© LOGOS & EPISTEME, VII, 2 (2016): 171-183 MODAL RATIONALISM AND THE OBJECTION FROM THE INSOLVABILITY OF MODAL DISAGREEMENT Mihai RUSU ABSTRACT: The objection from the insolvability of principle-based modal disagreements appears to support the claim that there are no objective modal facts, or at the very least modal facts cannot be accounted for by modal rationalist theories. An idea that resurfaced fairly recently in the literature is that the use of ordinary empirical statements presupposes some prior grasp of modal notions. If this is correct, then the idea that we may have a total agreement concerning empirical facts and disagree on modal facts, which is the starting point of the objection from the insolvability of modal disagreement, is undercut. This paper examines the no-separation thesis and shows that some of the arguments against the classical (empiricist) distinction between empirical and modal statements fail to be conclusive if they are taken to defend a strong notion of metaphysical possibility. The no-separation thesis appears to work only in theoretical frameworks where metaphysical modalities are considered (broadly) conceptual. For these reasons, the no-separation thesis cannot save modal rationalism from the insolvability of modal disagreement. KEYWORDS: metaphysical modality, modal rationalism, principle-based account, modal disagreement, Alan Sidelle, Robert Brandom 1. Are There Modal Facts? The claim that there is a substantial separation between modal knowledge and ordinary knowledge is a staple of (classical) empiricism and it has persisted in a radical and dominant form in the analytic tradition of the first half of the past century. Although the rehabilitation of modal notions is the joint result of many contributions, both logical and philosophical, Kripke is generally credited with the decisive role in dispelling the prevalent modal scepticism of the time, which originated partially in empiricist doubts about strong modal notions. But Kripke also acquiesced to (or at least did not explicitly reject) the idea that there is a fundamental distinction between the modal and the non-modal. As a result, the attempt to develop and maintain a substantial account of robust metaphysical modality while at the same time holding that modalities have an exceptional (viz., going beyond empirical evidence) character has been the main challenge of postMihai Rusu 172 Kripkean theories of modality. Most of these theories have taken a cue from Kripke by explaining metaphysically necessary truths as being derived from necessary a priori principles.1 This is the fundamental idea of modal rationalism, i.e. the tenet that modal a posteriori truths are dependent on necessary principles that are known a priori. Now, there is an objection to such principle-based accounts that is, at least in my opinion, quite forceful. While I must concede that an adequate understanding of its mechanism and significance requires a high degree of familiarity with the contemporary literature on the subject matter, I will try to summarize this objection in what follows.2 As already stated above, the modal rationalist holds that necessary a posteriori truths are grounded in a priori principles. For instance, it is necessarily true that Isabella Rossellini is the daughter of Ingrid Bergman. This modal a posteriori truth has its source in the a priori principle called 'Necessity (Essentiality) of origin,' which states that if a certain thing (living being, artefact, etc.) has a certain origin, it has it as a matter of necessity. We just 'fill in' this principle with some empirical information (such as the fact stated above) and we obtain our necessary conclusion by modus ponens. E.g.: If Isabella Rossellini is the daughter of Ingrid Bergman, then necessarily, Isabella Rosselini is the daughter of Ingrid Bergman. Isabella Rossellini is the daughter of Ingrid Bergman. Necessarily, Isabella Rossellini is the daughter of Ingrid Bergman. The objection to modal rationalism that serves as the starting point of this paper can be articulated in the following way. If, as modal rationalists want it, modal distinctions are objective, then there is one correct account of modal truth. This account is supposed to give us the right image of modal reality, and also explain how it is that we come to know it. But it seems plausible that two equally sophisticated philosophers who develop their reflections starting from the same 1 A brief formulation of the modal rationalist stance can be found in Saul A. Kripke, Naming and Necessity (Cambridge: Harvard University Press, 1980), 109. 