Thinking Disagreement

Thinking Disagreement by VÍCTOR M. VERDEJO Universitat de València and XAVIER DE DONATO-RODRÍGUEZ Universidade de Santiago de Compostela Abstract: In this paper, we bring into focus the level of thought or content in the elucidation of disagreement. We set out the view that disagreement at this level involves a specific form of noncotenability, namely, noncotenability as captured by sense or intension as opposed to reference. We present the challenge that nourishes the alternative referential view and suggest, through examples, that (i) only intensional disagreement is apt to adequately accommodate basic rationality constraints on disagreement, and (ii) it can meet the aforementioned challenge insofar as we discriminate between noncotenability affecting one’s concepts, intensionally conceived, and noncotenability affecting merely one’s particular understanding of those concepts. We conclude that intensional disagreement is our best choice for an account of disagreement at the level of thought. Keywords: Disagreement, rationality, intension, reference, noncotenability, understanding 1. Introduction Disagreement has proven to be a fruitful interdisciplinary theme in the philosophical arena, with principal junctures in epistemology, the philosophy of language, and the philosophy of science. The roster of proposals tackle issues so important as the epistemology of disagreement, the semantics of statements about taste or value, and the logic of scientific controversies. It is certainly not our aim in this article to address any one of these complex topics in particular. Presumably, however, what we have to say here is of significance to them and other provinces of research on disagreement. This paper bears specifically on the question of what disagreement really amounts to at the level of thought or content and, more in particular, how disagreement should be best characterised at this level in the light of basic constraints of rationality. The thesis we aim to defend in this connection is that, contrary to a long-standing dominant view, the best elucidation of thought or content in THEORIA, 2021, 87, 1562–1584 doi:10.1111/theo.12364 © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. disagreement is in terms of Fregean sense or intension, and not merely reference. 1 The ensuing discussion is structured as follows. We bring into focus the level of thought or content in section 2. Following MacFarlane (2014), we set out the view that disagreement at this level involves noncotenability of a special form, namely, noncotenability as captured by sense or intension (intensional disagreement) as opposed to merely reference (referential disagreement). A central motivation for this view is that disagreement is answerable to the rational capacities of thinkers. In section 3, we elaborate on this idea and flesh it out in terms of the notion of “rational engagement”(Heck, 2002). Rational engagement, we propose, marks the existence of basic rationality constraints that make disagreement possible in the first place. This notion does not, however, in and of itself support the intensionalist approach we favour here. In the light of this, we explore the motivation for the alternative referential view –that is, the view that disagreement consists of noncotenability at the level of reference or state of affairs –and present the referentialist challenge to intensional disagreement (section 4). In response to this challenge, we go on to suggest through various examples that (i) only intensional disagreement is apt to adequately accommodate the basic rationality constraints on disagreement (section 5), and (ii) it can also meet the aforementioned challenge insofar as we discriminate between noncotenability affecting one’s concepts, intensionally conceived, and noncotenability affecting merely one’s particular understanding of those concepts (section 6). We conclude, in section 7, that intensional disagreement is our best choice for an account of disagreement at the level of thought. 2. Disagreement and Thought Several phenomena may justifiably go under the head disagreement. In this paper, we are concerned with an attitudinal, or attitudinally reportable conception. 2 From this angle, it is helpful to draw the distinction between genuine and merely apparent disagreement. Let C be the condition under which disagreement, in our attitudinal sense, obtains. We may therefore distinguish between the case in which 1 Drawing on Carnap’s developments, Kaplan used “intension”to denote a function from circumstances to extensions (Kaplan, 1989, pp. 501–502). In this paper, however, we confine the use of “intension”to refer to a Fregean sense or thought and take approaches invoking Kaplanian intensions to fall neatly under the remit of referential approaches (see section 2 and 4 below). 2 We follow Cappelen and Hawthorne (2009, pp. 60–61) as well as many others in confining attention to (dis)agreement of attitudinal states, as opposed to merely the behaviours or utterances of two individuals. Nonetheless, behaviours or utterances may indeed genuinely express or manifest disagreement in our sense. 1563THINKING DISAGREEMENT © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License subjects wrongly take themselves to be in a C-situation and the case in which they are, in actual fact, in a C-situation. The former, merely apparent case may have all the manifest features of the latter, but only the latter counts as real or genuine. Each candidate notion of disagreement below provides its own divide between genuine and merely apparent cases. As we will see, the way in which each candidate traces this distinction may count in fact as a central aspect of its assessment. 