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A Naturalist's Approach to Modal Intuitions

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Modal inquiry is plagued by methodological problems. The best-developed views on modal semantics and modal ontology take modal statements to be true in virtue of relations between possible worlds. Unfortunately, such views turn modal epistemology
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  gunnar.bjornsson@philosophy.su.se1(27)  A Naturalist’s Approach toModal Epistemology Gunnar BjörnssonStockholm University ABSTRACT: Modal inquiry is plagued by methodological problems. Thebest-developed views on modal semantics and modal ontology take modalstatements to be true in virtue of relations between possible worlds.Unfortunately, such views turn modal epistemology into a mystery, and thispaper is about ways to avoid that problem. It looks at different remediessuggested by Quine, Blackburn and Peacocke and finds them all wanting.But although Peacocke’s version of the popular conceptualist approach failsto give a normative account of correct modal judgments, it goes a long wayin suggesting how we come to make particular judgments of absolutenecessity. Building on that suggestion, the paper explains howconceptualism can be transformed into a radically naturalist account of correct modal judgment that fits into a more general approach tonaturalized semantics, represented by the writings of Richard Boyd andRuth Millikan, and suggests some lessons for modal epistemology. The problem with possible worlds Modal inquiry is plagued by methodological problems. The best-developedviews on modal semantics and modal ontology take modal statements to betrue in virtue of relations between possible worlds. Talk about possibleworlds is apparently very useful, and has proved quite exciting forphilosophers, giving metaphysicians a new, vast and intriguing subjectmatter. Unfortunately, it gives very little help with modal epistemology, forit is far from clear on any of those views what methods of arriving at modaltruths would be reliable. In particular, it is unclear why we should trust ourintuitions about what is absolutely necessary. What is absolutely necessarygunnar.bjornsson@philosophy.su.se2(27)is true in every possible world, we are told, but how are we to know whatthe possible worlds are?Lacking a substantial account of how we are related to modal facts suchthat we can make reliable modal judgments is not necessarily a problem.Suppose, for example, that a number of people make similar modal claimsindependently of each other. That would seem to be prima facie evidencethat their judgments are guided by the same reality, however that guidanceis achieved. Moreover, although there is plenty of modal disagreementamong philosophers, there is considerable and independently reachedconsensus on a number of everyday modal claims, and so it would seem thatthere are somewhat reliable methods for arriving at modal truth.However, this appeal to epistemic triangulation does not sit well with apossible worlds ontology, for it is not clear how facts about possible worldsare capable of “guiding” our modal judgments. Our best view of suchguidance is in terms of causal or nomological explanations, and theexistence of possible worlds does not seem capable of making a causaldifference to what modal judgments people actually make. These worlds areeither taken to be spatiotemporally and causally unrelated to our world, ortaken to be abstract objects without causal efficacy. If we appeal totriangulation, then, it would seem that we are forced to find somealternative to possible worlds accounts of modal ontology. If we stick tosome of those accounts, on the other hand, modal knowledge remains amystery. And even if we were to accept the mysteries of possible worldsaccounts of modal reality, the fact remains that these accounts give us nohand in cases of modal disagreement. There is nothing in realist accounts of possible worlds that gives us any clue as to how to solve disagreementsabout the possibility of zombies, swampmen, or of free action with naturalcauses.This paper is about ways of avoiding such mysteries while retaining theidea that there is such a thing as modal inquiry where some modal judgments and methods of arriving at modal judgment are more reliablethan others. The approach suggested here is naturalistic in that it takes itsdeparture from the fact that modal judgments are parts of nature, withnatural causes. Given this, and given the two further assumptions thatmodal judgments have truth-conditions and that we can make reliablemodal judgments, it seems that the explanation of why we make modal  gunnar.bjornsson@philosophy.su.se3(27) judgments will –  ! at least sometimes !  – invoke modal facts. The question,then, is what modal facts are such that they can play that causal orexplanatory role.The paper has four more sections. The  first looks at three approaches tomodal semantics that deal in laws or rules or in limitations of ourconceptual capacities rather than possible worlds. First, it outlines Quine’slaw-based account, and discusses its problems with our judgments of absolute necessity. Second, it sketches Simon Blackburn’s expressivistaccount of these judgments in terms of conceivability, and suggests thatBlackburn underestimates cognitivist resources. Third, it looks at thepopular conceptualist account, recently defended and detailed byChristopher Peacocke, showing how it promises to extend Quine’s law-basedaccount to our judgments of absolute necessity. The second remainingsection takes a more critical look at the conceptualist approach. Thesuggestion is that in order to provide a plausible account of modaldisagreement and of our modalizing in general, and in order to provide asemantics of modal judgment that is relevant