John Locke's Contemporaries' Reaction against the Theory of Substratum Mihretu P. Guta (Durham University) The goal of this paper is to critically examine the objections of John Locke's contemporaries against the theory of substance or substratum. Locke argues in Essay that substratum is the bearer of the properties of a particular substance. Locke also claims that we have no knowledge of substratum. But Locke's claim about our ignorance as to what substratum is, is contentious. That is, if we don't know what substratum is, then what is the point of proposing it as a bearer of properties? This question underlies the criticism Locke's contemporaries raise against the notion of substratum. In section I, I lay out the context for Locke's theory of substratum by pointing out his main motivation in proposing his theory. In section II, I give a brief analysis of the theory of substratum. In section III, I discuss the objections of Locke's contemporaries against the theory of substratum.1 I focus on Edward Stillingfleet, Lee Henry, G. W. Leibniz and John Sergeant. In section IV, I conclude that there is no warrant to dismiss Locke's theory of substance. 1. The Need for Substratum Locke's proposal of the theory of substratum aims at answering one key question. That is, do properties (e.g., color) or qualities need bearers? As we shall see, Locke answers this question affirmatively. But how does Locke go about the task of accounting for the bearer of properties? How does he describe it? Does the supposed property bearer have its own nature, i.e., its own identity via which we come to know what it is? Does Locke have a uniform and uncontentious way to characterize his theory of substratum? Such questions are still hotly debated and disagreements over what constitutes the right answer to them are far from over.2 1 For dialectical purposes, in section I, I consider the first objection against Locke's theory of substratum. In doing so, I will pave the way for my discussion of the other objections in section III. 2 Both David Hume and George Berkeley dismissed Locke's theory of substratum (see: Lowe 1995: 83-87). But contemporary Locke scholars proposed a number of interesting ways to amend the contentious aspect of Locke's substratum. Due to space limitations, we 2 What is a substance? Locke answers this question by pointing out the role of senses and reflections (Essay Book II, chap. XXIII).3 Locke claims that the mind is furnished with a number of simple ideas or qualities, which are found in 'exterior things.' But what is the source of these simple ideas? Locke claims that such simple ideas are obtained via the senses. Furthermore, for Locke, the mind on its own operations is capable of noticing the unity of qualities, i.e., such qualities 'go constantly together' in experience (Essay II, XXIII. 1). So such unity observed in simple ideas, is often attributed as belonging to one thing, even describing it under one name. But for Locke, what is being understood as one simple idea is rather a combination of many ideas (Ibid.). However, here we need to keep in mind that even if Locke considers an idea as subjective mental phenomenon (e.g., see Essay II, VIII. 8), his use of the term 'idea' is not always fixed. That is, Locke also uses the term 'idea' to refer to a quality of a subject existing external to the mind which produces a particular idea in our mind (see further Lowe 1995:19-22). Locke tells us that the notion of the unity we observe in simple ideas forces us to ask a question. That is, what enables these simple ideas, i.e., qualities of a physical object to stay in unity? More precisely, what underlies such unity? Initially, Locke's answer for this question may come across both as arbitrary and ad hoc. For example, Locke claims that simply because we cannot make sense of how qualities or simple ideas can subsist by themselves, we tend to assume that something grounds them or supports them. As Locke states: ...not imagining how these ideas can subsist by themselves, we accustom our selves, to suppose some substratum, wherein they do subsist, and from which they do result, which therefore we call substance (Essay II, XXIII. 1). will not be able to discuss the proposed solutions. However, towards the end of this essay, I will say something very brief in regards to the implications of the contemporary philosophers' attempt to amend Locke's substratum. While there are so many issues one can raise in relation to Locke's theory of substratum, for present purposes, the focus of this essay is narrow and is limited only to some of the issues Locke's four contemporary critics raise. 3 Unless indicated otherwise, all references of the Essay are from: John Locke, An Essay Concerning Human Understanding, ed. Peter H. Nidditch (Clarendon: Oxford University Press, 1975). 3 Here some take Locke's remarks at face value and think that Locke's proposal of substratum as the bearer of sensible qualities is just a place holder. That is, its significance lies only in helping one make sense of the underlying ground for the unity of qualities whether or not the idea of substance itself is real. Commenting on the above quote, Alexander Campbell Fraser suggests: The expressions 'not imagining how'-'we accustom ourselves to suppose' seem to refer to our idea of substance to 'imagination' and 'custom,' instead of finding it implied in the very intelligibility of experience; for although 'custom' may explain our reference of such and such 'simple ideas' or qualities to such and such particular substances, it does not show the need in reason for substantiating them, in order to conceive that they are concrete realities (in Fraser, v. 1: 390, footnote 3). If Locke's skepticism (or