2 See Christopher Peacocke, Being Known (Oxford: Oxford University Press, 1999), for a typical rationalist theory concerning modality, Crispin Wright, "On Knowing What is Necessary: Three Limitations of Peacocke's Account," Philosophy and Phenomenological Research 64 (2002): 65562, Sonia Roca-Royes, "Modal Epistemology, Modal Concepts and the Integration Challenge," Dialectica 64 (2010): 335-61, and my own paper, "On the Epistemology of Modal Rationalism: the Main Problems and Their Significance," Logos & Episteme. An International Journal of Epistemology VI, 1 (2015): 75-94, for a critical assessment of modal rationalism. Modal Rationalism and the Objection from the Insolvability of Modal Disagreement 173 empirical facts will work out incompatible accounts of modal truth and knowledge. For instance, one may endorse Necessity of origin and the other may reject it. Or, to take a more disputed principle, one may accept Essentiality of composition and the other may reject it. So, the two philosophers may agree on all ordinary facts regarding, e. g., Isabella Rossellini's biography or, using one of Kripke's famous examples, the this-worldly profile of a certain lectern, but disagree on modal truths regarding them. Now, the objection runs, there appears to be no objective modal fact that would help us decide which of the two endorses the correct account – because, more generally, there appear to be no modal facts to speak of. Suppose, at least for heuristic reasons, that from a logical point of view the modal profile of an object is virtually unlimited, that we are free to associate any logical predicate with any logical subject whatsoever, except perhaps for cases that would lead in an uncontroversial manner to contradiction (e.g., "Isabella Rossellini is not Isabella Rossellini," "Isabella Rossellini is younger than Ingrid Bergman and older than Ingrid Bergman," and so on). This is pretty much the classical Humean view. But anyone who takes modality at least a little seriously would agree that we nevertheless enforce some restrictions on the logical space in order to determine an object's modal profile. Say, few would accept that Isabella Rossellini, the actress, could have been a crocodile. Our two philosophers' accounts would lead then to two different restrictions being enforced on the logical space of possibilities, thereby leading the two thinkers to accept incompatible modal statements as true. One rules out all scenarios where Isabella Rossellini is not the daughter of Ingrid Bergman and the other doesn't. One allows cases where the lectern which is actually made of wood is made of iron (or of totally different pieces of wood), whereas the other rejects them. What the objection says is that the principles that ground these restrictions on possible scenarios do not (because they cannot) report on some modal facts or, at least, that whatever it is they report on, it doesn't have the same objective status that ordinary facts have. As an explanation of why our modal claims are not objective (or thinker-independent), while not being wholly subjective or arbitrary either, the critic may follow some of the alternative accounts of modality and propose that there is some convention, some sort of conceptual truth or a simple habitinduced shutdown of our imagination which engenders our modal intuitions.3 3 See Amie Thomasson, "Modal Normativism and the Methods of Metaphysics," Philosophical Topics 35 (2007): 135-60, Amie Thomasson, "Norms and Necessity," Southern Journal of Philosophy 51 (2013): 143-60, Robert Brandom, Between Saying and Doing: Towards an Analytic Pragmatism (Oxford: Oxford University Press, 2008), and Simon Blackburn, "Morals Mihai Rusu 174 The objection from the insolvability of (apparent) modal disagreement regarding the non-factual character of modal claims is, at least to my mind, a powerful one. Yet, there is one idea that resurfaced fairly recently in the literature regarding modal notions which may provide some hope for proponents of principle-based views. What some contemporary philosophers of modality hold is that the distinction between ordinary, non-modal facts and knowledge, on one side, and modal facts and knowledge, on the other, is a philosophical illusion. Specifically, the way this view may help reject the objection formulated above is by pointing out that if there is no separation between the modal and the nonmodal, the hypothesis of two thinkers agreeing about all ordinary facts, but disagreeing on modal ones, cannot stand. The two thinkers must disagree on some empirical fact as well, and it may be this empirical disagreement that helps us explain the modal disagreement (probably in conjunction with some further theoretical input). The no-separation idea has been developed in various ways in the last two decades or so, but in this paper I will be concerned only with what it can do in support of modal rationalism. As such, I will leave out explicit anti-rationalist views, such as Elder's4 or Miščević's5, that hold that there is no need for a priori principles in order to ground modal truth. The no-separation idea has been notably expressed in two different, though related, ways: (1) Modal claims are consequences of (our view on) ordinary descriptive sentences; and (2) Grasp of empirical terms used in ordinary descriptive sentences presupposes grasp of modal notions (this is what Brandom calls 'the Kant-Sellars thesis'). The discussion of these two philosophical claims will consider their formulation in the work of Alan Sidelle (for thesis 1) and Robert Brandom (for