Disability: Definitions and Models
Philosophers have always lived among, and often as, people who could not see, walk, or hear; who had limited mobility, comprehension or longevity, or chronic illnesses of various sorts. And philosophers have lived in societies that respond to these and other bodily differences in a wide variety of ways. And yet philosophical interest in these conditions and the social response to them was piecemeal and occasional until the past hundred or so years.
Some of these conditions were cited in litanies of life’s hardships or evils; some were the vehicle for inquiries into the relationship between human faculties and human knowledge (see entry on Molyneux’s problem). But the treatment of disability as a subject of philosophical interest in its own right is relatively new. The lack of attention to “disability” or the related concept of “impairment” may have a simple explanation: there were no such concepts to attend to until nineteenth century scientific thinking put variations in human function and form into categories of abnormality and deviance.
Once such categories were established, it became possible to talk, and generalize, about (first) “the disabled”, and (then) “their impairments”, and philosophers have done so for various purposes [Hacking, 1990; L. Davis, 2002: Ch. 4]).
The resurgent political philosophy of the second half of the last century, preoccupied with eliminating or reducing unearned disadvantages, tended to treat disability as a primary source of those disadvantages, to be addressed with medical correction or government compensation (Cohen 1993; Sen 1993). Somewhat later, social philosophers began to see disability as a source both of discrimination and oppression, and of group identity, akin to race or gender in these respects. And biomedical and other practical applied’ ethicists have been concerned to help policy-makers construct and interpret new legal and regulatory frameworks making central reference to “disability” and related concepts.
For these reasons and others, philosophers have had much to say, initially in passing and now at length, about what disability is and what “disability” means. This entry will discuss both issues—first, detailing philosophical engagement with longstanding debates over the correct “model” or general framework for understanding disability as a phenomenon; second, asking how philosophers have come to understand the meaning of concepts denoted by words like “disability” and “impairment”, as those have been used in various empirical and normative discourses concerning people with disabilities.
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1. Models of Disability
Many different characteristics have been considered disabilities. Paraplegia, deafness, blindness, diabetes, autism, epilepsy, depression, and HIV have all been classified as “disabilities”. The term covers such diverse conditions as the congenital absence or adventitious loss of a limb or a sensory function; progressive neurological conditions like multiple sclerosis; chronic diseases like arteriosclerosis; the inability or limited ability to perform such cognitive functions as remembering faces or calculating sums; and psychiatric disorders like schizophrenia and bipolar disorder.
Disabilities like these have been objects of study in sociology, medicine, and policy debates for much longer than they have been subjects of sustained interest in philosophy. These discourses do not tend to define “disability” by way of the sort of rigorous necessary and sufficient conditions philosophers often prefer. But they have been centrally concerned with broadly definitional issues, often discussed under the heading of “models” of disability—that is, general theoretical perspectives concerned to say what in the world social scientists are investigating when they investigate disability. These models generally pick out, both (1) a set of phenomenon as what needs explaining, when we explain disability, phenomenon typically but not necessarily characterized as disadvantages; and (2) an explanation of these phenomenon—again, typically, but not solely, an explanation of why disabled people experience the disadvantages they do.
1.1 Medical and Social Models
In their extreme forms, the medical and social models serve to chart the space of possible relationships between bodily difference and functional limitation more than to reflect the actual views of individuals or institutions. (A variety of more formal models, described in Altman 2001, graphically represent the causal complexity of disability.)
The medical model explains disability disadvantage in terms of pathological states of the body and mind themselves. It regards the limitations faced by people with disabilities as resulting primarily from their bodily differences. The medical model is rarely defended explicitly, but aspects of it are often adopted unreflectively, when health care professionals, bioethicists, and philosophers ignore or underestimate the contribution of social and other environmental factors to the limitations faced by people with disabilities.
