## 1. Introduction



Doctors are called on to deal with many states of affairs. Not all of
them, on any theory, are diseases. A doctor who prescribes
contraceptives or performs an abortion, for example, is not treating a
disease. Some women cannot risk pregnancy for health reasons, and
historically both pregnancy and childbirth have been major killers.
Nevertheless,they are not disease states, and modern women typically
use contraception or abortion in the service of autonomy and control
over their lives. In addition, it is very difficult to find a
philosophically or scientifically interesting cleavage between
diseases and other complaints (Reznek 1987, 71-73).



One dominant strand in modern medicine sees a disease as essentially a
process that recurs across individuals in slightly different forms: a
disease is an abstract kind that is realized in different ways (Carter
2003: Whitbeck 1977). But since a disease is a biological insult,
distinguishing it from injury is very difficult. Perhaps injuries are
not processes in the relevant sense but events. This essay assumes
that the conceptual issues raised by illnesses, injuries and other
medical conditions are similar enough to let us put this demarcation
problem aside. Disability is another important and neglected topic in
health and well-being. It will be addressed here only slightly, since
the contemporary debates on disease and disability tend to go on in
isolation from each other. Only rarely do authors such as Glackin
(2010) tackle both. It is worth noting, though, that the disability
debate is typically framed in a way that closely resembles the debate
over disease. Medical model adherents judge disability to be the
product of a functional impairment or failure in human physiology.
This resembles what will be called below the naturalistic model of
disease, at least as regards assessment of bodily impairment. It
contends that people with disabilities, like people with diseases, are
rendered worse off in virtue of these functional impairments, and the
explanatory burden of their disadvantage is borne chiefly by the
failure of their physiology or psychology to perform a natural
function. A concept of disability as dysfunction has been resisted by
rival pictures of disability that have made headway in recent
decades.



According to the rival "social model", disability is not a
departure from normal or healthy human functioning which makes an
atypical condition a "bad difference" from the norm;
rather it is a "mere difference" (Barnes 2016). Although
disabilities may make people worse off in general, this is due to the
way society is set up, rather than any physical impairment. Disability
in itself is just variation, analogous to features like sexuality,
gender and race. The social model was pushed by disability activists
who defined disability as "the disadvantage or restriction of
activity caused by a contemporary social organisation which takes
little or no account of people who have physical impairments and thus
excludes them from participation in the mainstream of social
activities" (UPIAS 1975, quoted in Shakespeare 2010). The
scientific basis for this position appeals to the idea that "the
partitioning of human variation into the normal versus the abnormal
has no firmer footing than the partitioning into races. Diversity of
function is a fact of biology" (Amundson 2000, p. 34). The
resulting partition, it is held, is a reflection of social norms
rather than underlying physical impairments. This position resembles
what will here be termed the constructivist position with regard to
health.



Health has received less philosophical attention than disease, and
this essay will correspondingly have less to say about it. The
conceptual terrain in the case of health is a little more complex than
that of disease; one way of thinking about health says that it is just
the absence of disease, so if disease is biological malfunction or
abnormality, it follows that a healthy person is someone whose
biological systems are all in order. But another way of looking at
health insists that it is not just the absence of disease but the
presence of something more; a positive state. The constitution of the
World Health Organization (WHO) defines health "a state of
complete physical, mental and social well-being and not merely the
absence of disease or infirmity" (WHO 1948). According to views
like this, we should think in terms not of health and disease alone,
but in terms of health, disease and normality. This essay will look at
theories of health after first discussing disease. The focus
throughout is on individuals, although some theorists (e.g. Inkpen
2019) have argued for a seeing humans and their associated microbiomes
as part of an ecosystem that can be evaluated, like other ecosystems,
as healthy or not. 


## 2. Naturalism and Constructivism



The tendency in recent philosophy has been to see disease concepts as
involving empirical judgments about human physiology and normative
judgments about human behavior or well-being (Bloomfield 2001, Boorse
1975, Ereshefsky 2009, Culver and Gert 1982, Thagard 1999). First, we
have beliefs about the natural functioning of humans - both our
common sense expectations about the body and scientific theories of
human biology. Second, we make judgments about whether some particular
condition or way of life is or is not undesirable, in some relevant
way. This second set of concerns obviously involves normative
criteria, to do with the extent to which a life is unnatural,
undesirable or failing to flourish in some way. (There is not a clear
consensus among writers here.) One important and controversial
question is whether the judgments we make concerning our biology are
also normative in some way. A further large question concerns the
relationship between the two types of judgments, in both medicine and
common sense.



Another strain in recent scholarship suggests that our normative
judgments alone determine who falls under the concepts of health and
disease. This view has been less influential in philosophy, but
commands widespread adherence in other areas of the humanities and
social sciences (e.g. Kennedy 1983, Brown 1990). Kitcher (1997,
208-9) summarizes the debate as follows:



> 
> Some scholars, objectivists about disease, think that there are facts
> about the human body on which the notion of disease is founded, and
> that those with a clear grasp of those facts would have no trouble
> drawing lines, even in the challenging cases. Their opponents,
> constructivists about disease, maintain that this is an illusion, that
> the disputed cases reveal how the values of different social groups
> conflict, rather than exposing any ignorance of facts, and that
> agreement is sometimes even produced because of universal acceptance
> of a system of values.
> 



Kitcher's objectivism is nowadays more often called naturalism, and
that usage is followed here. The simple naturalist/constructivist
opposition has also been complicated by more recent work and some of
those nuances will be introduced here. The next section starts with
forms of constructivism and the difficulties they face. Then
naturalism will be similarly treated, before the discussion moves to
health.



Kitcher's claim that an objectivist analysis, as he puts it, is
"grounded" on facts about the human body is perhaps not as
clear as it might be. Before arriving at some qualifications, then, we
should have straightforward statements of naturalism and
constructivism in hand. (Although, since the qualifications are not
yet in place, perhaps no theorist would fully endorse these bald
versions of the positions.) There are also taxonomies that cut finer.
Broadbent (2019, p.93) argues that naturalism and normativism are only
two of the distinctions we need to inform the debate. He thinks of
them as "diagonal opposites on a 2x2 matrix of possible
positions, being Value-Independent Realism and Value-Dependent
Anti-Realism respectively." Broadbent also recognizes
Value-Dependent Realism and his own Value-Independent Anti-Realism.
Whether or not constructivist analyses should really be seen as
anti-realist in a metaphysical sense is not always clear, though. For
reasons outlines below, the philosophical commitments of
constructivist views are sometimes hard to grasp.



At the bottom of the naturalist conception of disease (most
influentially stated by Boorse (1975) and defended in Boorse (1997,
2014) is that the human body comprises organ systems that have natural
functions from which they can depart in many ways. Some of these
departures from normal functioning are harmless or beneficial, but
others are not. The latter are 'diseases'. So to call
something a disease involves both a claim about the abnormal
functioning of some bodily system and a judgment that the resulting
abnormality is a bad one. Boorse uses'illness' to describe
the concept of a disease that causes one's life to deteriorate. This
language is not universal, but the distinction between bodily
malfunction and normative judgement is widely used. Naturalists
contend that the determination of bodily malfunction is an objective
matter to be determined by science. They may also argue (Boorse 1997)
that determining whether a malfunction is detrimental to human
well-being is also an objective matter, but often they concede that
normative considerations are the basis for that judgment. So the
naturalist position is that a disease is a bodily malfunction that
causes one's well-being to lessen. This malfunction could take many
forms: it is not a necessary part of the naturalist case that diseases
constitute a natural kind.



Rather, they could be a set of naturally occurring processes that are
held together in virtue of our interest in grouping them as a class.
Kinds that work like this include "weed" or
"vermin" (Murphy 2006): the existence of the superordinate
class depends on human interests but the subordinate members are
natural kinds whose natures can be investigated scientifically.



Constructivism, however, argues that human interests do not just
define the superordinate class of diseases. It is human interests, not
biological malfunctions, that explain the judgments that subordinate
members have the relevant biological character. Although
constructivists accept that disease categories refer to known or
unknown biological processes they deny that these processes can be
identified independently of human values by, for example, a science of
normal human nature. Constructivist conceptions of disease are
normative through and through, although the precise account of the
relevant norms will vary between scholars. Analytically, it seems that
constructivism is distinct from the claim that disease is normative.
However, constructivism and normativism do go together. One reason for
this often a professed skepticism about the existence of a
non-normative concept of malfunction. More broadly, constructivists
may think of disease labels as instruments of social control and
reflections of biologically ungrounded reactions to human difference.
There may also exist, though this is less often brought to the fore,
importantly different stresses on the kinds of value judgements that
different theorists think are part of disease categories and their
application. Typically, the relevant normative claim is taken to apply
to the life of the person whose health is under discussion - it is bad
for you to be that way. But in some contested cases the judgments are
often held to be wider value-disvalue claims about society more
broadly - it is bad for us if you are that way. To make things even
more complicated, theorists will sometimes hold that the second type
of judgement is what is really doing the work, but it masquerades as
the first type. Arguments about disease concepts, as we shall see, are
often bound up with political and social controversies in which
diagnostic labels are impugned as instruments of oppression or social
control. 