thesis 2). One may object that these thinkers are not modal rationalists either (and, unlike Elder and Miščević, they are not even realists about modality), but I believe and hope to show that the significance of the two theses is better evinced in the arguments I will discuss. This has to do with my general outlook on the compatibility of the no-separation idea and modal rationalism. As the reader may have guessed, I am fairly sceptical about this pairing for reasons that will be explained in this paper. Accordingly, my target is not any of the philosophers mentioned in this paragraph, but rather and Modals," in Essays in Quasi-Realism (Oxford: Oxford University Press, 1993), 52-74 for theories of this sort. 4 Crawford Elder, "An Epistemological Defence of Realism About Necessity," Philosophical Quarterly 42 (1992): 317-36. 5 Nenad Miščević, "Explanining Modal Intuition," Acta Analytica 18 (2003): 5-41. Modal Rationalism and the Objection from the Insolvability of Modal Disagreement 175 thinkers who are ontological realists about modality,6 while maintaining that there is no separation between the empirical and the modal realm, and also that (some of) our modal knowledge is underpinned by a priori principles. 2. Modal Assertions as Consequences. Sidelle's Argument In "Modality and Objects,"7 Alan Sidelle proposes an argument against metaphysical views which combine realism about objects with conventionalism about modality, such as Ted Sider's position from Four Dimensionalism.8 We will call this combination of doctrines 'the hybrid view' from now on. The argument is developed as follows. Suppose one thinks that Socrates is essentially human, but his being so is a matter of convention. However, as a realist, one must believe that 'Socrates' refers to some thinker-independent object, viz., that Socrates is a mind-independent object (a human being, in this case). But suppose also that we had introduced another name purportedly for the same object, 'Socrateez' – which is an aggregate term that applies whenever all the elements in the aggregate exist. The question is: is Socrates the same with Socrateez, do the two names refer to one and the same object? Sidelle thinks that the realist must give an affirmative answer to this question. But if this is so, it opens the defender of the hybrid view to the following counterargument:9 1. Socrates is essentially human. 2. There could have been conventions applied to Socrates in virtue of which he would not have been essentially human. [by conventionalism about essences, and mind-independence about objects] 3. In some such situations, Socrates is not (or ceases to be) human. [from (2)] 4. Therefore Socrates is not essentially human. [from (3)] So, Socrates is essentially human, but Socrateez, who is one and the same object with Socrates, is not. And that is a contradiction. 6 Ontological realism about modality is not to be equated with the modal realism of David Lewis. The latter may be seen as an eccentric form of ontological realism that holds that possible worlds are real in the same way that our world is real, whereas generic ontological realism about modality just claims that modal statements are made true by objective modal facts. 7 Alan Sidelle, "Modality and Objects," Philosophical Quarterly 60 (2010): 109-25. 8 Theodore Sider, Four Dimensionalism: an Ontology of Persistence and Time (Oxford: Oxford University Press, 2001), 207. 9 Sidelle, "Modality and Objects," 111. Mihai Rusu 176 One quick objection to this argument is that the conventionalist view of essence precludes us from using the 'is essentially' predicate without any specification. If this use was acceptable, then conventionalism across the board could run into the same problem. If ever two different sets of conventions individuated the same object, the same contradiction would arguably arise. But even if this last hypothesis doesn't make sense, the defender of the hybrid view could still object that 'is essentially' from (1) doesn't have the same meaning as 'is essentially' from (2) and, consequently, (4). She may insist that the deep meaning of the modal conventionalist position is that 'is essentially P' should never be used without adding the qualification 'by convention X'. In this case, Socrates is essentially human by convention X, but not essentially human by convention Y. Never is he essentially human by convention X and not essentially human by convention X, so the contradiction doesn't arise. But perhaps this is too easy or too vague an objection, so we should inspect closely the theoretical claims that Sidelle uses to defend his view, as they provide some deeper insights into his position. Sidelle considers a different fundamental objection to his argument: it just states the uncontroversial fact that we are able to provide non-modal conditions for the existence of an object that don't carry any modal commitments for particular objects. To this objection he replies that "while merely actual conditions may tell us when we have an object, we need more to tell us, for any object, what makes it the object