seeming agnosticism) towards the reality of substance is substantiated, then so much is worse for Locke. Lowe remarks that, among other things, the reason why Locke's account of the idea of substance generated more controversies than any other topic we find in Locke's Essay has to do with its implications for theological thought. This was most importantly in relation to the accounts of God's nature and the immortality of the soul. So, doctrines such as (1) transubstantiation, i.e., a view that bread and wine transforms into the body and blood of Christ; and (2) the Trinity, i.e., the Father, Son and Holy Spirit while distinct persons, yet share the same indivisible divine nature, are rooted in the idea of substance (Lowe 2005:59). So the only plausible way that seems available to maintain the intelligibility of the idea of substance, as Lowe remarks, "would be to declare it innate" (Ibid.). In light of this, Lowe further remarks that for the religious establishments of Locke's time, Locke's empirical based understanding of the idea of substance was seen as a slippery slope down the road of atheism (Ibid.). This is because, inter alia, since God is taken to be a substance, to endorse Locke's account of substratum would require us to confess ignorance about our knowledge of God himself. But such confession (for the religious establishment of Locke's day) of our ignorance of the knowledge of God is nothing short of moving in the direction to embrace atheism. But is the above fear of the dangerousness of Locke's view of substance justifiable? Details aside, one way to answer this question is to 4 look at Locke's response to one of his main critics, the Bishop of Worcester Edward Stillingfleet. As we recall, Locke employs some suspicious sounding phrases when he talks about substratum or substance: "...we accustom ourselves to suppose..." For Stillingfleet, such phrases came across as unacceptable on the basis of their implications for theological thought as briefly discussed earlier. So, in his third Letter to Stillingfleet, Locke clarifies his use of the phrase 'supposing' claiming that it should not be taken as a ground to label him as being skeptical of the reality of substance. In his Letter to Stillingfleet, Locke makes it clear that since we cannot conceive the existence of qualities per se without being substantiated, it follows that there must be something we call substance that underlies them (see Fraser, footnotes Essay II, XXIII. 1:390-391). In this case, Locke is claiming to be a realist about substance ontology. Taken this way, the suspicion we put forth earlier as to whether or not Locke is a realist about substance ontology seems to lack any ground. Thus, we can say that the notion of 'substance' for Locke is not just a place holder after all. But as we shall see, such a positive characterization of Locke as a realist about substance ontology does not seem to weaken the objections his critics raise against his theory of substratum. 2. What is Substratum? Locke claims that we have no idea of the notion of pure substance in general, or substratum. All that we can say with respect to substratum is something that supports the qualities that produce simple ideas in us, yet we can give no further analysis for it. For Locke, pure substance is simply something 'one knows not what supports'. As Locke states: If any one should be asked, what is the subject wherein Colour or Weight inheres, he would have nothing to say, but the solid extended parts: And if he were demanded, what is it, that Solidity and Extension adhere in, he would not be in a much better case, than the Indian...who, saying that the world was supported by a great Elephant, was asked, what the Elephant rested on; to which his answer was, a great Tortoise: But being again pressed to know what gave support to the broad-back'd Tortoise, replied, something, he knew not what (Essay II, XXIII. 2; also cf. Bk. II. Ch. Xiii § 19). 5 Here Locke's point is that inquiry into what exactly substratum is, is not an open ended one. Even if, we know well that qualities (e.g., colour, weight) have owner or subject that instantiates them, the qualities themselves have no role to play by way of revealing the 'identity' of the thing that underlies them. So 'substratum', despite its key role in underlying qualities, is epistemically inaccessible to us. Hence, we cannot keep on asking endlessly what substratum is. In light of this, Locke suggests that the best way to end our curiosity, to get to the bottom of the identity of substratum, is by confessing ignorance.4 Perhaps, here Locke's emphasis on ignorance could be taken as a deterrent to unnecessary explanatory regress. But despite such prima facie benefit, Locke's own insistence on the unknowability of pure substance turns out to be less illuminating. We will return to this discussion in section III. But insofar as Locke is concerned, he sums up his theory of substratum as follows: The idea then we have, to which we give the general name Substance, being nothing, but the supposed, but unknown support of those Qualities, we find existing, which we imagine cannot subsist, sine re substante, without something to support them, we call that Support Substantia; which, according to the true import of the Word, is in plain English, standing under, or upholding (Essay II, XXIII. 2). 