A DOGMA OF METAPHYSICAL REALISM David Leech Anderson (Illinois State University) Penultimate Draft (Published in American Philosophical Quarterly 32 (1), January 1995, pp. 1-11. Website: http://www.press.uillinois.edu/journals.php) There is an assumption about metaphysical realism that is well-nigh universal. Descartes and Locke were committed to it; virtually all contemporary metaphysical realists embrace it; even skeptics and antirealists accept it. The dogma is this: If one is a metaphysical realist about the external world, then one ought to be a semantic realist about (all) external-world statements. Of course metaphysical realism does not entail unqualified semantic realism. Yet it is universally assumed that if one has good reason to be an ontological realist about the external world, then one gains thereby good reason for being a semantic realist about all external-world statements. But on what grounds? Neither the fact that there exists a mind-independent table nor even the fact that I am capable of grasping realist truth-conditions and thus am capable of believing in a mind-independent table demonstrates that my every utterance of a "table"-statement is a claim about a mind-independent table. Some further semantic argument is required. Most realists, I suspect, embrace the dogma not because they are in possession of such an argument, but simply because the doctrine is rarely if ever challenged. There is, however, good reason to challenge it. There is good reason to believe that most of our statements about the external world require an antirealist interpretation, even if metaphysical realism is true and even if speakers believe it to be true. While metaphysical realists must interpret some statements realistically, they should be semantic antirealists about most external-world statements. In what follows, metaphysical realists will be shown first how to be (limited) semantic antirealists and then why they should be so. I Metaphysical (or ontological) realism is a theory about the ultimate metaphysical nature of the external world. Some reserve the name, "metaphysical realism," for the modest doctrine that there is a reality (of some sort) that exists independently of the epistemic perspective of human beings.1 In this discussion, however, it will refer to the following, stronger ontological claim: our experiences of the external world are (for the most part) caused by mind-independent objects that possess, as part of their intrinsic nature (and not as mere artifacts of our epistemic faculties), many of the properties that we commonly attribute to them. Metaphysical realism so construed is an ontological doctrine, and it is not dependent upon the truth of any semantic theory. However, if anyone is going to believe that metaphysical realism is true, semantic realism must be presupposed in the following way: it is not possible to be a metaphysical realist about the external world unless one is able both to understand and to believe certain statements that assert the existence of objects in the external world-statements that are interpreted realistically. That is to say, the statements must in fact have realist truth-conditions, even though the metaphysical realist herself need not believe that they do so. There are those who have challenged this assumption, insisting that one could be a metaphysical realist even if no statement has realist truth-conditions.2 This is a mistake. To be a realist it is not 2 enough merely to believe in tables, trees, and mountains. Even antirealists believe in such things. It is also necessary that the statements expressing one's belief in those objects have realist force. As I am using the terms here, the distinction between realist and antirealist truth-conditions is intended to capture the rough-and-ready distinction between (i) how things stand with respect to ultimate ontology and in particular the non-human world (e.g., there exists a mind-independent tree) and (ii) how things stand with respect to the epistemic situation of human beings (e.g., there is and will continue to be in the long run non-defeated evidence-visual, tactile, microscopic. etc.-of a publicly accessible "tree"). A statement is interpreted realistically if it asserts a claim about how things are independent of the epistemic perspective of human beings; a statement is interpreted antirealistically if it makes a claim about what is epistemically justified (ideally and in the long run) from the perspective of human beings.3 Knowing that I will succeed in being a metaphysical realist about the external world (e.g., about the tree in my backyard) only if my language has the resources to express realist claims, I must then assume that there are at least some statements about the external world (e.g.. some "tree"statements) that have realist truth-conditions. But must I be a realist about all external-world statements? Given the sophistication of contemporary debates about realism and antirealism, one might suspect that this would be a controversial question. After all, it is common for people today to be realists about one domain of discourse and antirealists about another: One might be a realist about the external world and an antirealist about theoretical entities and character traits; or one might be an antirealist about the external world and a realist about moral facts. Yet, with all these choices, most people assume they are limited by the following constraint: Each domain of discourse identified by a single ontological category (e.g., external-world statements, theoretical-entity statements, moral statements, character-trait statements, "electron"-statements, "tree"-statements, what have you) will be governed by a single, broad theory of meaning.4 It is widely held. then, that the semantic theory that governs our