it is."10 So, when considering an object, it is not sufficient to think only of the actual conditions that may help us distinguish it, but also of its persistence and possibility conditions that make the modal profile intrinsic to the object. The hybrid view only works in a static perspective about objects, according to Sidelle, but we should adopt a dynamic one.11 Valid as it may be, this important point changes the whole story of Sidelle's own argument. If the defender of the hybrid view accepts the fact that we need to integrate a temporal dimension to our metaphysics of individuals, she will also quite plausibly reject identifying Socrates the human being with Socrateez, the aggregate of elements, as long as the two conventions individuate objects with divergent histories. If, say, Socrateez is an aggregate of physical elements, namely of particles, then he/it is rather a part of the composite spatiotemporal individual that is Socrates the human being. Of course, by hypothesis, the defender of the hybrid view will hold that we can have two modal conventions regarding the same object, so we should find a better example. But if she is sensitive to the point Sidelle makes, the realist will also refuse to accept any two conventions that give 10 Sidelle, "Modality and Objects," 111. 11 Cf. Sidelle, "Modality and Objects," 117. Modal Rationalism and the Objection from the Insolvability of Modal Disagreement 177 us only temporarily overlapping objects. If this is so, and we are held to attach to the same object only modal conventions that trace an identical spatiotemporal itinerary, then there is no moment or period of time when (3) is true, that is, Socrates is not (or ceases to be) human, so Sidelle's argument breaks down. What is more, I think Sidelle's requirement of always having to consider the persistence and possibility conditions of objects is unnaturally strong. Let me elaborate on this claim. First of all, it is not clear that we need necessary conditions for persistence through time; sufficient conditions appear to be able to do all the work that is normally required. Suppose, for instance, that there is a small accident at Socrates' birth that ends up with him having a small scar behind his left ear for all his life. Thus, being the son of Sophroniscus and Phaenarete that has a scar behind his left ear should suffice for identifying Socrates all through his lifetime, given that none of his male siblings had a similar scar. But this obviously reports a contingent fact about Socrates. Now, Sidelle would probably insist that this may work for singling out Socrates, but not for determining what kind of object he is. While this may appear to be a sensible philosophical requirement, it is not at all uncontroversial that it is indispensable for the realist. It may very well happen, as it often does, that the purportedly essential properties of the object (e. g., humanity, rationality, etc.) are not sufficient for individuating it and we should add contingent properties for singling it out, as in the example above. But this is not my concern here. The question is rather if necessary properties are needed at all in order to talk and think about an object and track it through time. As some externalists would probably hold, the temporal profile of an object may not be constrained by our knowledge of some necessary conditions for persistence. Admittedly, this may look awkward for the realist. If two different conventions are really about the same individual with the same history, then it is natural to suppose that there must be some deep common fact that makes this work, even if we don't know what it is. But there is still a problem. Even if the defender of the hybrid view may be forced into admitting that some facts about persistence through time are not optional, there is still a long way to go before showing that this requirement should carry over to the modal case. Some theoretical input is needed at this point in order to better understand the implications of the claim that we need temporal and modal conditions for keeping track of objects. This claim regards two aspects: (a) a semantic dimension and (b) a metaphysical dimension. Arguably, Sidelle may be taken to defend the strong thesis that we need persistence and possibility conditions both at a semantic and at a metaphysical level. Now, in the temporal case, it seems plausible that a realist would be inclined to agree to a metaphysical constraint for persistence conditions, Mihai Rusu 178 but it is not clear at all that she should also be committed to the corresponding semantic constraint. All this has to do with the nature of the so-called referential terms, that is, proper names and natural kind terms. If the Kripke-Putnam theory or, more generally, some form of semantic externalism is right, then there are expressions in our language that are not tied to any type of descriptive content, including persistence and possibility conditions.12 So, names and natural kind terms may provide us with a way of referring to objects without any corresponding criteria. It