The key constructivist contention, as seen in the remark by Amundson
quoted above, is that there is no natural, objectively definable set
of human malfunctions that cause disease. Rather, constructivists
assert that to call a condition a disease is to make a judgment that
someone in that condition is undergoing a specific kind of harm that
we explain in terms of bodily processes. But the bodily processes are
not objectively malfunctioning; rather, they are merely judged by us
to be unusual or abnormal because they depart from some shared,
usually culturally specific, conception of human nature. The crucial
difference between the positions then is that for naturalists,
diseases are objectively malfunctioning biological processes that
cause harms. For constructivists, diseases are harms that we blame on
some biological process because it causes the harm, not because it is
objectively dysfunctional.



However, constructivism is hard to define satisfactorily, for two
reasons. First, its core claim is a denial of the naturalist thesis
that disease necessarily involves bodily malfunction. Since there are
many views one might hold about the nature of the biological processes
involved in disease that are compatible with the denial of
malfunction, the positive constructivist claim varies across theories
and is often elusive. Reznek (1987) for example, explicitly denies
that malfunction is a necessary condition for disease. He does assert
(ch 9) that diseases involve "abnormal" bodily processes,
but he does not say what that means. Constructivists often, as we will
see later, argue that disease judgments appeal to biological processes
that are to be understood in terms of human practices rather than
membership in some putatively biologically definable class of
abnormalities or malfunctions. We have decided that some harmful
conditions are the province of the medical profession, and those are
diseases.



That brings up the second reason why constructivism can be an elusive
target: it has often rested on (perfectly reasonable) claims about the
role that value judgments have played in medical practice, or on the
prevalence of culturally specific disagreements about abnormal human
behavior or physiology. This means, as we shall see, that
constructivists, especially in the social sciences, do not tend to
offer necessary and sufficient conditions. Rather, they often seek to
reconstruct the concept of disease as revealed by our practices.
Constructivism, therefore, often looks like a thesis about how inquiry
is carried on: first we identify a condition we disvalue, then we look
for a biological process that causes it and say that, whatever it is,
it is abnormal. This stress on our practices is a common
constructivist trope, whereas objectivists more often seek to analyse
a concept that will clarify what disease really is, however fumbling
and biased our attempts to uncover it may have been.



That both medical practice and lay thought shape disease concepts is
undeniable. Because of this, we need to introduce a second
distinction. Both naturalism and constructivism can take either a
revisionist or a conservative form. A conservative view says that our
folk concept of illness should constrain a theoretical picture of
health and disease worked out by scientists and clinicians. A
revisionist thinks that our existing concepts should be amended in the
light of what inquiry uncovers. One could be a conservative or
revisionist naturalist, as well as a conservative or revisionist
constructivist.



Health and disease, like many other concepts, are neither purely
scientific nor exclusively a part of common sense. They have a home in
both scientific theories and everyday thought. That raises a problem
for any philosophical account: suppose we try to say what health and
disease really amount to, from which it follows that the scientific
concept should fit the facts about world. If the picture we end up
with deviates too far from folk thought, should we worry? You might
think that everyday language puts constraints on a concept of health
that need to respected, and that if we move too far from ordinary
usage we have stopped talking about health and started talking about
something else. Furthermore, it is not really possible to argue that
scientific and vernacular uses of the concepts are fully independent,
since the development of science influences everyday thought, and many
scientific concepts begin in pre-scientific contexts and carry the
marks of those origins deep into their careers.



Although there is a thriving body of work that tries to analyse the
concept of disease - as we'll see in a moment - other
theorists dispute the prospects for a successful analysis of the
concept of disease. Schwartz (2007) contends that the biomedical
sciences do not share a general concept of disease that is coherent
enough to be analyzed. He recommends seeing the proposed analyses as
introducing new concepts of disease that are related to existing usage
but not bound by it. Concepts so introduced may work in some contexts
but not others, and different concepts of disease could be needed for
different medical purposes. Hesslow (1993) argues that diseases are
not interesting theoretical entities in medicine and are irrelevant to
most clinical decisions. These focus on how to improve a patient's
condition and do not need to depend on a judgment of disease.



Furthermore, the concept of disease that is currently employed in most
areas of medicine has undergone a process of development. For much of
the modern era there has been a dialectic between two concepts of
disease. On the one hand, there has been the idea that a disease is
just an observable suite of symptoms with a predictable course
unfolding. This notion dates back to Sydenham in the late seventeenth
century. Kraepelin applied it to psychiatry as the basis for
differential diagnosis, for example between subtypes of what was later
called schizophrenia (1899, 173-175). The approach was
supplanted as medicine matured by the concept of diseases as
destructive processes in bodily organs which "divert part of the
substance of the individual from the actions which are natural to the
species to another kind of action" (Snow 1853, 155; for
discussion see Whitbeck 1977, Carter 2003, Broome 2006). This is
perhaps still the core medical conception of disease. It seeks
explanations that cite pathological processes in bodily systems. More
recent medicine has tended to weaken this slightly by adopting what
Green (2007, ch, 2) calls an 'actuarial' model of disease.
This model takes the presence of elevated risk, for example as
indicated by high blood pressure, to be a disease even in the absence
of overt symptoms or a clearly destructive pathological process (see
also Plutynski 2018, ch. 2).



Medicine recognizes illnesses like hypertension and Cushing's disease
that are the outcome of systems in a poorly regulated state that is
stable, albeit suboptimal. The idea of a specific pathogenic process
in medicine includes dysregulation, but this may not accord with folk
thought.



Modern medicine looks naturalistic about disease. One question, then,
concerns the extent to which common sense and biomedical concepts are
related. Perhaps both have naturalist commitments, or perhaps common
sense is driven by values and medicine is not, or perhaps physicians
are really constructivists who are self-deceived or arguing in bad
faith.



There is little reason to expect scientific and common sense concepts
to agree in general, so if medicine and everyday thought disagree
about disease, we may ask which concept should be adopted. If we wish
to distil a concept that can play a role in medical inquiry, we may
side with the scientists. But such proposals, which argue for a sharp
separation between scientific and folk uses, are not neutral pieces of
observation about the language. They are proposals for purging science
from commonsense constraints that hinder its development. A
revisionist view of this sort, in this case, says that our concepts of
health and disease might be a necessary starting point but should not
constrain where the inquiry ends up. Other forms of revisionism are
possible. A revisionist naturalist argues that we should follow the
science where it takes us and come up with concepts that further
scientific inquiry, for example, even if that means that we eventually
use the language in ways that look bizarre from the standpoint of
current common sense. But a revisionist constructivist could argue
that our thought, whether medical or lay, should be reformed in the
service of other goals, such as emancipation for hitherto oppressed
groups. Such revisionist thought was important in overturning the
psychiatric view, dominant until the 1970s, that homosexuality is a
mental illness. Activists argued that homosexuality was diagnosed for
offensive moral reasons and not for medical ones and the
classification of homosexuality as a disease was changed as a result
of lobbying on moral grounds rather than on the basis of any new
discovery. Naturalists will respond that this was not an example of
using constructivism for emancipatory ends, but of bringing
psychiatrists to understand that they were not obeying their own
naturalist principles about mental disorder, and showing them that
there was no good reason to retain the diagnosis. Much debate between
naturalists and constructivists involves competing histories in just
this way. Constructivists strive to uncover the role that moral and
social values have always played in medical diagnosis and argue that
our disease categories are hence not properly naturalistic.
Naturalists, though they must concede that many diagnoses have been
based on moral values that we would now renounce, still insist that
the concept of disease, when correctly applied, as it often is, is
thoroughly naturalistic and not impugned by past failures by the
medical profession to live up to its own scientific ambitions.



Naturalists tend towards conceptual conservatism. They typically
appeal to our intuitions about illness as support for their own
emphasis on underlying bodily malfunction. This assumes that our
current concept is in good shape, that common sense and medicine share
a concept of disease, and that medicine should respect lay intuitions
about what is or is not a disease. Like many philosophers who think
about other concepts with both scientific and common sense uses,
conservative naturalists about disease think that folk concepts
specify what counts as health and disease. The job of medicine is to
look at the world and see if anything in nature falls under the
concept as revealed by analysis (cf the "Canberra plan" of
Jackson 1998) For revisionists, this understanding of common sense in
its relation to science is needlessly submissive to folk intuitions. A
more revisionist view takes the relevant concepts to be defined by
their role in scientific theories - Boorse (1997) has argued
that disease is a term of art in pathology.



