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 occured 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. 

Locke's second edition discussion of personal identity seems to have been influenced by a number of metaphysical debates involving the notion of person that took place in the seventeenth century. Among these were debates over the relations between spiritual and material natures in the constitution of human persons, and even of the whole material world. 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. But Descartes also keyed off other responses, such as Hobbes's pure materialism, the atomism of Gassendi, and the neoplatonic responses of the Cambridge Platonists, not to mention Spinozan and Leibnizian transformations of the Cartesian position. All 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. In certain important respects, his answer reached its focal point in his new chapter on 'Identity and Diversity' in 1694, where he set the identity conditions for matter, living beings, as well as for persons in terms of his empiricist conception of clear and distinct ideas. 

Although most of these influences on Locke are well known, in the present article, I will consider an influence on Locke's discussion of personal identity that is more specific than these general metaphysical debates and which focuses more directly on the concept of person. The influence that I have in mind comes from the debates that occurred in the latter part of the seventeenth century over the nature of God, and how it might be possible for God to be composed of three persons. In fact, this debate over the Trinity reached its greatest intensity in the 1690's in Britain, during the very years, between the first and second edition of Locke's Essay, when Locke must have come to formulate the position he presents in the second edition. Furthermore, Locke, himself, was immediately drawn into the debate over the Trinity. He was drawn indirectly into it when Toland (1696) and Gastrell (1696) used his ideas, respectively, to reject and to explain the trinity of persons. And he was drawn directly into the it, when Bishop Stillingfleet (1697), in his own vindication of the Trinity, blamed Locke for Toland's use of the way of clear and distinct ideas, in his Christianity Not Mysterious (1696), to dismiss the Trinity as incomprehensible and impossible ⁽³⁾. 

Despite Stillingfleet's accusation, the suggestion that three persons in one God was rationally impossible did not have to wait for 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 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 heresy 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 on the debate and call a cease-fire, requiring all to use only traditional language to discuss the Trinity. ⁽⁴⁾ 
William Sherlock and the Trinitarian Debate  

The person at the centre of this controversy was William Sherlock, Dean of St. Paul's cathedral, and one of the most philosophical of the theologians of his time. And it is mainly his views on the Trinity that seem to have had an influence on Locke. In 1690 - six months after the first edition of Locke's Essay came out - Sherlock published his, Vindication of the Trinity ⁽⁵⁾, in an attempt to provide a rational account of the Trinity that could put to rest the Socinian objection that God was a unity that could be no more than one person. In his theory he used the relatively novel notions, of self-consciousness and mutual consciousness: self-consciousness to distinguish the persons of the Trinity, and mutual consciousness to account for their unity in the Godhead.  

At first traditional theologians were quite pleased with Sherlock's account, 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 enter the fray to quiet things down. After this Sherlock partially retreated from his position in several more publications, the last of which, in 1698 (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 main 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, that were being considered at this time. 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 I will now present. The author writes: 

Dr. 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 that was repeatedly used in attacks on his Ciceronian view. 

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

Cudworth's work ⁽¹¹⁾, published in 1678, was an enormous tribute to ancient platonic philosophy, and he expended great 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.  

It should also be noted 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. In a quotation that Cudworth referred to from him, Plotinus had written:  

It was not Cudworth, himself, but one of his renegade students, who first used the term self-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 was a weird mixture of platonic, cartesian, and materialistic ideas. He also expended a good deal of effort attacking Descartes's views. Since Sherlock's use of this notion of self-consciousness was more coherent, and much more likely to have influenced Locke, I'll leave aside a discussion of Turner's views. ⁽¹⁴⁾ 

Let us return now to our Socinian survey of views of the Trinity. He continues: 

Our author closes his discussion with one more view: 

Sherlock's account of the Trinity begins with a discussion of the limits of human knowledge, and of the difficulties forming clear and distinct notions of the substance of things both involving matter and spirit. Because of similarities here between Locke and Sherlock, it has been suggested by John Yolton (1968) and Michael Ayers (1991) that Sherlock's discussion was influenced by Locke's recently published first edition of the Essay. However, the language that Sherlock uses in his book on the Trinity is different in style from that of Locke, and it seems to me that he could have found similar ideas elsewhere. In particular, Gassendi, in his objections to Descartes' Meditations, raised sceptical questions about the limits of our knowledge of the substance of matter and of spirit, and Ayers, himself, claims that Locke's discussion of substance, "is nothing other than a restatement and elaboration of the sceptical position adopted by Gassendi". ⁽¹⁷⁾ If it can be assumed here, that Locke is merely elaborating on Gassendi, why then is it necessary to suppose that Sherlock, himself, is borrowing from Locke, rather than from Gassendi, or from one of Gassendi's followers in England, such as Boyle? In any event, in his book on the Trinity, Sherlock asserts that: 