3 But, other than in terms of the contrast to merely apparent disagreement, how should we characterise the relevant notion of disagreement at the level of thought? Candidates for disagreement at this level unfold in an array of variable intentional complexity. These can all be seen as particular readings of what MacFarlane and others call “noncotenability (MacFarlane, 2014, Chap. 6, esp. 121–123): two attitudes are noncotenable in this sense if they cannot be coherently adopted by the same person at the same time. MacFarlane’s notion of noncotenability concerns specifically disagreement with attitudes. In what is a notational variant, we take subjects to be the bearers of the disagreement relation (A disagrees with B in relation to x). For present purposes, we will be assuming that some form of noncotenability is characteristic of disagreement at the level of thought. This assumption might seem initially objectionable to some theorists. MacFarlane himself goes beyond this notion in the full characterisation of disagreement. 4 It might therefore seem arbitrary to fixate precisely on noncotenability here. By focusing on noncotenability, however, we are not denying the importance of other notions (crucial, for instance, regarding the clash between relativists and contextualists). Our aim is rather to show that, even if we focus on noncotenability, several theoretical options will need to be adjudicated before one can be said to have a grip on the notion of disagreement at the level of thought. 5 What follows can be seen, 3 See also Heck, 2002, pp. 26–27; Plunkett, 2015, pp. 835–837. Although partially overlapping, the notion of apparent disagreement in this sense departs from the notion of (merely) verbal dispute (Hirsch, 2005; Chalmers, 2011). Apparent disagreement is broader than verbal dispute in that the former is not confined to cases of verbal interaction. Moreover, apparent disagreement does not, in and of itself, call for a positive characterisation. Here, apparent or non-real disagreement is subservient to the notion(s) of disagreement under consideration. 4Byreflecting, especially, on (objectivists, contextualists and relativists) construals of preclusion of joint accuracy or the idea that “…in at least one sense of disagreement that we care deeply about, when two people disagree in virtue of having certain beliefs, those beliefs cannot both be accurate. If two people disagree, they can’t both be right”(MacFarlane, 2014, p. 126). See also Marques (2014) and Palmira (2017) for characterisations of disagreement beyond noncotenability. On the notion of relative truth and the semantics of statements about taste or value, see also Kölbel (2004), MacFarlane (2007), Kölbel and García-Carpintero (2008), Baker (2012). 5 We take this point to be explicitly advanced by MacFarlane (2014, p. 121, n. 6). We will return to MacFarlane’s views below. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1564 VÍCTOR M. VERDEJO AND XAVIER DE DONATO 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License therefore, as an inquiry into the main forms of noncotenability at the disposal of the theorist of disagreement to capture or approximate such a characteristic notion. A paradigmatic case of noncotenability in the relevant sense is present when subjects endorse doxastic attitudes with contradictory contents of the form p and not-p. As many authors have emphasised, noncotenable attitudes need not have directly contradictory (or exclusionary) contents but may rather concern contents whose consistency is compromised by rather indirect or presupposed contentrelations (e.g., MacFarlane, 2007, p. 24; L opez de Sa, 2008, 2015; Marques, 2014, §3.2; Khoo and Knobe, 2018) or, relatedly, may involve attitudes – such as desire or intention –which are satisfactionor action-conducive rather than truth-conducive (e.g., Huvenes, 2012; MacFarlane, 2014, Chap. 6; Marques and García-Carpintero, 2014; Marques, 2015; Sundell, 2011). 6 Under certain interpretations, disagreement at least some times (and arguably often) involves a form of metalinguistic negotiation, that is to say, conflicting views over meaning or concept use (Barker, 2002; Plunkett and Sundell, 2013; Plunkett, 2015). Others have also set forth a notion of disagreement about reasons (Scanlon, 1995; Kalderon, 2005) which requires not only that the disputants disagree over which proposition is to be believed but also about what counts as a reason to accept or reject it. For ease of exposition, however, we will here confine attention to belief noncotenability involving directly contradictory contents. This is admittedly only a subclass of the full range of attitudinal conflicts yielding disagreement. Once doxastic noncotenability with contradictory contents is in view, we can finally locate the proper boundaries of our discussion. In standard formulations, when two subjects A and B disagree over p, they do so in virtue of a form of noncotenability between their beliefs that is stated in truth-involving or truththeoretic terms. Three levels or aspects of this truth-involving analysis can be demarcated: use or expression, assessment or index, and content or thought. The first two of the triad are often discussed under the Kaplanian distinction between “context of use”and “circumstance of evaluation”(Kaplan, 1989; see also Lewis’s (1980) related distinction between “context”and “index”). However exactly understood, both use and assessment intervene crucially in the truththeoretic analysis of interpreted sentences. To a first approximation, the use level includes the contextual elements (e.g., location, time, world) contributing to the expression of a thought or content by a sentence as uttered, produced, or tokened by a given agent. On the other hand, the assessment level comprises the 6 Stevenson (1948/1963) provides a classic statement of the last point via the distinction between disagreement in belief and disagreement in attitude. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1565THINKING DISAGREEMENT 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License contextual elements (e.g., location, time, world) that determine the truth value of the thought or content so expressed. With slight terminological variations, use and assessment have attracted much attention in the literature on disagreement. 7 Under this light, use marks the context in which disagreement is expressed or accepted, whereas assessment determines the (conflicting) truth value of the thoughts so expressed or accepted in the disagreement. This paper concentrates however on the remaining, content or thought level. This level of analysis concerns that which is expressed by the utterance, production, or tokening of a sentence. It thus pinpoints the kind of propositional content or thought that is precisely at stake in the expression and assessment of a disagreement. Not so much attention, we believe, has been paid to this level in the characterisation of disagreement. This is problematic. Although use, assessment, and content are obviously intertwined, the thought or content level is not exhausted by the use and assessment levels. Provided that no independent account is given of thought or content, a full specification of use and assessment leaves undetermined the nature –and indeed the presence –of disagreement in fundamental ways. Acknowledging this point is critical for a complete characterisation of disagreement. To illustrate, consider the thoughts or contents expressed by A and B when uttering the sentences in (1): 1. A: “Hesperus is a planet.” B: “Phosphorus is not a planet.” Let us assume that the contextual elements relevant to the dispute have all been settled in such a way that it is clear (a) that a determinate thought has indeed been expressed by the utterances (via a specification of the use aspect corresponding, say, to the actual world), and (b) what its associated truth value is (the assessment aspect assigning, say, the truth value true to A’s utterance and false to B’s utterance). This situation still leaves undetermined, we submit, whether A and B really disagree with one another. The problem concerns what kind of noncotenability is involved at the thought or content level. Two main contenders clearly stand out at this point. A popular view among philosophers is, first, that disagreement is achieved if A and B possess noncotenable beliefs in the sense that they involve contradictory referential 7 When not exactly conforming to Kaplan’s usage, the use and assessment levels appear in discussions of disagreement via the distinctions between “context of use”and “context of assessment” (MacFarlane, 2007, 2014), “context of acceptance”and “circumstance of evaluation”(Rieppel, 2011), “context”and “point of evaluation”(L opez de Sa, 2012), “world of acceptance”and “point of evaluation”(Belleri and Palmira, 2013), among others. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1566 VÍCTOR M. VERDEJO AND XAVIER DE DONATO 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License propositions or states of affairs (or functions that determine such propositions). We may use the label referential disagreement to denote disagreement arising from this referential noncotenability. As we will see, the view that disagreement at the thought level is referential in this sense signals a firm consensus in the philosophy of language and the theory of attitude reports at least since Kaplan’s seminal developments (see section 4 below). This contrasts, secondly, with the notion of disagreement we will be advocating here. Disagreement, we think, requires a more demanding form of noncotentability than referential noncotenability. We want to suggest, more precisely, that it requires noncotenability of Fregean intensions or senses. We may call this intensional disagreement. On this view, for two beliefs to constitute disagreement it is not enough that their contents involve contradictory referential propositions or states of affairs (e.g., regarding the properties of an astronomical object). They must also involve contradictory intensions, that is to say, contradictory referential propositions thought or grasped under the same sense or intension. 