Revisionist naturalists argue that facts about physiological and
psychological functioning, like other biological facts, obtain
independently of human conceptions of the world. Our intuitions might
tell us that a condition is not a disease. But scientific inquiry
might conclude that people with the condition are really suffering
from a biological malfunction. In that case, a conservative would
recommend finessing the analysis to ensure that the concept of disease
does not cover this case. A revisionist would say that we must bite
the bullet and judge that this case falls under the concept even if
that judgment is counterintuitive. A revisionist naturalist regards
health and disease as features of the world to be discovered by
biomedical investigation, and therefore loosely constrained, at best,
by our everyday concepts of health and disease. Lemoine (2013) argues
that conceptual analysis always involves a stipulative element
concerning controversial or borderline cases. Because contending
parties will be led by their intuitions to see different stipulations
as reasonable, conceptual analysis will be very unlikely to decide
between competing analyses that are all reasonably successful at
capturing core cases. He suggests that instead philosophers should aim
to naturalize disease by trying to first understand general features
of theories in the medical sciences and then looking for perspicuous
and coherent accounts of different disease types, with a view to
eventually establishing an overall picture of the role disease
thinking plays in medicine. This approach treats diseases as putative
natural kinds and could be highly revisionist, while also leaving open
the possibility that some diagnoses represent contingent historical
outcomes that have left us with an incoherent category. Fuller (2018)
follows Lemoine in dissenting from traditional conceptual analyses. He
argues that we should try to work out what kinds of things diseases
are rather than worrying about the concept. Fuller reviews the
ontological options and asks first about instances of disease -
what kinds of things are they? - rather than the concept, but,
looking at chronic disease, he goes 'bottom-up', by
attempting to work out what instances of chronic disease have in
common and making inductive generalizations about them. Fuller thinks
of diseases - at least chronic ones but perhaps acute cases too
- as dispositions (cf Hucklenbroich (2014). 



Lange (2007) starts his account of disease from a similar impulse,
insisting that diseases play an absolutely essential role in
explaining a patient's symptoms. He argues that this explanatory role
is characteristic of natural kinds elsewhere in science, and warrants
thinking of diseases as natural kinds. Lange views diseases as natural
kinds of incapacities. Stegenga (2018, ch.2.5), discussing Lange's
urging that we dissolve broader disease categories in favour of
finer-grained biological descriptions, argues that we should see this
as an eliminativist position, since it dispenses with the concept of
disease altogether and replaces it with diverse successor concepts.
Any theory of disease could advocate for descriptions at finer grains,
while retaining a broad category, as Stegenga says, for education and
public communication even if it has no real scientific application.
The extent to which we should see a theoretical reform as
eliminativist or merely very revisionist is hard to answer. In both
cases we might secure an epistemic advance, but one might worry that
our new vocabularies will deprive people of their ability to
understand themselves by replacing a familiar vocabulary with a
remote, scientific one tailored to the demands of experts. 



Constructivists are usually revisionists. They tend to say that
concepts of health and disease medicalize behavior that breaks norms
or fails in some way to accord with our values; we don't like pain, so
painful states count as diseases: we don't like fat people or drunks,
so obesity and alcoholism count as diseases. Constructivists will
often make this case with special vigor when it comes to mental
disorder. The critique of the concepts that guide disease applications
is central to constructivism. 



Constructivists are often social scientists and their interests may
not map neatly on to philosophical concerns. They are not usually
interested in conceptual analysis so much as in tracing the social
processes by which categories are formulated and changed over time.
Conrad (2007, 7-8), for example, says he is "not
interested in adjudicating whether any particular problem is really a
medical problem... I am interested in the social underpinnings of
this expansion of medical jurisdiction".



But constructivists often present their theories as unmasking common
sense or medical conceptions of disease, and hence as a kind of
revisionism. They may accept that diagnoses of ill-health involve
objective facts that people appeal to, or presume that they can appeal
to, when they say that somebody is sick. The assumption might be that
germs or other medically relevant causal factors are present in a
person and have given rise to visible phenomena that indicate
ill-health. But a constructivist will claim that the actual, often
unacknowledged, judgments driving the initial assertion that someone
is unhealthy are derived from social norms. We may discover facts
about obesity and its relationship to blood pressure or life
expectancy. But the constructivist says that our search for the
relevant biological findings is undertaken because we have already
decided that fat people are disgusting and we are trying to find a set
of medically significant properties in order to make our wish to
stigmatize them look like a medical decision rather than a moral or
aesthetic one. The crucial constructivist claim is that we look for
the biological facts that ground disease judgments selectively, based
on prior condemnations of some people and not others. Because they
claim that social norms rather than disinterested inquiry drive
medicine (and especially, psychiatry), constructivists tend to be
revisionists about folk concepts, seeking to bring to light the
unacknowledged sources of our concepts of health and disease. But
constructivism could be a conservative view, aimed at uncovering our
folk theory of health and disease. A constructivist who takes this
view says that our folk concept of disease is that of a pattern of
behavior or bodily activity that violates social norms. 



The most philosophically sophisticated recent constructionist view is
Glackin's (2019, p.260). He distinguishes the constitution question,
which asks for the physical basis of a person's condition, from the
status question, which asks what makes a physical configuration a
disease? This way of carving the terrain, and the importance of both
status and constitution, is standard among most people who write about
disease. The distinctive feature of social construction, in
Glackin's sense, is the priority of value judgements. Glackin
uses the grounding relation to supply an answer to the problem of the
relation between constitution and status. That is, the frame for
grounding is fundamentally evaluative; the normative has a
metaphysical priority. As Glackin (p. 262) puts it, disease states are
grounded by the underlying biology or behaviour, but this grounding
relation exists in virtue of a set of normative facts that provide the
frame (in the sense of Epstein 2015: a set of possible worlds that fix
the grounding conditions for social facts). 



One could be a constructivist about some diseases, and a naturalist
about others. For example, one could be a naturalist about bodily
disease but a constructivist about psychiatry. Thomas Szasz (1960,
1973, 1987), for instance, is usually read as a constructivist who
denies that mental illness exists. But in fact Szasz has a very strict
objectivist concept of disease as no more than damage to bodily
structures.



Szasz argues that mental disorders cannot exist because they are not
the result of tissue damage. He is a naturalist about disease, which
leads him to deny that mental illness is real and to offer a critical
analysis of our psychiatric practices. And indeed claims that we are
merely taking conduct we don't like and calling it pathological are
more plausible in psychiatry than in other parts of medicine, since
there is a long history of psychiatrists who have done just that.
Samuel Cartwright argued in 1843 that American slaves who tried to
escape were afflicted with "drapetomania" or the
"disease causing slaves to run away" (Cartwright 2004,
33); slaves were also found uniquely prone to "dyesthaesia
Aethiopica", which made them neglect the property rights of
their masters (Brown 1990). Nineteenth century physicians regularly
practiced cliterodectomy to cure women of sexual desire, which
everybody knew never afflicted normal females of good family (Reznek
1987, 5-6). More recently, Soviet psychiatrists found that
political dissidents suffered from "sluggish
schizophrenia". And Horwitz and Wakefield (2007) have suggested
that depression has been severely overdiagnosed by recent generations
of American psychiatrists, leading to the pathologizing of ordinary
sadness.



Our current taxonomy of illness could involve both naturalist
intuitions about some conditions and constructivist rationalizations
about others. You could use this depiction of everyday thought as a
premise in an argument for revisionism, on the grounds that our folk
concepts are too confused to serve as constraints (Murphy 2006 makes
this argument with respect to psychiatry).


## 3. Problems for Constructivism



Constructivism seems correct about some putative diseases; that is,
societies have at times thought that some human activities were
pathological because of values rather than scientific evidence.
However, it is another task to show that constructivism is correct
about our concept of disease. And this would be true even if there
were no diseases; it might still be the case that our concept of
disorder is naturalist even if nothing falls under it.



The chief problem for constructivism is that we routinely make a
distinction between the sick and the deviant, or between pathological
conditions and those that we just disapprove of. Our disease concepts
cannot just be matter of disvaluing certain people or their
properties. It must involve a reason for disvaluing them in a medical
way rather than some other way. Illness has never been the only way to
be deviant. So Szasz is just wrong to claim that "when a person
does something bad, like shoot the president, it is immediately
assumed that he might be mad" (1974, 91). Most of the time when
people do bad things nobody doubts their sanity, just their morals.
Physically or mentally ill people, even if they are seen as
norm-breakers, are seen as a distinctive class of norm-breakers.
What's distinctive about them?