talk of middle-sized objects is monistic. Whenever I speak of this table in the study-whether to tell my daughter to move it so that I can vacuum the carpet beneath or to tell a student that it is a mind-independent table (as I strike it with my fist)-it is assumed that the term "table" makes the same semantic contribution in each case. Philosophers may trade in neologisms like the "phenomenal-table" and the "table-in-itself" but the term "table," when unadorned and employed to speak of that object which is holding up my computer, has but one basic meaning. The task of the philosopher, it is assumed, is to determine which it is. Thus, while there is considerable controversy about which semantic theory (if any)5 is the correct one, there is virtual unanimity that the true theory will be monistic. This commitment to semantic monism plus the metaphysical realist's need to interpret some statements realistically leads inevitably to universal semantic realism (i.e.. the view that all external-world statements should receive a realist interpretation). 3 However obvious semantic monism may seem, semantic pluralism can hardly be ruled out in advance of considerations of our actual linguistic practice. Given the way we use such statements, it is at least possible that some "tree"-statements have realist truth-conditions and others have antirealist truth-conditions. Yet the presumption in favor of semantic monism must remain strong until some version of semantic pluralism is shown to be at least remotely plausible. Thus, the first, modest objective of this paper is to show that, if semantic realism is coherent (contra Dummett and Putnam), then it is at least possible that a natural language be semantically dual. By possible, here, I mean simply that there is a possible world, a not too distant neighbor of the actual world, in which the inhabitants speak a language that is dualistic in this respect: all middle-sized-object statements receive one of two syntactic markers specifying which of two distinct interpretations-realist or antirealist-is in force. It is, then, (at least presumably) at the speaker's discretion whether she makes a realist or an antirealist claim with any given "tree"-statement. If this example is successful, then the reader should admit this much: that were she an inhabitant of that world, the language she speaks would be syntactically dual. If the reader is herself a metaphysical realist, and thus convinced that human beings have the capacity to grasp realist truth-conditions, then she should admit even more: that the language she would speak in that world would be genuinely semantically dual. II Welcome to the Land of Subscript, a fascinating place where people speak a curious language, EnglishSUBSCRIPT (or EnglishS, for short). The Land of Subscript is virtually identical to Great Britain in the actual world. It is located in WS, a possible world that so closely neighbors the actual world (Wα) that it has, for most of its history, been indistinguishable from it. For example. John Locke and Bishop Berkeley were eighteenth century inhabitants of both WS and Wα and published exactly the same works with the same publication date in both worlds. The complete history of each of the two worlds is indistinguishable from the other up until a point late in the eighteenth century when a social phenomenon arose in WS which is absent in Wα. For reasons still largely mysterious, the entire population of Great Britain, in WS, became obsessed with philosophy, primarily metaphysics and epistemology. Philosophical debate became a national pastime, fashionable as diversionary entertainment-metaphysics purveyed as pop-culture. In the late eighteenth century of the actual world, the baker and the blacksmith rarely spent their leisure time arguing the merits of Berkeleyan idealism; in the Land of Subscript, they did. Metaphysics and epistemology were discussed alongside politics and the weather at the local pub. Of particular note, the population became embroiled in a lively dispute regarding the ultimate nature of the external world. Deep divisions arose as people took sides defending competing metaphysical theories. Most citizens were committed to one of three popular ontologies: (i) Metaphysical Realism =DEF Mind-independent objects are the immediate cause of human experiences of middle-sized objects. Middle-sized objects genuinely possess all or most of the properties that we attribute to them. 4 (ii) Theocentric Idealism =DEF The interaction of God's mind with human minds is the immediate cause of human experiences of middle-sized objects. (This is, roughly, Berkeley's view that "chairs" and "tables" are mental entities.) (iii) The BIV Hypothesis =DEF We all are and always have been brains in a vat, à la Hilary Putnam's famous description.6 Our present experiences are caused by a computer that is stimulating our disembodied brains. Metaphysical realism was, not surprisingly, the most popular alternative embraced by philosophical dilettanti in WS-1800. Yet, there were also vocal advocates for Berkeleyan idealism and, while the appeal of the BIV hypothesis is hard to see, it too was defended by a small yet quite visible minority of hearty souls. There existed, then, nothing like a consensus-e ven among lay people-regarding the ultimate ontological explanation for our commonly shared experiences of kittens and kiwis and other middle-sized objects of common sense. People from all stations of life actually did spend time arguing about whether Aunt Martha's cat, Tabby, is nothing more than a thought in the mind of God. In this climate metaphysical arguments were difficult to avoid. Just as in the actual world, where any assertion regarding the ethics of abortion may incite an argument, so too British citizens in WS-1800 were equally quick