Philosophical Papers Vol. 41, No. 1 (March 2012): 23-56 ISSN 0556-8641 print/ISSN 1996-8523 online © 2012 The Editorial Board, Philosophical Papers http://dx.doi.org/10.1080/05568641.2012.662806 http://www.tandfonline.com Kantian Monism Uriah Kriegel I will not make poems with reference to parts But I will make poems, songs, thoughts, with reference to ensemble And I will not sing with reference to a day, but with reference to all days, And I will not make a poem nor the least part of a poem but has reference to the soul Because having look'd at the objects of the universe, I find there is no one nor any particle of one but has reference to the soul Walt Whitman, Starting from Paumanuk Abstract: Let 'monism' be the view that there is only one basic object-the world. Monists face the question of whether there are also non-basic objects. This is in effect the question of whether the world decomposes into parts. Jonathan Schaffer maintains that it does, Terry Horgan and Matjaž Potr that it does not. In this paper, I propose a compromise view, which I call 'Kantian monism.' According to Kantian monism, the world decomposes into parts insofar as an ideal subject under ideal conditions would divide it into parts, but it does not decompose into parts in and of itself, that is, in an entirely mind-independent manner. After articulating Kantian monism more precisely (Section 1), I present a prima facie case for preferring it over more standard varieties of monism (Section 2). 1. Kantian Monism: Exposition Before arguing for the superiority of Kantian monism over other kinds of monism, it is important to get clear on what Kantian monism exactly is. I start with an exposition of monism in general (Section 1.1), then consider the Kantian approach to decomposition (Section 1.2), and end with a presentation of Kantian monism as it emerges from their combination (Section 1.3). 1.1. Monism and the Special Decomposition Question Twentieth-century discussions of the metaphysics of concrete objects, such as tables and butterflies, often start from two assumptions: 24 Uriah Kriegel pluralism and mereology. The former concerns basic concreta, the latter non-basic concreta. The first assumption is that there are very many basic concreta, typically construed either as sub-atomic particles or as spacetime points. The second assumption is that the extent of non-basic concreta is determined by mereological composition of basic concreta: there are as many non-basic concreta as there are mereological fusions of basic concreta. Pluralism comes in two main varieties. According to one, the basic concreta are sub-atomic particles, or whatever ultimate science will designate as the smallest units of matter. According to the other, the basic concreta are space-time points. In the background is a dispute about the relationship between concrete particulars and the space-time regions they occupy: on one view, particulars are identical to the regions they occupy ('occupation is identity,' if you will); on the other, particulars 'fill' the regions but are distinct from those regions ('occupation is not identity'). Mereological views come in three main varieties, appreciated through the prism of the so-called Special Composition Question (van Inwagen 1990): for any plurality of concrete objects O1, ..., On, under what conditions is there an object O, such that O1, ..., On compose O? Mereological universalism answers: under all conditions. Mereological nihilism answers: under no conditions. Mereological restrictivism answers: under some but not all conditions.1 Combining the two sets of options-the two versions of pluralism and the three views on mereological composition-modern discussions offer a matrix of six main options for understanding the structure of reality, at least as it pertains to the realm of concreta. These are: universalist point pluralism, universalist particle pluralism, nihilistic point pluralism, 1 For a defense of universalism, see Lewis 1991 and Van Cleve 2007. For a defense of nihilism, see Rosen and Dorr 2002 and Sider Ms. For a defense of restrictivism, see van Inwagen 1990 and Markosian 1998. Note that restrictivism comes in many different varieties, depending on how special the conditions for composition are. Thus, for van Inwagen, O1, ..., On compose O just in case O is alive, whereas for Markosian, O1, ..., On can compose O also when O is not alive. Kantian Monism 25 nihilistic particle pluralism, restrictivist point pluralism, and restrictivist particle pluralism. Much of contemporary discussion of the metaphysics of concreta revolves around the choice between these six options. Historically, however, the very pluralist assumption has often been rejected, with the thought that it is in fact the world as a whole that is ontologically basic.2 This monist alternative to pluralism has been redeveloped recently, making viable a new set of options. Notably, Horgan & Potr (2000, 2006, 2008) have argued for what they call blobjectivism, and Schaffer (2007a, 2007b, 2009, 2010a, 2010b) for what he calls priority monism. Both views maintain that the only basic concretum is the world as a whole: (M) There is an object W, such that W is basic, and for any object O, if O W, then (i) O is part of W and (ii) O is not basic. This is monism as such.3 Some clarifications are in order. First, here and in what follows, I use the term 'object' to mean concrete particular; I use the term 'entity' to cover both concrete particulars and non-concreta. Secondly, I use the term 'basic' to mean 'basic object,' not 'basic entity'; it may well be that some concrete object is basic even though it is ontologically derivative upon, or grounded in, some non-concrete entities (say, tropes).4 Thirdly, I use 'there is' to mean 'there is in the 2 Such monism is associated most closely with Spinoza (see Goff 2012), but importantly, characterizes also Hegel and a whole slew of nineteenth-century British idealists (see Schaffer 2010b for discussion). 3 This is not how the term 'monism' is always used in the literature. Schaffer calls 'priority monism' what I here call monism, and uses the term 'existence monism' for the specific version of monism according to which not only is there only one basic object, there are zero non-basic objects. Thus he would use 'monism' as a label for an essentially disjunctive thesis. Trogdon (2009a) uses 'monism' as a label for the view that the properties of proper parts of the world are grounded, in some sense, in the properties of the world. It is clear that there are close connections between all these theses and what I here call monism (and Schaffer calls) priority monism. But my usage is nonetheless distinct. 4 Thus, a philosopher who maintains that all concrete objects, including the world, are nothing but, and ontologically grounded in, bundles of (compresent) tropes, but who maintains also that all concrete objects are ontologically grounded in the world, such that the whole as a whole is the only basic entity among concrete objects, qualifies as a monist by my lights. This is monism about concreta, then, rather than monism about entities. 26 Uriah Kriegel actual world'; non-actual entities are not in the scope of the existential quantifier, so construed. Within this monistic framework, the notion of basicness cannot, of course, mean 'partlessness' (as it might within the pluralist framework). Some other explication is needed. My approach is to proceed in two steps. First, we define a relation of more-basic-than. This would be an asymmetric relation of ontological priority, akin to (or perhaps the same as) supervenience or grounding.5 Second, we define a basic object as one no other object is more basic than. That is, O is basic iff there is no O*, such that O* is more basic than O.6 What Horgan & Potr and Schaffer disagree on is whether the world has parts: Horgan & Potr claim that it does not, Schaffer that it does. The contrast can be articulated in terms of a monistic analog of the Special Composition Question, which we may call the Special Decomposition Question: For any object O, under what conditions are there objects O1, ..., On, such that O decomposes into O1, ..., On? Horgan & Potr 's view is a sort of nihilistic monism: under no conditions does the world decompose, and therefore there are no parts of the world. Schaffer's view is a non-nihilistic monism: under (at least) some conditions the world does decompose, and therefore there are parts of the world. We may formulate nihilistic monism as follows: (NM) There is an object W, such that W is basic, and there is no object O, such that O W. And at least to a first approximation, we may formulate non-nihilistic monism as follows: (NNM) There is an object W, such that W is basic; for any object O, if O W, then (i) O is part of W and (ii) O is not basic; and there is an object O*, such that O* is part of W.7 5 For grounding, see Fine 2001. 6 This way of proceeding is essentially the same as Schaffer's (2010a). 