The problem is that we routinely judge that people are worse off
without thinking they are ill in any way - for example, the
ugly, the poor, people with no sense of humor or lousy taste or a
propensity for destructive relationships. We don't treat these
judgments of comparative disadvantage as a prelude to medical inquiry,
so why do we do so in some other cases?



Notice that the problem is not just one of establishing that someone
is badly off or is in some other disvalued state. Rather, the trouble
is caused by the requirement that someone is badly off in a specific,
health-related or medically significant way. Rachel Cooper, for
example (2002, 272-74), analyzes the concept of disease as a bad
thing to have that is judged to require medical attention. She deals
with the objection that specifying when someone is badly off is very
difficult. Cooper admits that it is a hard problem, but replies that
it is a widespread problem, one which crops up in many areas of moral
philosophy.



This response is correct as a general point but does not touch the
present objection. The objection is not that it is hard to say when
someone is badly off, but that it is hard to isolate the specific
class of ways of being badly off that we regard as medically relevant
without relying on a notion of natural malfunction. Glackin (2019,
p.272-3), however, denies that this is a problem at all. He argues
that to justify treating some conditions as medical issues, and
"others as social or legal, rather than medical, all a normativist
needs to say is that this is morally speaking the right thing to do."
For Glackin, we can defend the claim that someone is sick by saying
that according to our values they are sick, and no more need be
said.



Other scholars do think there is more to say. John Harris, for
example, posits an "ER test" (2007, 91) according to which
we can think of a disorder as a condition that makes someone worse off
and is such that emergency room personnel would be negligent if they
did not remedy it if they could. But as it stands the ER test is much
too broad. Taken literally the ER tests requires medical personnel to
teach the local language to immigrants whose lives are worsened by a
lack of competence in it. A general theory of ill-being would be as
desirable as a theory of well-being. But without further elaboration
it would not discriminate between medical and non-medical forms of
ill-being. Like Cooper, Harris faces the difficulty of specifying what
is distinctively medical about the conditions that we expect medical
personnel to treat: of course, a thesis about what counts as a medical
intervention that was put in terms of combating disease or pathology
would be circular. Reznek (1987, 163) argues that we can delimit a
purely medical sphere "enumeratively without reference to the
concept of disease - in terms of pharmacological and surgical
interventions." However, as we saw at the start of this essay, a
lot of medical attention is directed at conditions which we do not
call diseases. Prescribing contraceptive pills is a pharmacological
intervention, but it is not directed against a disease; going on the
pill is not like beginning a course of anti-malarial tablets.



The naturalist answer to the question what makes some medical
interventions directed against disease is that conditions which
doctors treat are diseases in so far as they involve natural
malfunctions. The constructivist view is that the class of what we
call malfunctions is picked out by its involvement in medical
practice, and not the other way round. Cooper and Harris try to base
their analysis on our practices, but they are unable to distinguish
medical practices from non-medical ones. 



Broadbent (2019) has a value-independent account, but it is also
avowedly anti-realist about disease and so can be treated here.
Broadbent calls his view of disease subjective but he has a different
way of dealing with the problem of specifying the human response that
is characteristic of disease judgments. His theory is that health and
disease are secondary qualities like color "that depends on, or
perhaps is partly constituted by, the dispositions of observers or
thinkers to have certain perceptual or cognitive reactions"
(p.108). What human observers bring to physiological states of affairs
is not value judgments, but a disposition to track them as making
characteristic contributions to survival and reproduction. Broadbent
is alert to the issue that there might be cross-cultural differences
in judgments about health and disease, but regards these as compatible
with very broad agreement on the extension of healthy and diseased
states, just as he thinks there is sufficient agreement on spectral
phenomena to speak of color in different contexts. The same treatment
would need to be given with respect to judgments within a society that
vary over time, assuming that objects can change color as a society
alters its color categories. 



So apart from Glackin there seems to be agreement that the
constructivist needs to explain how the judgments that we direct at
putative sick or healthy people form a special class of judgments. And
that explanation has to show, in addition, why we think the conditions
that we single out as diseases with those special judgments are
candidates for a particular set of causal explanations. It's all very
well to point out, as Reznek does (p.88) that an etiology only
explains a pathology if we have already decided that it is a
pathology. This is correct, but it dodges the conceptual question of
why we first decide that only some people or conditions are
pathological. The naturalist says this: we think some people are worse
off because of a special kind of causal process, namely a disturbance
of normal physical or psychological function. It is that causal
judgment that has conceptual priority, even if, as a matter of timing,
the violation of a norm is what is detected first. Note that it does
not refute naturalism to point out that the concept of disease is
sometimes misapplied, so that we think people are sick but discover
that they are not. In such cases (e.g. homosexuality) the explanation
for why it happened may be that our values caused the initial
judgment, but that does not show that the concept of disease is
constructivist, rather than naturalist. No concept is correctly
applied every time.



Reznek, for instance, argues that to judge "that homosexuality
is a disease we first have to make a value-judgment. We have first to
judge that we would be worse off being homosexual" (1987, 212).
Reznek then says that we could discover that homosexuality is not a
disease if we find out that it develops by a normal psychological
process. Reznek calls this is a form of constructivism (or
normativism, in his terms) because value judgments have conceptual
priority: but in fact in the case he describes it seems that value
judgments are actually only heuristics, drawing our attention to
whether something might be wrong with someone. If the initial judgment
can be overturned by a biological discovery, then it seems that
biological facts are necessary for a final judgment. That is to say
that our concept of disease necessarily involves both biological and
evaluative judgments. That is a version of naturalism, since the
biological facts are the ultimate foundation for the judgment. Indeed,
naturalism seems to explain why constructivist interpretations are
sometimes correct. We say now that homosexuality was never a disease,
and was just diagnosed on moral grounds, because it was not caused by
malfunctions according to any even moderately correct theory of human
biology or psychology. Values stopped people from getting the science
right, but homosexuality was correctly understood, and no longer seen
as a disease, when the science was done in a properly disinterested
way.



Naturalism embodies the important insight that we do in fact think
that disease involves a causal process that includes biological
abnormalities. It does not mean, however, that all diseases have to
receive the same biological explanation. The class of diseases will
include a variety of different conditions that receive different
causal explanations. That is, even if diseases are natural kinds, the
superordinate category of disease may not be. Not just any sort of
story about the causes of abnormal behavior will do, and it is
difficult to reach a satisfactory specification of the sorts of causes
that common sense might recognize. We also distinguish, based on our
common sense understanding of human biology, between pathological and
non-pathological versions of the same outward phenomena. Because aging
is normal we acknowledge that an elderly person will differ from a
young adult, so our assumptions about normality are sensitive to
background conditions. But when aging is abnormal, we call it a
disease. Hutchinson-Gilford progeria syndrome, for instance, causes
children to undergo all the stages of human aging at a bizarrely
accelerated rate. They nearly always die by seventeen, far gone in
senescence. Even though we don't know much about it, we think of
Hutchinson-Gilford as a disease not just because we don't like being
old but because we think it is different from getting old in a way
that must be caused by some underlying pathology. The concept of
disease necessarily requires, just as naturalism insists, that a
condition have a causal history involving abnormal biological systems.
So let's turn to naturalism, and see whether it should be a
conservative or revisionist position.


## 4. Naturalism


### 4.1 Forms of Naturalism



When we have decided that someone's biological systems do not function
properly, we still face the question, how should we think about that
person's condition? Naturalists usually admit that there is more to
the concept of disease than biological malfunction even if they think
that biological malfunction is a necessary condition for disease. This
involves a two-stage picture (Murphy 2006, ch 2) which inverts the
constructivist portrayal of our practice. Naturalists who buy the two
stage picture think that, first, we agree on the biological facts
about malfunction. At the second stage we make the normative judgment
that the person with the malfunction is suffering in some way. (This
is the order of conceptual priority, not the chronological sequence in
which judgments are made.) Spitzer and Endicott (1978, 18) for
example, say that disease categories are "calls to
action"; assertions that something has gone wrong within a
person's body in a way that produces consequences we think we need to
remedy (see also Papineau 1994).