In contrast, the social model explains the characteristic features of disability in terms of a relation between an individual and her social environment: the exclusion of people with certain physical and mental characteristics, or “impairments”, from major domains of social life. Their exclusion is manifested not only in deliberate segregation, but in a built environment and organized social activity that preclude or restrict the participation of people seen or labeled as having disabilities. A variety of social models are embraced by disability scholars and activists in and outside of philosophy. The “British social model” associated with the Union of the Physically Impaired against Segregation (UPIAS 1976) appears to deny any causal role to impairment in disability:
In our view, it is society which disables physically impaired people. Disability is something imposed on top of our impairments by the way we are unnecessarily isolated and excluded from full participation in society. Disabled people are therefore an oppressed group in society. Disability [is] the disadvantage or restriction of activity caused by a contemporary social organization which takes no or little account of people who have physical impairments and thus excludes them from participation in the mainstream of social activities.
Two features of this influential statement are worth noting, although we will only discuss the second at length. First, it limits itself to physical impairments; second, it contrasts impairments, individual characteristics or conditions, with disabilities, disadvantages imposed by society on those with impairments. The first feature inaugurates a long tradition in disability activism and scholarship of focusing exclusively on “physical” disability, to the neglect, if not the exclusion, of intellectual, psychiatric, and other “mental” disabilities. Both scholars and activists have long criticized, and sought to broaden, this narrow focus, and even those philosophers who continue to focus on physical disability recognize that adequate models and definitions must include mental disabilities as well. In the rest of this entry, we will not distinguish between the two types of disability except when it is relevant to a particular model or definition; we will note when an account is limited to physical disabilities or criticizes other accounts for that limitation.
The second feature, the distinction between impairment and disability, will be more central to our discussion. It is through those terms that the medical and social models have been distinguished, and it is this “anatomy” of disability that several recent philosophical definitions have rejected or significantly modified.
Implicit in the UPIAS understanding of disability are two ways that society imposes limitations on disabled people, corresponding to two distinct strands that might be a part of any social model. When the UPIAS claims that society “excludes” people with impairments, this suggests the minority group model, which sees people with impairments as a minority population subject to stigmatization and exclusion. On this view, the main reason people with disabilities encounter hardship is because they suffer discrimination along the same lines as racial or ethnic minorities. Accordingly, civil rights protections and anti-discrimination laws are the proper responses to disability (e.g., Hahn 1987 [1997] and Oliver 1990). Perhaps the most familiar expression of the minority-group model is found in the preamble to the Americans with Disabilities Act (ADA), which describes people with disabilities as “a discrete and insular minority”—an explicit invocation of the legal characterization of racial minorities.
The UPIAS also asserts that “contemporary social organization” fails to “take into account” people with disabilities. This suggests the human variation model, according to which many of the challenges faced by disabled people do not result from their deliberate exclusion, but from a mismatch between their characteristics and the physical and social environment. On this view, disability is
an extension of the variability in physical and mental attributes beyond the present—but not the potential—ability of social institutions to routinely respond. (Scotch & Schriner 1997)
This view of disabilities as the result of human variations is closely related to the view that disability is a universal human condition (Zola 1989) or shared human identity (L. Davis 2002: Ch. 1). The claim that disability is universal can be taken as nothing more than a prediction that we will all acquire familiar disabilities at some point in our lives. But that claim is better construed as one about the nature of disability; as maintaining that all human beings have physical or mental variations that can become a source of vulnerability or disadvantage in some settings.
These two versions of the social model are not incompatible, differing mainly in emphasis. The discrimination stressed by the minority group model generally leads to, and is expressed in, the societal failure to accommodate people with various differences. In some contexts, it is appropriate to analogize people with disabilities to racial or other minorities; in others, it is important to reject a dichotomy between disability and normality and treat impairments as continuous variations. If one goal of social policy is to remove discrimination and its enduring disadvantages, another is to encompass the full range of human variation in the design of the physical environment and social practices.
Although the social model, in one version or another, is now the dominant legislative, social-science, and humanities paradigm for understanding disability, stronger versions of it – particularly the British Social Model exemplified by UPIAS – have been subject to extensive criticism. Some argue that an adequate conceptualization of disability requires a recognition of impairments as an objective basis for classification, to distinguish disability discrimination from other types of discrimination (Bickenbach 1993). Several critics argue that extreme versions of the model implausibly deny or understate the role of impairment itself as a source of disadvantage (Anastasiou & Kauffman 2013; Terzi, 2004, 2009; Shakespeare 2006). Others, however, contend that this criticism is misplaced, because the British Social Model does not deny the importance of impairments but rather seeks to restrict the application of the term “disability” to social exclusion and oppression (Beaudry 2016).