for modal epistemology,conceptualism must be quite radically transformed. The third remainingsection explains how this new account of the correctness of modal judgmentsfits into a more general approach to naturalized semantics, represented bythe writings of Richard Boyd and Ruth Millikan. The  final section takesstock and briefly returns to the issue of modal epistemology, applying thenaturalist account. Laws and rules In a spirit very different from that of most possible worlds theorists, Quineargued that “necessarily” was intelligibly attached only to conditionalssupported by law-like generalizations. When we think that it makes senseto say “Necessarily Q”, this is only because we are inclined to say“Necessarily, if P then Q”, given some salient actual P, and take “if P thenQ” to be supported by a law-like generalization. Quine’s argument was aninference to the best explanation of the following contrast:(i)   Well-known past events are not easily classified as necessary ornot.gunnar.bjornsson@philosophy.su.se4(27)(ii)   Conjectured events (future, past or present) often are.In the latter cases, we judge the occurrence of the event, Q, as necessaryinsofar as we have some specific evidence, P, such that we are willing to saythat if the evidence holds, the event occurs, or occurred. The evidenceprovides a salient antecedent for a conditional to which “necessarily” can beattached. In the case of well-known events, however, no conditional willstand out as relevant for the application of “necessarily” for we have toomany diverse kinds of evidence. Moreover, not any material implicationmakes for intelligible statements of necessity, and Quine suggests that weare inclined to talk about necessities only if we take the conditional to besupported by some law-like generalization, or a disposition, which in itself relies on some law-like generalization. 1 Given Quine’s semantic verificationism, his epistemological holism andthe resulting semantic holism, logical and mathematical generalizations are just particularly central parts of our web of beliefs, being otherwise like anyother law-like generalizations. This means that the necessity of logical andmathematical truths falls under the same analysis as the necessity of anyother truth. Such truths are necessary relative to some law-likegeneralization supporting a conditional with the mathematical or logicaltruth in the consequent. The epistemology of logical and mathematicalnecessity would be the epistemology offered by Quine’s general empiricismand pragmatism. Also, it is not so hard to see why we would be interested inkeeping track of law-like regularities and their instances. Any creatureneeding to adjust its behaviour to environmental factors will have to rely onregularities in nature, and any creature capable of reflecting on its groundsfor belief will need conceptions of its representations of such regularities. OnQuine’s account, then, the mysteries of possible worlds seem to vanish. Butother problems appear.One major dissatisfaction is that Quine, like the modal realist, runs intoproblems with absolute necessity. 2 The difficulty is not how to account for 1 See “Necessary Truth” in The Ways of Paradox and Other Essays , second edition,Cambridge MA: Harvard U. P. 1976, pp. 68-76. 2 Another complaint would be that only a realist version of possible worldssemantics offers a wide range of theoretical benefits. But I am willing to argue that !  gunnar.bjornsson@philosophy.su.se5(27)our knowledge of absolute necessities –  ! according to Quine, all necessitiesare relative !  – but to account for our intuitions that some truths areabsolutely necessary while others are contingent and only relativelynecessary (physically or epistemically necessary, say). For even if we denythat there are absolute necessities, we need to explain their apparentexistence. As Simon Blackburn has pointed out, Quine’s appeal to theobviousness or epistemological centrality of what we take to be absolutenecessities doesn’t cut it, for there are truths that are both obvious andseemingly beyond the revisions prompted by empirical inquiry that we stilldo not take to be absolutely necessary: that there are trees, say, or that thesky is blue. 3 Moreover, the natural move – to say that the latter are obviousonly under certain circumstances !  – seems to invoke the idea that they haveempirical content, whereas the absolute necessities lack such content. Butgiven the rejection of this distinction within Quine’s holistic empiricism, thiswill not do. We need to say something more to explain that distinction. 4 Blackburn’s own explanation of why we make the distinction betweennecessary and contingent truths points to its practical importance. Withcontingent truths, we can “make something of” mistaken states of mind,beliefs that P under circumstances when not P: we understand what it is forsomeone to believe that the sky is blue even if it were red, or how someonecould be so deluded. With absolute necessities, we cannot do this: we cannotmake something of someone being mistaken in her belief that if A and B,then A. For that reason, the distinction is very important for how we dealwith each other. Furthermore, Blackburn proposes that talk about absolutenecessities expresses (rather than states) our inability to “make somethingof” their negations, and conversely that talk about contingencies expressesour ability to make something of their negations. The result is anexpressivist, or quasi-realist account of our modalizing, on the model of expressivist or quasi-realist accounts of our moralizing. Instead of making ! to the extent that these are real benefits, they can equally be accommodated byother accounts. 3 See pp. 112-3 of Quine’s “Carnap and Logical Truth”, in The Ways of Paradox  , pp.107-32 and p. 63 of Blackburn’s “Morals and Modals” in Essays in Quasi-Realism Oxford: Oxford U. P. 1993, pp. 52-74. 