Normative considerations, on this account, inform our judgments about
disease but do not have the conceptual priority accorded them by
constructivists. We make judgments that someone is suffering in ways
we associate with inner malfunction. We also see people who are
suffering but who we don't think are ill or injured, because we do not
regard their bodily dysfunction as symptoms of disease: vaccination,
surgical incisions, ear-piercing or childbirth are examples. Or
imagine a skin condition that in some cultures causes the sufferer to
be worshiped as a god, or become a sought-after sexual partner. The
two-stage picture is designed to distinguish between the physical
abnormality and the difference it makes to the life of the person who
has it. The idea is that whether someone's body is not functioning
correctly is a separate question from whether it is bad to be like
that. Stegenga (2018, p.23) calls such a theory a hybrid account, as
it argues both that "there is a constitutive causal basis of disease
and a normative basis of disease." He also adds a fourth alternative,
which he calls eliminativist, arguing for replacing the notion of
disease with successor notions tied more closely to the science. This
goes beyond what has here been called revisionist naturalism, in that
it advocates getting rid of the disease concept altogether, rather
than just liberating it from commonsense constraints. Hybrid accounts
have been very popular among naturalists since at least the
dissemination of Wakefield's (1992) influential discussion of mental
disorder 



The second stage, the question about whether life is worsened by a
malfunction, is omitted by simple naturalism. Simple naturalists say
that all there is to disease is the failure of someone's physiology
(or psychology) to work normally. The view has fewer adherents, but as
noted above, Szasz (1987) uses simple objectivism about disease to
justify his claims that mental disorder is a myth, and Boorse has long
advocated such a view, as does Williams (2007). The popularity of
hybrid accounts, though, is a problem for scholars like Glackin (2019,
p. 258), who argues that the debate exists between
"normativists, who think the concept is inherently evaluative,
and naturalists who think it is purely empirical". But it is
possible to think that there is an empirical question about the causal
basis of disease and a further normative question about the judgments
made on that basis, which hybrid theorists also think are necessary
for disease. 


### 4.2 Specifying Causes



We have arrived at a generic naturalism that says judgments of illness
are sensitive to causal antecedents of the right sort, as well as to
value judgments about the effects of those causes. What are the right
causal antecedents? Culver and Gert's (1982) requirement that the
antecedents be a "nondistinct sustaining cause" is a
biologically noncommittal criterion. Culver and Gert analyze the
concept of a malady, which involves suffering evils, or increased risk
of evil, due to "a condition not sustained by something
distinct" from oneself (1982, 72). The cause can be physical or
mental, (p.87), provided it is a sustaining cause that is not distinct
from the sufferer (p.88). A wrestler's hammerlock, because its effects
come and go with the presence or absence of the cause itself, is an
example of a sustaining cause. But because the wrestler is a distinct
entity from the sufferer, someone in a hammerlock does not have a
malady. If the cause is inside the body it is nondistinct just in case
it is difficult to remove (e.g. a surgical implement left behind in
the body) or it is biologically integrated in the body (e.g. a
retrovirus). This is an attractively simple solution but it is too
inclusive. Culver and Gert (p.71) say that loss of freedom,
opportunity or pleasure count as evils. But if that is so, then black
citizens of South Africa and Mississippi (among many other places)
used to suffer from maladies, since they were unfree, unhappy and
oppressed. And they suffered these evils because of black skin, which
was a nondistinct sustaining aspect of their nature. But it wasn't a
disease. Of course, the presence of racism, backed up by coercive
social structures, was also necessary, but aspects of the environment
are implicated in many maladies. 



This counterexample is instructive, however, since there are two ways
of amending the proposal in the light of it. First, perhaps the
principle of nondistinct sustaining causes fails to capture our
intuitions about causes of disease. A second possibility is that the
principle is a good causal condition, but that the account of evils is
too broad, and needs to be restricted to a more intuitively medical
set of evils, rather than the broader class of impediments to
well-being. The section on health will go over the terrain that's
relevant for the second option; the current discussion is about the
causal condition. Boorse (1975, 1976, 1977, 1997) and his followers
have opted for a more restrictive view of the causes of disease. They
contend that disease necessarily involves biological malfunction.
Boorse distinguished "disease" from "illness".
The former is the failure to conform to the "species-typical
design" of humans, and the latter is a matter of judgments that
a disease is undesirable, entitles one to special treatment, or
excuses bad behavior. An account of malfunction must be parasitic on a
theory of function. Boorse thinks a function is a
'species-typical' contribution to survival and
reproduction (1976, 62-63). Disease is failure to function
according to a species design, in which functional efficiency is
either degraded below the typical level or limited by environmental
agents (1977, 550, 555, 567; 1997, 32). Boorse understands this as
functioning "more than a certain distance below the population
mean" (1977, 559) for the relevant set of humans. (Since not all
members of a species have the same design in every respect, we need to
specify reference classes according to biologically relevant
subgroups.) This cutoff point, he thinks, can only be specified as a
matter of convention, but this conventional element does not threaten
the objectivity of diagnoses. Responses to Boorse since the original
theory was formulated have concentrated on two issues. First is the
apparent existence of states like tooth decay that are widespread, so
apparently statistically normal, yet definitely pathologies. The
second is the"line-drawing problem" Schwartz (2007) which
comes in two related guises: how we are to reference classes and how
we can distinguish between normal and abnormal levels of functional
efficiency.



Boorse's position has been very influential and shaped the entire
recent literature. Williams (2007) retains the spirit of the proposal
but departs from it in arguing that disease is realized not in
systemic malfunctions but failures of interacting cellular networks;
he regards applications of disease language to organs, for example, as
not strictly speaking correct. Most theorists, though, have continued
to emphasis malfunction in physiological mechanisms more broadly. In
psychiatry, for instance, Wakefield (1992, 1997a, 1997b), follows
Boorse (1976) in assuming that humans have a species-typical design,
which he assumes is a product of natural selection. Wakefield applies
the picture to both mental and physical illness: in Wakefield's
version we first judge that a psychological mechanism is not
performing the function for which natural selection designed it;
second, we judge that the malfunction is harmful. An appeal to natural
function, by adding extra commitments to the idea of a cause of
illness, rules out skin pigment as a cause of evil.



Cooper (2002, p.265) suggests that a straightforward appeal to
dysfunction must be qualified in light of some apparent
counterexamples. A woman taking contraceptive pills, for example, may
be interfering with typical functioning, but ingesting contraceptives
is not a disease. (Boorse would have to call it a self-inflicted
disease that does not make the woman ill.) Cooper also raises the
problem of individuals with chronic conditions that are controlled by
drugs. She argues that these are cases of diseased subjects who
nonetheless function normally and suggests that the analysis must be
amended to talk of a disposition to malfunction. But, as Cooper sees,
the big problem faced by Boorsian accounts is that of coming up with
an acceptable conception of normal function in the first place. 



There are two problems that we can distinguish here. The first is
whether a non-normative account of malfunction is possible, about
which much debate has taken place. A second problem has come into
focus more recently. If there is a positive scientific account of
function and malfunction that is pertinent to disease, which science
owns it? The debate deriving from Boorse's work has assumed that
physiologists and pathologists have the last word here. Following
Boorse, Hausman (2015, p. 9) is explicit that physiologists and
pathologists are the relevant medical specialists whose judgments we
care about. Lemoine and Giroux (2016) question the great stress on
physiology to the exclusion of other medical specialties in Boorse
- they think he has backed the wrong doctors. Lemoine and Giroux
think we should see physiology as the science of how organisms work
considered as assemblies of organ systems. But they think that the
science of health and disease is defined by broader medical
considerations that go beyond the physiological. Tied up with this is
a broad consensus that the correct explanation of disease states is
mechanistic, though this too has been challenged in the name of more
abstract explanations from different parts of medicine (Darrason
2018). 


### 4.3 Functions



The Boorsian analysis is of a commonsense concept of disease which
bottoms out in a notion of malfunction as the cause of illness. The
view is that conceptual analysis determines the empirical commitments
of our disease concepts and then hands over to the biomedical sciences
the problem of finding biological functions and malfunctions. Some
recent theorists, notably Wakefield, have argued for an evolutionary
account of function as that which has historically been spread by
natural selection. Others have argued that the biomedical sciences
employ a different conception of function. Besides identifying the
right concept of function for the job, other problems affect the whole
naturalist community. A reliance on scientific, functional
decomposition as the ultimate justification of judgments of health and
disease requires a revisionist, rather than a conservative, account.
Also, it may not always be possible to settle contested cases by an
appeal to a notion of normal human nature, because that notion is
itself contested.



