John Locke's discussion of personal identity in the 1694, second edition, of his Essay Concerning Human Understanding⁽²⁾ has had enormous influence on subsequent discussions of personal identity down to our own times. Almost all modern discussions of the concept of person look back to Locke, and only to Locke, as their starting point. It is as if Locke were the first person ever to consider the topic of personal identity, though this is certainly not the case. In fact the concept of person, and what determines the nature and identity of persons, has had a long history in western thought. However, what truly marks the difference between this history and Locke's discussion, is that most of the previous discussion of persons occurred in the context of heavenly rather than earthly matters. The most intense discussions of the nature and identity of persons were tied to questions like: "How could the same human person arise again at the resurrection?"; "How do angels, or heavenly persons, differ from human persons?" "How is it possible for three distinct persons to be one God?"; and "How can Christ be a person that is both man and God?"

With the exception of the problem of the resurrection, these questions tend to focus on distinctions concerning spiritual rather than human persons. And even the problem of the resurrection, which comes closest to the problem of personal identity in the Lockean sense, focuses on heavenly rather than earthly continuity. Now, while it is certainly the case that Locke, himself, was concerned about the resurrection when he constructed his account of personal identity, many of his modern followers are not so concerned, but adopt his notion of personal identity based on consciousness for purely earthly concerns. Nevertheless, if we are to understand Locke's revolution in the consideration of the grounds for personal identity in their true historical context, we must see it with reference to the questions concerning heavenly as well as earthly persons that dominated debate about the nature of persons and their identity in the seventeenth century.

A key influence on these debates was Descartes, whose theory of a fundamental dualism between thinking and extended substances had important ramifications throughout the century, eventually overthrowing traditional Aristotelean metaphysics. During the process of this transition, a number of other metaphysical positions would be discussed, such as Hobbes's pure materialism, the atomism of Gassendi, and the neoplatonic responses of the Cambridge Platonists, not to mention various transformations of the Cartesian position. Most of these metaphysical positions appeared before Locke wrote his Essay and influenced his thoughts on what could be known about the material and spiritual worlds. But they also influenced another metaphysical debate - that dealing with the concept of person as it applies to God. It is this latter metaphysical debate on which I wish focus in the present paper. I will try to show how it led to a new Cartesian conception of person - one that had a direct influence on Locke's discussion of personal identity in his new chapter on 'Identity and Diversity' published in the 1694, second edition of his Essay.

The debate over the nature of God, and whether three persons could be one God reached its zenith in the 1690s in Britain, during the very years, between the first and second edition of Locke's Essay, when Locke must have formulated the position he presents in the second edition. And Locke, himself, was immediately drawn into the debate over the Trinity. He was drawn into it, indirectly, when Toland (1696) and Gastrell (1696) used his ideas, respectively, to reject and to explain the trinity of persons. And he was drawn into the it, directly, when Bishop Stillingfleet (1697), in his own vindication of the Trinity, blamed Locke for Toland's use, in his Christianity Not Mysterious (1696), of Locke's way of clear and distinct ideas in order to dismiss the Trinity as incomprehensible and impossible⁽³⁾.

Despite Stillingfleet's accusation against Locke, the suggestion that three persons in one God was rationally impossible did not have to wait for the arrival of Lockean ideas. In fact, as far back as Servetus, in the 16th century, Protestant theologians were questioning whether three persons could make one unified and personal God. Followers of Servetus and Socinus, who called themselves Socinians, and later Unitarians, believed that God was a unitary person, and that only the Father could be true God, with debate ensuing over what to make of the Son and Holy Spirit. The Socinians had been a minor sect in England since early in the 17th century, but they burst on the scene with a series of tracts in the 1680's and 90's. These anti-Trinitarian tracts produced a counter-blast of Trinitarian defences, all of which tried to make rational sense out of the mystery of three persons in one God. But what really raised the stakes of the conflict was that these Trinitarian defenders began to debate among themselves, accusing each other of heresies of various traditional forms, while the Socinians, or Unitarians, gleefully facilitated the internecine warfare. By 1696 things got so out of hand that the King, himself, had to interpose a cease-fire on the debate and require all to use only traditional language to discuss the Trinity.⁽⁴⁾
 

At first traditional theologians were quite pleased with Sherlock's account of the Trinity, and thought that they finally had a answer for the Socinians. But then, when the Socinians accused him of tritheism, a traditional theologian, Robert South, joined in, and provided a vicious attack on Sherlock's work. This was followed by mayhem, where Sherlock defended himself, both anonymously and then in his own name, against the Unitarians and South, and South renewed the attack, eventually getting Sherlock's ideas formally decreed as heretical at Oxford. Sherlock answered this decree belligerently (Sherlock, 1696), and it was at this time that the King had to intervene in order to quiet things down. After this, Sherlock partially retreated from his position in several more publications, of which the last (Sherlock, 1698) provided a history of the debate and also attempted to provide a traditional account of the Trinity by tracing its entire history, while, at the same time, still suggesting that his innovations needn't be viewed as tritheistic. Despite this final attempt to explain himself, most interpreters of Sherlock's retreat saw him as swinging back from tritheism to sabellianism, the traditional heresy that assumed that God was a singular being who appeared in three modes.⁽⁶⁾ Although I'm not convinced that Sherlock fully forfeited his original position, I will not try to defend him here. My goal is to present and explicate his original view, and to show how it may have influenced Locke.