to fight about questions of ultimate ontology. Any public expression of a metaphysical commitment invited serious disputation; unless one was prepared for a heated argument it was best to avoid making such claims. In one important respect, however, the dispute over ultimate ontology in WS is different from the abortion debate. With abortion, one can avoid controversy simply by resolving never to utter statements which express any commitment on the issue. When discussing the physiology of pregnancy, for example, one may use a neutral term like "fetus" instead of inflammatory phrases like "unborn child" or "mass of fetal tissue." The same strategy is not so easily implemented for proponents of metaphysical realism in WS. The problem is this: most metaphysical realists in the eighteenth century (and today, for that matter)-in both WS and Wα-are also semantic realists about external-world statements. An eighteenth century Cartesian in WS will, like Descartes, be committed to the view that mind-independent objects are the cause of our present middle-sized object experiences, but she will also hold that statements about middle-sized objects are to be interpreted realistically, and thus, that every statement about a chair or table, a kitten or kiwi will be a controversial claim about the mind-independent existence of those objects. A realist follower of Descartes or Locke making an innocent comment like, "Tabby is in the kitchen," would be interpreted as asserting the existence of a mind-independent object, which would lead to a heated debate about the truth of metaphysical realism. Thus, a seemingly intractable dilemma for realist inhabitants of WS: given a commitment to a monistic realist semantics, a metaphysical realist can avoid expressing a commitment to metaphysical realism only by refraining altogether from uttering statements about the objects of common sense-which is an extremely high price to pay for a little philosophical peace and quiet. However passionate one is about one's metaphysical commitments, there are times when it is preferable to disengage from controversies of 5 high metaphysics and to discuss other issues-issues which remain regardless of who is correct about ultimate ontology. To accomplish this, one must be able to escape to the safety of a discourse that simply finesses the question of ultimate ontology. As will soon become apparent, an antirealist interpretation of middle-sized object statements does precisely that. Assume that I am a citizen of Subscript and that I want to make an innocent (non-philosophical) comment about Tabby's prodigious size relative to other housecats on the planet, but Berkeleyan idealists who know my realist convictions interpret my "Tabby"-statement as a denunciation of their position. In such a context, however, I have no interest in denouncing their position. All sides agree that our cognitive and sensible faculties confront us with certain constraints, both operational and theoretical, which warrant the empirical claim "Tabby weighs 42 pounds." Since there is a consensus at the empirical level but not at the level of ultimate ontology, the obvious way to avoid controversy is to talk about the empirical rather than the ontological. After sufficient empirical tests have been made (placing "cats" on scales. etc.), all sides will agree that if the sentence "Tabby weighs 42 pounds" is interpreted antirealistically (i.e., as a strictly empirical claim) it is true. And, if I am arguing with a Berkeleyan idealist about whether Tabby or Fluffy is the heavier cat I obtain the only concession I care about when I get her to admit that "Tabby weighs more than Fluffy" is true on an antirealist interpretation. In this context it is the empirical issue and not the metaphysical one that primarily concerns me. If I were to insist upon a realist interpretation of my utterance, I would shift the focus of the discussion away from the empirical question, thereby changing a normal every day speech context (a context in which claims about "cats" are settled by appeal to empirical evidence) to an explicitly philosophical speech context (where the issue can never he settled empirically-Dr. Johnson's stone-kicking not withstanding). Thus, an utterance with antirealist force (i.e., an utterance about what is empirically justifiable, not about what exists mind-independently) allows me to say what I am most concerned to say without broaching the issue of ultimate ontology. I may wholeheartedly believe that Tabby is a mind-independent object, but expressing that belief will not be my goal in the speech-act that I am now performing. Rather. my intention is to make an empirical claim which (if I am right about Tabby's prodigious size) will be true regardless of the ultimate nature of reality. In a remarkably short period of time, the inhabitants of Great Britain (Ws-1800) saw the practical advantages of being able to restrict everyday claims to the antirealist variety, and the practice of subscripting was born. It became a part of the very grammar of EnglishS that middle-sized object statements require a subscript, either "R" or "A." to indicate whether a realist or an antirealist claim is being expressed. This results in two distinct sentences. "[The cat is on the mat]R" and "[The cat is on the matt]A," which replace the single sentence-type in our version of English. In practice, then, speakers would advance antirealist claims in normal everyday contexts and would advance realist claims only in contexts where questions about ultimate ontology were expressly at issue. Grammar school primers actually taught the following general rule: 6 Semantic Dualism for Middle-Sized Object Statements: Middle-sized object statements (henceforth, "MSO-statements") uttered in normal, everyday contexts will receive an