What Tends to Be

The Philosophy of Dispositional Modality

Rani Lill Anjum, Stephen Mumford

• Publisher: Routledge
• Year: 2018
• ISBN:
  9781351009782
• Edition: 1
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

People tend to enjoy listening to music or watching television, sleeping at night and celebrating birthdays. Plants tend to grow and thrive in sunlight and mild temperatures. We also know that tendencies are not perfectly regular and that there are patterns in the natural world, which are reliable to a degree, but not absolute. What should we make of a world where things tend to be one way but could be another? Is there a position between necessity and possibility? If there is, what are the implications for science, knowledge and ethics?

This book explores these questions and is the first full-length treatment of the philosophy of tendencies. Anjum and Mumford argue that although the philosophical language of tendencies has been around since Aristotle, there has not been any serious commitment to the irreducible modality that they involve. They also argue that the acceptance of an irreducible and sui generis tendential modality ought to be the fundamental commitment of any genuine realism about dispositions or powers. It is the dispositional modality that makes dispositions authentically disposition-like. Armed with this theory the authors apply it to a variety of key philosophical topics such as chance, causation, epistemology and free will.

Part I

Modality

1 Theory

Introducing the dispositional modality

1 Modality

There is a standard basic framework for modality that every student of philosophy will know. Modality concerns necessity and possibility. Among the propositions that are true, some are also necessarily true. Among the propositions that are false, some of them are nevertheless possibly true. We call it the philosophy of modality because the addition of necessity or possibility is a mode of, or modifies, the proposition in question. Hence, it may be false that a particular door is white but we nevertheless think, on good grounds, that it is possible it is white (or the proposition that the door is white is possibly true). 2 + 2 = 4 is true. But it is not only true; it is necessarily true. It could not be otherwise. With these two basic modal values, and the addition of negation, we can also say that something is impossible. We can say that it is not possibly true or, the stronger, it’s necessary that it is not true. For more on the standard framework, see Melia (2003) and the classic Hughes and Cresswell (1996). These works, and countless others, have presented, discussed and developed what we will call the received view.

We believe there to be a problem with the received view and it is a major problem. Put simply, it does not allow us to say much of what we want to say and ought to say. The standard picture, of necessity and possibility (together with the derived impossibility), is not nuanced enough to accurately capture much of what we seem to believe about the world. For example, suppose you drop a china cup onto a wooden floor. Should we say that it is necessary it will break? It seems not. We have all seen that occasionally a dropped cup survives a fall. And there may be a moment, as you see it drop, that you hope the cup will survive the impact. You wouldn’t have that hope if you thought it a matter of necessity that the cup will break. So we don’t want to say that the breaking of the cup is necessary.

Do we, then, want to say that the breaking of the cup is possible? Well, yes, the breaking of the dropped cup is certainly a possibility. Some call a possibility a contingency: something that could be either true or false. The problem is that it is also more than that. Lots of things are possible. Some philosophers think that anything that is non-contradictory is possible. Others say that something is possible merely if there is some possible world at which it is true. On these accounts, it’s ‘possible’ that the cup lands safely on its base without bouncing, that it switches direction in mid-air and comes directly back to your hand, or that instead of breaking on impact, it evaporates, or that it smashes through the floor unscathed, and so on and so forth. We want to say something much stronger than that breaking is a ‘mere’ possibility among all these others. The possibility of breaking seems a stronger one than all the others. It is special or privileged in some sense. It’s the possibility that you really need to be concerned about. Almost all the others, you can forget. And, yet, although this is the possibility you should plan for, as we saw above, it is still short of a certainty.

The example of the fall of a cup concerns an ordinary, mundane causal process happening (or not) in the natural world. There are ample other cases, from a wide range of subject areas, in which we cannot really express what we mean by sticking to the dual modal notions of necessity and possibility. Here’s an example from the moral sphere: you ought to be kind to animals. There is nothing unusual or contrived about this example. It’s as simple as you get. It is no doubt true. Yet it seems hard to explain its real force in terms of the standard account of modality. Saying you ought to be kind to animals is not saying that kindness to animals is a necessity. Many people are cruel to animals, even if they’ve been told the moral rule. Indeed, if kindness to animals were necessary, then there would be no need to tell anyone to do it. But the rule tells us more than that kindness to animals is a possibility. The rule has a stronger force than that. It is a sort of imperative: not just that you could be kind to animals, but that you should be. Of all the possibilities, then, this one – kindness to animals – has been specially selected. It’s the possibility, among many, that you should strive to achieve, or something like that.