4 That said, however, it is important to keep in mind that for Locke, the general idea of substance is not made of via a process of combining many simple ideas, which eventually lead to the formation of complex ideas. By contrast, the abstract or general idea of substance is formed only by the process of abstraction and hence it refers to a mental process. As Locke puts it, "The use of Words then being to stand as outward Marks of our internal Ideas, and those Ideas being taken from particular things, if every particular Idea that we take in, should have a distinct Name, Names must be endless. To prevent this, the Mind makes the particular Ideas, received from particular Objects, to become general; which is done by considering them as they are in the Mind such Appearances, separate from all other Existences, and the circumstances of real Existence, as Time, Place, or any other concomitant Ideas. This is called ABSTRACTION, whereby Ideas taken from particular Beings, become general Representatives of all of the same kind; and their Names general Names, applicable to whatever exists conformable to such abstract Ideas....Thus the same Colour being observed to day [sic] in Chalk or Snow, which the Mind yesterday received from Milk, it considers that Appearance alone, makes it a representative of all of that kind; and having given it the name Whiteness, it by that sound signifies the same quality wheresoever to be imagin'd or met with; and thus Universals, whether Ideas or Terms, are made" (Essay, II, XI. 9). See Berkeley's objection to Locke's doctrine of abstraction in the introduction to the Principles. 6 3. Reactions against Locke's Theory of Substance Other contemporaries of Locke also followed Stillingfleet's footstep in critiquing Locke's view of substratum. Here is how Henry Lee begins by explaining his own version of substance before he critiques Locke's: This Name of Substance we give to any thing whose Existence we conceive independent upon every thing else, and in which several Properties or Qualities are united and combined. And this, as old as it is, is taken to be a perfect Definition of Substance in General: because hereby the Mode of its Existence is distinguishable from that of Qualities or Properties: namely, its Existence does not depend upon any other created Substance or any Quality or Property. Whereas Qualities or Properties do depend upon one Substance or other, and have no qualities united in them. (II.23.1: 110). Here Lee's analysis of the notion of substance is Aristotelian in its tone. Lee thinks that the relation that exists between substance and properties or qualities is asymmetrical, that is not equal. To make sense of the asymmetry Lee draws here, we can do no better than return to Aristotle himself. Aristotle inter alia, holds that substances (ousia) are ultimate subjects of predication and ontologically independent. In the Categories, Aristotle argues that primary substances have ontological priority, i.e. while other things depend on them for their existence, the converse is not true. Aristotle claims that primary substances such as individual men and horses are subjects that ground the existence of other nonsubstantial things such as qualities and quantities. For Aristotle, the primary substances are ultimate subjects of which other things are predicated but which are not themselves predicated of anything else (1028b 36-37). In the Categories, Aristotle does not treat primary substance as complex bodies although he does treat primary substances as complex bodies in his Metaphysics (see further: Mary Louise Gill 1989: chap.1). Because of such a shift in Aristotle's thinking, there is a debate on whether complex entities, i.e. entities with combination of matter and substantial form are primary substances. Yet Aristotle's own commitment to the primacy of substance over stuff still stands. This line of thought has been rigorously defended in recent years (see e.g., Lowe 1999: chap. 1; Lowe 1998: chaps. 6-9; Michael Loux 1998: chap. 3). Since for Aristotle, stuff has only potentialities as opposed to actualities, stuff 7 fails to be basic. To say that rock is stuff of a building is to say that rock has only a potential to become a building. By contrast, actuality is prior to potentiality (Book Θ 8, 1049b 18-25). Since substance is actuality, it follows that substance is prior to stuff. But Locke rejects the Aristotelian notion of substantial forms. But for now, the details do not concern us.5 Here the point is that when Lee refers to his construal of substance as 'old', his approach is broadly Aristotelian. If this is correct, then what is Lee's point here? Before we answer this crucial question, it is important to bear in mind that Aristotle's discussion of substance ontology is inextricably linked with his metaphysics. In fact, it is hardly an overstatement to say that we can only arrive at a proper understanding of Aristotle's substance ontology, if we take Aristotle's metaphysics seriously which underlies Aristotle's overall approach in his investigation of the nature of reality. In Metaphysics Γ.1, Aristotle tells us that the object of the investigation of first philosophy is not as limited as some special sciences, which only tend to focus on their respective area of interest. For example, mathematics focuses on things that are countable and measurable. But for Aristotle, metaphysics is a universal science that studies being qua being.6 But what does Aristotle mean by 'being qua being'? As S. Marc Cohen remarks, Aristotle's description of 'the study of being qua being' does not imply as if there is a single subject matter-being qua being- which is under investigation. Instead the phrase, 'being qua being' involves three things: (1) a study, (2) a subject matter (being), and (3) a manner in which the subject matter is studied (qua being), (Cohen 2012: sec. 1). As Cohen further points out, Aristotle's study does not focus on some recondite subject matter identified as 'being qua being'. Rather it is a study of being. In other words, for Aristotle, first philosophy studies beings, in so far as they are beings (Ibid.). So as Michael Loux argues, metaphysics considers things as existents and tries to specify the properties they exhibit in so far as they are beings. The chief goal of metaphysics is not just to grasp the concept of being but also to grasp general concepts such as identity, difference, 5 For an excellent discussion on 'substantial form', see Oderberg 2007: 65-71. 