8 Thus, for an advocate of intensional disagreement, the scenario depicted in (1) might be one in which distinct intensions prevent the presence of disagreement. Assuming –plausibly –that the terms “Hesperus”and “Phosphorus”have different cognitive impacts on the mind of a rational subject, (1) might be a case in which A and B express beliefs that are cotenable. A and B would be, as it were, just thinking past each other. On the other hand, if one joins the referentialist in thinking that reference or state of affairs is all that matters for disagreement-constituting noncotenability, we would be urged to concede that there is disagreement between A and B after all. This point shows that the thought level of analysis is a critical element of the account of disagreement that goes beyond use and assessment as standardly conceived. This point has already been advanced, albeit shortly, in John Macfarlane’s own discussion of noncotenability. After presenting what he calls the “simple view of disagreement”as the view according to which two people disagree whenever they have beliefs with incompatible contents, he observes in a footnote that “if contents are individuated coarsely –for example, as sets of possible worlds or Russellian propositions –more must be said”(MacFarlane, 2014, p. 121, n. 6). His example, of which (1) is indeed a variation, is one in which 8 An alternative way of setting up the present discussion is as follows: the proponent of referential disagreement would only have at their disposal noncotenability in the sense of contradictory referential functions or “intensions”in the Kaplanian sense (see n. 1), whereas in this paper we would be advocating noncotenability in terms of finer-grained contents or “hyperintensions”. We take this alternative way of describing the polemics to be largely equivalent to the one we propose in the paper, and to reveal the generality of the problem we are addressing, which could also be stated with resources characteristic of possible-world semantics. We thank an anonymous reviewer for bringing this point to our attention. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1567THINKING DISAGREEMENT 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Hammurabi believes that Phosphorus is not visible, whereas Sammurabi believes that Hesperus is visible, in which the beliefs clearly involve contradictory referential propositions. MacFarlane’sfirst suggestion in the footnote is to contemplate a conception of content “on which Hesperus is visible is compatible with Phosphorus is not visible”(ibid.). If we understand him correctly, the solution amounts to a conception of disagreement as intensional disagreement in the sense specified above. MacFarlane does not however commit himself to this solution: he also contemplates another possibility that consists in requiring, besides referential incompatibility, that this incompatibility be knowable a priori. This may seem to go in line with favouring referential disagreement and complementing it with some further epistemic condition in a way we will address below. In this paper, we explore in detail the intensionalist conception of disagreement merely gestured at by MacFarlane and present a positive argument for the claim that it provides the best account of the connection between rationality and disagreement. But how should we then settle the issue between the referentialist and the intensionalist about disagreement? A key to the resolution of this conflict, we propose, will come from reflection on the nature of disagreement as an exercise of rational capacities. In the next section, we elaborate on this suggestion. 3. Disagreement and Rationality The basic idea we want to consider in this paper is that subjects are, even if perhaps oblivious to their resolution, rationally answerable or accountable for the attitudes constituting their disagreements. Disagreement, to use Richard Heck’s turn of phrase, “serves to make it possible for people to engage one another rationally”(Heck, 2002, p. 16). 9 Without this rational engagement, we would lose touch with a thinker’s capacities to take a stand on, provide reasons for, and sensibly communicate a disagreement (or a retraction for that matter). Intensional disagreement, we wish to suggest in this essay, is the best candidate to capture this fundamental feature of disagreement. One caveat is in order at this point: as we noted earlier, we here confine attention to disagreement as a state rather than as an activity (see section 2). It follows that to determine whether disagreement obtains between A and B is a matter of determining whether certain states of A and B obtain, namely, noncotenable 9 Heck’s phrase refers to communication or understanding but takes (not merely verbal) disagreement to be constitutively related to them (see esp. Heck, 2002, p. 26). The idea of rational engagement or rational conflict in disagreement also transpires in the very notion of noncotenability as attitude incoherence (see above and also Plunkett and Sundell, 2013; Plunkett, 2015; Coliva, 2019). On the notion of rational engagement, see also Dickie and Rattan, 2010. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1568 VÍCTOR M. VERDEJO AND XAVIER DE DONATO 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License beliefs. For this reason, we do not take rational engagement in disagreement to require –strictly speaking –that subjects actually engage in a particular exchange or interaction. Nor does it imply that subjects can only disagree if they are rational subjects (arguably, subjects may irrationally hold disagreement-constituting beliefs). Rather, just as rational constraints would seem to govern attitudes in general, and belief in particular, so too they would seem to govern disagreementconstituting attitudes, such as noncotenable beliefs. Having said that, we do not aim in this paper to provide a full account of rational engagement. To flesh out the relevant connection to rationality, we suggest rather to limit our