antirealist interpretation and will be true or false in virtue of how things stand with respect to the epistemic situation of human beings (e.g., there is and will continue to be in the long run non-defeated evidence-visual, tactile, microscopic, etc-of a publically accessible "cat." MSO-statements uttered in certain special speech-situations, where the context clearly indicates that a claim is being made about the ultimate furniture of the universe, will receive a realist interpretation and will be true or false in virtue of how things stand with respect to ultimate ontology and in particular the nonhuman world (e.g., there exists a mind-independent cat). Citizens of Subscript, then, were taught to speak a language that has a dual syntactic structure, a language that they assumed to be (genuinely) semantically dual as well. It is interesting to note that as time passed people in Subscript no longer bothered to write down the syntactic markers (i.e., "R" or "A"), since the context almost always made disambiguation a fairly straightforward affair. III To appreciate how EnglishS might be employed in a typical conversation, imagine that you are an inhabitant of WS, that you are committed to the mind-independent object theory (metaphysical realism) and that you have a teenage daughter who, as is common with the younger generation, has gleefully embraced an anti-establishment view of the world: Berkeleyan idealism. Your daughter, call her Katherine, has neglected her responsibility to mow the lawn and you say to her: (1) Katherine. I want you to mow the lawn immediately! Katherine, knowing your commitment to both ontological and semantic realism, says: (2) I am sorry, but I can't. I know that when you say "Mow the lawn" you mean "Mow the mindindependent lawn." Unfortunately, your command cannot he cannot be carried out, by me or anyone else. There exist no mind-independent objects. And I have persuasive arguments to substantiate this claim if only you grant me a few hours to make my case. Now, in the face of this challenge to one's deeply held ontological commitments, one could opt for the totalitarian response and say: (3a) So long as I pay the bills around here I determine questions of ultimate ontology. If I say that there is a mind-independent lawn, then there is-and you had better mow it immediately or you will be grounded! The problem with this alternative is that many will find it unnecessarily draconian. When it comes to the ultimate nature of reality one should teach one's child to seek the truth and be true to her own convictions. It hardly seems appropriate to become an intellectual tyrant just for the sake of getting 7 the lawn mowed. A response that would more likely reflect the intention of most parents would be to say: (3b) I don't care what the ultimate nature of the lawn is. You have an obligation to make this lawn- whatever its ultimate nature-shorter by dinner time. If you don't, you'll he grounded. This last utterance reflects the antirealist bias of "lawn-mowing" discourse in normal contexts and shows how the previous, torturous exchange could have been avoided if only you, the parent., possessed the resources of EnglishS. Wherewith you could have said: (1A) [Katherine. I want you to mow the lawn immediately.]A Here Katherine is being commanded to do something that does not presuppose the truth of any ultimate ontology. She is being ordered to take appropriate action so as to bring about an empirical change, to make it the case that it is verifiable from the human perspective that there is a neat, trim, publicly accessible lawn. This is a command that Katherine can carry out (i.e., she can make it true that [The lawn has been mowed.]A even if Berkeleyan idealism is true. The advantages of (1A) are obvious. First, the parent achieves the desired end: the lawn gets mowed. If it is true that there is a mind-independent lawn, then that lawn will be mowed in the process. However, if Berkeley is right and there exists no mind-independent lawn, the parent is still interested, presumably, in getting a tidier "lawn" at the empirical level. Notice also that the parent's utterance of (1A) in no way constitutes a philosophical compromise. The parent is not denying a commitment to metaphysical realism. In uttering (1A) she is simply choosing to speak about empirical conditions that all sides can agree about rather than to make a contentious claim about realist conditions. Thus, the limited semantic antirealism that is partially constitutive of EnglishS is no threat to metaphysical realism. Semantic antirealism is a threat to metaphysical realism only if it is global. It is arguments (like Dummett's and Putnam's) that none of our statements express realist claims that undermine metaphysical realism: since humans are thereby denied the capacity to believe any statement with realist truth-conditions. In contrast, semantic dualism-which simply adds a layer of antirealist discourse to the realist discourse already assumed to be available-is no threat to metaphysical realism; we retain the resources necessary for believing in mind-independent objects, since there remain statements within the language that are capable of expressing one's belief in a mind-independent lawn (e.g. "[The lawn has been mowed.]R" or "There exists a mindindependent lawn that has been mowed"). IV I am prepared to claim that the version of English that we speak in the actual world is semantically dual, that we ourselves speak EnglishS (absent only the syntactic markers). But what reason does the metaphysical realist have for accepting such a radical claim? What relevance does the Land of 8 Subscript have for settling questions about the semantics of our own language? There is reason to suspect that traditional realists will be little moved by the stories about