6 Here the term 'qua' comes from Latin and it means 'in so far as' or 'under the aspect'. 8 similarity, and dissimilarity that apply to everything that there is. In light of this, Loux further remarks that central to Aristotle's metaphysics is the description of what Aristotle refers to as categories. These are the most general kinds under which things fall. So the business of a metaphysician is to identity those general or highest kinds. But the task does not end here. That is, a metaphysician is also supposed to specify the features unique to each category. The upshot of engaging in such an activity provides us with a map of the structure of all there is (Loux 1998: 3-4).7 So for Aristotle, metaphysics is the study of the fundamental structure of reality.8 Insofar as Aristotle is concerned, a metaphysician's success in the investigation of the nature of reality depends on whether or not his/her approach is a realist one, which is to say that whether or not one accepts the existence of a mind-independent reality. For Aristotle, a mind-independent reality is the starting point of his metaphysical theorizing. If this is true, then I fully agree with Kit Fine when he says, "I take Aristotle's primary concern in his metaphysical and physical writings to be with the nature of reality rather than the nature of language. I am rarely tempted, when Aristotle appears to be talking about things, to construe him as saying something about words...", (Fine 1996: 83-84).9 7 See also, other contemporary neo-Aristotelian advocates of the traditional metaphysics: Lowe 1998; ibid. 2002; ibid. 2006; Oderberg 2007; Hoffman and Rosenkrantz 1997; Schaffer 2009: chap. 12; and Tahko (ed.) 2012. 8 Similarly, in his recent Writing the Book of the World, Ted Sider describes metaphysics as an inquiry into the fundamental structure of reality (Sider 2012). However, it is somewhat troubling to note that there is no mention of Aristotle in Sider's book. One wonders what justifies Sider's decision to do so. 9 But the hitherto brief description of the traditional metaphysics was rejected by David Hume, Immanuel Kant and in modern times, by post Hume-Kant thinkers such as W.V. Quine. Most notably, a serious attack was launched against the traditional metaphysics by the 1930s and 40s Vienna Circle logical positivists, such as Rudolf Carnap and others. As is well known, logical positivists promoted a movement that restricts the source of genuine knowledge to what can only be empirically verifiable (see e.g., Uebel 2012). Though, at present, the 'verification principle' largely has fallen out of favor, it is safe to say that its spirit is still around. Recently Huw Price in his essay entitled, "Metaphysics after Carnap: The Ghost Who Walks?", argued that metaphysics [traditional] is 'as dead, or at least deflated, as Carnap left it' (Price 2009: 322). Here Price's remark is not only very strong but it is also entirely unfounded in light of the work of notable contemporary neo-Aristotelian advocates of traditional metaphysics (see e.g., the representative sample I gave above under footnote # 7). One can confidently say that Aristotelian metaphysics is back on the stage, 9 In light of the foregone considerations, we are better prepared now to see Lee's point when he refers to his construal of substance as 'old'. In this regard, Edwin McCann in his essay 'Locke's Theory of Substance under Attack!', points out that Lee is basically distinguishing what he calls the 'old' notion of substance from Locke's 'new' one. In doing so, Lee wants to show that Locke's notion of pure substance obscures the old notion of substance. Lee's main goal then is to diagnose Locke's mistake (McCann 2001: 95). As Lee puts it: He [Locke] would have a clear notion of pure Substance (that is) abstracted from all Properties or Qualities whatever. I answer, there is no such Substance in the whole World. Every Substance has some Qualities or other: A Spirit its Thinking, Space its Expansion, Body its Solidity. And then how can any man have a distinct Notion of that, from which you suppose all its Properties (by which it should be distinguish'd) separated or abstracted?...there is really no such Substance in the World abstracted from all Qualities, nor no Qualities abstracted from all Substances (II.23.3:110-111). Here the biggest worry Lee expresses against Locke's notion of pure substance seems to be that of the divorce Locke introduced between pure substance and property. As we recall, for Locke, substratum, though it is a property bearer, is not itself knowable. So Lee's point is that once we divest pure substance of all its properties (via which we come to know what pure substratum is), the result is to find ourselves in the dark. What then is the implication of such ignorance of what pure substance is? If we let Lee himself answer this question, he might say that if a substance is devoid of a property that defines its identity, then the very existence of such a substance can be called into serious question. Lee contra to Price's claim and all those who are sympathetic to his remarks. But I don't intend to argue for this claim here for that would take us too far afield. That said, however, unlike Hume who dismissed both Aristotelian metaphysics in general, and his substance ontology in particular (see Treatise Book I part