7 This is only a first approximation because of a certain complication that will arise in Kantian Monism 27 There are two versions of non-nihilistic monism: restrictivist monism is the view that under some conditions the world decomposes and under some it does not, whereas universalist monism is the view that the world always decomposes. Interestingly, universalist monism casts the world as gunky, since it insists that every part of the world has its own parts.8 Thus the distinction between universalist and restrictivist monism is a distinction between gunky and non-gunky monism. As with pluralist views, monistic views can differ also on whether occupation is identity, that is, on whether the world is one and the same as the space-time it occupies. Schaffer (2009) argues for space-time monism, but Horgan & Potr are uncommitted on this question. In any event, the monist framework offers us its own matrix of six main options for understanding the structure of (concrete) reality: universalist spacetime monism, universalist cosmos monism, nihilistic space-time monism, nihilistic cosmos monism, restrictivist space-time monism, and restrictivist cosmos monism.9 Both Schaffer and Horgan & Potr offer a number of arguments for monism and against pluralism. Other philosophers have argued against monism (Sider 2007, 2008; Korman 2008), and there are also arguments from elsewhere in philosophy that threaten it, e.g., arguments to the effect that 'the world' (or 'the universe') is not a referential term (van Fraassen 1995; Simons 2003). At the same time, other philosophers have defended monism (Potr 2003; Trogdon 2009a, 2009b; Cameron 2010), or more generally the thesis that some wholes are ontologically prior to the simples that compose them (Elder 2007), and the aforementioned threatening arguments are highly controversial (Varzi 2006). In this paper, I propose to set aside the choice between monism and pluralism and focus on a question of interest mainly to monists; namely, whether Section 1.3; see footnote 19. 8 A world is gunky if it does not have mereological simples, that is, objects that do not have parts. 9 Here I use the term 'cosmos' technically, to mean the world understood as non-identical with the space-time it occupies. 28 Uriah Kriegel monists would do better to adopt Horgan & Potr 's nihilistic monism, Schaffer's non-nihilistic monism, or some third option. In other words, the question I want to address is whether the monist should allow the world to have parts. The question should be of interest to pluralists as well, insofar as making the case for pluralism would presumably require arguing against the best version of monism; wherefore it is of interest to get clear on what the best version is. I want to suggest a version of monism that is a compromise between Horgan & Potr 's nihilistic monism and Schaffer's non-nihilistic monism. On this compromise view, the world has no parts mind-independently, but does have parts mind-dependently. This is, in crude strokes, the view I call 'Kantian monism.' To make better sense of it, let us consider the notion of mind-dependent decomposition it appeals to. 1.2. Decomposition as a Secondary Quality Discussions of mereology are often conducted against the background of certain assumptions that, while common, are not mandatory. I already mentioned the assumption of pluralism, the view that there are many basic objects. Another assumption is what we may call necessitarianism: mereological facts are necessary, so any mereological view would have to be necessarily true if true at all. This assumption is common but sometimes denied (Rosen 2006; Cameron 2007; Bohn 2009; Miller 2009). Another such assumption is what we may call objectivism: the view that there are mind-independent facts of the matter concerning which fusions and fissions exist. This assumption is denied by two kinds of philosopher. Some reject any facts of the matter (Hirsch 2002, 2005; Sidelle 2002). More moderately, I, elsewhere, countenance facts of the matter but take them to be mind-dependent (Kriegel 2008).10 In that paper, I argue for the thesis that composition is a 'secondary quality,' somewhat in the sense in which colors, for example, have 10 Sidelle (2002) sometimes remarks in passing that there may be facts of the matter for mereology, but they would have to be 'conventional,' which may be not very dissimilar from my mind-dependent facts. Kantian Monism 29 sometimes been considered secondary qualities. Just as, plausibly, x is yellow iff x would appear yellow to normal observers under normal conditions (see, e.g., Boghossian and Velleman 1989), so I suggest that O1, ..., On compose O iff O1, ..., On would appear to compose O to normal intuiters under normal conditions. After explicating the thesis, I motivate it by methodological considerations (pertaining to the role of pre-philosophical intuitions in theory choice) that will not concern us here. In that paper, I work within the pluralist framework, and thus concern myself with the Special Composition Question.11 But a monist could apply this nonobjectivist approach to the Special Decomposition Question articulated above. However, I am now tempted to frame the view in terms not of normal intuiters but ideal subjects. The thesis I propose in the present context is therefore this: an object O decomposes into objects O1, ..., On iff O would appear to ideal subjects under ideal conditions to have parts O1, ..., On. Call this the thesis of decomposition as a secondary quality (henceforth, DSQ). The thesis can be profitably cast as a response-dependent biconditional. Such biconditionals take the form 'a priori, x is F iff x is such as to elicit response R in subjects S under conditions C' (see Johnston 1989; Pettit 1991).12 So cast, DSQ becomes the thesis that decomposition is a response-dependent relation, that is, a relation whose instantiation conditions advert to some response in some respondent. I have already indicated that the relevant respondent is the ideal subject. As for the relevant response, it is natural to construe it as the response of representing there to be objects O1, ..., On. Thus DSQ may be formulated, at first pass, as follows: (DSQ1) A priori, for any object O, there are objects O1, ..., On, such that O decomposes into O1, ..., On iff O is such as to elicit in 11 I do so despite being a monist because of the prevalence of pluralist assumptions among metaphysicians working on mereology. Since both monism and the secondary quality view are heterodox, I chose to take up only one battle at a time! 12 The biconditional must be a priori because someone who does not think the relevant property is response-dependent could still think that, as a matter of empirical fact, the biconditional holds (Wright 1992). 30 Uriah Kriegel ideal subjects under ideal conditions the response of representing there to be objects O1, ..., On.13 Some clarifications are in order: of the notions of ideal subjects, ideal conditions, representing (there to be an object), and 'such as to elicit.' In ideal observer theories, an ideal subject is often construed as a cognitively idealized human subject, that is, an otherwise normal human who happens to be (i) well-informed and (ii) a perfect reasoner. By 'otherwise normal,' I mean a subject who is set up like actual subjects, in particular in terms of the biological function of its reasoning faculties; namely, the function of promoting its prospects for survival and reproduction. We could say that a 'perfect reasoner' is a subject who is in a position to draw every (deductive and non-deductive) epistemically justified inference and avoid drawing any (deductive or non-deductive) epistemically unjustified inference. However, this restricts matters to personal-level cognition, whereas there is no reason to deny the ideal subject perfect sub-personal cognitive capacities as well. So my inclination would be to construe the ideal subject as one who performs or undergoes all and only epistemically justified or warranted (personal or sub-personal) cognitive processes. As for making the ideal subject 'wellinformed,' we cannot give her any knowledge of the facts regarding proper parts of the world, since we are appealing to her to fix those facts. However, we are free to give her any other knowledge, including all knowledge of the facts regarding the world as a whole, except of course decompositional facts. Thus our ideal subject is an otherwise normal human subject who (i) performs or undergoes all and only epistemically justified/warranted cognitive processes and (ii) knows all the nondecompositional facts regarding the world as a whole.14 13 In line with the previous footnote, the biconditional is a priori in order to rule out the possibility that the ideal subject tracks independent facts about decomposition rather than (in some sense) constitutes such facts. It is only in its constitution version that the biconditional secures the relevant kind of mind-dependence of decomposition. 