the Land of Subscript, that they might respond something like this: All right. So the inhabitants of Subscript speak a dualist language. That is because they were in an odd situation in which they were forced to abandon their realist claims by a kind of philosophical terrorism. They changed the nature of their discourse (from realist to antirealist) to avoid unpleasantness. What has that to do with the actual world? There are no such pressures to make us change the force of our utterances. This is not the proper moral to be drawn from the story of Subscript. In saying that the inhabitants changed the meaning of their utterances, our interlocutor is assuming that the meaning of those utterances was realist before the metaphysical disputes arose. This begs the question. I shall argue that the events that precipitated the development of a syntactically dualist language did not change the meaning of normal middle-sized object discourse; it merely forced the inhabitants to get clear about what they had meant all along. Consider the parallel with natural kind terms. Prior to the time that Kripke and Putnam introduced us to their well-chosen counterfactual conditionals, we were in the following situation: we believed that all tokens of the stuff that we call "gold" possess both the superficial properties identified by Locke (i.e., being shiny, yellow, malleable, dissolvable in aqua regia, etc.) and possess some deep, explanatory microphysical property, probably the one identified by our scientists (i.e., having atomic number 79). Never having been forced to think about the matter, we blithely assumed that the definite description theory was true. Twin-earth type thought experiments forced us to choose. We were presented with counterfactual conditionals and we had to decide whether a particular hypothetical stuff-which possessed the same microphysical structure but lacked the superficial properties-did or did not fall within the extension of the term "gold."7 Likewise in Subscript. Prior to the time that the metaphysical disputes arose, metaphysical realists were in the following situation: they believed (at least tacitly) that their normal middlesizedobject statements were true under either a realist or an antirealist interpretation. Never having been forced to choose, they blithely assumed that such statements were governed by a realist semantics. The rabid Berkeleyan idealists forced them to choose, by pressuring them to decide whether certain statements (e.g., "Katherine mowed the lawn") would be true so long as they are epistemically justified (in the long run), even if there exist no mind-independent objects to make them true. The judgment that "Katherine mowed the lawn" is true even if Berkeley is right confirms the antirealist interpretation of the statement. It is easy to misconstrue the foregoing argument. The story about Subscript, of course, cannot settle the question by itself; it is just a story and it may well elicit conflicting intuitions. To substantiate the claim that normal middle-sized-object statements have antirealist truth-conditions, there must be compelling evidence that our actual linguistic practice is consistent with an antirealist interpretation but not with a traditional realist interpretation. The difficulty, of course, is that most sentences will have the same truth-value on either a realist or an antirealist interpretation; every middle-sized9 object sentence that a metaphysical realist believes is true under a realist interpretation she will also (typically) believe to be epistemically justified (ideally and in the long run)-and thus true under an antirealist interpretation. To discover whether the truth of statements in this class really is sensitive to ultimate ontology and not merely to the epistemic perspective of human beings, statements must be found whose truth-values will diverge on a realist versus an antirealist interpretation. As in the case of natural kind terms, the only statements that will do the job are carefully chosen counterfactual conditionals, such as: If Berkeleyan idealism is true, then will Katherine's utterance, "I mowed the lawn?" be true or false?8 Traditional realists have answered, "false." I suggest that competent speakers who are fully apprised of all relevant considerations will agree that the correct answer is "true," for the simple reason that competent speakers do not believe that the truth of such statements is threatened by revolutionary changes in ultimate ontology (so long as what is epistemically justifiable in everyday situations remains unaffected). If our society underwent a Berkelcyan revival and we "discovered" that the ultimate nature of reality is mental rather than physical, we would not say that all our previous "lawn-mowing" statements were false. The truth-value of a normal middle-sized-object statement is simply not sensitive to ultimate ontology. Admittedly, it is true that if I am in a philosophical argument with a professed Berkeleyan and I claim that: (4) Katherine mowed a mind-independent lawn. then that claim will be falsified if Berkelevan idealism is true. But it is obsessively philosophical and a misrepresentation of the meaning of our discourse to insist that in an everyday context Katherine's utterance of (5) I mowed the lawn. will he falsified if Berkeleyan idealism is true. What Katherine says in uttering (5) is simply not sensitive to ultimate ontology. What she says is true regardless of whether Berkeleyan idealism or any other ultimate ontology is true. V It has been argued that normal everyday utterances about middle-sized objects will be true even it Berkeleyan idealism (or the BIV hypothesis, or any other ultimate ontology) is true. If this claim is true, then there is reason to believe that the semantic theory embraced by most