is plausible that both the semantic and the metaphysical constraints break down in the modal case. The semantic commitment for modal conditions is straightforwardly dismissed if there are referential expressions that don't have a descriptive semantic content. The metaphysical commitment may be similarly dismissed if, with Kripke, one holds that we don't need criteria of transworld identification, but, pace Kripke, one also holds that there are no properties that should belong to an object in any possible situation. In order to support his claim, Sidelle needs a supplementary justification of why the realist cannot avoid commitment to essential properties, i.e., properties that an object must have in any possible scenario. At least from an epistemological point of view, there seems to be no such constraint on modal imagination, even for realists. Consequently, the hybrid view can be defended against Sidelle's arguments. To sum things up, the realist is entitled to hold that we may refer to and keep track of objects without being in possession of some necessary conditions for doing that. Although the hybrid-view realist may run into some metaphysical trouble for persistence in the actual world, no such trouble should incur in the case of possible worlds/scenarios. No particularity of a general realist standpoint seems to be able to prevent the realist from entertaining divergent possible scenarios concerning the possession of a certain property by a certain object. What does this all mean for the argument from the insolvability of (apparent) modal disagreement? Well, it seems that in order to drive his point home, Sidelle needs too much of his own conventionalist perspective. He argues that we need persistence and modal conditions for keeping track of objects, but his claims can be countered both at a semantic and at a metaphysical level. If the Kripke-Putnam theory is correct, for instance, then we can refer to objects directly, without having to appeal to descriptive criteria. But perhaps we need persistence conditions for objecthood from a metaphysical standpoint. Even if this 12 Kripke, Naming and Necessity and Hilary Putnam, "The Meaning of 'Meaning'," Minnesota Studies in the Philosophy of Science 7 (1975): 131-93 are the most important sources of KripkePutnam semantic theories. Modal Rationalism and the Objection from the Insolvability of Modal Disagreement 179 is right, it is still unclear that this constraint should carry over to the modal case, that we need (semantic or metaphysical) criteria for identifying an object in different possible situations. Without a substantial conventionalist commitment, Sidelle's argument will not be able to get off the ground. Therefore, it doesn't establish that objects necessarily have intrinsic modal profiles. In the following section, I will discuss a different approach to the critique of the separation between modal and empirical notions. This approach was propounded by Robert Brandom in his Between Saying and Doing. Brandom builds an argument for what he calls 'the Kant-Sellars thesis' – the claim that using empirical terms presupposes a grasp of modal distinctions – which we will now review. 3. The Kant-Sellars Thesis Brandom formulates the Kant-Sellars thesis (KS from now on) in the following way: "The ability to use ordinary empirical descriptive terms such as 'green,' 'rigid,' and 'mass' already presupposes grasp of the kinds of properties and relations made explicit by modal vocabulary."13 As its name says, KS has been defended in less explicit versions by Kant and Sellars, but Brandom articulates his own case to support it. KS is related to Sidelle's claim that we need persistence and possibility conditions for objects (i.e., every object must have a modal profile), but it runs deeper: descriptive terms are inherently modal, thereby licensing or precluding various counterfactual claims about the properties they name. If we did not have a counterfactual inferential profile associated with these notions, we would not be able to use them to acquire knowledge about the world. Brandom's argument starts from the premise that every autonomous discursive practice must have an observational vocabulary. The second claim is that those who engage in discursive practices must be able to distinguish between materially good and materially bad inferences ('material' meaning that the inferences contain non-logical terms in an essential manner). If we are not able to determine the character of some inferences wherein some term is involved, that term has no cognitive content. But (third premise) material inference is nonmonotonic, which is to say it is defeasible by special circumstances. To take a simple example, I might be entitled to infer, based on the physical properties of the glass bottle in front of me, that if the bottle fell to the floor, it would break. Now, what Brandom says is that (obviously) this inference and similar ones don't 13 Brandom, Between Saying and Doing, 96-97. Mihai Rusu 180 function as formal inferences in logical systems. If I add another premise, thereby