«1. Introduction Try Googling ‘applied metaphysics’: you’ll be led to a motley collection of new age healers, self-help tracts, and sacred ...»
(http://www.csog.econ.cam.ac.uk/) Both philosophical and scientific ontology are seen as respectable pursuits in this context.
Philosophical ontology is not to be confined to philosophy departments, and the distinction between the two seems to be one of degree rather than kind; this is reminiscent of the ‘specificity conception’ of applied philosophy discussed in chapter 1 of this Companion. In line with this specificity, social ontology beyond philosophy is more often closely informed by empirical studies than is philosophers’ social ontology. Moreover, it is set in disciplinary contexts in which different ideas count as orthodoxy, to be accepted as default or else to be actively resisted. For example, Tony Lawson of the Cambridge group describes his intellectual trajectory as prompted in part by dissatisfaction with standard methodologies within economics. It seemed to Lawson that these methodologies focused on formal models, whilst neglecting ‘social reality’, i.e. how economic systems work in practice (Hirsch and DesRoches 2009). Philosophers interested in the nature of social reality are likely to begin from other motivations.
5. Case Study III: Natural Kinds in Psychiatry and Medicine Within psychiatry, and within medicine more generally, a great deal of classification goes on.
Diagnosis is a form of classification – of the patient, or of her condition – and diagnosis is often a necessary precursor to treatment. Medical research can advance when previouslyconfused conditions are distinguished from one another, opening up the possibility of different types of treatment, or when seemingly-disparate symptoms are identified as aspects of a common condition. Even when diagnosis of an underlying condition proves elusive, identifying and classifying the patient’s symptoms may be a first step towards alleviating them.
Classification has an especially central role in psychiatry, due to the immense practical significance of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM), now in its fifth edition. This authoritative (or authoritarian) text itemises the various clusters of symptoms or behaviours which are to count as mental disorders: over the years, disorders have been added, deleted, and reconceptualised, sometimes in highly controversial ways. The DSM is the standard point of reference within psychiatry, but is also used in legal contexts, and is central to reporting and billing of psychiatric treatment to health insurers. But what basis do such classifications have?
There is a long tradition within metaphysics of understanding classification in terms of natural kinds. Chemical elements, as represented within the periodic table, are a paradigm case of natural kinds: any atom belongs to one, and only one, of the elements, and understanding which element an atom belongs to enables us to predict and explain its behaviour. Biological species are also often thought of as natural kinds: to know which species an organism belongs to is, it seems, to know something fundamental and powerful about that organism.
So it is unsurprising that philosophers of medicine, and philosophers of psychiatry, have sought to understand whether diseases are natural kinds. The concept of disease fits into an interrelated cluster of concepts including health, wellness, injury, illness, and disability; these concepts are not purely descriptive, but involve normative judgements about the badness of disease, and the desirability of health. For example, the discredited claim that homosexuality is a disease may seem less judgemental than the claim that it is a moral failing, but it still incorporates the assumption that heterosexuality is, to put it crudely, Best, and that a ‘cure’ for homosexuality would be welcome.
We cannot investigate these important and interesting philosophical issues here, even though they involve aspects of applied metaphysics: the Stanford Encyclopedia of Philosophy articles on ‘Health’, on ‘Disability: Definitions, Models, Experience’, on ‘Feminist Perspectives on Disability’, on ‘Mental Illness’, and on ‘Homosexuality’ provide ways into the relevant debates. Instead, let’s assume that we have some grasp of the contrast between disease and health, in order to discuss some metaphysical issues concerned with the individuation and categorisation of diseases.
There is no consensus even with metaphysics about what natural kinds are. Rachel Cooper (2013) helpfully distinguishes three approaches. The kinds-in-science tradition takes natural kinds to be those categories, whatever they are, which are fruitful sources of explanation, prediction and understanding in science. The Aristotelian tradition takes kinds to be the source of identity, persistence and individuation for particular objects. The new essentialist tradition focuses on the features of a kind which are essential to it: for example, it seems essential to oxygen that oxygen atoms have eight protons in the nucleus.
As Cooper argues, mental illnesses in particular seem very different from chemical elements, for various reasons: for example, they can be chronically imprecise categories, and they can incorporate feedback loops, whereby categorising a patient can affect her behaviour and symptoms, for better or worse (Ian Hacking has written extensively about this phenomenon, e.g. in respect of multiple personality disorder in his 1995). Cooper herself argues that, if we adopt the more permissive kinds-in-science approach, then we can recognise that plenty of mental disorders are natural kinds. Beyond psychiatry, philosophical treatments of disease more generally sometimes draw upon metaphysical discussions of natural kinds, as when Benjamin Smart (2014: 252) sets out to ‘posit a metaphysical ontology of diseases, that is, [to] give an account of what a disease is.’ What is the value of developing a ‘metaphysical ontology’ of diseases, or of mental disorders? Classification and categorisation can be an aid to understanding: to diagnose a patient is to identify respects in which she resembles other patients with the same diagnosis, and thus, it is hoped, to better understand her condition. In medicine and psychiatry, we often think of understanding as a route to treatment, though of course this presupposes the normativity of health; this fits with the ways in which Cooper likens some mental disorders to the phenomena studied by other sciences, seeing classification as a means to improve our ability to predict and control the world.
But categorising people and their conditions – in particular when we use categories thought of as ‘natural’ – may also seem to have ethical or political consequences. If we take the example of chemical elements as paradigmatic, we may think of natural kinds as determining the intrinsic, essential features of the world, and as drawing sharp, immutable boundaries between different kinds of people. We can begin to imagine a nightmarish periodic table of humanity At this point, metaphysics can come in very handy. Pursuing metaphysical investigations can help us understand the many forms of classification and categorisation, to see that we sometimes group things together not because of their intrinsic similarities, but because of their common environments, or reactions to those environments. Moreover, we can begin to understand the variety of ways in which classification schemes can be objective, subjective, conventional, contingent, essential and so on, and to separate out entangled concerns.