traditional realists, a theory we might call universal (traditional) semantic realism, is false. On the other hand, this claim is compatible with semantic dualism, thus giving traditional realists reason to be semantic dualists. There is a weakness in this argument, however. It makes the controversial assumption that semantic dualism offers the only alternative to the traditional semantic view. There are, of course, other 10 alternatives. Of special note is a species of causal semantic realism that rejects the traditional belief that the proposition expressed by a given English sentence is determined primarily by what goes on "inside the head" of competent speakers (i.e., by narrow content). Causal realists believe, instead, that the referent of a middle-sized-object term is determined by whatever it is that causally regulates the use of that term (i.e., by wide content). This is not merely to hold that causal connections are sometimes relevant to determining the referent of a term (a view that many people hold, including myself), rather it is to believe that the reference-relation that bears between a middle-sized-object term and its referent consists in the obtaining of a causal connection of a certain type. Thus for example, in the possible world in which Berkeleyan idealism is true, the term "lawn," bears no causal connection to a mind-independent lawn but presumably to something mental instead (possibly, a thought in the mind of God). On this reading of causal semantic realism, utterances like: (6) Katherine mowed the lawn will remain true even if it turns out that the actual world is a Berkeleyan world because those sentences will (unbeknownst to the speakers) be expressing true claims about God's thoughts.9 Thus, the judgment that (6) is true even if this is a Berkeleyan world, is consistent both with an antirealist and a causal realist interpretation of normal MSO statements. To convince all metaphysical realists to be semantic dualists-even those tempted by this species of causal semantic realism-a further argument is required to show why semantic dualism is to be preferred over the causal theory. A responsible assessment of causal semantic realism, however, is a major undertaking. This is a theory that offers a radical new account of the very nature of cognition. The most that can be offered here is a brief sketch of one feature of causal realism that many metaphysical realists should find unsavory.10 Realists of all varieties typically reject global antirealism (of a Dummettian kind) because it is revisionist, it tells us that certain things we are disposed to think and say, can't be thought or said. For example, global antirealism holds that radical skepticism is incoherent. On this account, the inhabitants of Subscript are deeply confused. They believe that they understand the competing theories of metaphysical realism, Berkeleyan idealism, and the BIV hypothesis; but they are wrong. These theories attempt (unsuccessfully) to exceed the limits of language. All three theories agree about what is verifiable (even in the long run) and they can have no coherent content beyond that. Their dispute is simply incoherent. Many realists will be troubled to discover that causal semantic realism is also revisionist. Causal realism, like global antirealism, ensures that certain skeptical hypotheses will be incoherent, thus determining that we cannot think certain things that we (seem to) find ourselves thinking. Consider Putnam's brains in a vat (BIV) hypothesis. Causal realists typically respond to his argument by agreeing with Putnam's claim that a BIV could not entertain the BIV hypothesis (and thus could not think that it is a WV). But, they insist, we can entertain the hypothesis so long as we are not in fact 11 BIVs (since in that case our sentence "I am a BIV" would express the appropriate skeptical proposition). But this misrepresents the causal realist's position. No one can consistently entertain the possibility that the brains in a vat hypothesis is true of the actual world while also embracing causal semantic realism. The problem is this. First, I must entertain the skeptical hypothesis: S: We all are and always have been brains in a vat. That is, I must conceive of a possible world in which we are BIVs and in which causal semantic realism is true. Next, since I must believe that the actual world is the world just described, I must believe that the cognitive act just performed-my act of believing that S is true in the actual world- is the act of a BIV. Believing that the causal theory is true, however, I must also believe that the cognitive content of my act (of entertaining S) is determined solely by causal relations of a semantically relevant type. Given the BIV hypothesis, the terms "brain" and "vat" in sentence S does nor bear the appropriate causal relation to physical brains and physical vats and so cannot refer to them. Instead, those terms are causally regulated by something else-either the computer hardware or the software or even the subjective character of the experiences themselves. In any case, I cannot consistently believe that the proposition expressed by S is in fact a "skeptical HIV hypothesis." It is impossible to believe that the actual world is a world in which (1) the skeptical BIV hypothesis is true, (2) I am a person who believes the skeptical BIV hypothesis, and (3) causal semantic realism is true. There exists no possible world in which all three are true. (I have an extended discussion of this argument elsewhere)11 Causal semantic realism, therefore, is revisionist for reasons that parallel the revisionism of universal semantic antirealism. With the latter, we are held captive in a prison of verification conditions. With the former, we are held captive in a prison of causal relations. Nothing we