IV), Kant was a friend of substance ontology, which he went on defending it. As he insightfully remarks, "...the necessity with which this concept of substance forces itself upon us, we have no option save to admit that it has its seat in our faculty of a priori knowledge", (Kant, Critique of Pure Reason, B.6). So whatever reservations one might have about Locke's characterization of substance, it should not be a reason to reject Aristotelian substance ontology. One should keep in mind that despite his departure from the Aristotelian tradition, the roots of Locke's own conception of substance ontology can be traced back to Aristotle. Despite some knee jerk reactions of some modern philosophers, Aristotelian substances continue to occupy a central place in our discussion of identity, agency and causation, inter alia (see e.g., Ruggaldier 2006: chap.3; also see Lowe 1998: chaps. 4-7). 10 also might say that we have no epistemic ground to talk about a substance that is abstracted or separated from its property. This is simply because for Lee, we cannot conceive a substance apart from its property on the one hand and the instantiation of properties without their bearer on the other. In light of this, Lee remarks: But if he [Locke] expects we should answer what a Substance is, 'tis not kindly done to suppose, first, the Question is unanswerable, as it is, if we strip it of all of its Properties and Qualities, and then ask us, what it is? (II.23.4:111). Along similar lines with that of Lee, Leibniz also in his New Essays expresses serious doubts against Locke's characterization of pure substance. Here are Leibniz's own remarks: THEO. If you distinguish two things in a substance the attributes or predicates, and their common subject it is no wonder that you cannot conceive anything special in this subject. That is inevitable, because you have already set aside all the attributes through which details could be conceived. Thus, to require of this 'pure subject in general' anything beyond what is needed for the conception of 'the same thing' e.g. it is the same thing which understands and wills, which imagines and reasons is to demand the impossible; and it also contravenes the assumption which was made in performing the abstraction and separating the subject from all its qualities or accidents. The same alleged difficulty could be brought against the notion of being, and against all that is plainest and most primary. For we may ask a philosopher what he conceives when he conceives 'pure being in general'; since the question excludes all detail, he will have as little to say as if he had been asked what 'pure substance in general' is. So I do not believe that it is fair to mock philosophers, as your author does [xiii.19] when he compares them to an Indian philosopher who was asked what supported the world, to which he replied that it was a great elephant; and then when he was asked what supported the elephant he said that it was a great tortoise; and finally when he was pressed to say what the tortoise rested on, he was reduced to saying that it was 'something, he knew not what'. Yet this conception of substance, for all its apparent thinness, is less empty and sterile than it is thought to be. Several consequences arise from it... (II.23.2:218).10 10 Gottfried Wilhelm Leibniz also criticized Locke's remarks on the doctrine of innate ideas (New Essays on Human Understanding, 1740). Here 'innate idea' refers to the notion that the basic components of human knowledge and understanding are not rooted in sense experience. Rather such items of knowledge and understanding (e.g., necessary truth) were imprinted in the human mind. So human beings, so to speak are born with such innate or primary ideas to which universally all humans assent to. For Leibniz, as it is true for Rene Descartes, such construal of innate ideas is perfectly justifiable (see, e.g., John Harris in 'Locke on Human Understanding,' I.C. Tipton (ed.), 1977: chap. II; Mackie 1976: chap. 7). But Locke thinks that such blind acceptance of innate ideas stifles honest inquiry into how we acquire our knowledge thereby encouraging dogmatism as well as obscurantism. So 11 It is clear that Leibniz also thinks that divesting the concept of substance of its attributes is problematic. This is because for Leibniz, we can only come to grasp the very nature of substance via its qualities or properties. In light of both Lee's and Leibniz's insistence on the importance of ascribing a property to a substance (obviously the move Locke resists), the question remains: what sort of property can we ascribe to a substance? Here essential property and accidental property come to mind. Roughly speaking, an object is said to have an essential property if it cannot exist without it. For example, being extended is an essential property of a house, without which a house cannot continue to exist. By contrast, an object is said to have an accidental property if an object can lose it without ceasing to exist. For example, suppose that John is sad now. It is possible for John to have lacked the property of being sad now. So being sad is an accidental property of John. For present purposes, I will put aside complicated and detailed discussions that surround these two domains of properties, i.e. essential and accidental (see further Lowe 2002, chap. 6; Code 1986; Fine 1992; McGinn 2000; Plantinga 1974). In light of this, it might be the case that both Lee's as well as Leibniz's complaints against Locke's characterization of substratum or pure substance as 'something we know not what' seem to have targeted on the loss of an essential property of a substance. However, here we may argue that Locke does not necessarily deprive a substance