances between the contents of their episodes? Both criteria may have the paradoxical consequence that an earlier self is the same self as two different later selves. There is an enormous literature about such difficulties. But on the ipseical version of substance dualism, it can be said quite simply that two simultaneously existing selves are distinguished by their different ipseities, and that an earlier self is the same as a later self if and only if the later self has the same ipseity.
It is worth comparing the doctrine that two simultaneously existing selves are distinguished by their different ipseities with what Richard Swinburne has to say about the individuation of human souls. Swinburne is a substance dualist for whom it is essential to a human soul that it has some mental property, where a mental property ‘is one to whose instantiation the substance in whom it is instantiated necessarily has privileged access on all occasions of its instantiation’.Footnote 15 He also thinks that souls have thisness, in the sense that they are exempt from the principle that diverse entities have different properties. Souls, he believes, ‘just differ solo numero’.Footnote 16 It is true that if, as Swinburne thinks, properties are universals, entities with several instances, then on ipseical substance dualism two simultaneously existing selves need not have different properties. But two such selves do not on this doctrine just differ solo numero: they differ rather in their contingently unshared, non-dispositional features, in their ipseities. Each self has its own mysterious feature, in the natural way of things hidden both from itself and form other selves, open only to analogical speculation, but a positive feature, richer than a mere numerical identity. But perhaps I exaggerate the austerity of Swinburne's view. He does to some extent favour the view that souls or subjects of consciousness are substances which can exist on their own as individual essences, and he conjectures that an individual essence is what Duns Scotus meant by a haecceity or contraction of a specific form.Footnote 17 Perhaps this takes him closer than at first appears to the ipseical form of substance dualism.
According to the substance dualist, your body could be and perhaps is outlasted by the immaterial substance which is your soul or self. On the ipseical theory the self is not essentially conscious and could survive the body even if human consciousness requires a functioning brain. Could there be value in the survival of a non-conscious self? This is just one of the many questions which now suggest themselves but into which this paper will not enter. Here though to end with are some brief remarks on selves as agents.
Agency
Selves are praised or blamed neither for the thoughts which strike them nor for the experiential contents which are presented to them. But they are praised or blamed for their volitions, for their decisions and other acts of will. For this to be appropriate there must be a relation between the self and its volitions which does not hold between the self and its thinking or between the self and its experiencing, a relation which cannot therefore be completely captured just by saying that when the self wills something it has a property of willing. The self must somehow be the origin of its volitions, in a way that it is not the origin of its thoughts or experiences. What can this mean? Some philosophers have suggested that for the self to be the origin of volition is for it to be that volition's cause: here, if not elsewhere, causation is a relation not between events but between a substance and an event. This is hard to understand. What is the difference between the self's causing its volition, and its being true that the self exists and has a property of willing? We do not seem to have any experience of such a causal relation. Certainly one can be aware of willing, and sometimes one knows that one's willing is effective. But when one wills one does not seem to be aware of any causal relation between oneself and one's willing.
Two thoughts suggest themselves. The first takes a hint from Berkeley's Philosophical Commentaries. ‘Substance of a Spirit is that it acts, causes, wills, operates, or if you please (to avoid the quibble yt may be made on ye word it) to act, cause, will, operate.’Footnote 18 Suppose you remember deciding to climb up Whernside. Then you seem to remember not just your self, the decider, and the content of your decision, but also a third, volitional element, which we can call a force. In the case of thinking or experiencing there are by contrast just two elements, the self and the presented mental content. But is there really a pre-existing self which is distinct from and yet simultaneous with the force, and which, as well as deciding, is aware of the force and the content of the decision? Why not say rather that the force, for as long as it exists, takes over the thinking and experiencing functions of the self, together with the self's ipseity? The self, though it sometimes exists without being conscious, and sometimes functions as a subject of thought or experience, never itself functions as an agent. When the force starts, the self ceases to exist, and when the force stops, the self is reborn. Our praise and blame can be directed to the force itself, not to a pre-existing self by which the force is somehow mysteriously originated.
The other and less radical thought is this. It was earlier conjectured that an ipseity may as it were be more or less stained or clarified by what the self has done or undergone, just as a given hue may be present with a greater or lesser degree of brightness or of saturation. May it not be that before a self wills there is an unobservable heightening, in some dimension, of the ipseity of that self, and that the willing is in fact caused by that heightening? On this view of things, the self originates its volition and is responsible for it not because the volition is caused by the substance which is the self, but because it is caused by an event which is an intensification of the essential feature of the substance which is the self.