do succeeds (or ever could, in principle, succeed) in being the contemplation of that which lies beyond the causal web. If I am a causal realist, then I cannot entertain the possibility that my present beliefs about the external world might be globally false because some Cartesian demon scenario might possibly be true. For even if a Cartesian demon scenario were true, that would not threaten the bulk of my beliefs about the external world. In that case, my external world beliefs would be true beliefs about the demon's thoughts (or the computer software, or what have you); they would not be false beliefs about physical objects. For the causal realist, my beliefs about the external world simply cannot be globally false in a Cartesian way. Either my external-world statements are causally regulated, in an orderly way, by some feature of reality (e.g., by physical objects or the electrical stimulations of a computer or by a demon's thoughts) or they are not. In the former case, the majority of my beliefs will be true beliefs about that feature of reality (whatever it is); in the latter case, my beliefs will have no consistent content and thus will have no truth-value whatsoever. The theory that I have advanced, semantic dualism, is radically different. It does not tell us that we cannot say and think things that we are disposed to think and say. It preserves the traditional 12 resources of realism, granting to speakers the capacity to entertain skepticism of a radical sort. While the dogma that all v1SO-statements have realist truth-conditions can be preserved on the back of causal semantic realism, it comes at too high a price. It requires that the realist abandon her commitment to the coherence of certain familiar kinds of radical skepticism. For many, the primary motivation for embracing realism in the first place is the strong conviction that radical skepticism is coherent. The metaphysical realist has a choice, however. Instead of denying the coherence of radical skepticism, she need only embrace semantic dualism. VI It is time to take stock. Arguments have been advanced challenging the dogma that metaphysical realists ought to be unqualified semantic realists. In particular, the following two theses have been advanced: (i) In some cases, two utterances of the same middlesized-object sentence, which are assumed (by all familiar semantic theories) to express the same proposition with the same truthconditions, are in point of fact treated by competent speakers as having distinctly different truthconditions: and this fact about our linguistic practice supports the thesis that (ii) middle-sizedobject discourse has a dual semantic structure. The primary objective of this paper is to draw attention to (i), which (if true) is a significant fact about our linguistic behavior that has been littlenoticed. Further, the evidence in support of (i) does give the metaphysical realist a compelling reason to accept (ii), semantic dualism. This is not to suggest, of course, that the arguments briefly sketched here ultimately settle the question in favor of a dualist theory. In the first place, semantic dualism is a radical departure from the received view with a host of significant consequences that have yet to be fully explored. While I am confident that the theory will stand up to scrutiny, a thorough assessment must be made to insure that semantic dualism does offer a workable account of all relevant features of our discourse.12 In the second place, one might attempt to block the inference from (i) to (ii) either by admitting that one's theory is revisionist and justifying its revisionist features or by insisting that the data of (i) are best accommodated within a theory of pragmatics rather than directly within one's semantic theory. While final judgment must await the development of such alternatives, it is doubtful that any will prove superior to semantic dualism. All caveats aside, the principal claims of this paper stand. The linguistic practice of competent speakers indicates that the truth-value of middle-sized-object statements uttered in normal contexts is not sensitive to ultimate ontology. If this is true, then metaphysical realists can no longer embrace universal (traditional) semantic realism without being revisionist. Further, causal semantic realism will not be a satisfactory alternative for those who have an unqualified commitment to the coherence of radical skepticism. A third alternative, semantic dualism, has resources which the other two lack, providing everything that is necessary to account for (1) the coherence of radical skepticism, (2) the linguistic practice of competent speakers with regard to normal middle-sized object statements, and (3) the ability of speakers to understand and believe realist truth-claims.13 13 ENDNOTES 1 Michael Devitt refers to this weak form of metaphysical realism as "fig-leaf realism" because it is such a meager doctrine (see Realism and Truth (Princeton: Princeton University Press, 1984). p. 22). Even Kant qualifies as a metaphysical realist on this account. While he does not believe that we can coherently think or say anything about mind-independent reality, he does (in a minimal sense) believe that it exists. Hilary Putnam, too suggests, that all of us may, inevitably, be weak realists (in Reason, Truth, and History (Cambridge: Cambridge University Press, 1981), pp. 61-62). In most contexts, a definition that makes both Kant and Putnam metaphysical realists is unhelpful. 