14 I am assuming what seems to me highly plausible, that numerically distinct ideal subjects would converge in their decomposition-belief formation. With the knowledge and Kantian Monism 31 As for ideal conditions, let them be those conditions under which a subject can perform the cognitive task she is faced with to the best of her abilities. This relativizes ideal conditions to subjects and tasks, as one would expect: conditions C are ideal relative to subject S and task T iff S can perform T maximally competently under C, that is, iff there are no conditions C*, such that S performs T better (more competently) under C* than under C. What makes performance better or worse (more or less competent) depends, of course, on what the value is by which we judge the performance. Typically, the relevant value is accuracy, but in the present context it cannot be, since there are no independent, preexisting facts for the ideal subject to be accurate about. Instead, we must conceive of the relevant value directly in terms of the subject's broader goals-survival and reproduction. Thus we obtain the following: conditions C are ideal relative to subject S and task T iff there are no conditions C*, such that S's performance of T under C* enhances S's survival and reproduction prospects more than S's performance of T under C; call such conditions maximally enhancing. What is involved, now, in representing something as an object? There is a flourishing literature about subjects' cues for distinguishing object from background in cognitive psychology that could be of help here. But philosophically, the fundamental idea is that we have a concept of an object and we apply it to some chunks of the world and not others. To represent some chunk of the world as an object is simply to represent it in a way that applies one's concept of an object to it. Here I use the phrase 'chunk of the world' analogously to the way 'plurality' is used within the pluralist framework; just as we can ask which pluralities constitute fusions, hence composites, so we can ask which world-chunks constitute fissions, hence 'decomposites' (i.e., parts). We may say that a chunk of the world, in this technical usage, is an epistemically possible part of the world. (The term is doubtless sub-optimal.) Thus to speak of the the reasoning capabilities at their disposal being exactly the same, it is hard to see why they would diverge. This is why I will often speak of 'the ideal subject,' as though there was just one. 32 Uriah Kriegel response of representing O1, ..., On to be objects is effectively to speak of a subject entering representational states whose contents are of the form <Oi is an object>, where 'Oi' denotes an epistemically possible worldpart. One last clarification: there are a number of ways to understand the locution 'such as to elicit.' The most natural is in dispositional terms: x is such as to elicit y just in case x is disposed to elicit y, where 'eliciting' is just causing or triggering.15 With these clarifications in place, we are in a position to formulate a second pass of DSQ: (DSQ2) A priori, for any object O, there are objects O1, ..., On, such that O decomposes into O1, ..., On iff O is disposed, under maximally enhancing conditions, to elicit representations with the content <Oi is an object> in subjects who (i) perform or undergo all and only epistemically justified/warranted cognitive processes and (ii) know all the non-decompositional facts regarding the world as a whole. Further and more refined formulations would be generated through explication of various components of this thesis, including the nature of dispositions, warrant and justification, mental representation, etc. For our present purposes, this explication of DSQ should do-I will not seek a third pass. Before closing, I do wish to stress that there is no circularity in DSQ2. One appearance of circularity may be due to the mention of Oi on the right-hand side of the biconditional. This is discussed at length in Kriegel 2008, but the fundamental point is that Oi occurs in an opaque context on that side of the biconditional. Another possible appearance of circularity, special to the monist framework, might be due to the appeal to a subject, who presumably would be part of the world and not the world in its entirety. However, the relevant appeal is not to any actual 15 There could also be a categorical reading of the locution, where it is interpreted as denoting the categorical basis of the relevant disposition. For discussion, see Kriegel 2008. Kantian Monism 33 subject, but to a merely possible subject, since what grounds parts' existence is only the world's disposition to elicit certain representations; whether the disposition is manifested plays no role in grounding the existence of non-basic objects in this picture. Thus, even in a world in which an ideal subject does 'exist,' what makes that ideal subject be a part of the world is only the fact that the world is disposed to elicit certain representations in a subject like her. The fact that the world does in fact elicit such representations in her plays no role in grounding her 'existence' in that world.16 1.3. Kantian Monism: Monism with Response-Dependent Decomposition We are now in a position to articulate clearly the view I call 'Kantian monism.' Its core is simply the combination of monism about basic objects with the Kantian approach to non-basic objects. But it goes beyond a simple conjunction of M and DSQ2. For it makes one more claim; whereas DSQ2 only sets out the conditions for decomposition, Kantian monism claims that these conditions are satisfied. That is, Kantian monism claims that an ideal subject would, in fact, represent there to be objects (in the plural). This additional claim is highly plausible. For starters, perceiving and cognizing the world in terms of parts works well for us, and it is implausible to suppose that what makes it work well for us is our inferential imperfections and/or partial ignorance of the facts regarding the world as a whole-that is, our nonideality. More likely, it works well for organizing and managing the overflow of information we face on a daily basis-which would benefit the idealized subject just as well. This suggests to me that the ideal subject would likely partition the world broadly along the same lines that we do, though with local improvements galore. But even if the ideal subject's partition was substantially different from ours, it is extremely plausible that some 16 I put existence talk (in the last two sentences) in scare quotes because, strictly speaking, it is only in the actual world that a putative entity can exist. In other worlds it may occur, be present, reside, or counterpart-exist, but it cannot just exist. 34 Uriah Kriegel partition would occur. Imagine a world otherwise like the actual, but populated exclusively by well-informed and inferentially flawless humans, exactly half of whom represent the world to decompose into objects while the other half do not-where this representational tendency is hereditary. My contention is that the group that represents the world to decompose would be more successful in surviving and reproducing, leading after a long enough process of natural selection to substantial evolutionary takeover. Kantian monism, then, is effectively the conjunction of three propositions: monism, the thesis of decomposition as a secondary quality, and the claim that an ideal subject would in fact represent the world to decompose. That is: (KM) 1) There is an object W, such that W is basic, and for any object O, if O W, then (i) O is part of W and (ii) O is not basic; and, 2) A priori, for any object O, there are objects O1, ..., On, such that O decomposes into O1, ..., On iff O is disposed, under maximally enhancing conditions, to elicit representations with the content <Oi is an object> in subjects who (i) perform or undergo all and only epistemically justified/warranted cognitive processes and (ii) know all the non-decompositional facts regarding the world as a whole; and, 3) W is disposed, under maximally enhancing conditions, to elicit representations with the content <Oi is an object> in subjects who (i) perform or undergo all and only epistemically justified/warranted cognitive processes and (ii) know all the nondecompositional facts regarding the world as a whole There may be some ways to formulate Kantian monism more economically, but that will not matter here.17 What will matter is the 17 One natural option is as follows: There are objects W, O1, ..., On, such that (i) W is basic, (ii) O1, ..., On are not basic, and (iii) O1, ..., On exist because (or in virtue of the fact that) W is disposed, under maximally enhancing conditions, to elicit representations with Kantian Monism 35 fundamental idea that there is only one basic object, the world as a whole, which decomposes into parts insofar as an ideal subject would, under ideal conditions, take epistemically possible parts of the world ('world-chunks') to be parts. This is the fundamental idea of Kantian monism, and its present precisification will not play a major role in what follows; it is provided merely to demonstrate that a precise formulation is possible-that no hidden incoherencies lurk-and to illustrate one way the view could assume more texture. Kantian monism is a compromise view lying somewhere in-between Horgan & Potr 's nihilistic monism and Schaffer's non-nihilistic monism, catering to some of each view's sensibilities and not others. On the one hand, as far as what exists tout court, Kantian monism