Comments on John Divers’s “On the Significance of the Question of the Function of Modal Judgment”. Draft. Final version to appear in a volume edited by Bob Hale with Oxford University Press.

The question of the function of modal judgement is an interesting philosophical issue, and John Divers's paper (this volume) has persuaded me that it has not received the attention it deserves. I think it is an important and interesting question even apart from any more ambitious claims that are made about its role in settling other issues about modality. Even if we became convinced that the story about function put no constraints whatsoever, epistemologically or metaphysically, on a theory of modality, it would still remain an interesting question about one of the pervasive and perhaps fundamental things we do in our cognitive lives. Divers’s paper is primarily concerned with establishing the legitimacy and importance of the question of the function of modal judgement, and disposing of some “quick answers” that might incline you to think there was not much of importance to be found here. There is too much that is thought-provoking to try to cover everything, so in these comments I want to talk about three things. The first two are challenges to Divers’ project. Should sorting out the function of modal judgement be a job for philosophers in the first place? When we think about the question of function in other areas of theory, don’t we realise that it should not play a very central role in modal theorising? Then I’ll end with something perhaps more constructive: a quite general kind of answer we should consider to Divers’ central question.

Should Philosophers Be Doing This? On the face of it, why people do certain particular things, and why certain social institutions exist, sound like questions for the social sciences. In particular, questions about why we make certain sorts of judgements look like psychological ones, or perhaps sociolinguistic ones if we focus on the practice of making public utterances expressing and evaluating these judgements. We need not assume that there is just one function, or a

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unified story about function for the whole, so the question “what are the functions of modal judgement?” is likely to be controversial, thorny, and might well repay some observation of people actually modalising. It’s a lesson we learned slowly in the modern and contemporary period, but often if you want to find out how these conventional activities work and what they are aimed at, getting out of the armchair and having a look is usually important. Indeed, some empirical work has been done on modal judgement: a landmark is Jean Piaget’s two pioneering volumes in developmental psychology Possibility and Necessity (1981, 1983): and if I were a psychologist or sociolinguist, I hope I would know of more. Something like that would be the challenge, I take it. In fact, even though the function of modal judgement is an eminently a posteriori issue, I think philosophers do potentially have a useful role to play in answering it. There are a variety of things that can be usefully done from the armchair, even on empirical questions. There is useful ground clearing to be done in distinguishing different questions, suggesting initially plausible hypotheses for further scrutiny, assembling reminders about some of the kinds of phenomena to take into account, and so on. That does not sound like much in the abstract, but I think it can sometimes take us quite some way in a field that is in its infancy, and the investigation of the functions of modal judgement seems to me to be such a field. One might object that discovering the function of modal judgement is a philosophical issue, because it is a normative one: we are not being asked just to work out when, in fact, people make modal judgements, or what in fact the effect of modalising is, but rather what we should be modalising for (if anything), what good it does us (if any). I agree that part of the question of the function of modal judgement is normative, but I would disagree with the view that this moved it out of the reach of the social sciences. Perhaps the natural sciences can avoid studying the normative, but most social sciences cannot: they are up to their neck in theories about function. It is an interesting question in the philosophy of social sciences how empirical investigation can shed light on normative questions, but that is what it seems to be doing.

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So we should keep in mind that decent answers to questions about the function of modal judgement may have to await input from psychologists, sociologists, and others. Nevertheless, I think we (and particularly Divers) can probably get on and do some useful work before we call in the non-philosophers.

Is The Functional Constraint Too Strong? The second challenge is to the central role that Divers wants to suggest for considerations of function when we are formulating the rest of our theory of modality. Divers suggests a “functional constraint”: [O]ne ought to accept no more substantial a theory than is required in order to account for the body of (functionally) de jure modal assertion. The body of de jure modal assertion comprises the kinds of modal assertion that we (in some sense) need to make in order to serve whatever are the legitimate and identifiable purposes of our modalising. First a comment about this as a piece of advice about how to proceed: it might be counterproductive to insist on a story about what a set of judgements are for before we have a good story about what they amount to: if you don’t understand a topic, you are unlikely to be able to perfectly understand what the information is good for, as anyone who has filled out a grant application aimed at non-specialists can probably tell you. Of course we do not need to treat this constraint as a starting point, and I’m not sure Divers wants us to: perhaps it is best seen as standing in a dialectical relationship to our theorising - we have a stab at what is going on, and from that vantage point we work out if some of our commitments are unneeded for what seems to be the relevant purposes, and back again, simultaneously improving our understanding of modality and the role of modal judgement. Even so, I think it is implausibly strong. When trying to work out how to constrain