First, why suppose that the relevant concept of function is an
adaptive one, and that dysfunction is a failure of a biological system
to fulfill its adaptive function? This analysis of function is often
termed the etiological account, and although it is widespread in
philosophy of biology it seems to be conceptually tied to fitness
rather than health (Methot 2011). Advocates of a thoroughgoing
evolutionary approach to medicine (such as Gluckman, Beedle and Hanson
2009) can be read as providing a framework within which we can make
sense of a number of processes that have an effect on health and
disease, but not as offering analyses of health and disease that are
tied to fitness. Gluckman et al. (p.5) consider the difference between
lactose intolerance, which develops after weaning and is normal for
most human populations, and congenital hypolactasia, a condition in
which newborns cannot digest maternal milk. The former is a
consequence of the absence of pastoralism in most historical human
populations and does not affect fitness in those populations, whereas
the latter would have been fatal in the past and thus was selected
against. However, they do not define disease in terms of
fitness-lowering: they note rather that an evolutionary perspective
can make us sensitive to hitherto neglected causes of pathology and
also sensitive to over-hasty judgments of pathology in cases where the
condition is normal among populations with a given evolutionary
trajectory.



Wakefield's approach is not that of a thoroughgoing evolutionary
theorist of disease in that sense. Rather, he plugs an etiological
account of function into a Boorsian model, and his approach has been
developed with little attempt to argue that medicine does in fact use
an evolutionary, teleological account of function. In opposition,
Schaffner (1993) has argued that although medicine might use
teleological talk in its attempts to develop a mechanistic picture of
how humans work, the teleology is just heuristic. It can be completely
dispensed with when the mechanistic explanation of a given organ or
process is complete. Schaffner argues that as we learn more about the
causal role a structure plays in the overall functioning of the
organism, the need for teleological talk of any kind drops out and is
superseded by the vocabulary of mechanistic explanation, and that
evolutionary functional ascriptions are merely heuristic; they focus
our attention on "entities that satisfy the secondary [i.e.
mechanistic] sense of function and that it is important for us to know
more about" (1993, 390).



In effect, Schaffner is arguing that the biomedical sciences employ a
causal, rather than a teleological, concept of function. This is in
the spirit of Cummins's (1975) systemic analysis of function as the
causal contribution a structure makes to the overall operation of the
system that includes it. Cummins's concept of function is not a
historical or evolutionary concept. According to Cummins, a component
of a system may have a function even it was not designed or selected
for. Wakefield has tied disease conceptually to an evolutionary
concept of function as a naturally selected capacity. It is doubtful
if this connection can be found in either science or common sense
about disease. Perhaps in some areas of biology functional ascription
is indeed teleological. However, most theorists who have attended to
biomedical contexts agree with Boorse and Schaffner that the function
of an organ or structure can be understood without thinking of it as
an adaptation. Lange (2007) explicitly follows the systemic approach
to function. He argues that diseases are incapacities that explain
symptoms in causal-analytic terms.Medical understanding requires that
functional structures can be identified and analyzed in terms of their
contribution to the overall maintenance of the organism as a living
system. However, it is also clear that the contribution of some
systems - especially reproductive ones - have a purpose that is not
tied to homeostatic regulation and organisation in this way, which
complicates the picture. Theorists who prefer a causal-historical
account to a teleogical one argue that explanation in medicine takes a
model of the normal realization of a biological process and uses the
model to show how abnormalities stem from the failure of normal
relations to apply between components of the model. This requires a
non-historical function concept, one that is at home in
causal-mechanistic, rather than evolutionary, explanation. Proponents
of a teleogical account can respond that those systems, even if they
admit of mechanistic explanation, only exist in the first place
because they have facilitated survival and reproduction, and that the
etiological perspective provides an overall conceptual framework. 



An evolutionary approach faces problems in specifying what the overall
evolved function of a system might be and showing how functions
contribute to it. First, it is very difficult to assess the relevant
evidence that a given biological systems is -- as in Wakefield's
treatment -- the product of natural selection (Davies 2001,
Chapter 5). Since many ailments do not prevent one from living and
having children, it is even harder to show that a disease is
necessarily the product of a malfunction that lowers fitness or
-- as in Boorse -- interferes with survival and
reproduction. Another problem for Wakefield is that if you regard
evolutionary dysfunction as partly constitutive of disease then if an
illness depends on structures that have no evolved function, it cannot
really be an illness. A biological structure might be a spandrel or a
by-product, or have some other non-selective history. Such a structure
cannot malfunction in Wakefield's sense, and so it cannot be diseased
in the primary, evolutionary sense.The idea would have to be weakened
to suggest that it is diseased in a derivative sense in virtue of its
implications for other selected effects elsewhere in the system 



Objections to an evolutionary notion of medical malfunction do not
show that there is anything wrong with the general idea of basing
judgments of health and disease on a scientifically established
picture of the normal functional decomposition of human beings.
However, on this account, it becomes harder to retain the conservative
project that looks for the natural phenomena that fall under, and are
therefore constrained by, our folk concepts of health and disease.
Wakefield, for instance, thinks some psychiatric diagnoses flout our
intuitions by attributing disorder on the basis of behavior alone
without looking for malfunctioning mental mechanisms (1997a). He
appeals to intuitions to derive necessary and sufficient conditions
for the folk concept of mental disorder, and assumes that science
should search for the psychological processes that fit the concept
thus defined. But it is one thing to take intuitions as a starting
point, and another to say that they are hegemonic. Boorse, too,
adduces everyday linguistic usage and commonsense intuitions as
evidence, even though he claims to be discussing the clinical concepts
of health and disease. 



A revisionist can say that a condition we currently disvalue but do
not regard as a disease may turn out to involve malfunction and hence
to be a disease, whatever our intuitions say. Conversely, we may think
something is a disease but we might be wrong, just as we were wrong
about drapetomania or masturbation, which do not causally depend on
any biological malfunction. Conservatives resist this possibility.
Wakefield claims that we have intuitions about human nature that make
it "obvious from surface features" whether underlying
mechanisms are functional or dysfunctional (Wakefield 1997b, 256). But
it is an empirical discovery whether one's physiology or psychology is
functioning properly, not something to be decided from the armchair,
or even from inspecting surface features. A conservative may, though,
seek to distinguish debunked intuitions that can be explained away
(perhaps as products of local norms, as in the masturbation case) from
more resilient intuitions that survive debunking and can still feature
as constraint on analysis. 



However, once we hand over the task of uncovering malfunction to the
sciences we can no longer make common sense the ultimate arbiter,
unless we wish to explicitly import, into the concept of disease,
considerations derived from folk theories of what normal human nature
amounts to.



It seems that the analysis of disease as depending on malfunctioning
biological components requires a functional decomposition of human
biology. If that decomposition is to be independent of what we think
people should be like, it should not be regulated by common sense
theories of human nature, but discovered by science. We must be able
to ascertain, within acceptable limits of variation, the biological
standards that nature has imposed on humans. The goal of finding out
how a biological system works is fixed by our interests in health and
well-being, but the naturalist's assumption is that the goal is met by
discovering empirical facts about human biology, not our own,
culturally defined, norms. So, we diagnose someone as suffering from
mesenteric adenitis not just because they are in discomfort due to
fever, abdominal pain and diarrhea, but because the lower right
quadrant of the mesenteric lymphatic system displays abnormal
inflammation. This thickening of the nodes is not just the objective
cause of the discomfort, it is an objective failure of the lymphatic
system to make its normal contribution to the overall system. For the
naturalist's program to work, the biological roles of human organs
must be natural facts just as empirically discoverable as the atomic
weights of chemical elements. That may result in the overturning of
common sense.



This raises a further issue. It is widely believed that function
concepts are intrinsically normative, since they are teleological (for
a recent review see Barnes 2016). Therefore, the objection continues,
claims about natural functional and malfunction introduce normative
considerations into the foundations of medicine, which are supposed to
be purely scientific.



A response might be to maintain that whether or not functional claims
should be seen as normative, it is not the socially relative
normativity appealed to by constructivists. The crucial point is that
in the life sciences, some biological system can fail to behave as a
theory predicts without impugning the prediction: we can say that the
system is malfunctioning. This contrasts with other sciences, in
which, if a system fails to behave as predicted, the fault lies with
the science, not the system.



Griffiths and Matthewson (2018) attempt to rehabilitate an
evolutionary account of function in this context. They tie a selected
effects interpretation of function to life history theory, with the
advertised aim of providing an explication of pathology that grounds
it in a mature science rather than trying to recover some commonsense,
or even medically prevalent, concept of disease. Their key contention
is that this gives them a scientifically sound way to make
discrimination that would otherwise be puzzling, such as the
distinction between disease states and senescence, and the means to
sort populations into principled reference classes. The resulting
picture (Matthewson and Griffiths 2017) is one which generates a
variety of evolution-based ways in which organisms can "go wrong".
This sets up a taxonomy of opportunities for intervention: some
organisms are malfunctioning; others are working properly but in the
wrong environment; others are badly off because the environment is
inhospitable even though it is normal for them and they are working as
they have evolved to; still others generate a development pathway
based on misleading information about what optimal development will
require. This way of setting up the issues is strongly revisionist,
and arguably is no longer an attempt to define disease at all as most
of the scholars we have discussed would understand it. Matthewson and
Griffiths argue for the congruence of this account with our best
science and its stress on the continuity of human and non-human
biology.