is in agreement with non-nihilistic monism, admitting a great many concreta in addition to the world. On the other hand, as far as what exists regardless of subjects and their responses is concerned, it is in complete agreement with nihilistic monism: there is only one such object. Given the current prevalence of realism and objectivism about matters of existence, composition, etc., I suspect many ontologists would see Kantian monism as essentially a notational variant on nihilistic monism, with extra flourishes tacked on for the benefit of the nonnihilist. Let me therefore say a little more by way of underlining the substantive difference between Kantian monism and nihilistic monism. One view one might have is that there are two grades of existence, a fullblooded mind-independent one and a more lightweight minddependent one, and that non-basic objects possess only the latter. This is not the view I am proposing, in large part because I do not understand it, insofar as I do not understand what it would mean for there to be two kinds of existence. I understand better what it would mean for there to be two ways of possessing existence.18 The existence possessed by basic the content <Oi is an object> in subjects who (i) perform or undergo all and only epistemically justified/warranted cognitive processes and (ii) know all the nondecompositional facts regarding the world as a whole. 18 This is not to say that talk of possessing existence, and different ways of possessing 36 Uriah Kriegel objects and by non-basic objects would be one and the same. What would be different is the possessing of existence: basic objects possess existence in and of themselves, so to speak, whereas non-basic objects possess it in virtue of bearing a response-dependent relation to basic objects. This is just to say that the grounds for the possession of existence are different, but the existence possessed is one and the same. Given this, ultimately, Kantian monism is more similar to nonnihilistic monism than nihilistic monism. For it commits to the existence of objects other than the world, and commits to their existence in the very same sense in which it commits to the world's. So in that single sense of existence, there exists a plurality of concrete objects-which is the position of non-nihilistic monism. If anything, then, Kantian monism is more similar to non-nihilistic monism than to nihilistic monism. Indeed, KM logically entails NNM. However, I will reserve the label 'non-nihilistic monism' to the objectivist variety of the view, and let 'Kantian monism' denote the non-objectivist variety.19 This bookkeeping system will serve to underline the important difference between Kantian monism and the paradigmatic non-nihilistic monism-Schaffer's priority monism-as well as the commonality between Kantian and nihilistic monism (namely, their insistence that nothing exists in and of itself, and independently of any minds and their responses, but the world as a whole). In any case, it is less important what we call the view than what the view is, and I hope it is clear by now what the view is. One thing I have not commented on is the relationship between Kantian monism and Kant's own metaphysics. I have not commented on this because I intend the term 'Kantian' mostly suggestively-to intimate a central dimension of mind-dependence-rather than exegetically. Nonetheless, there are surely interesting connections between Kantian monism and Kant's own metaphysical system, especially understood in light of the so-called one- existence, is entirely unproblematic. It is just that, although certainly initially puzzling, it is at least intelligible. 19 This means that NNM above is only a first approximation of non-nihilistic monism, because it does not impose this objectivity requirement. Kantian Monism 37 world interpretation (see Allison 1983, and especially Allais 2004, 2007).20 The matter is tremendously complex, of course, but one can envisage a view according to which the medium-sized objects we live among are mind-dependent 'phenomenal' objects, while the world as a whole is a 'noumenal' object we know nothing of except that it exists and is responsible for our experience of the phenomenal objects. Such a view would be very similar to both Kantian monism and Kant's own metaphysics. The question about Kantian monism that I wish to focus on here is not how Kantian it is, but how plausible. In Section 2, I offer some reasons to prefer Kantian monism over the alternatives. None of the reasons are intended as demonstrative arguments, arguments whose conclusion is strictly necessitated by their premises. Rather, they are intended as plausibility considerations that collectively generate converging lines of evidence in favor of Kantian monism. Note well: I will not argue here that Kantian monism is plausible; merely that it is more plausible than other versions of monism. Whether it is also more plausible than various versions of pluralism is something I will not touch on. Thus my thesis can be thought of as a conditional: if we adopt monism, it is specifically Kantian monism that we should adopt. 2. Kantian Monism: Argumentation Below, I discuss three theoretical virtues essential to the evaluation of the relative merits of versions of monism. Most importantly, in Section 2.1 I argue for the superiority of Kantian monism along one dimension of explanatory depth: it explains better the fact that the world is structured. I then argue, in Section 2.2., that it is also well-positioned to score especially high in terms of conservatism. Finally, I argue in Section 2.3 that it does not score lower on parsimony. 20 On this interpretation, Kant's noumenal/phenomenal distinction is not a distinction between two realities, but between two aspects of one and the same reality. 38 Uriah Kriegel 2.1. Structure The first argument is that Kantian monism has the best monistic explanation for the world's having structure.21 In general, pluralism has a much more straightforward explanation of structure than monism. Consider a world that looks like this: The pluralist has a straightforward explanation of this world's structure: the world has two parts, call them Jimmy and Johnny, and Jimmy is black while Johnny is white. Thus the structure of the world arises from the character of its parts. This explanation is obviously unavailable to the nihilistic monist, since she denies that the world has parts, and therefore cannot admit Jimmy and Johnny into her ontology. More interestingly, this explanation is also unavailable to the non-nihilistic monist, even though the latter can admit Jimmy and Johnny. The reason for this is that explaining the properties of the world in terms of the properties of its parts gives explanatory priority to the parts, whereas the monist insists on the ontological priority of the world. This is problematic, because the explanation in question is precisely ontological explanation: it is not causal explanation, but what we might call constitutive explanation.22 It is 21 How to elucidate the notion of structure is something I am unsure about, and so leave intuitive here. 22 The notion of ontological or constitutive explanation is not a straightforward one to elucidate, but it is pervasive in metaphysics and metaphysicians know it when they see it. Consider Armstrong's (1978) classic argument for universals. The argument is that we need Kantian Monism 39 extremely odd, borderline incoherent, to claim that A is ontologically prior to B but nonetheless that the properties of B ontologicallyconstitutively explain those of A. If we are told that the properties of non-basic objects cannot be explained in terms of the properties of basic objects, and moreover that the properties of non-basic objects explain the properties of basic objects, we start losing our grip on the alleged basicness of the basic objects.23 There are, however, four possible monist explanations of the world's structure.24 A fifth approach is to simply deny the datum: claim that a world such as the one above has no structure. I will assume that this is a last resort, a view to be adopted only if no remotely plausible explanation of that world's apparent structure can be offered. The first monist explanation of the world's structure is in terms of what I will call holistic spatial properties. Recall that monism comes in two varieties, depending on whether occupation is identity. If occupation is identity, then the world is identical to space-time. If occupation is not identity, then the world merely 'fills' space-time but is not identical to it. A monist of the first variety is ipso facto a monist about space-time, but a monist of the second variety can be a pluralist about space-time. This second type of monist could explain the above world's structure as follows: although that world may have no parts, the space-time it occupies does have parts, its top half and its bottom half, and the top half is black while the bottom half is white. More generally, the structure of any world can be explained in terms of the properties of parts of the to posit universals to explain the objective similarity among concrete particulars. The explanation here is clearly not causal or scientific, but the kind of explanation I am referring to as constitutive or ontological. 