4 “Morals and Modals”, p. 63. gunnar.bjornsson@philosophy.su.se6(27)our modalizing intelligible by giving a substantial account of facts that ourmodal judgments are meant to keep track of, Blackburn tries to makemodalizing intelligible by pointing to its fruits, in much the same way thatmoral expressivists have tried to make moralizing intelligible by pointing tothe fruits of moralizing (social and personal coordination of action) ratherthan by giving a substantial account of moral facts.I have various misgivings about expressivist accounts in general and thisaccount in particular. One general problem with the expressivist approachis that in providing no substantial accounts of modal or moral facts, it failsto provide epistemological guidance for these domains of inquiry, no lessthan standard possible world accounts of modal facts. Here, however, I willstress another problem, specific to Blackburn’s expressivist position onmodal discourse, namely that it leaves us without explanation of  why wecannot make something of someone’s believing in what is absolutelyimpossible. Now, Blackburn does not take this to be a problem, but ratheran essential part of his account:On this account, part of what it is for us to make nothing of thetruths that we deem impossible is that we cannot explain naturalistically our own failure to see what it would be for them tobe true. 5 Blackburn’s argument for this claim seems to be the following. Suppose thatR is something that we take to be absolutely necessary. A genuineexplanation of our inability to make something of the hypotheses that P isactually false will involve an explanation of how, given that R were false, wewould actually think that it were true. And if we could explain that, wewould be “making something of” the hypothesis that P were false, in whichcase we wouldn’t take it to be absolutely necessary. Modal thought,Blackburn claims, has its place where naturalism has its limits. 6 I believe that this argument is quite a muddle. To explain an actualinability to conceive of not-P, we do not need to “make something of” thehypothesis that we are wrong to think that P. It is enough that we are ableto show why, given the way the world actually is, we have come to have the 5 “Morals and Modals”, pp. 70. 6 “Morals and Modals”, pp. 70-1.  gunnar.bjornsson@philosophy.su.se7(27)limitation. Moreover, such an explanation seems readily available, andBlackburn himself seems to point to exactly that explanation. 7 As a firstattempt, we might say that the reason that we fail to make something of thedenial of some P that we take to be absolutely necessary is the following.Our grasp of the concepts by which we try to represent not-P consists ininferential tendencies that would have to be given up if we were to acceptnot-P as true. When we try simulate accepting it, there is no longeranything to accept, so to speak. For example: in trying to grasp arepresentation of A and B but not A, we have to abandon the veryinferential dispositions the acceptance of which constitutes ourunderstanding of conjunction and negation. 8 Could Blackburn agree with this while holding on to his expressivistaccount? It might seem that he could, for what has been added is just anexplanation of the states of mind that Blackburn suggests are expressed inour modalizing. On the other hand, the explanation seems to point directlyto the most popular attempts to give positive accounts of modal knowledge.Such attempts take claims about absolute necessity to be true in virtue of rules governing the correct application of concepts, rules that are known byanyone possessing these concepts. If the truth of a representation followsfrom the rules of the concepts involved, we can rightly prefix therepresentation with “necessarily”. Although this assumes that Quine’srejection of such things as semantic rules is misguided, it is of coursecompatible with his claim that “necessarily” applies to conditionals: theconditional to which “necessarily” would be attached would be “if C is theconceptual structure of P, P is true”.This conceptualist approach has recently been refined by ChristopherPeacocke, although he starts from the notion of a genuine (absolute)possibility rather than from the notion of necessity. Very roughly, hissuggestion is the following: 7 “Morals and Modals”, pp. 72. 8 We could almost say that intuitions of absolute necessities derive from theexistence of “one-criterion concepts”, understood along Putnam’s suggestion in “The Analytic and the Synthetic” in Mind, Language and Reality , Cambridge:Cambridge U. P. 1978, pp. 33-69. gunnar.bjornsson@philosophy.su.se8(27)(GP)It is  genuinely possible that P  if and only if (C) and (R) aresatisfied, where (R) overrides (C):(C)P adheres to the very same rules that actually determinereference and truth-values of the concepts that constitute P.(R)If the rigidly referring concept C is a constituent of P, then Padheres to the rule that C has its actual referent. 