But before going into Sherlock's original view of the Trinity, it is worthwhile to consider the range of other views of the Trinity, and of the nature of persons, which were being considered at this time. It is only in this way that we can see the turmoil in metaphysical discussion of the concept of person that occurred in the seventeenth century, which ultimately resolved itself in the conception of person based on unity of consciousness, first presented by Sherlock and subsequently developed by Locke in his influential chapter on identity. In one of the Socinian works, published in 1693, that critiqued Sherlock along with other recent attempts at explicating the Trinity, there is a nice description of these alternative views that, though presented in terms of their seventeenth century exponents, nicely provides a mini-history of metaphysical concepts of person that have been influential in western thought. The author writes:
 
For Memory and Method's sake, and because the Division is so just; we may distinguisth the Accounts, or Explications of the Trinity contrived by our Opposers; after this manner. There is, first, the Trinity according to Tully, or the Ciceronian Trinity; which maketh the three Divine Persons, to be nothing else but three Conceptions of God; or God conceived of as the Creator, the Redeemer, and Santifier of his Creatures. Dr. Wallis, after many others, hath propounded and asserted this Trinity, in his Letters, and his Sermons...⁽⁷⁾
 
John Wallis, who also published a defence of the Trinity in 1690⁽⁸⁾, had used a triangle as a metaphor for the Trinity, and had suggested that the word person was an arbitrary designation, and so substituted "three somewhats", a term repeatedly used in attacks on this view, which had its origin in Cicero's conception of person as a role or mode of activity of an individual.

The second view of the Trinity to be distinguished here was the one proposed by Sherlock:

The next is the Cartesian Trinity, or Trinity according to Descartes: which maketh three Divine Persons, and three Infinite Minds, Spirits and Beings, to be but one God; because they are mutually, and internally, and universally conscious to each others Thoughts. Mr. Des Cartes had made this Inventum to be the first Principle and Discovery in Philosophy, Cogito, ergo sum; I think, therefore I am: and he will have the very Nature of a Mind or Spirit to consist in this, that 'tis a thinking Being. Therefore, says Dr. Sherlock, three Persons can be no otherways one God, but by Unity of Thought; or what will amount to as much, as internal and perfect Consciousness to one anothers Thoughts. Any one may see, that Dr. Sherlock's Mutual Consciousness, by which he pretends to explain his Trinity in Unity, was by him borrowed from the Meditations and Principles of Monsieur Des Cartes...⁽⁹⁾

It is important to note here that Sherlock's accuser is indicating that Descartes is the original source for his viewpoint, not Locke. Although there are innovations in Sherlock's views compared to Descartes, it is fair to say that Descartes was the originator of the view of person that Sherlock adopts to explicate the Trinity, or, for that matter, of the view of person that Locke, himself, adopts. But more on this shortly. First let us consider the remaining views given by Trinitarians to explicate the Trinity that are here under attack.
 
The Third is the Trinity of Plato, or the Platonick Trinity; maintained by Dr. Cudworth, in his Intellectual System. This Trinity is of three Divine Co-eternal Persons, whereof the second and third are subordinate or inferior to the first; in Dignity, Power, and all other Qualities, except only Duration. Yet they are but one God, saith he; because they are not three Principles, but only one; the Essence of the Father being the Root, and Fountain of the Son and Spirit: and because the three Persons are gathered together under one Head, even the Father.⁽¹⁰⁾

Cudworth's work⁽¹¹⁾, published in 1678, was an enormous tribute to ancient platonic philosophy, and he expended considerable effort showing how the platonic trinitarian ideas related to the Christian Trinity. The view he presents here was, however, attacked as Arian, because he subordinates the second and third persons to the first, as the ancient heretic Arius had done.