attention to two interrelated principles that seem to be especially plausible if subjects are indeed rationally answerable for their disagreements. They are thus necessary conditions for rational engagement in disagreement, no matter whether they are also sufficient. We may call them Non-reflexivity and Absoluteness: Non-reflexivity. It seems to be a corollary of the idea that subjects are rationally answerable for their disagreements –and hence, that they exhibit at all the kind of rational capacities mentioned above –that they cannot be in disagreement with themselves at the same time. Thus, for any p and subject S, it should not be the case that S rationally disagrees with S over p. 10 Absoluteness. If disagreement is a rational phenomenon, a related point seems unassailable, namely, that subjects either rationally disagree or do not disagree over p. More precisely, once all contextual elements (for use and assessment) are fixed (see section 2 above), subjects cannot rationally disagree and also not disagree (agree or neither disagree nor agree) about whether p with other subjects. For any p, therefore, and distinct subjects S and S0, if S disagrees with S0over p, then it is not the case that S does not disagree with S0over p (and conversely). Absoluteness entails that if subjects are to disagree over a subject matter at a given moment, and this subject matter is identical to another subject matter, then they also must, rationally speaking, disagree over the latter. More schematically, 10 This condition only concerns synchronic intrapersonal disagreement (diachronic intrapersonal reflexive disagreement typically indicates a change of mind, and is thus relatively unproblematic). Annalisa Coliva (2019) has argued that genuine disagreement can also be synchronic and reflexive in certain cases (of self-deception and implicit bias). This claim is however perfectly in agreement with Non-reflexivity if we restrict the principle to what she calls “belief as commitment”. Indeed, Non-reflexivity is entailed by her own principle of “Strong Consistency”for this species of belief (see Coliva, 2019, §4). Moreover, we also agree with Coliva in subscribing to an approach to disagreement that is constrained by a “no rational cotenability condition”(although our reading of this condition vis-à-vis the cases she discusses is somewhat different). © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1569THINKING DISAGREEMENT 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License for any p and q and any distinct S and S0, if S and S0disagree over p, and q =p, then they will also disagree over q. 11 In what follows, we explore the consequences of taking seriously the idea that disagreement requires rational engagement at least to the extent that it complies with these principles. More precisely, we take it to be a desideratum of any account of disagreement –whether referentialist or not –that they accommodate the existence of Non-reflexivity and Absoluteness as fundamental enabling conditions for disagreement. To illustrate the significance and neutrality of this position, we may consider the disagreement expressed by uttering the sentences in (2): 2. A: “George Orwell wrote 1984, not Eric Blair.” B: “No, George Orwell didn’t write 1984. Eric Blair did.” Let us focus, in particular, on the following seemingly uncontroversial feature of the case: knowledge of the coreferentiality of the terms “George Orwell”and “Eric Blair”by A and B would make the disagreement between them rationally unacceptable. The explanation of this feature, we suggest, is that to allow for disagreement in the presence of such knowledge would be to sanction a notion of disagreement that flagrantly violates Non-reflexivity (A and B would both be disagreeing with themselves over the authorship of the novel) and Absoluteness (they would be agreeing and disagreeing with each other over the authorship at the same time). For this reason, should this knowledge be available, A and B would seem to be rationally obligated to believe or endorse their interlocutor’s expressed thought and hence arrest the disagreement. The point holds no matter whether they indeed do so, and no matter whether they conceive of themselves as being, or having been in disagreement after such knowledge is acquired. Although this point highlights the import of rationality constraints in the account of disagreement, it does not allow us to adjudicate between referentialists and intensionalists. Both referentialists and intensionalists may seem to have a story to tell about the effect that knowledge of coreferentiality has on A’s and B’s confrontation. For instance, the proponent of referential disagreement would forcibly point out that A and B’s disagreement-determining knowledge reflects or corresponds with a condition entirely describable in referential terms: if there is knowledge of coreferentiality, referential noncontenability (and disagreement) will be rationally barred. Likewise, advocates of intensional disagreement may provide accounts in which knowledge of coreferentiality in such cases aligns with matching intensions. 11 Other principles might be added to the list, such as transitivity and symmetry of the disagreement relation, but only the ones listed will be doing important work in our argument. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1570 VÍCTOR M. VERDEJO AND XAVIER DE DONATO 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License here right to suggest, we believe, that central cases in which there is disagreement expressible with (3) are cases in which subjects would, plausibly, know about the coreferentiality of the terms. But, in order to be of use to the referentialist as a response to our previous discussion, they would need to make it also plausible that knowledge of coreference in these cases is actually a matter of reference alone. This is however unlikely. The reason is that knowledge of coreference – together with contradictory referential contents –is neither necessary nor plausibly sufficient for the presence of disagreement. Let us spell out the point. Knowledge of coreference is not a necessary condition because, as Herman Cappelen and John Hawthorne have pointed out in a different context, agreement and disagreement in the static, attitudinal sense that concerns us here “is perfectly applicable to interaction-free pairs of individuals so long as there is some view about the world that they share”(Cappelen and Hawthorne, 2009, p. 60). For instance, ordinary people nowadays plausibly disagree with John Dalton, the chemist, over the indivisibility of atoms (Verdejo, 2016), and the ancient Greeks and Indians disagreed over funerary rituals before these civilisations got in touch with one another (MacFarlane, 2014, §6.1), or, likewise, Ptolemy and Galileo disagreed over the movement of celestial bodies even if they never got to know each other (Belleri and Palmira, 2013, p. 145). This point makes clear that A and B can be in disagreement without so much as knowing anything about one another, let alone the coreference of their respective terms. But the situation for the referentialist is perhaps more compromised than these remarks suggest. For knowledge of coreference –combined with referential noncotenability –is not only not necessary for disagreement. It is also plausibly not sufficient. To appreciate this, suppose that a layperson, call it Martha, who ignores practically everything about chordates (as opposed to cordates above) – say, someone who does not even know that a chordate has a distinctive anatomical feature –is watching the TV and, while intently enjoying a program about various species of the phylum, spots footage of what happens to be a lancelet (or any other cephalochordate). Suppose that, by pointing to the image on the screen, Martha expresses a thought by sincerely uttering “Those chordates have no heart.”As we are envisaging this case, it is not merely that Martha has said something true probably by sheer luck. She is moreover rationally limited insofar as she would find it, to say the least, quite challenging to come up with good reasons to back her statement. Now, suppose that a nearby spectator, Eve, refuses to accept the target claim and expresses a thought via “Those chordates indeed have a heart.”Suppose further that Eve knows that chordates have a dorsal nerve cord but, possibly misled by a hasty reading of Quine, 17 also happens to believe that 17 But not, of course, by Quine himself (cf. Quine (1970/1986, p. 8). © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1577THINKING DISAGREEMENT 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License all chordates are hearted. Is Martha in disagreement with Eve? That might seem to be an audacious position on the assumption that disagreement requires rational engagement. The problem is that Martha would seem to lack any sensible knowledge or understanding of the subject matter of the disagreement. It seems clear that this would preclude her from activating the sort of capacities that rational engagement intuitively requires. Indeed, this is a scenario in which violations of Non-reflexivity and Absoluteness would be easily in view for uninformed Martha. And, nevertheless, by pointing to the screen, the words “those chordates”as uttered by Martha and Eve would seem to refer to the same (class of) animals. Not only that, in her interaction with Eve, Martha would also seem to know about the coreference of her and Eve’s terms. This is, hence, a case in which coreferentiality and knowledge of coreferentatiality are granted; yet, the speaker might not have any sensible understanding of chordates and, consequently, would be seemingly alien to the engagement necessary to ground disagreement over chordates. If correct, this shows that knowledge of coreferentiality might not be sufficient in order to explain what subjects must have in common, cognitively speaking, in order to disagree. 18 It seems safe to conclude, therefore, that neither coreference, nor coreference combined with knowledge of coreference, adequately keep track of disagreement. 19 6. Responding to the Challenge (II) Let us finally concentrate on (ii) above. Note, to begin with, that the outcome in regard to (3) would be different with terms that are cointensional as well as coreferential. No matter whether intensions require other conditions of their own, it seems unobjectionable that the cointensionality of terms t (as used by A) and t0 (as used by B) indicates that A and B would be aware of the coreferentiality of t and t0(if they indeed are competent with the terms in question). Moreover, no matter whether they actually interact in an exchange, the cointensions would guarantee that A and B are never caught in violations of Non-reflexivity and Absoluteness. For this reason, we submit, the interlocutor’s disagreement-grounding rational engagement would be captured by their cointensions. Crucially, however, 18 See Heck, 1995, p. 101, n. 33 for a related example in which knowledge of reference does not suffice for understanding or communication. 