None of this work will in isolation help us understand disease or mental disorder, but it does provide a framework for engaging with these more ‘applied’ issues in a clearer way;
Cooper’s distinctions between the different approaches to natural kinds, and her advocating of a deflationary ‘kinds-in-science’ picture is a good example of this sort of contribution.
6. Further Examples I focused on the three preceding topics for various reasons (including my own tastes and interests): both applied ontology and social ontology deal with metaphysics in the practical sphere, and each is developing a disciplinary identity of its own, whilst the issue of kinds in psychiatry and medicine is a fruitful example of philosophical debates about naturalness, realism and classification more generally. But other, sometimes underdeveloped, topics could equally well serve as examples of ‘applied metaphysics’, and in this section I will briefly mention a few, providing references for the curious.
The non-identity problem is an ethical issue which has roots in metaphysics. Many of our actions today – perhaps especially with regard to the environment – will have consequences for future generations of people, including those who are not yet born or even conceived. For example, our first-world habits of taking long-distance flights for leisure (or to give philosophy talks) contribute significantly to climate change, to the detriment of living standards later this century. We might think we should take future generations into account in thinking about whether to fly, take the train, or just stay at home this summer.
However, it seems plausible that our decisions about whether to fly will have consequences for which people will exist in the future. Perhaps you’ll meet a charming future spouse when you take the train, instead of marrying that loser you would have met on the plane; perhaps the airlines will employ fewer people, and some of the people who are laid off will decide not to have kids. That is, some of the children who will be born if we take the flights will not be born at all if we stay at home. So who exactly are we harming if we decide to fly? If a future person complains that she is living in climate chaos because of our flights, we could remind her that she would not have existed at all if we hadn’t taken those flights; instead, someone else would have been enjoying the fruits of our restraint. How, then, can we understand the idea that we owe it to future generations to fly less?
The non-identity problem is so-called because it turns on the non-identity of the people who exist in the two future scenarios, where we fly or don’t fly. But this non-identity is a metaphysical claim, turning on seemingly abstract thoughts about the nature of identity, essence, and possibility: could the same person have been born from different parents? If not, why not?
Urging bioethics towards ‘better philosophy’, Julian Savulescu, editor-in-chief of the Journal
of Medical Ethics, writes:
Failure to appreciate this metaphysical fact about identity-determining reproductive acts infects legislation and policy. For example, in the UK and Australia, the supposed guiding principle ‘paramount in law’ for making reproductive decisions is the ‘best interests of the child’. But these are almost entirely irrelevant to identity-determining reproductive acts such as IVF and genetic selection, and cloning. Legislation and practice are based on confusion. (Savulescu 2015: 28) Savulescu’s point is that a child who comes into the existence as a result of IVF, genetic selection or cloning will not exist at all if those procedures do not take place, so it is mere confusion to think about whether that child would be better or worse off as a result of the procedures: this is an instance of the metaphysical nonidentity problem. (See ‘The Nonidentity Problem’ in the Stanford Encyclopedia of Philosophy for details.) Turning to a different issue: the nature of causation in the law is both important and contested. It seems plausible that, for someone to be legally responsible for some harm, she or he must have caused that harm (which is not to say that, moving in the opposite direction, causation entails legal responsibility). What, then, to say about cases in which we hold people responsible for what they haven’t done, for example in cases of negligence? Can we say that an absence, a non-event, is really the cause of a disaster? The question of causationby-absence is a paradigmatically metaphysical question, applied here to an issue of great practical significance. (See ‘Causation in the Law’ in the Stanford Encylopedia of Philosophy for an overview of this and other issues, Moore (2009) for a major recent book, and Schaffer (2012) for a metaphysician’s friendly critique of Moore.) Finally, risk is a topic where metaphysical issues have been underexplored. Philosophers thinking about risk have primarily focused on ethical and political questions about when it is permissible to incur or impose risk, or on epistemological questions about how to identify and reason about risks. Threaded through these discussions are metaphysical questions about the nature of risk which do not always receive explicit attention; for example, in his ‘Towards a Political Philosophy of Risk’, Martin Kusch argues that ‘We need a much better understanding of what is socially constructed about risks, and what this social construction entails for their reality and objectivity’ (2007: 148). (See ‘Risk’ in the Stanford Encyclopedia of Philosophy for a useful introduction to this area.)
As you read through the other chapters in this Companion, I hope you will now be able to spot metaphysical assumptions and ideas where they crop up, and to appreciate both the scope of metaphysics, but also the difficult of separating out metaphysical concerns from other philosophical and extra-philosophical questions.
Can we draw any general conclusions about the nature, possibility or value of applying metaphysics? It’s useful to bear French and McKenzie’s (2012) toolbox idea in mind: there is a lot to be gained by drawing on the distinctions, conceptual connections and clarifications made by metaphysicians, even for those who are sceptical about metaphysics of the most ambitious kind. It’s also worth bearing in mind the many ways in which metaphysical questions permeate other areas of philosophy; metaphysics can crop up where you least expect it But on the whole I think we shouldn’t expect or even want a very general story about how and where metaphysics can be applied: instead we should be open to new possibilities, new problems, and new ideas. I hope that the range of examples discussed in this chapter give some flavour of what can be exciting about applying metaphysics.
Acknowledgements This work was supported by a Major Research Fellowship from the Leverhulme Trust, which I gratefully acknowledge. Many thanks to Helen Beebee for her very useful comments.