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theories, I often think it’s better to start with examples where we seem to have been doing pretty well - maybe the analogies won’t transfer across, but if not it would be interesting to hear what the dissimilarities might be. So let’s consider astronomy, and let’s go back to its infancy. In ancient times, what was the function of astronomical judgement? Well, there were a few star-gazers, theologians, and other theorist types who really cared about the stars and planets themselves, but a lot of people wanted to know about two things: astrological stuff, about how the stars and planets were going to affect them, and “applied astronomy” such as treating the heavens as a navigation aid, as a calender, etc. Suppose our proto-astronomer Diveros told us that astronomy should be subjected to a functional constraint: that we should not endorse any astronomical judgements that did not serve the “legitimate and identifiable purposes” of our astronomical judgements. Let’s finally suppose we, anachronistically, manage to work out that we should reject astrology, or at least be agnostic about it. Here are two ways of doing astronomy: coming up with tables of where the lights are in the sky when, on the one hand, and speculating about what the lights are and what relationships they stand in to each other, on the other. The latter involves a lot of theorising that seems to go beyond the function of astronomical judgement, at least insofar as that is given by navigation and time-keeping purposes. But of course trying to work out what the planets are doing up there is by far the better way of coming up with a good astronomical theory: even if people like Ptolemy added instrumental glosses to his theory, it was the glory of Greek astronomy that it speculated about the nature of the planets, and came up with orbits and all the rest. Okay, so maybe some planetary speculation was called for because we had a hunch we could improve the tables that way. (I doubt that hunch was particularly justified until planetary theorising was fairly advanced, but no matter.) Should we, on grounds of function, stick to coming up with an instrumentally understood planetary theory that saves the phenomena? In the early modern period, instrumentalism and realism clashed again. Perhaps Divers, with Osiander, would urge us to treat the Copernican shift as a mere instrument. An attempt by Galileo or Newton to go beyond function and try to

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work out a plausible physics of the celestial bodies seems rather uncalled for, at least by the best accounts of the functions of astronomical judgement at the time of Osiander. (Unless just getting it right about the heavenly body is an important function of theoretical astronomy - but this sounds rather like the “bluntly cognitive” response Divers finds unsatisfactory.) But let’s face it, if your account of astronomical method condemns Newton’s Principa as poor astronomical theory construction—in this case, because it took on too many commitments that took us beyond the pre-established “function” of astronomical judgement—then that is a reductio of the functional constraint, not a problem for Newton’s astronomical theory. The fact that Newton’s theory went well beyond what we need to tell the time or find out which way is north does not tempt anyone I’ve ever met, at least, to think we should be instrumentalist about it.1 Perhaps we could try to say that while it fails to be good astronomy, it is good physics because of some function of physics it serves well—but frankly, sugaring a cyanide pill doesn’t make it more appealing. Consider another example (at less length). Suppose I worry that geology has lost its way—too much contemporary geology does not directly serve the “functions of geological judgement”. Let us just suspend judgement about a lot of geology, and just keep the stuff that will find us oil or uranium or tell us when volcanoes are likely, and that sort of thing. Who’s with me? Why not? You might think one of the main functions of geology is to get it right about how the Earth’s crust, and perhaps below, is arranged. This “bluntly cognitive” function would serve to rule out most functionalist clamour to suspend judgement, of course, but if Divers is right, citing this sort of function “misses the point” and should be set aside. Another reason we might be suspicious of imposing functional constraints on either astronomy historically or geology today is the somewhat holistic nature of the enterprise. To have the best geological theory about the location of oil deposits, we need to bring in 1

Perhaps Bas van Fraassen is an exception.

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all sorts of information about tectonic shifts, past land levels rising and falling, geological movements in different sorts of rock, and so on, and a lot of that information may have been first discovered and tested in areas that appeared to be only of “academic interest”. And we should not burn, or cease believing, the unnecessary knowledge today, either, since progress on topics that may eventually serve an instrumental purpose may come from study of rocks or formations or movements that are far from mainstream interest today. The path that led us to our current understanding of the solar system and beyond, and abilities to predict astronomical phenomena beyond the dreams of the ancients, depended on a diverse range of enquiries interacting in ways that could not have been predicted in advance, including investigation into many phenomena, terrestrial and celestial, that seemed to be of no practical interest. Likewise with our understanding of our planet and its geology. If this sort of epistemic holism is right in astronomy and geology, might it be right in the theory of modality? If it is, and I’m inclined to think that it is, we should try to work out what’s right, and then work out what can be useful to us. Of course we do not need to wait until theoretical inquiry is finished before beginning the practical inquiry, and we don’t, but even for those uninterested in the theory of modality for its own sake should be cautious about dispensing with sections of modal theorising as not currently useful for today’s practical purposes. To get it right about the things that practically matter, I’m afraid we have to investigate matters that are not otherwise of practical interest - as test cases, as sources of insight, as reminders. At least that’s true in astronomy and geology, and if it’s not in the theory of modality I would like to hear the reasons why. What does this say about the functional constraint? It could be read as consistent with it—lots of modal judgements do serve a function, it’s just that they serve those functions indirectly as being part of our overall project of inquiry. They help get the practical bits right (whatever they are). Of course, if we want to count any modal investigation as “functional” in this sense, fine: but then we’ve saved the functional criterion at the cost of eviscerating it, since the most academic mucking around with Kripkean essentialism of origin for tables or the modal profiles of tropes might get a free pass quickly once some

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modalising, somewhere, is legitimated by reference to some instrumental purpose, and it is established that it matters that we get things right.