defining a circumstance where gravity is weaker, or the floor is actually made of a soft material, or what have you, then I cannot draw the wanted conclusion. Every material inference has its own host of 'unless'es. If the bottle falls to the floor, it will break, unless gravity is much weaker, unless the floor is made of cardboard, unless...We can certainly have an idea of what these defeasors should look like, but we are certainly not able to provide a complete list thereof. Fourth, many of a subject's beliefs may only be justified as conclusions of material inferences. Finally, in order to count as a discursive practitioner, one must be epistemically responsible, that is, minimally committed to justifying one's beliefs.14 If our knowledge of the world works this way, then according to Brandom, it should yield an updating problem. Each time we modify our beliefs, this change may be relevant to the justification of every prior belief – it may act as a defeasor, or it may make the subject give up some premise she relied upon or a counterdefeasor. Each potential change may ruin a whole edifice of beliefs. The way out of the updating problem cannot be to review all of one's beliefs every time there is a change of belief, as this is practically impossible. So, the solution, according to Brandom, is to associate which each belief a set of material inferences in relation to which that belief may act as a defeasor. But this yields, for each material inference, a set of defeasors that defines the counterfactual robustness of that inference.15 I recall at this point that I am interested in Brandom's account as an argument against the idea that two people may agree about all the relevant empirical facts and disagree about the modal ones, which was a starting point for my doubts concerning the facticity of modal claims and disputes. Well, it certainly seems that Brandom's account could be interpreted this way. For Brandom, the users of empirical vocabulary must have an idea of the counterfactual robustness of their ordinary descriptive terms. This in turn means that agreement about some empirical claim may be illusory if our two subjects disagree about all or most of the related counterfactual claims. However, I don't think that Brandom's account vindicates an objective notion of possibility, i.e. metaphysical possibility, and I don't think it sets out to do that. Let me elaborate on these claims. I will use a short critical assessment by Stjernberg that raises some legitimate doubts about Brandom's argument for KS.16 14 See Brandom, Between Saying and Doing, 106-08 for the detailed argument. 15 See Brandom, Between Saying and Doing, 108-09. 16 Fredrik Stjernberg, "Brandom's Five-Step Program for Modal Health," in Proceedings of the Workshop on Bob Brandom's Recent Philosophy of Language: Towards an Analytic Modal Rationalism and the Objection from the Insolvability of Modal Disagreement 181 The overarching idea is that the account is sketchy, which is to say it needs to be developed so that it explains adequately the way the updating process works, most notably the way we manage to delineate and use counterfactual profiles for empirical notions. This is correct, but we may suppose that Brandom's sketch could be developed into a full-fledged account of the modal basis of our knowledge, as there is no manifest contradiction or conceptual tension therein. Now, one of Stjernberg's criticisms that elaborates on the perceived sketchiness of Brandom's account is that his line of reasoning is not strong enough to support the strong conclusion that we must know roughly the same counterfactuals if we are to count as epistemically responsible agents.17 Stjernberg claims that this conclusion is desirable for Brandom and that in order to be able to support it, we also need to show that "the use of a particular modal or counterfactual statement is justified, that there is some way to distinguish correct from incorrect use."18 In other words, in order to be entitled to draw the strong conclusion from Brandom's argument, we need some supplementary epistemological premise that reports on our ability to get a grip on objective possibility (i.e., something that justifies ontological realism about modality). I disagree with Stjernberg that the strong reading is the desirable conclusion of Brandom's argument. If we frame the argument in the context of Brandom's theory of modality, it appears that Brandom doesn't need the strong version; moreover, it seems to run counter to his basic tenets. In Brandom's view, KS should be interpreted in accordance with the idea that the expressive role characteristic of alethic modal vocabulary is to make explicit semantic or conceptual connections and commitments that are already implicit in the use of ordinary (apparently) non-modal empirical vocabulary.19 So, it must be emphasized that Brandom sees modality as a fundamentally conceptual matter: our modal assertions are actually statements of rules concerning concept use. The idea of a correct use of modal and counterfactual notions, insofar as it supposedly tracks some real, objective possibility, is secondary at best. That is why Stjernberg's weak reading of Brandom's argument – with the conclusion that "we must be in agreement on some counterfactuals, if we Pragmatism, eds. Cristina Amoretti, Carlo Penco and Federico Pitto (Genoa: University of Genoa, Department of Philosophy, 2009), 18-22. 