But more central to our present concern is the fact that Cudworth was the person who introduced the use of the term consciousness in a philosophical sense into the English language, a term he no doubt adopted from Descartes but also reasonably attributed to Plotinus.⁽¹²⁾ In a quotation that Cudworth used to present Plotinus' concept of consciousness, Plotinus had written:

Nature has no grasp or consciousness of anything, but the imaging faculty has consciousness of what comes from outside; for it gives to the one who has the image the power to know what he has experienced.⁽¹³⁾
 
Cudworth himself defined Consciousness as that

which makes a Being to be Present with it self, Attentive to its own Actions, or Animadversive of them, to perceive it self to Do or Suffer, and to have a Fruition or Enjoyment of it self.⁽¹⁴⁾

This definition is very close to the notion of reflexive consciousness used by Descartes, but here Cudworth follows Plotinus and extends the power to other animals as well. In Cudworth's account, humans differ from other animals in being cogitative as well as conscious beings, thus, unlike other animals, they can come to know of their own existence as selves and persons by reflecting on consciousness. As we shall see more clearly later, this reflexive definition of consciousness is not the definition with which we are particularly concerned, since it presupposes the self or person, who is conscious of current acts or thoughts of self. It is the origin of the definition of self or person in terms of unity of consciousness rather than in terms of reflexive awareness, which we are attempting to trace. Nevertheless, this latter sense of consciousness developed out of this earlier sense initially defined by Cudworth.

It was not Cudworth, but one of his renegade students, who first used the term consciousness to define the concept of person and to use this concept in a discussion of the Trinity. In a publication in 1685, Turner used the term to explicate a version of the Trinity that opposed Cudworth's, though his own interpretation of the Trinity was a weird mixture of platonic, cartesian, and materialistic ideas.⁽¹⁵⁾ He also expended considerable effort attacking Descartes's views. Turner extended the term consciousness beyond the simple reflexive definition of Cudworth, by treating "mutual self-consciousness" as a basis for unity among the persons of the Trinity. However, his use of this term was still very much tied to Cudworth's definition, and did not quite break free of it. By contrast, Sherlock's used the term consciousness in a more coherent fashion that focussed directly on the issue of unity. Since Sherlock's view is also much more likely to have influenced Locke, I'll leave aside further discussion of Turner.

But, first, let us return now to our Socinian survey of views of the Trinity. The author continues:

The fourth is the Trinity according to Aristotle, or the Aristotelian or Peripatetick Trinity; which saith, the Divine Persons are one God, because they have the same Numerical Substance, or one and the self-same Substance, in Number: and tho each of the three Persons is Almighty, All-knowing, and most Good; yet 'tis by one individual and self-same Power, Knowledg and Goodness, in Number. This may be called also the Reformed Trinity, and the Trinity of the Schools; because the Divines of the middle Ages, reformed the Tritheistick and Platonick Trinity of the Fathers, into this Sabellian Jargonry; as Dr. Cudworth, often and deservedly, calleth it. This is the Trinity intended by Dr. S[ou]th, in his Animadversions on Dr. Sherlock....It never had any other Publick Authority, saith Dr. Cudworth, but that of the fourth Lateran Council; which is reconded by the Papists among the General Councils, and was convened in the Year 1215.⁽¹⁶⁾

This Trinity of Aristotle is the traditional Catholic interpretation of the Trinity, which was generally found unsatisfactory at this time by many rationalizing Protestants, who could find only Sabellianism or only a single personal God in all the discussions by the scholastics of the internal relations of persons of the Trinity. It is also the view defended by Stillingfleet in his debate with Locke. In that debate, Locke, himself, refused to take a position on the issue of the relationship between his own more earthly conception of person and the persons of the Trinity.

Our author closes his discussion with one more view:

We must add to all these, the Trinity of the Mobile; or the Trinity held by the common People, and by those ignorant or lazy Doctors, who in Compliance with their Laziness or their Ignorance, tell you in short, that the Trinity is an unconceivable, and therefore an inexplicable Mystery; and that those are as much in fault, who presume to explain it, as those who oppose it.⁽¹⁷⁾

We see here the range of ideas about the Trinity that were in discussion during this period, and some of the intensity of the debate about what the term person should mean in the context of this debate. Moreover, we see how the concept of consciousness as the basis of personal identity first arose in the context of this debate. It is time now to consider more fully how this Cartesian interpretation based on consciousness was developed by Sherlock, so that we can then see how it might have influenced Locke.
 

Though Sherlock's language here differs from Locke's, when Sherlock writes his later Defence in 1694, he does mention Locke in this context:
 
we know nothing of a Spirit, but what we feel in our Selves, and can Philosophize no farther about it; for as Mr. Lock has truly observed, we can form no Idea but either from external Impressions; or internal Sensations; and therefore we can know no more of the Unity of a Spirit neither, than what we feel.⁽²¹⁾
 
This is one of only two references made to Locke in Sherlock's works on the Trinity. And he seems here to be using Locke's generally admired book to support what he had previously said in his own words. So, though it is possible that Sherlock had read the Essay before writing his first book on the Trinity, I don't agree with Ayers that the first passage, given above from Sherlock, indicates that there are "a number of Lockean touches" in Sherlock's book.⁽²²⁾ What appears to me to be the case is that, based on accumulated tradition, Locke and Sherlock independently arrived at the opinion that there are certain limits to human knowledge, and that this applies equally to matter and spirit. But let us return to Sherlock's first book on the Trinity.