We have given two examples, then, one concerning a physical causal process and the other concerning a moral imperative where it seems that what we want to say is something short of a necessity but more than merely possible. But what does this mean? What is it? Can something be more than contingent and yet still not necessary? This lack of philosophical resource – that is, a failing of the received view of modality to provide what we need – is our reason for developing the theory of dispositional modality. Our aim is to explain, in this first chapter, what the dispositional modality is and then, in the rest of the book, show how this proposed new modality gives us what we need to explain a range of diverse phenomena. In particular, we will argue that progress has been held back in a host of philosophical problems because of the previous unavailability of this third modal value, which is somehow weaker than necessity but more than mere possibility. This chapter, then, will provide the groundwork before we move to the applications. We aim to set out some of our basic assumptions and commitments behind the main idea of the book: that there is a third modal value whose strength lies between necessity and possibility.

Before we leave the idea of modality in general, we should make one very basic assumption clear. We take it that it is not just propositions that have a modal value; indeed, we see thinking of necessity and possibility as modifications of propositions as part of a harmful trend of linguistification of essentially metaphysical problems. That this is harmful is controversial, of course, but there is little doubt that there have been several historic attempts to eliminate metaphysics from philosophy and that one way to do this is to treat questions about the way things are as mere matters of language. We cannot spend time engaging with this tradition here: one that has its roots in Hume, was revived in logical positivism and continues today in some extreme forms of naturalism. Within this view, there is often a considerable scepticism that modality can be a feature of things in the world. Necessity gets reduced to relations of ideas, for instance, and possibility to conceivability. The world just is what it is and we cannot say of something that is that it is also necessary, nor of something that is not that it is also possible. It is not that we don’t have an answer to this challenge (see Anjum and Mumford forthcoming: chs 1 and 2, for instance), but that a convincing refutation of it would take us too far afield and use a considerable space. We have a different task ahead of us. All that we can do, then, is make it clear that we take it that things in the world – events, processes, facts, effects, and so on – can have modal features, values or properties; and it is not just propositions or statements that have these. We can wonder whether something that happened, happened necessarily (or with a lesser modal strength). We can wonder whether some state of affairs was possible even though it was not actual, and so on. There is no need to approach these issues indirectly, via their linguistic shadows. Certainly when something is possible, there may be a true statement that says it’s possible. But the former does not consist solely in the latter. Indeed, the latter would not be true without the former.

2 Tendencies

We seem unable to express what we want to express if our modal notions are restricted to necessity and possibility, as there are common cases we have identified – the breaking of the cup, kindness to animals – where we want more than mere possibility but less than necessity. Our solution, which is admittedly bold, is to reject the received view. We think that the traditional dual modalities, of necessity and possibility, are not all that there is. Instead, there is a third worldly modality that we call the dispositional modality. Furthermore, we believe that this modality is not just reserved for a limited class of special cases. Rather, it’s the modality that’s everywhere. It’s the modality that’s involved in all natural causal processes, for a start, which obviously makes it far reaching. And we will see that it is found quite naturally in our epistemological practices: our reasoning and inductive inferences. It is found in our moral understanding and in attributions of free agency, thus in responsibility. It is found in many other domains, not all of which we will detail here. So, while the received view says there are only two modal values (see Vetter 2015: 4, for instance), we argue for a richer modal picture and that it is in this space between necessity and pure possibility that all the really important and natural modal claims are to be found. We are not the first to suggest more than two modal values though. Kant (1781: A80/B106) had three, but his additional one is not the same as ours. And we will see in Chapter 2 that there are a number of forebears of the main idea we want to develop. So the idea of adding to the standard picture is not new. The way in which we do so might seem radical but this is largely because the orthodoxy is so enshrined, we believe. It is also noteworthy that the hegemony of modal dualism – the view that necessity and possibility are the only modal values – has produced its own polar opposite camps. Humeanism is associated with the view that all is contingent. The opposite view we can call Leibnizianism: that all is necessary. Is either a credible explanation of how our world works? Anti-Humeans will sometimes be necessitarians (see Ellis 2001 and Bird 2007, for example) but are either of these options credible? We think not. And is it any more credible to divide everything that happens into some things that are necessary and everything else purely contingent? Again, this is not very plausible either. We need something else: something we can locate between the two extremes. It is this intermediate modal value that we sometimes call the dispositional modality, and a more natural word to express it is tendency.

What do we mean by tendency? We find that it is hard to spell this out in a way that would satisfy a philosopher claiming that they have no idea what it is. We suspect that most people actually have a very good idea what is meant by a tendency but we will take the claims to the contrary in good faith and try as best we can to explain it as if to someone who had no prior idea of it at all. But this will not be an easy task, partly because we think the notion indicates an irreducible sui generis modality. It thus cannot be explained truthfully in other terms, so the words we use, if true, will just be synonyms of tendency. Hence, we can say that the idea of a tendency is that of disposing towards an outcome but this might not make things clearer.