23 This is probably why Trogdon (2009a) formulates monism precisely as the thesis that the properties of the world's proper parts are 'grounded' in the properties of the world. The relevant grounding relation is presumably the relation that ontological explanations target (try to describe). 24 The first three explanations are sketched by Schaffer (2007b). To my mind, none of the four I will consider is as good as the pluralist explanation-none is as simple, conservative, etc.-and that is certainly a strike against monism. The claim of monists must be that other advantages of monism compensate for its disadvantage in explaining the world's structure. 40 Uriah Kriegel space-time the world fills. Let us say, when a world occupies space-time part P which has property F, that the world has the property of being Fat-P. For example, the above world has the properties of being black-ontop and being white-in-bottom. Properties of this kind-properties of the form being F-at-P-are what I call holistic spatial properties. The present suggestion is to explain the structure of the world in terms of the world's holistic spatial properties, which are grounded in the properties of parts of the space-time the world occupies.25 This is a reasonable explanation. The holistic spatial properties posited are not particularly queer, and their positing does explain what it attempts to explain. There are four related liabilities associated with it, however. First, it commits one to the view that occupation is not identity, which is controversial. Thus, in defending a monism that identifies the world with space-time, Schaffer (2009) makes this explanation unavailable to him. It would be better for the monist if she could be free of commitments on the occupation relation. Secondly, in denying that occupation is identity, the monist increases her overall ontological commitment; this is bound to be vexing to the monist, who more than the pluralist is temperamentally attached to the value of parsimony. Thirdly, in explaining structure in terms of the properties of space-time, it commits to space-time being an eligible bearer of many properties it would otherwise seem only occupiers of space-time can bear (e.g., color). Fourthly and most importantly, there is something a little odd about combining monism about objects with pluralism about the space-time they occupy, especially when much of the explanatory work turns out to be done by the pluralist part of the package.26 It should be disconcerting to learn that if a metaphysician decides to adopt monism about objects, then she must also adopt pluralism about space-time to compensate for 25 This seems to be the explanation embraced by Horgan & Potr (2008). 26 Pluralism about space-time would be the view that space-time points are ontologically prior to space-time as a whole. (This is needed if the properties of the space-time as a whole-the holistic spatial properties-are explained in terms of the properties of spatiotemporal points, as is the case in this first monist explanation.) Note that pluralism about space-time is not the view that there are many overall space-times. Kantian Monism 41 the explanatory losses implicated in her monism about objects. Indeed, the fact that all the explanatory heavy-lifting is done by the pluralism about space-time, makes the monism about objects lose much of its initial luster. A second explanation is in terms of a relativized instantiation relation. The main idea is that the instantiation relation between an object and its properties does not hold absolutely, but only relative to part of the space-time occupied by the object. Thus, where the first explanation of the above world's structure is that the world is black-on-top and is whitein-bottom, this second explanation is a little different: that the world ison-top black and is-in-bottom white. This explanation, too, requires denying that occupation is identity, and adopting pluralism about spacetime. But instead of relativizing certain properties to regions, it relativizes the instantiation relation to regions. To my mind, this explanation is considerably worse than the first. It retains all four liabilities, and suffers from the additional one that while holistic spatial properties are not particularly queer, the relativized instantiation relation posited in this one certainly is. A third monist explanation of the world's structure is in terms of what Parsons (Ms) calls distributional properties. Distributional properties are akin to holistic spatial properties, except that they are not analyzable in terms of properties of parts of the occupied space-time. Parsons argues that the property of being polka-dotted red on white, for example, cannot be reduced to the property of having certain red parts and certain white parts spatially related to each other in certain ways. Rather it is a sui generis property of the whole polka-dotted object. I will consider Parsons' argument for this momentarily. But if we do accept the existence of such sui generis properties, those are distributional properties, and they are different from holistic spatial properties. These distributional properties then afford a third way to explain the structure of the above world: it simply has the right black-cum-white distributional property. It is natural for us to describe this distributional property in natural language by saying that the world is black-topped-and-white42 Uriah Kriegel bottomed, that is, in terms of spatial relations among parts. But we should do so with caution, as natural language is somewhat misleading here, insofar as it uses terms that are naturally interpreted as denoting parts of the world, whereas the appeal to distributional properties is precisely supposed to spare us the need to refer to such parts. In many ways, then, it would be preferable to introduce a new, simple predicate for the relevant distributional property-being 'borlish,' say-that would designate it directly in a way that would make its status as a primitive property more manifest. We could then explain the world's structure by saying that the world is borlish.27 This explanation has some advantages over the explanation in terms of holistic spatial properties, in that the monist can appeal to it regardless of her position on whether occupation is identity. This advantage further helps avoid the other pitfalls of the first explanation: in particular no explanatory work is done by pluralism about space-time. The disadvantage is evident, however: distributional properties are extremely queer. There is no reason to believe that being polka-dotted does not reduce to having suitably shaped parts suitably related; that is, that being polka-dotted is a distributional property rather than a holistic spatial property. Moreover, again it appears that in order to compensate for the explanatory losses incurred by going extra-lean about the concrete world, the monist finds herself forced to beef up elsewhere in her ontology: although most ontologists have no need for distributional properties, the monist does. Parsons' own argument for positing distributional properties seems to me unpersuasive, and I am unaware of any other argument. Parsons' argument proceeds as follows: 1) if being polka-dotted is reducible to having appropriately colored and shaped parts, then necessarily, polkadotted objects are composed of spatiotemporal points; however, 2) it is not necessary that polka-dotted objects are composed of spatiotemporal points; therefore, 3) being polka-dotted is irreducible. There are many 27 This seems to be the explanation embraced by Schaffer (2007a, 2007b). Kantian Monism 43 problems with this argument, the most important of which is this. Contrary to Premise 1, the reduction of being polka-dotted does not require that polka-dotted objects be composed of spatiotemporal points (necessarily or otherwise). It would go through on any scenario in which polka-dotted objects are composed of homogeneous parts (whether extended or point-like). Since the ultimate simples-the objects that have no parts-are plausibly homogeneous (whether or not they are points), it is highly plausible that being polka-dotted is reducible to being composed of simples bearing certain intrinsic properties and certain spatial relations to each other. A fourth explanation of structure would appeal to the aforementioned response-dependent properties, and appropriate one of the above three 'ontological innovations' (if you please). Thus, instead of explaining the world's structure in terms of the world's pattern of holistic spatial properties, it would explain the world's structure in terms of the representation (by the ideal subject under ideal conditions) of the relevant pattern of holistic spatial properties. Instead of explaining the above world's structure in terms of its properties of being black-on-top and white-in-bottom, it would do so in terms of the world's responsedependent properties of being represented-to-be-black-on-top and being represented-to-be-white-in-bottom (or perhaps just being