of its nature. Rather Locke only insists that we have no knowledge of the nature of substance. But such response does not satisfy Locke's critics. This is because, since by Locke's own account we have no idea of what the nature of substance is, it remains unclear what entitles us to say anything substantial about it. So the heart of Lee's and Leibniz's charge against Locke's characterization of substance seems to be that Locke deprived pure substance of all its content. But some disagree with such a conclusion. Locke dedicates Book I of his Essay to refute the doctrine of innate ideas before he returns in Book II of his Essay to the discussion of substratum and particular substances. For more information on Locke's take on innate ideas and the controversies surrounding it, see e.g., Lowe 1995: chap. 2 and 2005: chap. 2; J. Gibson 1917: chap. 2, § 6; J.W. Yolton 1956; R.I. Aaron 1955; D.J. O'Connor 1967: 39-40, Greenville Wall in Locke on Human Understanding, I.C. Tipton, ed., 1977: chap. I, Margaret Atherton in Locke, Vere Chappell, (ed.), 1998: chap. II and J.L. Mackie 1976: chap. 7. 12 For example, McCann claims that both Lee and Leibniz mischaracterized Locke's characterization of substance. McCann thinks that Locke did not leave us with an empty conception of substance nor did he subtract all properties and qualities from it, as both Lee and Leibniz claim. Furthermore, for McCann, Locke does not rob the notion of substance of all content. This is because, as McCann argues, Locke's characterization of the idea of substance as self-subsisting property bearer of objects (serving as their common subject) exactly matches Lee's own characterization of substance as the 'old' conception of substance (McCann 2001: 96). However, McCann's defense of Locke's conception of substance appears to be overly simplistic. If indeed Locke's conception of substance exactly matches that of Lee's, then that means that Locke takes an Aristotelian conception of substance without reservation. But that is indeed not the case. Locke clearly does not endorse some core notion of substance in the Aristotelian tradition in general and scholastics, in particular. For example, although Locke calls such things as man, horse, sun, etc., as particular substances, he does not consider them to be substances in the fundamental ontological sense. McCann's misunderstanding here arises from his unjustifiable inference that because Locke grants that substance is a property bearer, it follows that Locke's conception of substance is not devoid of content. The real issue here is not the lack of consensus or awareness of the fact that Locke clearly takes pure substance to be a property bearer. Rather the real issue has to do with what pure substance itself is, on its own ground apart from being a property bearer. Does it have its own nature or identity, if it does what is it? How do we come to know it? So, only knowing pure substance as a property bearer per se is not a substitute as McCann seems to think for settling such fundamental questions. So, contrary to McCann, it is not wrong to say that Locke left us with an empty conception of substance. For example, Jonathan Bennett argues that many philosophers rightly point out that Locke's notion of pure substance or substratum is impossible or intolerable. But why is that? Bennett thinks that the answer concerns with conceptual emptiness. By this Bennett meant that since it is thought that because substratum has to be the bearer of all the qualities, it must be therefore, in itself, bare or unqualified in some problematic way (Bennett 1998: 131 in Vere 13 Chappell, ed.). But as Bennett further points out the defender of substratum theory is inevitably accused of requiring content in something that had been stripped of all content (Ibid.: 132). McCann's move in trying to bring Locke's conception of pure substance closer to the traditional understanding of substance turns out to be inconsistent with McCann's own suggestion about what he thinks Locke is up to, in advancing his theory of substance. McCann points out that Locke's main agenda in Book II of the 23rd chapter of his Essay has been understood in terms of (1) Locke giving us a positive theory of substance more in line with the traditional view of substance; and (2) Locke giving us a negative theory of substance, which is taken to imply that he is entirely rejecting his theory of substance (e.g., see Essay II.13.17-20 & II.23.2). But McCann suggests his own alternative: (3) the 'no-theory' theory of substance. As McCann puts it: Locke is giving an account of an idea we have, the idea of substance in general, which is derived from simple ideas given in sensation and reflection but which, given the vagaries of this derivation, is hopelessly and irremediably confused and obscure. An idea this confused and obscure cannot be used to explain anything, including the six phenomena....Locke's realization of, and indeed insistence upon, this fact explains why it is that he never, either in the Essay or in the correspondence with Stillingfleet, claims to explain anything in terms of that idea. It is an idea we've arrived at faute de mieux, serving mainly to mark our inability to conceive how qualities exist by themselves by supposing they exist in something, something, given the circumstances, we know not what (McCann 2001: 94-95). Here by 'six phenomena' McCann is referring to six features attributed to the theory of substance which he himself recognizes can be traced back to Aristotle. In a nutshell, these features are (a) predication relation that is, certain terms are predicated of other in an asymmetrical fashion. We can say, the 'flower is red' but it is wrong to say 'The red is a