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. ⁽²⁰⁾ 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: 

 
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. ⁽²⁴⁾  

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 substances relate to and anticipate those found in Locke. But before turning to Locke's own discussion of these matters. I would like to provide one more quotation from Sherlock. This one comes from his anonymously written Defence published in 1694. ⁽²⁶⁾ The Defence was published approximately a month after Locke's second edition appeared in print.⁽²⁷⁾ Thus, Locke did not read this defence before he wrote his own account of personal identity, and, given the single month between their publication dates, it is also extremely unlikely that Sherlock read Locke's second edition before he wrote his Defence. In any event, the passage I quote immediately follows the passage given above which invokes Locke. And because of its immediate connection to that passage, it could leave the impression that Sherlock was somehow dependent on Locke for his theory of personal identity. Yolton has made this inference.⁽²⁸⁾ But this cannot be the case, since Sherlock is here merely restating his original view in slightly different language, and is not invoking Locke's account of personal identity, but merely using some general principles of Locke's philosophy, which appeared in the first edition of the Essay. Yet, because the language he uses here is especially close to that used by Locke, himself, and immediately follows his reference to Locke, it is important to consider them in relation to each other. 

I begin with an extended version of the passage in which he mentions Locke, and continue on: 

Let us now consider the development of Locke's own thoughts on consciousness and personal identity. First, it is important to realize that Locke's use of the term consciousness shifts dramatically between the first and second editions of the Essay. In the first edition he uses the term conscious often, but the term consciousness only 4 times. In this edition he gives the term consciousness the following definition: "Consciousness is the perception of what passes in a man's own mind." ⁽³⁰⁾ This definition is essentially the same as the one first introduced into English by Cudworth, and both are based on Descartes' definition of thought found in the Appendix to the Replies to the Second set of Objections to the Meditations. There Descartes writes:  

This use of the term consciousness appears in the Oxford English Dictionary as definition 4: "The state or faculty of being conscious, as a condition and concomitant of all thought, feeling, and volition." ⁽³²⁾ The OED gives Cudworth and then Locke's first edition use above as examples of this definition. This is not the definition of consciousness that is of interest to us here.  

Rather, the definition of consciousness that is of interest to us appears as the fifth definition in the OED:  

Locke also gets early credit in the OED for another crucial concept that appears here, the term self. The OED's third "mostly philosophical" definition of self is: 

You will note that here the choice from Locke even includes the phrase, "as far as that consciousness extends" a phrase which appears first in Sherlock, but in a slightly different context. ⁽³⁷⁾ I quote again from his 1690 book on the Trinity: 

I will consider in greater detail the relations between Sherlock and Locke's use of the concept of unity of conciousness in the next section, but before turning to that, it is necessary first to conclude this section on Locke, by considering his use of the term personal identity in the Essay, and also in his unpublished notes that were the basis for the ideas developed in the Essay.  

In 1683 in his notebooks he gives his first definition of personal identity: 

 It is time now to evaluate more fully how Sherlock and Locke use unity of consciousness in their works in similar and in different ways. Both use the idea that there are boundaries to the range of mental events over which consciousness extends or reaches, but they use this concept somewhat differently. In Sherlock, the notion is one of accessibility of a particular mental event in an internal sort of way - one that does not involve inference but has an immediacy, as if it were happening to one’s self. However, for Sherlock, even a mental event that is not one’s own might appear to one with such an immediacy - at least for the three persons of the Trinity. Sherlock 
supposes that there are three spirits in the Godhead, each with its own mind, but each accessible to the minds of the other persons or spirits. Yet, this accessibility is internally presented, as if the thoughts of the the other persons were one’s own thoughts, though presented as the thoughts of another spirit, and differentiated from ones own thoughts. How this is possible is a question that arises for Sherlock’s account.   