Supporters of an evolutionary account of function advertise the ease
with which an account of malfunction follows from the theory as one of
its virtues. Their idea is that we can say when a system is
malfunctioning by observing that it is not carrying out the job which
natural selection designed it to perform. In contrast, it is widely
believed that systemic accounts of function cannot deal with
malfunction at all. The argument goes like this: what a system is
taken to do is relative to our explanatory interests, and that a
putative malfunction can just be understood as a contribution to a
different property of the system. Davies (2001) argues that the first
of these claims can be defeated by restricting functional ascriptions
to hierarchically organized systems in which lower level capacities
realize upper level ones. That gives us a characterization of function
independent of our explanatory interests.



Godfrey-Smith (1993) argues that systemic concepts of function do
permit attributions of malfunction. He argues that a token component
in a system is malfunctioning when it cannot play the role that lets
other tokens of the same type feature in the explanation of the larger
system. Davies (2003, 212) denies this. He says that functional types
are defined in terms of what they can do and that if a component
cannot carry out its normal contribution to the overall system then it
ceases to be a member of a type. However, Davies' objection appears to
fail, at least in medical contexts, if we can identify components
apart from their functional roles. Suppose we can identify biological
components in terms of their anatomical position and relationships to
other organs. If so, we can say that an organ in the position
characteristic of its type remains a member of that type even though
it has lost some capacity characteristic of that type, and hence is
malfunctioning. Reasoning like this permits doctors to identify organs
as normal or abnormal during autopsies, even though every system in a
corpse no longer possesses its normal function in Davies's sense.



This leaves unaddressed the issue of how we determine what normal
function is. Wachbroit (1994) argues that when we say that an organ is
normal, we employ a biomedical concept of normality that is an
idealized description of a component of a biological system in an
unperturbed state that may never be attained in actual systems. Boorse
(1977, 1997) insists that the notion of normality in biomedical
concepts is statistical -- how things usually are in a reference
class, but this view faces the problem of specifying the reference
classes in an informative way. But given the amount of variation
within a species, it will always be hard to find reference classes
which share a design. As Ereshefsky (2009) puts it, Boorse assumes
that statistical normality coincides with the kind of normality that
medicine cares about, but this looks wrong. Wachbroit (1994, 588)
argues convincingly that the role of normality in physiology is like
the role that pure states or ideal entities play in physical
theories.


### 4.4 Normality and Variation



Statistically, a textbook heart, for example, may be very rare indeed.
But it is the account of the organ that gets into the physiology
textbook. The textbook tells you what a healthy organ is like by
reference to an abstraction - an idealized organ. This concept
of normality is not justified by appeal to a conceptual analysis that
aims to capture intuitions about what's normal. It draws all its
authority from its predictive and explanatory utility: against the
background of assuming normal heart function, for example, we account
for variation in actual hearts (a particular rhythm, say), by citing
the textbook rhythmic pattern (which may be very unusual
statistically) and identifying other patterns as arrhythmic. The point
of textbook depictions of human physiology is to identify an ideal
system that enables us to answer "what if things had been
different questions" (Woodward 2003, Murphy 2006). The role of
an idealization, in this system, is to let us classify real systems
according to their departure from the ideal. So normal human
biological nature, in this sense, is an idealization designed to let
us impose order on variation.



Variation in biological traits is ubiquitous, and so establishing
whether a mechanism is functioning normally is difficult: nonetheless,
biologists do it all the time. As Boorse notes, many objections argue
that pathological states are aspects of natural variation and conclude
that there is no clear distinction between the normal and the
pathological. But he contends that is a non-sequitur, since the
existence of widespread and extensive variation is compatible with the
existence of pathological states. Boorse (2014, p. 696-8) and
Matthewson and Griffiths (2017) both point out that biologists often
judge that members of a species come in forms that are not normal
variants but pathological states.



However, how we ascertain what is pathological remains to be
determined. Not all diagnoses can be tied to a break between normal
and abnormal functioning of an underlying mechanism, such as a failure
of the kidneys to conserve electrolytes. Nor can we always discover
some other abnormality, such as the elevated levels of helicobacter
pylori bacteria that have been found to be causally implicated in
stomach ulcers (discussed in detail by Thagard 1999). Some conditions,
such as hypertension, involve cutting between normal and pathological
parts of a continuous variation, even in the absence of clear
underlying malfunctions that separate the populations. The Boorsian
tradition has tried to deal with the problem of variation by tying
assessments of function and malfunction to reference classes, which
Boorse (1977) treated as natural classes of organisms that share a
uniform blueprint. Kingma (2007, 2010) has recently argued that
reference classes cannot be established without normative judgements,
contra Boorse, who takes them to be objectively discoverable parts of
the natural order. Kingma contends that Boorse's account of
function needs to capture not only the qualitative causal contribution
made by a system to overall functioning, but also the quantitative
features of its contribution: a healthy heart is not just a pump, but
a pump that works at a given rate. In addition, a system must be
capable of working in a variety of situations, including rare ones
that require a physiological response to a crisis. Kingma argues that
Boorse's biostatistical theory cannot capture statistically
unusual yet functional situations, and concludes that we need to
appeal to situation-specific functions. (Cf. Canguilhem (1991 p. 196),
who argued that disease is only abnormal relative to a clearly defined
context.)



Kingma also points out that organs can become diseased even if they do
act in a situationally appropriate way. Liver damage due to
paracetamol overdose is obviously not healthy, she says, but the liver
is not doing anything situationally inappropriate. That is, a reduced
level of function in the context of paracetamol overdose is the
situationally appropriate way for the liver to perform. Kingma offers
Boorse a dilemma. First, he can either abandon the notion of
situationally specific functions. This means failing to recognize the
dynamic nature of physiology and leading to absurdities such as the
claim that a gut which is not currently digesting because it is empty
of food is, in fact, diseased. Or, second, Boorse can acknowledge
situation-specific functions, in which case he must say that some
systems are healthy (because they are acting as they should in that
situation) even though our intuitions insist that they are unhealthy,
because there are diseases that are statistically the norm in some
situations. Hausman (2011) responds that from a Boorsian perspective
the crucial question is whether the normal response - the
organism doing its job under stress - renders the system
incapable. The digestive system may respond appropriately to poison
but in doing so it becomes incapable of normal function on average. If
a victim of a poisoning were to a eat a large unpoisoned meal, her
digestive system would function much less well than that of the
average unpoisoned person in similar circumstances.



Following Boorse, Hausman assumes that there is an average range of
performance within a normal population in normal circumstances that
can tell us what physiological profile a healthy system ought to have.
His reply is developed and expanded by Garson and Piccinini (2014).
The issue is whether these normal circumstances can be specified
without begging the question, or whether Wachbroit is correct to think
of medical normality as an idealization that is unrelated to
statistical normality. On any approach, a worry is that if we cite
behavioral factors in establishing normality they will reflect
contested conceptions of human flourishing. Distinguishing failures to
flourish from functional abnormalities will always be a special
problem for psychiatry. For example, judgments of irrationality are
central to many psychiatric diagnoses, and our standards of rational
thought reflect not biological findings but standards derived from
normative reflection. The possibility of psychiatric explanation
employing the methods and models of physical medicine, then, depends
on how much of our psychology is like the visual system - i.e.
decomposable into structures to which we can ascribe a natural
function (Murphy 2006). Within medicine more generally, the prospects
for a general naturalism about disease depend on our ability to
understand human biology as a set of structures whose functions we can
discover empirically, and our capacity to understand disease causally
as the product of failures of those structures to perform their
natural functions.



More could be said on all these topics, but the essay will now shift
to discuss health. A simple account of health might hold it to be
simply the absence of disease, so that if we agree everything is
functioning as it should - subject to the complications outlined
above, then one is healthy. But most discussions of health insist that
health is not just the absence of disease but something more. 