The reason why Sherlock is stressing the limits of knowledge here, is that he wants to argue that there is a difference between lack of clear and distinct knowledge and contradiction. He believes that the Trinity may not be fully comprehensible but that this does not involve any logical contradiction, since the term God, or the substance of God, is not the same as the term person. He also wants to suggest that the only way that we can understand God in any clear and distinct manner is through analogy with what we do know, clearly and distinctly. And it is through our knowledge of ourselves as spirits that Sherlock believes we can come closest to understanding the Trinity of persons in God.

Sherlock begins his search for analogies to the Trinity with an inquiry into that which "makes any Substance numerically One". His discussion of what makes for identity and diversity, here, will find reverberations in Locke's own general discussion of this topic. Just as Locke will consider them in his second edition chapter, Sherlock begins by describing identity conditions for unorganized Matter:

Now in unorganized Matter it is nothing else but the union of Parts, which hang all together, that makes such a Body one; whether it be simple or compounded of different kinds of Matter, that is One numerical Body, whose Parts hang all together.⁽²³⁾
 
Next he considers living beings:
 
In Organical Bodies, the Union of all Parts, which constitute such an organized Body, makes it One entire numerical Body, though the Parts have very different Natures and Offices...⁽²⁴⁾

In this part of his discussion, Sherlock distinguishes between identity conditions for matter and for organic beings. Though Locke will differ in details on the identity conditions for these two categories, he will follow Sherlock in discussing them before moving on to discuss the third category of person.

Sherlock, himself, continues here with a discussion of the category of spirits:

In finite created Spirits, which have no Parts and no Extension neither, that we know of, no more than a Thought, or an Idea, or a Passion, have Extension or Parts, their numerical Oneness can be nothing else, but every Spirit's Unity with itself, and distinct and separate subsistence from all other created Spirits. Now this Self-unity of the Spirit, which has no Parts to be united, can be nothing else but Self-consciousness: That it is conscious to its own Thoughts, Reasonings, Passions, which no other finite Spirit is conscious to but itself: This makes a finite Spirit numerically One, and separates it from all other Spirits, that every Spirit feels only its own Thoughts and Passions, but is not conscious to the Thoughts and Passions of any other Spirit.⁽²⁵⁾
 
So, according to Sherlock, what distinguishes one created spirit - or person - from another is self-consciousness, a consciousness which sets a boundary on what we can 'feel' of any thoughts or passions. Sherlock wants to contrast this separated or divided consciousness, which we have as humans from the undivided consciousness, which he believes occurs in God, by suggesting a transitional possibility:

And therefore if there were Three created Spirits so united as to be conscious to each others Thoughts and Passions, as they are to their own, I cannot see any reason, why we might not say, that Three such Persons were numerically One, for they are as much One with each other, as every Spirit is One with itself; unless we can find some other Unity for a Spirit than Self-consciousness; and, I think, this does help us to understand in some measure this great and venerable Mystery of a Trinity in Unity.⁽²⁶⁾

Sherlock begins to apply this interpretation to the Trinity by first pointing out how the three Persons are distinct:

And the distinction between these Three Infinite Minds is plain according to this Notion; for they are distinguished, just as Three finite, and created Minds are, by Self-consciousness: . . . each Divine Person has a Self-consciousness of its own, and knows and feels itself (if I may so speak) as distinct for the other Divine Persons; the Father has a Self-consciousness of his own, whereby he knows and feels himself to be the Father, and not the Son, nor the Holy Ghost...as James feels himself to be James, and not Peter, nor John; which proves them to be distinct Persons: . . . Here is no confounding of Persons.⁽²⁷⁾
 
Sherlock goes on from here to describe the undivided or interconnected consciousness in God as a special form of mutual consciousness, that does not ever actually occur in created spirits:
 
Nor do we divide the Substance, but unite these Three Persons in One numerical Essence: for we know nothing of the unity of the Mind but self-consciousness... and therefore as the self-consciousness of every Person to itself makes them distinct Persons, so the mutual consciousness of all Three Divine Persons to each other makes them all but One infinite God: as far as consciousness reaches, so far the unity of a Spirit extends, for we know no other unity of a Mind or Spirit, but consciousness: In a created Spirit this consciousness extends only to itself, and therefore self-consciousness makes it One with itself, and divides and separates it from all other Spirits; but could this consciousness extend to other Spirits, as it does to itself, all these Spirits, which were mutually conscious to each other, as they are to themselves, though they were distinct Persons, would be essentially One.⁽²⁸⁾

The key idea in Sherlock's account is that consciousness is the basis of unity of a self, as well as the basis of the unity of God. As we shall see, shortly, Locke adopts almost exactly the language that Sherlock uses here when he suggests that, "as far as consciousness reaches, so far the unity of a Spirit extends, for we know of no other unity of Mind or Spirit, but consciousness." In the case of both of these authors, such phrases indicate a shift away from a simple reflexive interpretation of consciousness that presupposes the self, to a conception of unity of consciousness by which we can know the boundaries of what constitutes the self.