represented-to-be-black-on-top-and-white-in-bottom). This strikes me as by far the best monist explanation of the world's structure. It does not commit to the existence of the relevant properties or relations (the 'ontological innovations' themselves), only to representations of them. Compare: according to Armstrong (1978), there are no uninstantiated properties, so there is no such property as being a dragon; but there clearly are representations of dragons. Moreover, the explanation does not commit to pluralism about space-time, nor to the thesis that occupation is not identity. It thus avoids the battery of liabilities that attend these commitments (and that bedeviled the other explanations). This fourth explanation is clearly particularly congenial to the Kantian monist. Strictly speaking, of course, it is available to all monists. There is 44 Uriah Kriegel nothing preventing Schaffer or Horgan & Potr from adopting this explanation; there is nothing about their brands of monism that precludes the world's having response-dependent properties, including the sort appealed to in this fourth explanation of the world's structure. However, there is something much more natural in Kantian monism availing itself of this explanation. For nihilistic and non-nihilistic monism, every aspect of this explanation would be an add-on that does not flow from, nor coheres seamlessly with, the rest of the theory. For Kantian monism, all the elements needed for the explanation are already present in the theory's claims about what there is. Moreover, the elements of the responsedependent explanation motivate the Kantian monist position on what there is, whereas they do not motivate other monist positions on what there is. At bottom, the key difference is that this explanation creates a direct link between what Kantian monism says about what exists and what it says about why the world has structure, a link completely missing in the other varieties of monism that would avail themselves of this explanation. Yet the link ought to be expected: surely the structure of the world is not entirely divorced from what entities there are in it. If all this is right, then we have on our hands an argument by inference to the best explanation in favor of Kantian monism. The argument starts from the observation that the world has a certain structure, and that this calls for explanation. The world's structure is thus treated as an explanandum. It is then claimed that Kantian monism offers the best monist explanans. From this it is concluded (nondemonstratively, of course) that Kantian monism is the most plausible version of monism. In other words: 1) The world has structure; 2) Kantian monism has the best monist explanation of the world's having structure; therefore, 3) Kantian monism is the most plausible monism (other things being equal). 2.2. Conservatism In forming new beliefs, whether ontological or other, it is often thought epistemically responsible to make the least necessary departure from Kantian Monism 45 established beliefs. This is the theoretical virtue sometimes called 'conservatism' (see Quine and Ullian 1970). The more one has to revise one's overall theory of the world in order to accommodate some new material, the less conservative the resulting theory. In this section, I want to argue that Kantian monism is more conservative than nihilistic monism and as conservative as non-nihilistic monism. It is possible, of course, to deny that conservatism is particularly virtuous or valuable, in this area or in theory choice generally. This matter is too vast to delve into here. My discussion here will be limited to the question of how conservative the varieties of monism are, and will not comment on the question of how important it is for them to be conservative. When evaluating the three versions of monism for conservatism, it is important to get clear on what the established beliefs are. Since there is no expert consensus in this area, the only established beliefs are those of pre-philosophical, commonsense theory-'folk ontology.' Folk ontology seems to admit the following kinds of concrete objects: the world, subatomic particles, and some but not all chunks of the former and pluralities of the latter. Thus, it countenances some natural mediumsized objects, such as pebbles and zebras, and some artifactual ones, such as chairs and laptops, but does not countenance arbitrary fusions of such medium-sized objects, such as that of a zebra and a laptop. Evaluating the three varieties of monism for conservatism involves considering which departs the least from this kind of view. It might be objected that in fact there is an established mereological theory among experts, namely, so-called classical mereology (see Le niewski 1916). However, classical mereology is a formal theory, not an ontological one. Consider the common distinction between pure and applied mathematics. As pieces of pure geometry, Euclidean and Riemannian geometries are on a par: they are both consistent and complete, and neither is truth-apt. (In virtue of being purely formal systems, they have a syntax but no semantics, and hence are not semantically evaluable as true or false.) But as applied geometry, 46 Uriah Kriegel Riemannian geometry is true and Euclidean geometry is false, because as a matter of empirical fact, our world's space has the structure described in Riemannian but not Euclidean geometry. A similar distinction between pure and applied mereology ought to be drawn. As a piece of pure mereology, classical mereology is consistent and complete, but not truthapt. Interpreted as applied mereology, classical mereology will be truthapt, but no consensus will surround it. In particular, controversy will stalk its axioms of extensionality and unrestricted composition.28 Thus as far as applied mereology is concerned, there is no expert consensus theory for monists to conserve. The only theory they can hope to conserve is therefore that implicit in folk ontology. Now, some ontologists have argued that folk ontology is a bad theory, because it is committed to the existence of worldly vagueness (Lewis 1991; Sider 2001). Others have argued that worldly vagueness is not such a terrible thing to be committed to (Smith 2005). There is no need to enter this debate here. For what is at stake in it is how much weight to give to the theoretical virtue of conservatism. If folk ontology is a bad theory, then conservation of its verdicts in a mature ontology should not be of great value. If it is not a bad theory, then it might be of significant value. As noted above, however, my claim in this section is that Kantian monism fares well with respect to conservatism. Whether this is a major asset for Kantian monism or a minor one (or none at all) is something I do not comment on. Nihilistic monism seems to fare worst when it comes to conservatism, since it denies the folk view that there are medium-sized objects-as well as particles! It is natural to develop the view as committed to an error theory about folk ontology: folk-ontological beliefs are by and large false. This would be to concede that nihilistic monism fares poorly with respect 28 The axiom of extensionality says that if A and B have the same parts, then A=B. Thus it commits one to the identity of the statue and the clay, a highly controversial matter given the apparent difference in modal properties between them. The axiom of unrestricted composition says that for every plurality of objects, there is another object that is identical to their fusion. Thus it commits one to mereological universalism, obviously a very controversial thesis. Kantian Monism 47 to conservatism. Perhaps because of this, Horgan & Potr dedicate much of their defense of nihilistic monism to developing semantics for ontological statements that would make folk statements come out true. They develop 'contextual semantics' according to which a sentence such as 'there are tables' is false in the context of ontological inquiry but true in the context of everyday discourse (see especially Horgan & Potr 2008 Chapter 3). I will now argue against this move. While it is not entirely clear exactly how this is all supposed to work, presumably the thought is that 'there are tables' expresses one proposition in the context of ontological discussion and another in the context of everyday conversation, and the former proposition is false whereas the latter is true. It seems clear, in addition, that the proposition Horgan & Potr take 'there are tables' to express in ontological contexts is the same proposition that ordinary competent English speakers naturally and pre-reflectively take it to express in every context (including everyday contexts). The question is what the proposition is that Horgan & Potr take 'there are tables' to express in everyday contexts. There are several ways to go here, but the one Horgan & Potr (2006) mention sympathetically is problematic, and for reasons we have already seen. According to them, the proposition expressed by 'there are tables' in everyday contexts is the proposition (most competent English speakers would express by saying) that the world has the right (i.e., table-related) 'maximal