2 Over the years, Michael Devitt has argued vociferously that it is possible to be a metaphysical realist without presupposing the truth of any semantic doctrine (ibid., pp. 3-46). His motivation for this view, however, is misguided. He wants people like Quine, who eschew semantics altogether, to be realists (pp. 73-103). Quine is no realist-at least not when he is abstaining from semantic commitment. Those who deny that there are "meanings" in the world leave no room for either semantic realism or semantic antirealism. That semantic distinction collapses, along with its metaphysical counterpart. Devitt has made a small concession in the second edition of his book on realism, where he has begrudgingly admitted that metaphysical realism is, as he says, "a little hit .. semantic" (ibid, 1991, 2nd edition, p.4). He has yet, in my opinion, to make concession enough. 3 Some think that the realism-antirealism distinction is best understood as (1) a distinction between two different kinds of truth (realist-truth vs. antirealist-truth). I think that there is only one coherent notion of truth and thus believe that it is best understood as (2) a distinction between two different kinds of truthconditions (i.e., two distinct features of reality about which truth-claims are made). Still others speak as if (1) and (2) are equally acceptable ways of talking about the same thing. This paper is (loosely) structured on the assumption that interpretation (2) is the correct one. However, all of the arguments in defense of semantic dualism should go through just the same if one reconstrues them according to interpretation (1). In that case, the main conclusion of the paper would be that the dogma to be abandoned is the assumption that there is a single, univocal interpretation of the truth-predicate that governs all middle-sized-object statements. This issue receives a more sustained discussion in my, "The Truth in Antirealism" (under review). Terry Horgan has argued for (what I take to be) a version of semantic pluralism in which the truth-predicate is construed as being multiply-ambiguous. See "Metaphysical Realism and Psvchologisuc Semantics," Erkenntnis, vol. 36 (1991), pp.292-322 4 Dummett does consider the possibility that there might he domains of discourse that cross ontological boundaries. He has suggested that one might interpret present-tense statements differently from past-tense or future-tense statements and that statements that ascribe observational properties to material objects might be governed by a different semantic theory than those that ascribe dispositional or measurable properties to those objects (see Truth and Other Enigmas (Cambridge: Harvard University Press, 1978), p. 358ff and p.150). While there has been some discussion about such possibilities, they have done little or nothing to reduce the strong presumption in favor of semantic monism for middle-sized object statements. 5 There are, of course, those who shun substantive semantic theories altogether, insisting that a disquotational (or redundancy) account is the most that can be said about the meaning of our discourse. 14 While there are reasons for resisting this deflationary move, it is impossible to offer them here. The arguments in this paper presuppose that the philosopher's goal is to provide a substantive semantic theory, beginning with a substantive account of the type of conditions (realist or antirealist) that make our utterances true. 6 Reason, Truth, and History, pp. 1-21. 7 There is another relevant parallel to be drawn between the new theory of reference advanced by Kripke and Putnam and semantic dualism as advanced here. Neither Kripke nor Putnam claimed to be providing a genuine theory of the semantics of natural kind terms. Rather, they claimed that natural kind terms have a certain semantic feature (i.e., an ineliminable indexical component). Similarly, it is not my intention to advance a full-fledged theory of meaning, in the sense of offering necessary and sufficient conditions for the truth (or assertibility) of middle-sized-object statements. ] am not convinced that such a thing is even possible. I am claiming, however, that middle-sized-object discourse has a certain feature (i.e., a dualistic rather than a monistic structure). 8 While I imply that this conditional is to be analyzed as a simple counterfactual conditional. things are actually more complicated than that. A proper analysis requires appeal to what Robert Stalnaker calls a "diagonal proposition" (see 'Assertion,' reprinted in Pragmatics: A Reader. Steven Davis, ed. (Oxford: Oxford University Press, 1991), pp. 278-89). For a lengthy discussion of this more subtle analysis see my "The Truth in Antirealism" (typescript). 9 This assumes, of course, a version of causal semantic realism liberal enough to countenance the possibility that irreducibly mental entities might enter into genuinely 'causal" relations, one with another. 10 In "The Truth in Antirealism" (typescript) I argue that there is a further weakness to the causal theory. While it appears that causal semantic realism will make normal MSO-statements come out true regardless of considerations of ultimate ontology-this is not in fact the case. Causal semantic realism is not, then, fully consistent with the linguistic practice of competent speakers regarding normal MSO-statements. 11 "What is Realistic about Putnam's Internal Realism?" Philosophical Topics, vol. 20 (1992), pp.49-83, especially 70-76. 12 I leave to future publications the task of working out the details of a dualist semantics, of exploring its implications for other areas of philosophy and of defending it against objections. 13 Many people have offered helpful comments on the views advanced in this paper including: Barbara Abbott, William Alston, Ann Baker, John Barker, Larry BonJour, Thom Carlson, Harry Deutsch, Pat Francken, Michael Gorr, David Haugen, Larry Hauser, Jonathan Kvanvig, Michael Lynch, Kent Machina, Robert McKim, Hilary Putnam, Stephen Rosenbaum, Mark Siderits, Steve Sullivan, Paul Tidman, Mark Timmons, Charles Travis, Graham White, and an anonymous APQ reviewer.