It is also worth noting that what Sherlock describes, here, of several self-conscious agents knowing each other's thoughts as well as their own, is a phenomenon that actually occurs in some cases of multiple personality. Such cases involve several personalities that are mutually conscious to each other's thoughts while at the same time conscious of their own thoughts as distinct from the other's thoughts. It is as if each thought is tagged with the identity of the self whose thought it is. Yet, there are several co-conscious subjects whose thoughts they are, and who are aware of, though do not experience responsibility for, each other's thoughts. Sherlock has a somewhat different interpretation of mutual consciousness in the Godhead. For the divine persons, there is a kind of co-operation in each other's thoughts and activities not found in multiples. They not only are aware of each others thoughts, but also cooperate with each other by entering into each other's thoughts and engaging in joint actions. And it is just through this mutual consciousness and cooperation that the three persons become constituted as one God. Nevertheless, because they remain distinctly conscious of the difference between their own thoughts and the thoughts of the other divine persons, they also maintain distinct personalities.

Rather than following further Sherlock's interpretation of the mystery of the Trinity, it is worthwhile at this point to return from heaven to earth and to consider more carefully how Sherlock's views of personal identity and its relationship to consciousness in finite as well as infinite substances relate to those found in Locke.
 

Thought. I use this term to include everything that is within us in such a way that we are immediately conscious of it. Thus all the operations of the will, the intellect, the imagination and the senses are thoughts.⁽³⁰⁾
 
Though Cudworth had replaced Descartes' term 'Thought' with the term 'Consciousness', he provided this term with essentially the same meaning. This meaning appears in the Oxford English Dictionary as the fourth definition of consciousness: "The state or faculty of being conscious, as a condition and concomitant of all thought, feeling, and volition."⁽³¹⁾ Not surprisingly, the OED gives Cudworth and then Locke's first edition use above as examples of this definition. However, as I have already indicated, this is not the definition of consciousness that is of particular concern to us here.

But before going onto to another OED definition, the fifth, that is directly related to unity of consciousness, let us first consider how Locke's early discussions of personal identity only require use of this fourth definition. Prior to the appearance of Sherlock's book on the Trinity, Locke had already discussed the issue of personal identity in a less developed form in his notebooks and in the first edition of the Essay. In 1683 in his notebooks he gives his first definition of personal identity:
 
Identity of persons lies ... in the memory and knowledge of ones past self and actions continued on under the consciousness of being the same person whereby every man ownes himself.⁽³²⁾

The use of the term consciousness in this definition is of the form in Definition 4 in the OED. Here consciousness is a faculty by which we know the mental acts that belong to self, but consciousness is not here the means by which the self is itself constituted. In the first edition of the Essay, he makes a similar use of the concept of consciousness in his only discussion of personal identity:

If the soul doth think in a sleeping man without being conscious of it, I ask, whether during such thinking it has any pleasure or pain, or be capable of happiness or misery?…. For if we take wholly away all consciousness of our actions and sensations, especially of pleasure and pain, and the concernment that accompanies it, it will be hard to know wherein to place personal identity.⁽³³⁾
 
Again we have a reflexive use of consciousness as the basis of personal identity. If one is not reflexively aware of an experience, how can it be ours? These two definitions of personal identity are mirror images of each other. The earlier one, defines it in terms of reflexive consciousness in a positive sense (i.e., those acts or thoughts that we can recognize as our own through reflexive consciousness), while the later one defines it in terms of reflexive consciousness in a negative sense (i.e., those acts or thoughts we cannot recognize as our own through reflexive consciousness).