17 Stjernberg, "Brandom's Five-Step Program," 21. 18 Stjernberg, "Brandom's Five-Step Program," 21. 19 Brandom, Between Saying and Doing, 99. Mihai Rusu 182 are to see each other as epistemically responsible and hence discursive creatures"20 – seems more appropriate. However, I agree with Stjernberg that Brandom's argument doesn't discriminate between a correct and an incorrect use of counterfactuals; consequently, it does not (because it cannot) articulate a robust concept of metaphysical modality. But I don't regard this as a shortcoming of Brandom's account, for reasons just given. In a nutshell, the conclusion of this section is as follows. If KS is correct, then there cannot be empirical agreement and modal disagreement on strongly related matters. But KS is subtended by a conceptualist/expressivist perspective of modality. Our modal assertions articulate implicit rules concerning the structure and use of our concepts. A question remains however: couldn't something like KS (some version of the no-separation idea) be made to work in the framework of ontological realism about modality? After all, realists such as Williamson and Hale are supporters of the intertwining of the modal and the non-modal.21 I am fairly sceptical about the prospects of such an endeavour. While I don't have a well-developed argument in support of my scepticism, I see very little ground to allow one to uphold KS outside a broadly Kantian framework. A more detailed realist account of the fusion and interplay of the empirical and the modal would be needed. For instance, Hale makes the no-separation idea a staple of his theory of modality, but he provides very little in the way of development and illustration of this unity. Remember how Brandom's account works. We have modal concepts because we have rules for our concepts. That is why the updating problem is so important. Change occurs not only in the realm of ordinary beliefs; it may also affect the rules. This is where 'reality' appears to produce an effect on our modal faculty, whatever we take that to be. Now, for the conceptualist (in a broad sense) a change in our modal views just is a change in the rules, that is, a change in the structure of our ordinary concepts. But the ontological realist about modality would want to maintain that there are modal facts, which should also make her want to resist admitting that a change in our modal views always amounts to a change in the structure of our ordinary concepts. I see this as a strong reason for the realist to reject the no-separation idea, at least as it has been described in this paper. 20 Stjernberg, "Brandom's Five-Step Program," 20. 21 See Timothy Williamson, The Philosophy of Philosophy (Oxford: Blackwell, 2007), 137, and Bob Hale, Necessary Beings: an Essay on Ontology, Modality, and the Relations Between Them (Oxford: Oxford University Press, 2013). Modal Rationalism and the Objection from the Insolvability of Modal Disagreement 183 4. Conclusion There may be some substance to the no-separation thesis – perhaps there is a modal dimension to our ordinary statements, and modal disagreement should be reflected in empirical disagreement. However, if (some of) Sidelle's and Brandom's views are right, modal disagreement has a theoretical nature: we disagree about the confines of objecthood or the definition of a notion. If we take conventionalism out of Sidelle's argument, e. g., if we try to articulate it in a Kripke-Putnam semantic framework or if we try to make epistemological sense, so to say, from our modal scenarios, we see that the argument breaks down. Brandom's approach is not adequate for supporting ontologically robust concepts of modality. The arguments of this paper may cause significant distress for the modal rationalist, but they should not bring her an irreparable defeat. The other party must be heard, but this means that more should be done in order to describe and explain the link between the a priori principles of modal knowledge and the purportedly mind-independent modal reality. More precisely, some way of deciding satisfactorily between the opposing sides of a substantial modal dispute must be discussed and theorized. Otherwise, concerns about the status of modal facts and modal knowledge may indeed prove defeating for principle-based accounts of modality. My sceptically motivated paper ends with this invitation.22 22 This paper was supported by the Sectoral Operational Programme Human Resources Development (SOP HRD), financed from the European Social Fund and by the Romanian Government under the contract number POSDRU 159/1.5/S/133675. The author wishes to thank Mihai Hîncu and Adrian Ludușan for their comments and suggestions concerning some of the issues discussed in this paper.