We are not completely helpless, though. There are ways of explaining a phenomenon without giving a reductive account of it, and we will pursue some such attempts here. We have already stated the space that the dispositional modality occupies in relation to the two traditional modalities. It is stronger than pure contingency but weaker than necessity. This space, we say, concerns what tends to happen. But the dispositional modality is irreducible in the sense that we cannot define it in terms of the other two in the way that, for example, we can define possibly-X as not-necessarily-not-X.

Some examples could help as well. A favoured example is the striking of a match. Struck matches tend to light. We all know that there is no guarantee that they will light – there are many times a struck match fails to light. But the lighting of a struck match is more than a mere possibility. There are many mere possibilities towards which the struck match has no disposition. Struck matches do not tend to evaporate, for instance. They do not tend to dissolve or grow wings and fly. There is a definite tendency, which is more than a mere possibility, towards lighting. And it seems that we all know this. Indeed, it is a basis for action theory. People deliberately strike matches because they want them to light. Even knowing that the match might not light, it is still rational to strike it if you want it to light because, despite the lack of necessity that it does, there is a reasonably strong disposition for it to do so.

Here are more examples: cows that digest grass tend to produce milk, a light switch that is flipped tends to turn the lamp on, cuts to human skin tend to heal. These facts are reported with an explicit dispositional vocabulary, using the word ‘tend’ or ‘tends’. They all indicate the permissibility of exception cases, for instance. That cuts to skin tend to heal is consistent with some cases in which cuts do not heal. The dispositional force of a claim can be tacit, however. It can be said that oak trees produce acorns where this is intended to concern what tends to be the case, rather than a claim that something is absolutely the case (on generic claims and exceptions see Drewery 2000). Hence, finding an oak that does not or did not produce acorns would not necessarily be taken as a falsification of the initial claim, but could just be treated as a permissible exception. In all these cases, some outcome is possible; but it is more than merely possible. It is more than merely possible that cows produce milk: they have a definite tendency to do so, they are disposed to produce milk. But there are no grounds to say that they do so as a matter of necessity. Some cows don’t produce milk, for whatever reason.

There is an initial idea of the dispositional modality, then. It is a strength of modality that is more than pure contingency and less than necessity. We also have identified a commonplace notion that is used to signify this modal strength: tendency. And we have given some examples of claims that use this term, explicitly or implicitly. There is still more that we can do to illuminate the idea and this will be discussed later in this chapter.

It is also important, however, in outlining some idea that it is distinguished from similar or related notions that are not quite the same. This will help clear up possible confusions. A major clarification, then, is that we are not simply talking about probabilistic causation when we invoke the dispositional modality. It would be easy to think that we were. Since in classical probability theory probability = 1 means that something is certain and probability = 0 mean that it is impossible, one might think that the dispositional modality indicates probabilities of some degree between these two limits. Such a view might be even more attractive when we admit that tendencies or dispositions can come in various degrees of strength, which we do admit. Hence, both a wineglass and a car windscreen are fragile but the former much more so than the latter. Might it then be thought that the extent or strength of a tendency is the same as the probability of it manifesting itself, where that probability is >0 but <1? When we first started presenting the idea of a dispositional modality, this question was often put to us, or a positive answer was simply assumed. In print, Weckend (2014: 116) has stated our position in that way but we don’t want to pin the idea on her alone since we have heard so many say the same.

However, we do not think that tendencies are simply probabilistic dispositions, for various reasons, most of which we will explain in Chapter 3, ‘Overdisposed’. We stated that the dispositional modality was sui generis and irreducible. This includes it not being reducible to the notion of probability either. And, if we are right, then tendencies and their strength would be fit to play the role of the truthmakers of the truths of probability; which they would not be, on pain of circularity, if they were themselves probabilistic in nature. A tendency, then, is not the same as a probability, but it might be the ground of one.

3 Causal power

We have introduced the ideas of modality and that there is an additional modal value, which we can call tendency, that is in some way between the traditional modal values of necessity and possibility. There is a third major component in our account that should be explained, which is that of a causal power. We have said a lot about powers and our commitment to them elsewhere (Mumford and Anjum 2011a; for a different view, see Molnar 2003), but they need at least some introduction here for the uninitiated.

There are various reasons why causal powers are important in our account. Crucially, causal powers are the bearers of the dispositional modality. They are the things in the world that tend towards certain types of outcome. They might even be called the tendencies themselves, though one of our jobs in the chapter (Section 6) wil...

Table of contents

• Cover
• Half-Title
• Title
• Copyright
• Contents
• Preface
• Notes on Collaborators
• PART I Modality
• PART II Metaphysics
• PART III Logic
• PART IV Epistemology
• PART V Ethics
• Afterword: The Golden Mean
• References
• Index