These two reflexive or facultative uses of the term consciousness are to be contrasted with the definition of personal identity that Locke gives in the 1694 edition of the Essay, which shows an intimate connection to Sherlock's account of personal identity. And both of these accounts of personal identity use consciousness in the sense of the OED's fifth definition of consciousness:

Consciousness (Definition 5) The totality of the impressions, thoughts, and feelings which make up a person's conscious being. In plural = conscious personalities.⁽³⁴⁾

Note that this definition does not explicitly invoke reflexive awareness, rather the focus is on the collective or unified nature of the conscious acts of a person. The first citation that the OED gives for this definition comes from Locke's second edition chapter on Identity and Diversity:

If the same consciousness can be transferr'd from one thinking Substance to another, it will be possible that two thinking Substances may make but one Person.⁽³⁵⁾

As in the fifth definition, this example does not explicitly invoke reflexive awareness. Rather it presupposes that sameness of consciousness is what determines identity of person. Locke also gets early credit in the OED for another crucial concept that appears in this same second edition chapter, the term self. The OED's third "mostly philosophical" definition of self is:

That which in a person is really and intrinsically he (in contradistinction to what is adventitious); the ego (often identified with the soul or mind as opposed to the body); a permanent subject of successive and varying states of consciousness.⁽³⁶⁾

Here they use two quotations from Locke's second edition chapter:
 
Since consciousness always accompanies thinking, and 'tis that, that makes everyone be, what he calls self...⁽³⁷⁾
 
Self is that conscious thinking thing, whatever Substance, made up of Spiritual, or Material, simple or compounded, it matters not, which is sensible, or conscious of Pleasure and Pain, ... and so is concern'd for it self, as far as that consciousness extends.⁽³⁸⁾
 
In both of these instances, as well as in the definition, it is through consciousness that the self is defined rather than the reverse. It is the subject of the states of consciousness that are unified by the consciousness, rather than by a reflexive self-awareness. Further, you will note that the second quotation from Locke even includes the phrase, "as far as that consciousness extends" a phrase which appears first in Sherlock.

Indeed, these definitions of consciousness and self in the OED, though citing Locke as their first source, could equally well have cited Sherlock, who used the terms in much the same way, four years before they appeared from Locke's second edition. Moreover, that there is a dependence between these later appearances in Locke to those in Sherlock is made even clearer when we consider Locke's second edition definition of personal identity:
 
For since consciousness always accompanies thinking, and it is that which makes every one to be what he     calls self, and thereby distinguishes himself from all other thinking things; in this alone consists personal identity, i.e. the sameness of a rational being: And as far as this consciousness can be extended backwards to any past action or thought, so far reaches the identity of that person; it is the same self now it was then; and it is by the same self with this present one that now reflects on it, that that action was done.⁽³⁹⁾
 
This final definition, which has become the primary source for subsequent discussions of personal identity since Locke wrote this passage, finds such a close parallel to Sherlock's formulation (i.e., "as far as consciousness reaches, so far the unity of a Spirit extends, for we know no other unity of a Mind or Spirit, but consciousness"), that it almost certainly draws on Sherlock's highly visible and contentious work. It is clear from Locke's correspondence, as well as from the catalogues of his library that Locke knew of Sherlock's work.⁽⁴⁰⁾ And, the fact that his entire discussion of Identity and Diversity in the second edition of the Essay so closely parallels Sherlock's earlier book, strongly suggests that Locke must have reflected on that work when developing his own theory. Hence, it seems certain that what ultimately became an earthly conception of self and personal identity, had its original source in a discussion of heavenly persons.⁽⁴¹⁾
 

When Sherlock used the concept of consciousness to explicate the Trinity, the immediate response was to declare him a tri-theist. This accusation was made because he openly asserted that the three persons were three self-conscious agents with infinite minds. Hence he said that there were three infinite minds in God. While Sherlock saw this as a inevitable result of the fact that each person has their own mind, and in this case their minds were infinite, both Socinians and Trinitarians felt that Sherlock's position here went against the conventional rule that the persons in God were to be described as having only relative properties with respect to each other and not any absolute properties, which only apply to the Godhead as a whole. Hence, although God could have an infinite mind by this logic, none of the persons, themselves, could have one, without becoming, thereby, three Gods. Sherlock eventually tried to back off of his position, but didn't satisfy his antagonists. As a result Sherlock's positive account of the Trinity went without any followers. Even the poet-philosopher-theologian Samuel T. Coleridge, at the beginning of the nineteenth century, who read Sherlock in the original and made marginal notes on his Vindication of the Trinity, viewed Sherlock as a tri-theist.⁽⁴⁴⁾ Coleridge, nevertheless, tried to develop his own related account of the Trinity, based on what he called the "personeity" of the Godhead, by which he meant the ultimate source of subjectivity and self-consciousness in God.