19 Note that, arguably, the reference-fixing information attached to Martha’s and Eve’s“those chordates”to refer to the contextually salient x significantly differ: the latter but not the former involves a substantive (anatomical) condition for x to be a chordate. This indicates that their associated intensions are plausibly different too, and hence, that it is the (differing) intensions that may account for the lack of rational engagement and disagreement in this case. On the notion of reference-fixing information, see also below. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1578 VÍCTOR M. VERDEJO AND XAVIER DE DONATO 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License a requisite for shared intensions does not, in and of itself, turn into a requisite for shared understandings or comprehensions. There is indeed a vital distinction to be drawn between intensional disagreement and a third attitudinal candidate for the elucidation of disagreement, namely, the view that requires not only intensional noncotenability but also noncotenability in terms of the associated understanding or comprehension. This last option we may call comprehensive disagreement or disagreement as stemming from beliefs involving contradictory understandings or comprehensions. To make sense of this alternative, we may resort to the pretheoretical notion of possibly associated information. 20 When subjects use a term to think of an object or state of affairs, they may rely on all sorts of information (or misinformation) about that object or state of affairs. Comprehensive disagreement is the natural option if we take all or most of this information to have an equal status in the elucidation of the content expressible by that term. But this view would lump together dimensions of content (or meaning) that are clearly demarcated at least since C.I. Lewis’s developments (Lewis, 1946, Chap. 3). The main point in this respect is that not all of the information possibly intervening in thinking about the reference of a term plausibly contributes to fixing the reference of that term or, borrowing Lewis’s words, provides a “criterion in mind”to determine whether a term is correctly applied (e.g., Lewis, 1946, p. 43 and 133). We may thus distinguish between the intensions or concepts expressed, or grasped, by the participants in a disagreement, and the relative comprehensions or ways of understanding they might exploit in doing so (Higgimbotham 1998, Verdejo and De Donato-Rodríguez, 2015). From this angle, intension is better seen as the kind of information fixing the reference of a term, whereas comprehension or understanding corresponds to all the information (or misinformation) about a reference that a subject may possibly associate with the use of the term in question. Under this interpretation, the comprehension or understanding the subjects associate with a term stands in a many-to-one relation towards the intension of that term. 21 To fix ideas, and although we would like to remain liberal about the precise account to be offered, consider the term “week”and, as it might be, the reference20 We wish to remain neutral with respect to the exact nature of this notion. Several specific articulations—logical, psychological or informational-theoretic—are compatible with the basic traits introduced here. 21 We do not take the distinction, so drawn, to match exactly the one given by C.I. Lewis between “intension”or “intensional meaning”and “comprehension”. This is particularly so in the case of comprehension. For Lewis, comprehension is “the classification of all possible or consistently thinkable things to which the term would be correctly applicable”(Lewis, 1946, p. 39). However, we take a thinkable thing in this sense –whether imaginary or real –to roughly correspond to a possible specification of the determinable aspects of a reference contained in the intension, and to that extent, to be correctly approximated in the informational terms laid out in the main text. © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1579THINKING DISAGREEMENT 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License fixing information that a week is a period of exactly seven consecutive days (cf. Lewis’s, 1946, 40ff “square”example). Call this information i. According to the proponent of comprehensive disagreement, in order for there to be disagreement between A and B regarding the proposition expressible with “This is a busy week,” they would have to refer to the same stretch of time and exploit only information iin so doing. In this context, it is only natural to question whether A and B would be actually disagreeing in a situation in which, say, A thinks of a week as a period of exactly seven consecutive days starting on Monday, and B thinks of a week as a period of exactly seven consecutive days starting on Sunday. The advocate of intensional disagreement, by contrast, may here distinguish between the intension proper –in the example, the reference-fixing information i–and the various other pieces of information (or misinformation) that may possibly accompany the use of “week.”As long as these informational differences do not affect the way the reference is fixed, the idea goes, the proponent of intensional disagreement will not ipso facto count them as differences that may prevent disagreement between A and B. Once