cosmos-instantiable property.' This is, in effect, the proposition that the world has the relevant tablish holistic-spatial or distributional property. As we saw in Section 2.1, however, this is problematic in a variety of ways. The nihilistic monist would probably do better to adopt a fictionalist story about propositions expressed in everyday contexts. On this account, the relevant proposition is (what we would express in ontological contexts by saying) that in the pluralist fiction, there are tables. This notion of pluralist fiction would need developing, but see Sider 2008 for an impressive start. Although a full discussion of the matter would take us too far afield, it may well be that the combination 48 Uriah Kriegel of contextual semantics and fictionalism about propositions expressed in everyday contexts will accommodate folk ontology. The suggestion still faces a major problem, however. It is that in order to avoid an error theory about folk ontology, the nihilistic monist finds herself cornered into adopting an error theory about folk semantics. For on her view, the folk's beliefs about what their utterances mean in everyday contexts are by and large false.29 The folk believe that by 'there are tables' they mean (what we would express in ontological contexts by saying) that there are tables. But according to the nihilistic monist, the folk are in error here. What they actually mean by 'there are tables' is (what we would express in ontological contexts by saying) that in the pluralist fiction, there are tables. The folk's only true beliefs about the semantics of their own utterances pertain to some (but not all) of their utterances about the world as a whole.30 It is not clear to me that folk ontology is more important to conserve than folk semantics, but it is in any case instructive that the nihilistic monist is unable to conserve both. Somewhere in her system there is going to be non-conservative vice. In contrast, non-nihilistic and Kantian monists can, under certain presuppositions, conserve both folk ontology and folk semantics. Recall that non-nihilistic monism comes in two varieties: restrictivist and universalist. Universalist monism actually fails to accommodate folk ontology: in accepting universal decomposition, it commits to the existence of arbitrary 'decomposites,' such as the chunk of the world consisting in my laptop and the moon. However, restrictivist monism can accommodate folk ontology, depending on how exactly it restricts decomposition. As for Kantian monism, whether it accommodates folk ontology depends on how much the ideal subject's partition of the world would diverge from the folk's. The less it diverges, the more conservative 29 I am assuming here that what utterances mean is what propositions they express. Clearly, the folk do not have beliefs about an expressing relation between utterances and propositions. But they do have beliefs about what utterances mean. 30 For example, 'the world contains tables' does not, when uttered in everyday contexts, mean what the folk believe it means. But 'the world is big' does. Kantian Monism 49 Kantian monism is. It is hard to make strong claims about such speculative matters, but as I argued in Section 1.3, the ideal subject is likely to partition the world roughly along the same lines as the folk, probably with local improvements strewn about.31 I conclude that, under reasonable suppositions (restricted decomposition and sufficiently widespread folk-ideal convergence), nonnihilistic and Kantian monism fare well in terms of the theoretical virtue of conservatism. Does one of them fare better than the other? If it turns out that the folk's carvings diverge meaningfully from the ideal subject's, then non-nihilistic monism, in the right restrictivist version, would conserve folk ontology better than Kantian monism. To the extent that Kantian monism's prospects for conservation are beholden to a supposition restrictivist monism is not (the supposition of widespread folk-ideal convergence), restrictivist monism is positioned better. However, being in a position to do better along this dimension is not quite the same as actually doing better. For that, some reason would actually have to be adduced that the ideal subject's carving of the world would diverge meaningfully from the folk's. Moreover, presumably the relevant version of restrictivist monism would require an objectivist account of decomposition that returned results that converge with folk ontology. As is well known, however, this is not at all easy (van Inwagen 1990).32 It might be claimed that the restrictivist version of non-nihilistic monism is more conservative in another respect, namely, that it adheres to an objectivist decomposition of the world. On this suggestion, the very 31 Recall that what distinguishes the ideal subject from the folk are her much richer knowledge of the world's non-decompositional properties and her immunity to the folk's inferential imperfections. It is unclear why these features might make her avoid partitioning the world into tables, for example, or make her partition it into fusions of tables and the moon. 32 Markosian (1998) proposes that brute facts about composition just make it the case that folk mereology is broadly right. In the same vein, a restrictivist monist could appeal to brutal decomposition to account for convergence with folk mereology, but I hope it is clear that there is something unsatisfying about obtaining the convergence in this heavy-handed manner. 50 Uriah Kriegel fact that according to Kantian monism tables and butterflies exist only in a responseand hence mind-dependent way already puts Kantian monism in tension with the folk. However, judging by the sway that the 'cookie-cutter metaphor' holds with my undergraduates, it seems to me far from clear that the folk are wedded to an objectivist mereology. The metaphor suggests a picture of the world as an amorphous whole, a whole that does not have a structure in and of itself and awaits a sentient subject's carving or partition. The educated public is commonly fascinated by popular-scientific stories about cultural relativity in worldcarving, which relativity it often takes to demonstrate the lack of any objectivity in such matters. This cultural relativity is most conspicuous for properties (e.g., stories about the proliferation of terms for snow among the Inuit or paucity of number terms among the Pirahã), but also extends to individuation of concreta across temporal, spatial, and mereological variation (as in, e.g., the Tibetan belief-as I understand it-that the Dalai Lama has been one token-identical person since the bodhisattva Avalokite vara, perhaps earlier). It seems a common enough attitude among educated laypersons that belief in an objective structure of the world is a sign of naïveté and indicates dogmatism and cultural chauvinism. The cultural variation in conceptions of the architecture of reality is taken to undermine any such objectivity. My concern here is not with whether this bit of reasoning is a good one; merely with whether it is prevalent. I contend that it is prevalent enough to make it implausible to hold that there is a clear commitment to objectivism built into folk ontology as such. I conclude that nihilistic monism faces a conservative deficit relative to non-nihilistic and Kantian monism, and that the latter two are equally conservative, at least pending a reason to expect ideal subjects to carve the world very differently from the folk. This provides a third plausibility consideration for preferring Kantian monism over nihilistic monism, though not one for preferring it over non-nihilistic monism. Kantian Monism 51 2.3. Parsimony It might be objected that, regardless of how it fares along other dimensions, Kantian monism is clearly less parsimonious than nihilistic monism, and parsimony is the queen of virtues when it comes to ontology. After all, Kantian (like non-nihilistic) monism posits parts of the world whereas nihilistic monism does not. However, in assessing relative parsimony we should appreciate the variety of principles of parsimony available in theory choice. Schaffer (2007b) suggests that nihilistic monism may not be more parsimonious than his non-nihilistic variety, because his non-nihilistic variety adds to one's ontology only derivative entities, which are plausibly an 'ontological free lunch.' Different reasons might be adduced as to why derivative (i.e., non-basic) entities are an ontological free lunch. One thought is that their existence is necessitated by the existence of other entities. We might say, metaphorically, that God would not have to perform an extra act of creation in order to ensure that they exist, indeed could not prevent their existence given the acts of creation he had already performed. On this basis, we may suggest, with Schaffer, that the truly compelling principle of parsimony is not 'do not multiply entities without necessity,' but 'do not multiply basic entities without necessity.' Since both nihilistic and non-nihilistic (as well as Kantian) monism posit just one basic object, Schaffer concludes that the views are equally parsimonious, or more