flower'; (b) substances can exist on their own but the same cannot be said of modes or properties. That is, only the later need the former for their instantiation; (c) substances unify various sensory experiences (e.g., colors, shapes, feels, smells) to hang-together; (d) substances play the role of identifying or individuating individual objects. For example, a substance can persist via qualitative change while maintaining its numerical identity over time; (e) substances have a special sort of unity in that a substance is ens per se, i.e., a being through itself, which is 14 radically different from mere aggregates, which are entia per accidens, i.e., an entity that exists accidentally; (f) the theory of substance also needs to tackle the question of how many basic kinds or fundamental kinds of substance there are and how each basic kind differs from the other (Ibid.: 88-90). What is the problem with McCann's (3) above?11 The problem is not with McCann's overall characterization of Locke's theory of substance. Certainly one can ask whether or not Locke's theory of substratum is explanatorily adequate. But the issue here is whether or not Locke is successful in the way he characterized his theory of substratum. Leaving that aside for now, McCann's (3) is inconsistent with his earlier remarks that Locke's theory of substance 'exactly' matches both Lee's as well Leibniz's characterization of substance. How so? Given McCann's (3) Locke's theory cannot explain the six features of substance McCann himself lists as shown above in (a)-(f). That means that Locke's theory of substance hardly matches the account given by Lee as well as Leibniz. This is because the Lee-Leibnizan account is perfectly consistent with the six features pointed out by McCann, whereas Locke's theory of substance fails to match up with the six features. This is precisely because Locke's substratum or pure substance is so obscure and confused whose features we cannot tell (if such a task is even possible to undertake in the first place). If this is correct, then my early remarks regarding the Lee-Leibnizan account of substance being Aristotelian in its spirit stands their ground. If I am right about this, it follows that McCann's claim that Locke's conception of substance is equally rich in its content as that of Lee-Leibnizan turns out to be by its own standard both inconsistent and groundless. Moreover (3) can be given an ambiguous reading. Basically (3) does not tell us anything different that cannot be achieved either by adopting one of the other strategies, i.e., (1) or (2) as stated above. But the ambiguous reading I have in mind here can be spotted between (2) and (3). As it stands, one can understand (3) as Locke rejecting his theory of 11 As we recall, we already made (with some qualification) a positive case for (1). But we rejected (2) on the basis of claiming that Locke is a realist about substance ontology. In the above quote, McCann mistakenly thinks that the idea of substance is derived from simple ideas given in sensation and reflection. See footnote # 4 for Locke's own view. 15 substance, in which case the meaning of (2) is in place. On the other hand, one can also understand (3) as implying that Locke is not rejecting his theory of substance, instead he is simply stating the difficulties surrounding it to spell out what it is, in which case we settle for (3). But it is hard to tell which meaning fixes McCann's 'no-theory' theory of substance. In light of such considerations, therefore, option (1) seems to be the best alternative to adopt. Finally, the other contemporary of Locke worthy of mentioning is John Sergeant. Sergeant begins his discussion of Locke's 23rd chapter of Book II as follows: While I perused Mr. Locke's 23th Chapter, of the Idea of Substance, I was heartily grieved to see the greatest Wits, for want of True Logick, and thro' their not lighting on the right way of Philosophizing, lay Grounds for Scepticism, to the utter Subversion of all Science; and this, not designedly, but with a good Intention, and out of their Sincerity and Care not to affirm more than they know. He fancies that the Knowledge of Substance and Extension are absolutely Unattainable. Now, if we be altogether Ignorant what Substance or Thing means, we must bid Adieu to all Philosophy, which is the Knowledge of Things, and confess that we talk all the while of we know not what: And, if we be invincibly Ignorant of what Extension is, farewell to all the Mathematical Sciences; which, (those that treat of Number, or Arithmetick, excepted) do all of them presuppose our Knowledge of Extension, and are wholly grounded on that Knowledge (Reflection, 1697, 13.22-23: 238). Sergeant certainly gives credit to Locke for exercising an epistemological modesty by not pretending to know more than he does. Yet for Sergeant such epistemological modesty comes with a price. That is, suspending judgment in matters such as substance and extension creates a fertile ground for skepticism. Hence, the ultimate consequence of such skepticism shakes up the very foundation of our knowledge of things. So, Sergeant offers his own version of substance: Now, as we can consider the Thing according to its Modes or Accidents, so we can have another Notion or Consideration of the Thing as to its own self* abstracting from all these former Considerations; or a Notion of the Thing, (not according to any Mode it has, but) precisely according to its Thingship (as we may say) or Reality; that is, in order to Being; or (which is the same) we can consider it precisely and formally as an Ens, Res, Substance or Thing; and all we can say of it, thus consider'd, is, that 'tis capable to be actually. For, since we see Created Things