We have already briefly considered the case of an individual with Multiple Personality Disorder (MPD) as a possible example to explicate this hypothesis about the internal structure of the Godhead. However, there is a difference that needs to be considered further and which may be insurmountable. In the case of MPD, each of the personalities can distinguish its own thoughts from those of the other personalities by their respective ‘feels’. One’s own thoughts are those with which one can immediately identify, which one can accept as one’s own without any doubts. But in cases of MPD each of the personalities disown the thoughts of the other personalities as their own thoughts. In Locke’s terminology, which has been developed by William James, one owns or ‘appropriates’ only those thoughts with which one can immediately accept as one’s own, those which fit with one’s own immediate experience of being a self.⁽⁴²⁾ The other personalities have different ‘kinds’ of thoughts, that one may be able to know from an internal perspective, but cannot really appropriate as one’s own. Hence, assuming this to be the case, then one can distinguish one’s own thoughts from another personality’s thoughts by the very feel of the thought - it feels different when it is one’s own from when it is another’s thoughts. 

It may help here to give a concrete case of MPD to explicate further this notion of 
appropriation. In a patient called BCA by Morton Prince at the turn of the century⁽⁴³⁾, one of the personalities that developed after the woman’s husband died, did not accept that she was married to the man; she thought of herself as the woman had been before she married. The woman had found marriage difficult and was of two minds about it. On the one hand she was a ‘devoted wife’, but on the other hand she ‘rebelled’ against the marriage, especially its sexual requirements. Now when the newly formed personality - that developed after the death of the husband - thought back to the earlier period when the woman was still an integrated person, she identified and appropriated as her own only those thoughts that were rebellious and against the marriage. In one of her letters to Prince she even claimed, “I remember them now as my thoughts 
but at that time had never thought of myself as a ‘self’.”⁽⁴⁴⁾ Here we see a personality that develops at a later time engage in a retrospective appropriation or ownership of the thoughts that occured before she was a self. She could still identify her ‘own’ thoughts, based on their content or feel, not merely based on having remembered them from the inside. This same personality was also co-conscious of the thoughts of the second personality that developed after the husband’s death - the depressed, devoted wife.  So, this personality could read the thoughts of the devoted wife’s personality from the inside. But again, we may presume that she could recognize that they were not her own thoughts by their quality, even if there were not any other basis to recognize whose thoughts they were. These thoughts were of a kind with which she could not identify or appropriate as her own, so they must be those of the other personality. 

Now, if such a qualitative difference between thoughts that depends on one’s ability to 
identify with them or appropriate them, is the means by which one can identify one’s own from another’s thoughts, then it is difficult to see how the three persons of the Godhead could distinguish among their collective thoughts. For, as Sherlock has stated the case, each of the persons of the Trinity, are so much involved in each other’s point of view that it is as if the other person’s thoughts were their own. If any weaker identification occurs, then it would set a boundary between the persons of the Godhead that would seem to make it less than one substantial unity. However, Sherlock also demands that each has some kind of differentiation among the thoughts, and also can recognize which of thoughts of the three persons are its own. So, he obviously intends that there be some way to distinguish the thoughts and to identify one’s own as well as each of the other’s thoughts. So, there must be some other means by which one can distinguish one’s own thoughts from others, than just on qualitative differences due to appropriation. What these are, or can be is not clear. 

But let us assume that there is another qualitative difference among thoughts that can be used to tag them to the particular person of the Godhead, one based on their specific content. Even if all three persons appropriate - in some sense - each other’s thoughts, they may still distinguish among them in terms of content. An example that might explicate this notion is the kind of subselves that we often experience in our own normal personalities. We may, for instance, see ourselves as musicians, and lovers, as well as professors. Each of these aspects of our personalities are semi-independent of each other. Yet we appropriate each of these separable 
selves. Perhaps something similar can be used to distinguish the qualitatively different kinds of thoughts in the Godhead.  

But then, we still have the problem of how each of the persons can determine which of 
the three qualitative kinds of thoughts has the additional property of being its own. This is the problem of indexicality of thoughts. Is there a self-referential property of one’s own thoughts that can distinguish them from other qualitatively different thoughts that one also experiences internally and also fully appropriates? It would seem that Sherlock assumes that there is such a self-referential aspect to thoughts in the Godhead. Moreover, he supposes that there is a similar kind of self-reference that applies to our own thoughts as persons. For, he clearly distinguishes between self-consciousness and mutual consciousness, and he models self-consciousness on our own normal personal consciousness, which he claims to be bounded in the self. However, Sherlock doesn’t make it clear how such a bounded consciousness involving self-reference is supposed to operate in the Godhead where there is no boundary to conscious unity among the three persons. Thus, if quality alone doesn’t allow one to distinguish the persons in the Godhead, it seems that we must invoke some special indexical property that labels not only whose thought it is, but whether it is one’s own. Somehow, each of the persons of the Trinity, must know their own thoughts as their own, not through normal appropriation, which includes all the other thoughts of the other persons, or through distinguishing their qualities, but through some indexing of the persons, as “I” and “other”. 