Modal Desires The third thing I want to cover in my comments is a suggestion for a kind of function that we might propose for modal judgements, and one that might make for a quick answer to the question of the function of a lot of modal judgements. Often when we want to know what a piece of theorising is for, or why we should do it, we are told about how it serves some desires of ours. Why do we collect information about water use, or theorise about water use in Britain? Well, for a variety of reasons, but one of the important ones is because we want supplies of clean water for drinking, bathing, industrial purposes etc., and we want water for irrigation, feeding stock, and so on. The purpose of tracking water use in Britain is, in part, to enable us to get want we want, water-wise. We have many desires about water, and we seek to satisfy them. Analagously, we have a lot of modal desires. We desire to keep some possibilities open and close others off. We desire that some things have to happen, and other things do not have to happen. Since Divers brought up subjunctive conditionals, the field of desires with conditional content is very wide: I want it to be the case that if you steal from me, you go to prison, for example.2 (Incidentally, there’s a big problem for expressivism about conditionals waiting here: how could they express the contents of desires?) Now, to satisfy these desires with modal content, it’s very likely that we would need to make modal judgements. Finding out how the world is, modally speaking, is one of the first steps to changing it to suit us. There are more indirect connections too: sometimes when I care about something, I want to know how it stands, even if I cannot do much about it. (I want to know how tsunami reconstruction is going in Indonesia, even though there’s not a lot I plan to do about it either way.) Even for modal matters that we cannot easily affect, if we want them to be some way rather than another, modal judgement 2

Okay, maybe I’m more of a softy than that. But steal too much, and I want you to go to prison.

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seems called for to find out how they are. So here is one story about the function of modal judgement: it is to tell us how things stand with respect to matters that we have desires with modal content about. Of course, this invites some further questions: what modal matters do we care about? Do we need all of modalising to answer to this need? The answer is pretty clearly yes if the desires include those of modal theorists: I want to know how things stand modally, de re as well as de dicto, alethically as well as epistemically and deontically, even if nobody else does. But maybe a lot of it is dispensible to answer to the desires of the people on the street. (There is presumably a controversy to be had whether the people on the street care about what is metaphyscially necessary or not, for example.) There are another set of further questions: Divers may want to ask us what is the function of modal desires? Should we have them? Should they obey a functional constraint, that we should only have, or attempt to satisfy, those modal desires that we need to have “in order to serve whatever are the legitimate and identifiable purposes of our modalising”? But here the ground might shift a bit, especially for a Humean. I’m inclined to think that sometimes, indeed, often, having a desire for something gives one an identifiable purpose for getting it. The question about purpose makes sense for those modal desires that are instrumental for a non-modal goal—then it seems perfectly appropriate to ask whether they are suited for their purpose, and whether there might be a better thing to want in order to serve that goal. But we have been given no reason to think all our modal desires are instrumental, and I think it is very plausible that some of them are not. My desire to be free, for example, seems to me a modal one—it is a desire, at least in part, for a cluster of abilities, and absence of necessities constraining me—but I’m not sure I want that purely instrumentally.3 Being free rather than a slave or a prisoner or a serf helps me get 3

A referee pointed out that in some of the classic Frankfurt cases—where I do what I want when I φ but evil scientists stand ready to take over to ensure I φ whether I want to or not, for example—what is undesirable is not anything about what I in fact do, but only about what would happen were things otherwise.

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other things I want, but it’s a good state to be in as well. Likewise my desire to have various cognitive abilities—it’s not just instrumentally valuable for me that I’m not a vegetable. There are further interesting lines of inquiry open here as well: what modal desires of ours are non-instrumental? What are the ways modal desires could be instrumental for non-modal ends? Thinking about the function of modal desires opens up interesting questions. But I do think we should be very careful imposing a functional constraint on our modal desires. If I want something, I don’t want to have to wait until the philosophers have finished analysing its status, whether it is instrumental, whether my wanting it serves some purpose we would endorse: I want it now. So pro tem at least, we have one available story about the function of a lot of modal judgement: we make judgements about those topics because we have practical concerns about some modal matters. And while further investigation is fascinating, I don’t want to stop caring until the philosophers tell me it’s okay to be interested.4

Daniel Nolan Department of Philosophy University of Nottingham University Park Nottingham NG7 2RD United Kingdom

References Divers, J. 200x. "On the Significance of the Question of the Function of Modal Judgment". Piaget, J. 1981, 1983. Possibility and Necessity

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Thanks to anonymous referees and to Carrie Jenkins for discussion.