have Actual Being, yet so that they can cease to be; all that we can say of them, (thus consider'd) is, that they are Capable to be. Besides, since we see they have Being, were this Actual Being or Existence Essential to them, they would be of themselves, and so could not but be; and, consequently, must always be; which our 16 common Reason and Experience contradicts; in regard we know them to have been made; and we see many of them daily Produced, and others Corrupted (Reflection, 1697, 13.22-23: 239-40). Compared to the Lee-Leibnizans' account of substance, Sergeant's account is different. Sergeant spells out his notion of substance in terms of 'capacity to exist'. In this regard, McCann points out that Locke responded to Sergeant's definition of substance in two marginal comments on Sergeant's own Solid Philosophy. Locke's first comment reads: "All which amounts to no more but that Substance is something, which is what Mr. L. [Locke himself] says" (p. 241 as quoted in McCann 2001:97). The other comment Locke gave concerns direct criticism of Sergeant's own conception of substance: If the Idea of Substance be capacity to exist, then Accidents are Substances for they are capable to exist. If it be as J.S. puts it here and else where a thing capable to exist, then his Idea of substance or thing will be this, that a thing is a thing capable to exist, which as much clears the point as if he should say an [accident?] is an accident capable to exist, or a man capable to exist (p. 244 as indicated in McCann 2001: 98) Here I agree with McCann's remark that Locke's criticism of Sergeant's conception of substance is effective. Locke is certainly right to say that if the criteria for something to be a substance is based on the capability of whether that thing exists or not, then anything that is capable to exist can be given a status of substance, a notion that goes against what we have discussed so far. But where I still disagree with McCann is when he says, "Locke is criticizing Sergeant for departing from the traditional notion of substance'' (Ibid.: 98). Here my disagreement with McCann is based on the earlier claim that Locke is not committed to the traditional notion of substance to the extent McCann claims. Thus, at the least, it remains unclear whether or not Locke's point in criticizing Sergeant's construal of substance is motivated by Locke's commitment to the traditional understanding of the theory of substance. Although the four contemporaries of Locke have their own independent line of thoughts, what unifies them all against Locke is their insistence on the inadequacy of Locke's characterization of substratum or pure substance in general as 'something we know not what.' The question remains: where does all this leave Locke's theory of substance? Is Locke's theory of substance misguided? I personally think 17 not. As Sergeant rightly noticed, Locke's insistence on the unknowability of substratum is motivated by his epistemological modesty (i.e., by not pretending to know more than he does). Yet as we recall from sections I & II, Locke's main goal in proposing substratum does seem to be primarily metaphysical in nature. That is, Locke on a purely ontological ground, seems to have realized that properties or qualities necessarily need some sort of bearer for them to exist. Hence, there cannot be free floating qualities (cf. Lowe 1995: 76-77). More importantly, as Lowe remarks, when Locke characterizes substratum as 'something we know not what', he (Locke) seems to be implying that it may have a nature which may be known to other beings such as angels and God (e.g. Essay II, XXIII. 6; Letter to the Bishop of Worcester, p. 28 as quoted in Lowe, 2000:507). If so, the objections Locke's immediate critics raised against his theory of substance are not insurmountable. In light of such and similar other considerations, contemporary philosophers such as C.B. Martin, E.J. Lowe, M. R. Ayers, Jonathan Bennett, J.L. Mackie, Margaret Atherton, and Martha Brandt Bolton proposed various solutions to provide a defensible framework for Locke's theory of substance. Though the amendments these philosophers suggest differ from each other, they all agree that Locke's theory of substance is not a result of careless conjecture and thus must not be dismissed. For reasons already indicated, looking at these solutions is not our present concern (see for details, Martin, 1980; Lowe, 2000 & 2005; Ayers, in Tipton, I.C., 1977; Mackie, 1976; Bennett, Ayers, Atherton and Bolton, in Vere Chappell 1998). That said, however, one thing we can certainly say is that with some modification, Locke's theory of substance can be made free from the problems that beset it. 4. Conclusion In this short paper, we have looked at what Locke's motivation was in proposing the theory of substratum. We have also looked at some of the problems that beset the theory of substratum as pointed out by Locke's immediate critics. Yet Locke's insistence on the unknowability of substratum stems from his epistemological modesty. If so, the best that can be said about the merit of the objections raised by Locke's 18 contemporaries is that at the least, the objections show that Locke's theory of substratum is contentious. But such objections in no way prevent us from modifying Locke's account of substratum (as contemporary philosophers attempt to do). Therefore, I conclude that, as things stand, there is no warrant to dismiss Locke's theory of substance.12 Literature Ackrill, J.L. (Trans.). Aristotle's Categories and De Interpretatione. Oxford: Clarendon Press, 1963. Aaron, R.I. John Locke. Oxford: Oxford University Press, 2nd edition, 1995. Berkeley, George. 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