Coleridge was not alone in developing something like Sherlock's account of the Trinity. Throughout the 19th century, theologians tried to develop accounts of God's consciousness and how the three persons could emerge as parts of a single self-consciousness. By the 20th century, even traditional Catholic theologians were developing accounts not very different from Sherlock's. For instance, Father Lonergan, one of the more philosophical of Catholic Theologians, developed an account of the persons in the Godhead which recognized each as a self-conscious person. He writes: "a divine person is a subject that is distinct and conscious of itself, both as subject and as distinct".⁽⁴⁵⁾ He adds, in a phrase that seems very reminiscent of Sherlock's mutual consciousness:

Father, Son, and Holy Spirit through one real consciousness are three conscious subjects conscious of themselves and of the others and of their act' so that 'a conscious Father consciously understands, knows, wills; a conscious Son consciously understands, knows, wills; a conscious Spirit consciously understands, knows, wills.⁽⁴⁶⁾
 
Lonergan's position has not been uniformly accepted by Catholic theologians, and has been thought by some to represent a tri-theistic trend in interpretation of the Trinity that resulted from modern developments in the concept of person. Nevertheless, unlike that warfare generated around Sherlock's position, current discussion of the Trinity is on a friendlier basis. It is recognized that the Trinity is ultimately a mystery and that all discussion of the persons-in-unity can only be a metaphorical attempt to relate human personality and society to heavenly personality and society. While the debate over terms continues, the goals are the same: to relate earth to heaven and heaven to earth and to learn more about our selves and of our relations to God in the process.

Notes
1. The present paper is based originally on a talk first presented at the philosophy department at Dalhousie University on February 13, 1998. A later revised version of the talk was given at the Fifth International Conference on the Person, Santa Fe, August 4, 1999. I wish to thank listeners to both of these talks for their stimulating comments, which led to revisions of the current article. I would also like to thank the Research Development Fund of Dalhousie University, and the Social Science and Humanities Research Council of Canada, for grants which supported research that contributed to writing this article. Requests for reprints should be sent to: John Barresi, Department of Psychology, Dalhousie University, Halifax, NS, Canada B3H 4J1, or to jbarresi@is.dal.ca

2. John Locke, An essay concerning human understanding (First Edition, 1690; second edition, 1694) ed. by P.N. Nidditch, (Oxford, 1975).

3. F. Gastrell, Some considerations concerning the Trinity: And the ways of managing that controversy (London, 1696); E. Stillingfleet, A discourse in vindication of the doctrine of the Trinity (London, 1697); [J. Toland], Christianity not Mysterious: A treatise showing that there is nothing in the Gospel contrary to reason, nor above it: And that no Christian Doctrine can be properly call'd a mystery (London, 1696). See J.W. Yolton, John Locke and the way of ideas (Oxford, 1968) for Locke's involvement in the trinitarian controversy.

4. See R. Wallace, Antitrinitarian Biography: or Sketches of the Lives and Writings of Distinguished Antitrinitarians; Exhibiting a view of the state of Unitarian Doctrine and Worship in the Principle Nations of Europe, From the Reformation to the close of the seventeenth Century: To which is Prefixed A History of Unitarianism in England During the Same Period, V1-3 (London, 1850), and J. Redwood, Reason, ridicule and religion: The age of enlightenment in England, Chapter 7 (London, 1976) for this history.

5. William Sherlock, A Vindication of the Doctrine of the Holy and Ever Blessed TRINITY and the Incarnation of The Son of God. Occasioned by the Brief Notes on the Creed of St. Athanasius, and the Brief History of the Unitarians, or Socinians, and containing an Answer to both, Imprimatur, Jun.9.1690 (London, 1690).

6. R. South, Animadversions upon Dr. Sherlock's book (London, 1693), Tritheism charged upon Dr. Sherlock's new notion of the Trinity (London, 1695); W. Sherlock, A Modest Examination of the Authority and Reasons Of the Late Decree of the Nice-Chancellor of Oxford, and Some Heads of Colleges and Halls; Concerning The heresy of Three Distinct Infinite Minds in the Holy and Ever-blessed Trinity (London, 1696), The Present State of the Socinian Controversy, and the Doctrine of the Catholick Fathers Concerning A Trinity in Unity (London, 1698). See R. Wallace, Antitrinitarian Biography for the history of this controversy around Sherlock.

7. [Stephen Nye], Considerations on the Explications of the Doctrine of the Trinity, By Dr. Wallis, Dr. Sherlock, Dr. South, Dr. Cudworth, and Mr. Hooker; as also on the Account given by those that say, the Trinity is an Unconceivable and Inexplicable Mystery [London, 1693], 10.