Now let us consider Locke’s use of conscious unity. Like Sherlock, Locke invokes the 
notion of boundaries to consciousness. Only, for Locke the main factor determining the boundary of consciousness is what we are capable of being conscious of at a given time. Temporal unity or continuity is crucial to Locke’s account of the unity of consciousness in a way that doesn’t appear in Sherlock’s account. In fact, Sherlock does not deal with temporal issues at all. In his definitions of matter and of life, Sherlock focuses on spatial, and functional unity, but not on temporal unity. By contast, Locke focuses much of his attention on temporal properties of matter and life, along with the temporal properties of personal identity. And he uses the phrase ‘same 
consciousness’ in analogy with ‘same life’ to focus on temporal connectedness of phases of consciousness as he does in discussing temporal connectedness of a life. The difference between Sherlock and Locke here may be due in part to Sherlock’s central concern being the Godhead, for which duration and the temporal organization of thoughts is not an issue. Since God is eternal and outside of time, the less said about the topic of temporal activities the better.  
  
However, another reason for the difference between Sherlock and Locke on temporal 
connectedness, may be Locke’s special interest and concern over ‘forensic’ issues. Locke seems to believe that the primary function of the concept of person is to deal with issues associated with justice and the capacity for rational (i.e. conscious) ownership of past (and future) acts. And he was interested in providing an account to deal with the resurrection and last judgement as well as with issues of justice on earth.  

It may be that it is Locke’s concern over forensic issues that ultimately leads him into an inconsistent account of the role of conscious unity in personal identity. Because Locke places so much importance on conscious recollection of past acts in determining appropriation and ownership of those acts, his definition of personal identity, leads to a logical problem identified by Berkeley and Reid.⁽⁴⁵⁾ Any given person stage may be connected to a previous and a later stage through conscious recollection, but these two other stages may not be so connected to each other. 
Hence, on Locke’s model there is no transitivity of conscious relations, and a single temporal stream of interconnected conscious states, does not constitute a single person, but as many persons as there are distinct recollective relations between states of consciousness. It seems that Locke’s borrowing of Sherlock’s phrase - as far as consciousness reaches or extends - when viewed as a temporally situated form of connection, results in a not very satisfying conception of person. Yet Locke, apparently, did not see deeply enough into the limitations of his conception to move on to a continuity model of consciousness, that would only require that neighboring conscious states need have recollective relations in order to join all such states together in 
defining a person. 

A second concern that motivated Locke’s account of personal identity, which was 
different from Sherlock’s, was Locke’s attempt to make his account independent of whether the substance or substances that produced conscious states were material or immaterial, and whether they were the same through time or constantly changing. One of the great advantages of using unity of consciousness as a criterion of self and personal identity, is that it doesn’t require that one make any assumptions about the nature of substances that produce thought. Now this issue doesn’t really come up in Sherlock’s account of person (though something analogous does come up in the unity of the three as indicated above), because he presupposes the Cartesian model of 
spirit as an immaterial substance. Sherlock’s point is that we cannot really know this substance directly but only know our selves as spirits through the property of conscious thinking. However, Locke wants to go further, and break with the supposition that we are necessarily a single immaterial substance. While he thinks it is highly probable that we are such a single substance, he insists that - for all we know for certain - we may be composed of a series of substances that are not even immaterial but rather are material substances that enter into and for a period of time, compose our bodies. Thus, while not asserting directly that matter is the basis of thought and consciousness, he does assert that it may be. Here, unity of consciousness, provides a new criterion for personal unity that does not rely on an immaterial soul.  And Locke’s use of it for 
this purpose makes his discussion of personal identity a great advance over the more Cartesian use of the same concept in Sherlock, which still presupposes an immaterial soul.  In Locke’s more mundane and earthly use of this concept, he laid the foundations for an empirical science of mind, that would ultimately renounce its basis in Descartes’ dualism of immaterial and material substances. 