Another objection is that the social as well as the medical model both rest on a false dichotomy between biological impairments and social limitations. There are two versions of this objection. One maintains that disability is a complex phenomenon, in which biological impairment and social exclusion are deeply interwoven and difficult to tease apart (Martiny 2015; Anastasiou & Kauffman 2013). The other version of this objection rejects the treatment of impairment as a (strictly) biological phenomenon. “Impairment”, the argument goes, is no less a social construction than the barriers faced by people so classified (more on this below). Claims that there is a stable biomedical basis for classifying a variation as an impairment are called into question by shifting classifications; by the “medicalization” of some conditions (shyness) and “demedicalization” of others (homosexuality). Moreover, the social environment appears to play a significant role in identifying and, arguably, in constituting some impairments (dyslexia) (Cole 2007; Shakespeare 2006; L. Davis 2002: Ch 1; Tremain, 2001, 2017; Amundson 2000). What counts as an impairment may depend on which variations appear to be disadvantageous in familiar or salient environments, or on which variations are subject to social prejudice: Less-than-average height may be more readily classified as an impairment than greater-than-average height because the former is more often disadvantageous in environments designed for people of average height, or because it is generally seen as less desirable. For such reasons, it is difficult to establish the objectivity of the impairment classification by appeal to a clear and undisputed biomedical norm. Amundson (2000), indeed, goes so far as to deny that there is any biological basis for a concept of functional normality—a claim emphatically rejected by Boorse (2010).
1.2 An Affirmative Model?
The debate between the medical and social model about the source of the disadvantages disabled people experience has dominated academic discourse about disability since the 1970s. More recently, however, disability activists and disabled scholars have questioned the apparent shared assumption of both models, that disability is fundamentally a matter of disadvantage, exclusion, or functional limitation. This to take a (partly) different view on what an account of disability should explain; a view consistent in principle with either a more medical or more social view of what does the explaining. The affirmative model of disability and impairment, as articulated by John Swain and Sally French (2000), holds that disability is not in the first instance a problem—not simply or solely a “personal tragedy”, and implicitly, not simply or solely a social injustice either. Rather, disability is a different way of living in and experiencing the world, one not characterized by its disadvantages any more than its advantages.
Note that this is not a claim about what causally explains disability; rather, it is a claim about what aspects of the phenomena of disability should serve as the object of explanation in social scientific theories of disability. As such, the affirmational model is prima facie consistent with either the medical or the social model, and indeed tends to draw on considerations from both. The diverse mix of advantages and disadvantages that characterize life with disability can derive from biological factors, social factors, or interactions between the two. On the side of advantage, a person with a disability like blindness might celebrate the increased attention sightlessness saves for hearing and other senses as well as the solidarity they experience with other disabled people as they fight together against ableism and for social justice. On the side of disadvantage, the affirmational model will point to the considerations some would regard as personal tragedies as, instead, a combination of purely functional challenges to be overcome, and conditions of social exclusion that can make life harder without thereby making it any less valuable or worth living.
Still: though logically independent of claims about the evaluative import of disability, the medical and social models suggest different views about the impact of disability on well-being, and different views about how disability is relevant to reproductive decisions, medical interventions, and social policy. The affirmational model is likely to be more in sympathy with social than medical models here. Those who accept a social model of disability regard the association between disability and well-being as highly contingent, mediated by a variety of environmental and social factors (Campbell & Stramondo 2017). They also tend to question conceptions of well-being that give a central role to the possession or exercise of the standard array of physical and mental functions, as those conceptions imply, or are often taken to imply, that well-being is precluded or diminished merely by the absence or limitation of those functions (see entry disability: health, well-being, and personal relationships). As a result, they generally see the disadvantages of disability not only as externally caused, but as less formidable than they appear to people who view disability in largely biomedical terms. These differences are reflected in the conflicting assessments of life with disabilities found in the bioethics and public policy literature on the one hand, and disability scholarship on the other (contrast Brock 2005 with Goering 2008).