8. J. Wallis, The Doctrine of the Blessed Trinity (London, 1690)

9. Nye, Considerations, 10.

10. Ibid., 11.

11. R. Cudworth, The Intellectual System of the Universe: The First Part. (London, 1678).

12. See U. Thiel, Cudworth and Seventeenth Century Theories of Consciousness. In S. Gaukroger, Ed., The Uses of Antiquity: The Scientific Revolution and the Classical Tradition (Dordrecht, 1991)

13. Plotinus, Enneads IV, 1-9, trans. by A.H. Armstrong (Cambridge, 1984) 171-2; Cudworth, The Intellectual System, 159.

14. Cudworth, The Intellectual System, 159.

15. J. Turner, A discourse concerning the Messias, In three chapters. .... To which is prefixed a large Preface, asserting and explaining the doctrine of the blessed Trinity, against the late writer of the Intellectual System. And an Appendix is subjoyned concerning the divine extension, wherin the existence of a God is undeniably proved, and the main principles of Cartesianism and Atheism overthrown (London, 1685). See M. Ayers, Locke: Volume II: Ontology (London, 1991) for a discussion of Turner's views.

16. Nye, Considerations, 11.

17. Ibid., 11.

18. Yolton, John Locke and the way of ideas; Ayers, Locke: Volume II: Ontology, 31.

19. "For to tell the truth, I know nothing at all without the mediation of sense except the immediate sensation itself ... Now hence I infer, that I have no sense at all of the difference of a Spirits Substantiality in such modes and accidents from that of Matter, and therefore how can I know it?" (15), R.Baxter, Of the immortality of mans soule, and the nature of it and other spirits. (London, 1682)

20. Sherlock, A Vindication, 7-8.

21. [W. Sherlock], A Defence of Dr. Sherlock's Notion of a Trinity in Unity, In Answer to the Animadversions upon his Vindication of the Doctrine of the Holy and ever Blessed Trinity. With a POST-SCRIPT Relating to the Calm Discourse of a Trinity in the GODHEAD (London, 1694), 6.

22. Ayers, Locke, 323.

23. Sherlock, A Vindication, 48.

24. Ibid., 48.

25. Ibid., 48-9.

26. Ibid., 49.

27. Ibid., 67.

28. Ibid., 68.

29. Locke, Essay, II,1,18, 115.

30. R. Descartes, Meditations on first philosophy, with Objections and Replies (1641), In: The philosophical writings of Descartes, Vol II, Trans. by J.Cottingham, R.Stoothoff, & D.Murdoch (Cambridge, 1984), 113.

31. The compact edition of the Oxford English Dictionary, V.I-II. (Oxford,1971/86),I, 522.

32. Ayers, Locke, 255.

33. Locke, Essay, II,1, 11, 110.

34. Ibid., I, 522.

35. Ibid., 522; Locke, Essay, II, 27, 13, 337.

36. Ibid., II, 2715.

37. Locke, Essay, II, 27, 9, 335.

38. Ibid., II,27,17, 341.

39. Ibid., II, 27, 9, 335.

40. The most direct evidence that Locke read Sherlock's Vindication before he wrote his second edition account of personal identity is a letter written in October, 1690 to Locke from Holland, thanking him for forwarding Sherlock's book in a packet along with other books. Although we do not have Locke's side of their correspondence, Sherlock's opinion on the trinity, along with those of the socinians and South are briefly discussed in subsequent letters written by this correspondent - apparently under the assumption that Locke has also read these works - well before Locke began his revisions of the Essay. See The Correspondence of John Locke, edited by E.S. De Beer (Oxford, 1979), letters, 1325, 1329, 1344, 1351, and 1702. In addition, the catalogues of Locke's library show that he owned copies of most of the books involved in the Trinitarian debate, including a later edition of Sherlock's book, as well as several critiques of his theory that were published before Locke wrote the second edition chapter on Identity and Diversity. (See J. Harrison & P. Laslett, Locke's Library Catalogue, Oxford, 1965; G. Wedeking, "Locke on Personal Identity and the Trinity Controversy in the 1690s." Dialogue, 1990, 163-88.)

41. Because of limitations of space, I cannot go into a more detailed comparison of Sherlock and Locke's views. Nor can I show how their use of the term consciousness was sufficiently ambiguous between the two senses described here, that many of their critics claimed that circularity was involved in their attempts to invoke the second sense of consciousness to constitute the self. See Wedeking for a discussion of circularity in both Sherlock and Locke.

42. C.G. Davies, Conscience as consciousness: The idea of self-awareness in French philosophical writing from Descartes to Diderot (Oxford,1990).

43. R. Martin & J. Barresi, Naturalization of the soul: Self and personal identity in the eighteenth century (London, 2000)

44. S.T. Coleridge, The Literary Remains of Samuel Taylor Coleridge. Collected and Edited by Henry Nelson Coleridge. In The Complete Works of Samuel Taylor Coleridge, V.1, ed. by Professor Shedd (New York, 1858)

45. B. Lonergan, Divinarum Personarum conceptionem analogicam (Rome, 1957), cited in E.J. Fortman, The Triune God: A historical study of the doctrine of the Trinity (Philadelphia, 1972), 296-7.

46. Ibid., 298-299.