The aftermath  

Locke's discussion of personal identity, along with the rest of his Essay, had an enormous impact on the 18th century. It is primarily through Locke's use of the term consciousness in this context that the term came under general use both in England and on the Continent. ⁽⁴⁶⁾ Prior to Locke, continental philosophers had difficulties finding just the right word to use to represent the philosophical concept of consciousness. Although Descartes initiated the modern use of the Latin term, Conscientia, for consciousness in its facultative sense, the French version of the term - conscience - was too easily confused with conscience rather than consciousness. However, with the English differentiation of the two terms, and with the development of the concept of consciousness to reflect personal unity in Locke, translations of his work had the impact of carrying the new meaning of this term, and sometimes the term itself, back to France and to Germany. By the middle of the 18th century, consciousness had become a important technical term in the newly developed discipline of the philosophy of mind. Martin and Barresi have argued that this new concept of a self-conscious mind that might be materially based was a naturalization of the previous concept of the soul, and that Locke's views on personal identity were crucial to the development of this empirical philosophy of mind.⁽⁴⁷⁾The impact of this conception of the mind based on consciousness, was so thorough that by the middle of the 19th century, when mental philosophy transformed into scientific psychology, this discipline was initially defined as the science of consciousness. What was only hinted at in Descartes's metaphysical doubts had become a reality, though this reality would be a short-lived one, eventually becoming replaced by more materialistic scientific perspectives and the recognition of unconscious mental phenomena. Nevertheless, consciousness still plays a critical role in our concept of mind and what it is to be a person. And the general recognition of the importance of consciousness in our modern concept of person, has, during these three centuries, since the 1690's not only affected how we conceive of human persons but of divine persons as well. 

When Sherlock used the notion 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 the minds were infinite, both Socinians and Trinitarians, felt that Sherlock's position here went against the rule that the persons in God were to have only relative properties with respect to each other and not any absolute properties, which only applied 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 it 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. ⁽⁴⁸⁾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.  

And 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". ⁽⁴⁹⁾ He adds, in a phrase that seems very reminiscent of Sherlock's mutual consciousness:  

# 1. The present paper is based on a talk presented at the philosophy department at Dalhousie University, February 13, 1998. I wish to thank listeners of the talk for their thought provoking comments, which led to revisions for 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 supporting the research that contributed to writing this article.  

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

#13. Cudworth, The Intellectual System, 159.  

#14. 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.  

#15. Nye, Considerations, 11.  

#16. Ibid., 11.  

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

#18. Sherlock, A Vindication, 7-8.  

#19. [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.  

#20. Ayers, Locke, 323.  

#21. Sherlock, A Vindication, 48.  

#22. Ibid., 48.  

#23. Ibid., 48-9.  

#24. Ibid., 49.  

#25. Ibid., 68.  

#26. Sherlock, A Defence.  

#27. Locke's second edition of the Essay, was advertised in the London Gazette on June 5th, 1694; Sherlock's Defence, was advertised in the Gazette on July 9th.  

#28. Yolton, John Locke, 130.  

#29. Sherlock, A Defence, 6-7.  

#30. Locke, Essay, II,1,18, 115.  

#31. 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.  

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

#33. Ibid., I, 522.  

#34. Ibid., II, 2715.  

#35. Locke, Essay, II, 27, 9, 335.  

#36. Ibid., II,27,17, 341.  

#37. The reader may wonder if there is any more direct evidence that Locke read Sherlock's Vindication before he wrote his second edition account of personal identity. The most direct evidence that I am aware of 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 - apparently under the assumption that Locke has also read these works - in subsequent letters written by this correspondent, 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.  

#38. Sherlock, A Vindication, 68.  

#39. Ayers, Locke, 255.  

#40. Locke, Essay, II,1, 11, 110.  

#41. Ibid., II, 27, 9, 335.  

#42. See also Martin, Self-Concern: An Experiential Approach to What Matters in Survival (New York, 1998), for a somewhat different and well developed account of appropriation and its relation to self-continuity.  

#43. See Barresi, Morton Prince and B.C.A.: A historical footnote on the confrontation between dissociation  theory and Freudian  psychology in a case of multiple personality, In: Psychological  concepts and dissociative disorders, eds. R. Klein &  B. Doane (Hillsdale, 1994), 85-129, for a review of the case. 

#44. Ibid.,102. 

#45.G. Berkeley, Alciphron, Or, the minute philosopher (1732), In: The Works of George Berkeley, Bishop of Coyne, (London, 1837), VII, 11, 229, T. Reid, Essay on the Intellectual Powers of Man (1785), In Philosophical Works of Thomas Reid, ed. by  William Hamilton, (Edinburgh, 1895, republished in Hildesheim, 1967, III,VI, In: I, 351. 

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

#47. R. Martin & J. Barresi, Naturalization of the soul: Self and Personal Identity in the Eighteenth Century (London, 2000)  

#48. 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)  

#49. 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.  

#50. Ibid., 298-299.