9 If the truth of P follows from P’s own rules, then every representation thatrepresents a genuine possibility and assigns a truth-value to P will take P tobe true. Further, assume that:  P is absolutely necessary if and only if P is a genuine possibility and noassignment of any other truth-value than TRUE to P is a genuinepossibility.The result is the familiar one that every representation the truth of whichfollows from its own conceptual rules will be rightly held to represent anabsolutely necessary truth. And the applications are equally familiar. I havealready used the case of the logical connectives, and another stock exampleis the concept of bachelors. If a representation has someone being both abachelor and married, it seems to violate the rule for the concept of abachelor, or for conjunction, and its content is not genuinely possible.Directly or rigidly referring concepts provide a special case. Here, by(GP) and (R), it is not the rule that determines the referent that we are tohold fixed. Take my statement that I am here now. The conceptual rule for“I” seems to be that it refers to the speaker; the conceptual rule for “here”that it refers to the place of utterance; the conceptual rule for “now” that itrefers to the time of utterance. Given that, given the conceptual rule for thecopula, and given (C), it would seem to be a necessary truth that I am herenow. On the other hand, it seems to be no absolute or metaphysicalnecessity that I (Gunnar Björnsson) am here (in Stockholm) now (July 6 th 2004): I could have been in New York, say. However, given the assumptionthat “I”, “here” and “now” are rigidly referring, and given (R), the statement 9 See “Metaphysical Necessity: Understanding, Truth and Epistemology”, Mind 106:423 1997, pp. 521-74 and chapter 4 of   Being Known , Oxford: Clarendon Press1999.  gunnar.bjornsson@philosophy.su.se9(27)that I am not here now does express a genuine possibility, just as commonintuitions about metaphysical necessity would have it. Similarly, supposingthat the concept of water rigidly refers to the chemical kind H 2 O, we are notto think that it is  possible that something that does not consist of H 2 Omolecules is water. Conversely, we are to think that it is necessary thatwater consist of H 2 O molecules.Since it seems comparatively non-mysterious that we can know (fallibly)the actual referents of directly referential terms and the conceptual rules forother terms (including the modal operators), the mystery of modalknowledge inherent in the possible worlds views would seem to be dissolved.Modal knowledge thus seems no more mysterious than the acquisition of concepts in general. Compared to some possible worlds accounts that takemodal knowledge to derive from unanalyzed modal intuition, this seems tobe a major improvement. And compared to Blackburn’s quasi-realism, itseems to offer a deeper understanding of modal discourse. The substantialtruth-conditions offered by conceptualism not only explain the usefulness of our modal distinctions that Blackburn had as the core of his account, butalso seem to provide a standard against which various methods for arrivingat modal claims could be measured.  Problems with conceptualism The conceptualist account seems to improve matters, but there are at leastthree major and interrelated remaining issues. The first is the problem thatthere is much modal disagreement and that the conceptualist account failsto give guidance as to how such disagreement is to be solved, or even whywe should care to solve it. The second is that conceptualism does not in itself offer an explanation of why we have the concepts that we do have, and thatwhen we offer such an explanation, traditional conceptualism seems to besuperseded. The third is that on many approaches to philosophicalsemantics, truth-conditions and conceptual rules do not follow in a directway from an explanation of how competent thinkers reach their modal judgments: an account of conceptual “mechanics” does not translate readilyinto an account of modal semantics. I will discuss these related issues inturn, beginning with the problem of disagreement.gunnar.bjornsson@philosophy.su.se10(27) Although there is fairly widespread agreement about conceptual truthsin some areas, such as the domain of narrowly logical truths or trivialitieslike “no bachelor is married”, there are of course also areas of heatedphilosophical disagreement and these are the areas where a substantialmodal epistemology could be of most help. For example, there isdisagreement about the possibilities of zombies, swampmen, contentwithout consciousness and free action with natural causes, anddisagreement about the absolute necessity of mathematical truths. Whatcan conceptualists say about such disagreements?One option, of course, is to stress that conceptual analysis is difficult,and insofar as conceptual analysis has the scope that many philosophersstill think that it has, this seems quite true. It is most certainly hard tofigure out what the principles are that govern certain concepts. This mightbe the case with the concept of causation, for example. There is a widevariety of cases where people give pretty straightforward and fairlyunanimous verdicts about what does and does not cause what, but it is notclear by what inferential moves we reach these verdicts, or which of thesemoves are fundamental to our concept of causation. But the problem withcases of modal disagreement is not to find the underlying principles of theverdicts we actually make, but to decide what the correct verdicts are. Andthis problem tends to undermine the idea that there is a real disagreement.For Peacocke, for example, to possess a certain concept is a matter of havinga readiness to take certain things as evidence for and against thoughtsinvolving that concept. 10 Since careful, intelligent people disagree aboutwhat to count as evidence in areas of modal disagreement, the conclusionwould seem to be that those involved in the debates have different conceptsof, say, consciousness, mental content, free action or mathematical truth. If so, modal inquiry would be deluded about its subject matter, for there wouldbe no real disagreements.This is cause for pause, but three solutions suggest themselves. The firststarts from the observation that the problem of disagreement relies on the 10    A Study of Concepts , Cambridge, MA: A Bradford Book / The MIT Press 1992. In  Being Known , pp. 136.8, Peacocke further suggests that knowing a concept involvesknowing how it can be combined with other concepts in admissible representations,representations of genuine possibilities.
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