## 5. Health


### 5.1 Health and Biology



As noted above, conceptions of health, like conceptions of disease,
tend to go beyond the simple condition that one is biologically in
some state. In the case of health, one view is that a healthy
individual is just someone whose biology works as our theories say it
should. This is the counterpart, in theories of health, to simple
objectivism about disease. It is defended at length by Hausman (2015)
who calls it "functional efficiency". As with disease,
however, most scholars who write about health add further conditions
having to do with quality of life. For instance, Hausman argues that
what we are concerned to measure is the contribution that functional
efficiency makes to overall well-being. We track not health but the
things that make health important. Hausman thus distinguishes disease,
health and the value of health. Other scholars draw a similar
threefold distinction in different ways. One might have a partly
evaluative view of health, like a hybrid view of disease, while also
thinking that health should be distinguished from a broader concept
like well-being or flourishing. Such views dispute the line we find in
Boorse and Hausman that a non-evaluative conception of health is
viable. Alexandrova (2018), for instance, argues that health is one of
many partly normative concepts that give rise to what she calls
"mixed claims" in the social sciences, that relate,
empirical variables to normatively derived variables. The definition
and measurement of health, she insists, must depend on normative
judgments about what it takes to be healthy.



What kinds of normative claims are relevant? Carel (2007, 2008) thinks
that the important thing about health is one's lived experience of
one's own body, and in particular, that one should not feel estranged
or alienated from one's body. Carel argues that health should be
understood phenomenologically as the experience of being at home in
one's lived body, rather than merely the normal functioning of the
body seen as a biological unit.



From the naturalist perspective, one problem with this proposal is
that it ignores the fact that one can feel perfectly at ease with
one's lived body even if one harbors, unaware, a diseased system.
Indeed, Carel argues that someone who is ill can be, in her sense,
healthy, if they are adapted to their bodily predicament; from her
perspective, objections like the one just mentioned miss the point,
since they privilege a biological perspective rather than a
phenomenological one. Her project is avowedly revisionist: she wishes
to replace existing concepts of health with views that aim to capture
the experience of being healthy (or unwell).



Carel's stress on experience is directly challenged by views like
Gadamer's. He insists (1996, 113) that it is absurd to ask someone if
they feel healthy, since health is "not a condition that one
introspectively feels in oneself. Rather, it is a condition of being
involved, of being in the world, of being together with one's fellow
human beings, of active and rewarding engagement in one's everyday
tasks". Gadamer's healthy person is someone who is in harmony
with their social and natural environment, and disease is a
disturbance of this harmony. Canguilhem (1991, 2012) thinks of health
as flexibility, in the sense that a healthy organism can tolerate
environmental impacts, adapts to new situations and possesses a store
of energy and audacity. This is not something that can be measured by
physiology (2012, p.49). Canguilhem's approach suggests what is wrong
with Gadamer's objection to phenomenological accounts of health. A
phenomenological account does not have to hold, as Gadamer seems to have
supposed, that there is a special feeling that is the feeling of being
healthy. Rather, for a view like Canguilhem or Carel's, healthy people
experience the world as an arena to express themselves in rather than
a bunch of threats. Antonovsky (1987) puts this in terms of a sense of
coherence which enables one to understand the environment and mobilize
internal resources against external stressors. It may well be that
perspectives like Carel's are neglected in contemporary medicine, and
that they are especially important in disability studies. However, it
does not follow that the concepts of health and disease, rather than
aspects of our practices that employ those concepts, should be
reformed along the lines she suggests. In general, though, accounts of
health, compared to those of disease, are less concerned with trying
to capture a scientific or clinical concept.


### 5.2 Embedded Instrumentalism



Gadamer's view is reminiscent of what Richman (2003) calls
"embedded instrumentalist" theories, which claim that
health is indexed to goals: how healthy you are depends on how well
you can fulfill your goals. Such theories are very popular. Nordenfelt
(1995) considered two versions of this approach. One version defines
the goals relevant to health as needs, which are understood as having
a biological basis. Another view defines goals in terms of the
ambitions and desires of the individual. Nordenfelt (1995, 90) argues
that a healthy person is one who can satisfy her "vital
goals", which are those that are necessary and sufficient for
her to be minimally happy.



Embedded instrumentalist theories of health have an obvious appeal.
Once we argue that health involves judgments about how well a person's
life is going, we need a way to evaluate that, and an immediately
attractive idea is that someone's life goes well if they can achieve
their ambitions or satisfy their goals. An apparent difficulty,
however, is that much the same terrain is covered by theories of
well-being, and while people think that being healthy is important to
their well-being (Eid and Larsen 2007), they do not identify the two.
Rather, they think of health as a component of well-being or a
contributor to it.



Some embedded instrumentalist theories, though, appear to be in danger
of defining health in such a way that it is synonymous with
well-being. Richman (2003), for example, develops his view, (the
"Richman-Budson view") to deal with objections that
Nordenfelt raises against goal-based views, such as the worry that
someone with very low ambitions will count as healthy just because she
is easily satisfied. Richman (2003, 56-57) supposes that someone
is healthy if she can strive for a consistent set of goals that would
be chosen by an idealized version of herself if she were fully aware
of her "objectified subjective interest" (p.45). That is,
they are the goals she would choose if she had complete knowledge of
herself and her environment and perfect rationality.



In this case it seems that a theory of health is in danger of becoming
a general theory of well-being, and Richman does not discuss the
relationship between the two. A further complication is the
relationship between medical interventions designed to cure diseases,
and other medical interventions which are "enhancement
technologies" (Elliott 2003). The line between enhancement and
therapy is very hard to draw: Harris (2007, 21) for example, uses the
example of vaccination, which is both a therapeutic protection against
infection and an enhancement of our natural immune system. Perhaps,
too, many of us would benefit from a boost to our powers of
concentration, or a lift in our mood, which pharmaceuticals might
supply. But neurological enhancements, unlike vaccines, can help us to
meet our goals without guarding against disease. Perhaps what is
needed is a weaker view of the relation between health and
goal-directedness, such as that offered by Whitbeck (1981, 620).
Whitbeck defines health in terms of the psychophysiological capacities
of an individual that support her "goals, projects and
aspirations in a wide variety of situations". This view loosens
the tight Richman-Budson connection between health and goal-directed
action, and suggests a view on which we can see biological capacities
as at the core of health in so far as they help people's lives to go
better. So there seems to be a broad but not unanimous view that
whatever one thinks about the value-ladenness of health we need a
threefold distinction between disease, health (which may or may not be
partly evaluative, and some properties of a person's life that enable
us to evaluate how well it is going for them. Not all such properties
are health problems - someone who is oppressed is not unhealthy
simply in virtue of being oppressed (though oppression can certainly
cause health problems) - oppression itself can be distinguished
from the health problems that may follow from the nature of oppression




Schroeder (2013) has taken issue with the whole idea of defining health as a property or state of an individual. He argues in contrast
that "health" is a fundamentally comparative term like
"tall". Two human beings can both be tall even if one is
taller than the other, whereas it makes no sense to think of two
straight lines, one of which is straighter than the other. Schroeder
argues that if we see health as fundamentally comparative or relational 
we can recast several conceptual, ethical and policy debates. For
example, instead of thinking in terms of non health-related
differences among the healthy we could think in terms of gradations of
health. Schroeder also thinks that his approach makes
intergenerational or cross-temporal comparisons easier, since we can
say that a medieval serf was healthy in their time, but nonetheless
less healthy than a modern person who is, by our standards,
chronically ill. An approach like this might offer some traction on
the reference class problem outlined above.


## 6. Conclusions



Naturalism and constructivism have been distinguished for analytic
purposes in this essay but they are not always easy to tell apart in
practice. The difficulty comes from the fact that there is widespread
agreement that our thinking about disease pays attention to both human
values and biological phenomena, and it is not always easy to tell how
a theorist explains the interactions of these factors, nor whether a
given analysis is descriptive or prescriptive. For naturalists the
relevant biological processes are departures from good human
functioning, construed in one of several ways about which controversy
rages, but to be determined by the relevant science. These biological
problems result in what we judge to be difficulties in living, which
may or may not be partly constitutive of disease, just as positive
qualities may or may not be partly constitutive of health. For a
constructivist, it is the problems people face in their lives that
take priority. Their biological underpinnings are ones we count as
abnormal because we have judged them to be both relevant to the
conditions we disvalue and also the subject matter of a specific,
medical, class of interventions, therapies and other practices. The
obstacle to a successful development of naturalism is the problem of
establishing a satisfactory, science-based, distinction between normal
and abnormal human functioning. Overcoming this difficulty will
require a closer engagement by theorists of disease with the relevant
debates in the philosophy of biology.



For constructivists, the big problem is to say why we judge some human
phenomena to be symptoms of disease whereas others are taken as
evidence that someone is criminal or ugly or possessed by demons or
something else we do not admire. It is not generally true that we
think that if someone's life goes badly it is because he or she is
unhealthy, so constructivists owe us an account of what makes a
certain class of judgments distinctively medicalized.