accurately fare equally well by the lights of the truly compelling principle of parsimony. It might be objected that this defense of Kantian and non-nihilistic monism's parsimony requires the assumption of mereological essentialism (see Van Cleve 1986), which is highly controversial. According to mereological essentialism, an object has its parts necessarily, so that losing or acquiring a part would take an object out of existence and replace it with another, numerically distinct object. The above defense of non-nihilistic monism requires this principle, because it assumes that non-basic entities are necessitated by basic entities within the framework of non-nihilistic monism. For the existence of the world's 52 Uriah Kriegel parts to be necessitated by the world's existence, it would have to be the case that the world could not exist without having the parts that it does. But this kind of mereological essentialism is a substantive and controversial assumption, and it is a major virtue of nihilistic monism, the objector might insist, that its parsimony does not depend on it. In response, I think the non-nihilistic and Kantian monists would do well to admit that the parsimony of their views depends on the truth of mereological essentialism about the world, but deny that mereological essentialism about whole worlds is in any way problematic. Intuitively, a table could lose a particle without becoming a different table. But when we contemplate such a scenario, we do not envision that the lost particle evaporates out of existence, leaving the world with one particle fewer. Rather, we envision that the particle continues to exist elsewhere in the world, starting a life on its own perhaps. If we consider the entire world, with its entire history eternal or not, it becomes extremely intuitive that a world with one particle fewer is simply a different possible world. Thus while mereological essentialism about tables and butterflies is controversial, indeed most probably false, mereological essentialism about worlds is manifestly true. I conclude that it is far from obvious that nihilistic monism fares especially well with respect to the most important principle of parsimony. On the contrary, all three varieties of monism considered in this paper score equally well. 3. Conclusion The purpose of this paper has been twofold. In the first instance, I have been concerned to articulate an approach to the ontology of concrete objects which, despite esthetic appeal and historical pedigree, has seen relatively little play in recent discussions. The approach arises from the marriage of monism about basic objects with Kantianism about non-basic objects. My second concern has been to argue that this is a happy marriage: I have attempted to present a preliminary case for its superiority over other varieties of monism. I have argued that it provides Kantian Monism 53 the best monist explanation of the structure of reality, that it is either more conservative or as conservative as other forms of monism, and that it is no less parsimonious than other forms of monism. A fuller defense of Kantian monism would consider how it fares with respect to other theoretical virtues, and make the case that it is also more virtuous than the many varieties of pluralism.33 University of Arizona theuriah@gmail.com References Allais, L. (2004) 'Kant's One World: Interpreting 'Transcendental Idealism.' British Journal for the History of Philosophy 12: 655-684. Allais, L. (2007) 'Kant's Idealism and the Secondary Quality Analogy.' Journal of the History of Philosophy 45: 459-484. Allison, H.E. (1983) Kant's Transcendental Idealism. New Haven: Yale University Press. Armstrong, D. M. (1978) Nominalism and Realism: Universals and Scientific Realism, Vol. 1. Cambridge: Cambridge UP. Armstrong, D.M. (1997) A World of States of Affairs. Cambridge: Cambridge University Press. Boghossian, P. and J. Velleman (1989) 'Colour as a Secondary Quality.' Mind 98: 81-103. Bohn, E.D. (2009) 'An Argument against the Necessity of Unrestricted Composition.' Analysis 69: 27-31. Cameron, R.P. (2007) 'The Contingency of Composition.' Philosophical Studies 136: 99-121. 33 For comments on a previous draft, I would like to thank Dana Goswick, Will Leonard, Colin Marshall, Carolina Sartorio, Jonathan Schaffer, Kelly Trogdon, and an anonymous referee for Philosophical Papers. For helpful exchanges, I would like to thank Brian Fiala, Terry Horgan, and Sebastian Watzl. I also benefited from presenting the paper at LOGOS in Barcelona and at the University of Miami, and thank the audiences there, in particular Eli Chudnoff, Dan López de Sa, Colin McGinn, Genoveva Martí, David Pineda, Sven Rosenkrantz, Moritz Schulz, Miguel Ángel Sebastián, Nick Stang, and Amie Thomasson. 54 Uriah Kriegel Cameron, R.P. (2010) 'From Humean Truthmaker Theory to Priority Monism.' Noûs 44: 178-198. Elder, C.L. (2007) 'On the Phenomenon of "Dog-Wise Arrangement".' Philosophy and Phenomenological Research 74: 132-155. Goff, P. (ed.) (2012) Spinoza on Monism. Basingstoke: Palgrave-McMillan. Hirsch, E. (2002) 'Quantifier Variance and Realism.' Philosophical Issues 12: 5173. Hirsch, E. (2005) 'Physical-Object Ontology, Verbal Disputes, and Common Sense.' Philosophy and Phenomenological Research 70: 67-97. Horgan, T. and M. Potr (2000) 'Blobjectivism and Indirect Correspondence.' Facta Philosophica 2: 249-270. Horgan, T. and M. Potr (2006) 'Abundant Truth in an Austere World.' In P. Greenough and M. Lynch (eds.), Truth and Realism: New Essays. Oxford: Oxford University Press. Horgan, T. and M. Potr (2008) Austere Realism: Contextual Semantics Meets Minimal Ontology. Cambridge MA: MIT Press. Johnston, M. (1989) 'Dispositional Theories of Value.' Proceedings of Aristotelian Society 63: 139-174. Korman, D. (2008) 'Review of Austere Realism: Contextual Semantics Meets Minimal Ontology.' Notre Dame Philosophical Reviews. Kriegel, U. (2008) 'Composition as a Secondary Quality.' Pacific Philosophical Quarterly 89: 359-383. Le niewski, S. (1916) 'Foundations of the General Theory of Sets,' trans. D.I. Barnett. In his Collected Works, ed. S.J. Surma, J. Srzednicki, D.I. Barnett, and F.V. Rickey. Dordrecht: Kluwer, 1992. Lewis (1991) Parts of Classes. Oxford: Blackwell. Lewis, D.K. (1997) 'Finkish Dispositions.' Philosophical Quarterly 47: 143-158. Miller, K. (2009) 'Defending Contingentism in Metaphysics.' Dialectica 63: 23-49. Parsons, J. Ms. 'Distributional Properties.' (Unpublished Manuscript). Pettit, P. (1991) 'Realism and Response-Dependence.' Mind 100: 597-626. Potr , M. (2003) 'Blobjectvisit Monism.' in A. Baechli and K. Petrus (eds.), Monism. Frankfurt: Ontos Verlag. Quine, W.V.O. (1960) Word and Object. Cambridge MA: MIT Press. Kantian Monism 55 Quine, W.V.O. and J.S. Ullian (1970) The Web of Belief. New York: Random House. Rosen, G. (2006) 'The Limits of Contingency' in F. MacBride (ed.), Identity and Modality. Oxford: Oxford University Press. Rosen, G. and C. Dorr (2002) 'Composition as a Fiction.' In R. Gale (ed.), The Blackwell Guide to Metaphysics. Oxford: Blackwell. Ryle, G. (1949) The Concept of Mind. London: Hutchinson & Co. Sider, T. (2001) Four-Dimensionalism. Oxford: Oxford UP. Sider, T. (2007) 'Against Monism.' Analysis 67: 1-7. Sider, T. (2008) 'Monism and Statespace structure.' In Robin Le Poidevin (ed.), Being: Developments in Contemporary Metaphysics. Cambridge: Cambridge University Press. Schaffer, J. (2007a) 'From Nihilism to Monism.' Australasian Journal of Philosophy 85: 175-191. Schaffer, J. (2007b) 'Monism.' Stanford Encyclopedia of Philosophy. Schaffer, J. (2009) 'Space-time the One Substance.' Philosophical Studies 145: 131148. Schaffer, J. (2010a) 'Monism: The Priority of the Whole.' Philosophical Review 119: 31-76. Schaffer, J. (2010b) 'The Internal Relatedness of All Things.' Mind 119: 341-376. Sidelle, A. (2002) 'Is There a True Metaphysics of Material Objects?' Philosophical Issues 12: 118-145. Sider, T. (2008) 'Monism and Statespace Structure.' In R. Le Poidevin (ed.), Being: Developments in Contemporary Metaphysics. Cambridge: Cambridge University Press. Sider, T. Ms. 'Against Parthood.' Simons, P.M. (2003) 'The Universe.' Ratio 16: 237-250. Smith, N.J.J. (2005) 'A Plea for Things that aren't Quite All There: Is There a Problem about Vague Composition and Vague Existence?' Journal of Philosophy 102: 381-421. Trogdon, K. (2009a) 'Monism and Intrinsicality.' Australasian Journal of Philosophy 87: 127-148. Trogdon, K. (2009b) 'Physicalism and Sparse Ontology.' Philosophical Studies 143: 56 Uriah Kriegel 147-165. Van Cleve, J. (1986) 'Mereological Essentialism, Mereological Conjunctivism, and Identity through Time.' Midwest Studies in Philosophy 11: 141-156. Van Cleve, J. (2007) 'The Moon and Sixpence: A Defense of Mereological Universalism.' In T. Sider, J. Hawthorne, and D.W. Zimmerman (eds.), Contemporary Debates in Metaphysics. Oxford: Blackwell. van Fraassen, B.C. (1995) '"The World" is not a Count Noun.' Noûs 29: 139-157. van Inwagen, P. (1990) Material Beings. Ithaca: Cornell University Press. Varzi, A.C. (2006) 'The Universe among Other Things.' Ratio 19: 107-120. Wright, C. (1992) Truth and Objectivity. Cambridge MA: Harvard UP.