the distinction between intension and comprehension is clear, we can return to our claim that a requisite for shared intensions does not necessarily involve a requisite for shared understandings or comprehensions. To show this, let us suppose that A and B are comparable in their knowledge about cordates, except for the fact that A believes, and B disbelieves, that ants and other insects are cordates. We may therefore imagine these subjects having the disagreement they would express by uttering the sentences in (4): 4. A: “Ants are cordates.” B: “Ants are not cordates.” Let us suppose, for the sake of the argument, that both A and B grasp the intension of “cordate”and “ant”to the extent that they have knowledge of a simple reference-fixing description or information (say, “animal with a heart”and “small insect living in organised underground colonies,”respectively). The description may of course include other properties as well as biologically precise characterisations which are inessential here. The central point is that knowledge of this basic description may suffice for rational engagement in our sense. We suggest that, in such a scenario, the beliefs expressed by A and B would be disagreement-grounding (i.e., not rationally cotenable). However, even if it seems reasonable to say that A and B must be rationally engaged or accountable in order to accommodate their disagreement, we must be careful not to require too much of A and B in this regard. In particular –and this is the crux of the matter –it is not reasonable to require of A and B the very © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1580 VÍCTOR M. VERDEJO AND XAVIER DE DONATO 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License same comprehension of cordates or ants. This move is, however, not necessary if the distinction between intension and comprehension is recognised and exploited. It is not hard to imagine, thus, that one of the subjects may rely on more (mis) information about ants than the other. For example, B (but not A) may know that ants are of the Formicidae family, that ants are closely related to wasps and bees or that they are found in all continents except Antarctica. The important lesson to draw from these epistemic possibilities is that not having exactly the same comprehension of ants does not seem to prevent A and B from disagreeing about the issue of whether they are cordates. If it did, and as the referentialist would hasten to point out, disagreement over cordates, ants and many other matters would certainly seem exceptional, out of range even for those subjects who master highly technical theoretical definitions. This is implausible. The case would replicate for indefinitely many other scientific and ordinary terms. It follows that sharing the same comprehension is not required for disagreement. Because there is a distinction to be traced between comprehension and intension, however, we are not forced to conclude that intensional disagreement is not necessary either. Intensions may thus resist the referentialist challenge and still plausibly embody a reasonable approximation to disagreement. In sum, the referentialist falls short of –and the comprehensionist by far exceeds –the requirements for rational engagement that shape disagreement and a rational form of noncotenability. There is, apparently, only one promising route left for cashing out the notion of attitudinal disagreement between these Scylla and Charybdis: intensional disagreement. 7. Conclusion If the foregoing analysis is roughly correct, the map of notions of noncontenability available in the elucidation of thought or content can be represented as in Figure 1, in which the stripes cover the area corresponding to disagreement. In the diagram, every case of comprehensive noncotenability is a case of intensional and referential noncotenability, and every case of intensional noncotenability is a case of referential noncotenability, but not conversely. In this paper, we have endeavoured to offer a characterisation of the notion of disagreement at the level of thought or content, a subject matter whose elucidation is largely overdue and likely to affect a number of other areas of inquiry. Once engaged in this project, two main candidates suggest themselves: referential and intensional disagreement. We have shown that, even if disagreement admittedly involves the exercise of rational capacities, a neutral characterisation of the constraints this imposes on disagreement does not immediately rule out a referentialist standpoint. Moreover, intensionalists are called on to face the © 2021 The Authors. Theoria published by John Wiley & Sons Ltd on behalf of Stiftelsen Theoria. 1581THINKING DISAGREEMENT 17552567, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/theo.12364 by Readcube (Labtiva Inc.), Wiley Online Library on [22/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License referentialist challenge: to resist a notion of disagreement beyond noncotenability at the level of reference in ways that are explanatorily relevant and do not turn disagreement into a rare phenomenon. As we have argued, however, the notion of intensional disagreement goes a good way towards offering the most plausible analysis of disagreement answerable to rational capacities, and does so while meeting the referentialist challenge insofar as it makes space for the distinction between intensions and comprehensions. 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