1.3 Models, Decisions, and Policies
The different models of disability—and particularly, the medical and social models—have always been interpreted as favoring different responses to disability. The medical model appears to support the correction of the biological condition (or some form of compensation when that is impractical); the minority group model appears to favor measures to eliminate exclusionary practices or at least recognize their injustice; the human variation model appears to favor reconstruction of the physical and social environment to take into account a wider range of differences in human structure and function (measures that could in turn make the social environment less exclusionary).
But claims about the causal explanation of disadvantage do not always yield straightforward prescriptions for their remediation (Wasserman 2001; Samaha 2007; Barclay 2018). In some cases, medical or surgical “correction” may be the most effective way to escape discrimination; if correction is not appropriate, that is because it reinforces discriminatory attitudes and practices, not because it is discriminatory per se. Even an affirmational model does not straightforwardly imply that we should change society rather than disabled bodies: that disabled people have reason to be proud of their disabilities and/or impairments does not immediately entail claims in justice on the rest of us to incur the costs of accommodating these differences. This is to be expected: the proper response to the disadvantages associated with disability depends not only on causal attributions and prudential evaluations, the domains of the three “models”, but also on moral judgments about responsibility, respect, justice.
This is not to say that these causal attributions, much less prudential judgments, are morally irrelevant: to the extent that social causation of disability disadvantage makes social institutions morally responsible for the limitations disabled people face, it may be unfair and disrespectful for society to ask disabled people to change themselves rather than changing itself to be more inclusive (Aas 2020). Moreover, “correcting” disability may (as the affirmational model reminds) us involve destroying valuable forms of life and reducing the vibrant diversity of human embodiment; or it may not do not enough to counterbalance the benefits of uniformity (Garland-Thomson 2012). Contra the sense that the social, medical, and affirmational models each come bundled with obvious policy consequences, it seems clear on reflection that there is much yet to do to understand just what these different explanations of disability imply as to how we should respond to it.
2.Definitions of Disability
Until relatively recently, there was little independent philosophical discussion of definitions of disability. Instead, philosophers focused primarily on developing and interpreting legal and regulatory definition needed to implement disability policy. The legal definitions, in turn, were heavily influenced by the two-part “anatomy”—impairment and social response—of the social model of disability, which was developed by activists seeking to influence legislation and policy.
2.1 Philosophical discussion of Official Definitions of Disability
Thus, two familiar features are shared by most official definitions of disability, such as those in the World Health Organization (1980, 2001), the Disability Discrimination Act (UK), and the Americans with Disabilities Act (United States): (i) a physical or mental characteristic labeled or perceived as an impairment or dysfunction and (ii) some personal or social limitation associated with that impairment. Impairments are generally seen as traits of the individual that he or she cannot readily alter. Just what makes a condition a trait or attribute of an individual is obscure and debatable, but there seems to be agreement on clear cases. Thus, poverty is not seen as an impairment, however disabling it may be, nor is tasteless clothing, even if it is a manifestation of impaired fashion-sense rather than scarce income. On the other hand, diseases are generally classified as impairments, even though they are often neither permanent nor static conditions. Diseases that are especially transient, however, such as the flu and the measles, do not normally count as impairments.
As in early philosophical debates about competing models, the most controversial issue in defining disability is the relationship between these two features. At one extreme are definitions that imply, or are read to imply, that biological impairments are the sole causes of limitation. The definitions in the World Health Organization’s 1980 International Classification of Impairment, Disability, and Handicap, and the Disability Discrimination Act (UK) have been interpreted this way. At the other extreme are definitions that restrict the limitations faced by disabled people (as such) solely to “contemporary social organization”, such as the definition given by the Union of the Physically Impaired Against Segregation (UPIAS 1976). In between are definitions which assert that individual impairment and the social environment are jointly sufficient causes of limitation. Perhaps the best-known example is the WHO’s International Classification of Functioning, Disability and Health (World Health Organization 2001, referred to as ICF), which emphasizes that disability is a “dynamic interaction between health conditions and environmental and personal factors”.
Through much of the first two decades of this century, philosophers were largely content with this definitional approach to disability as a relationship or interaction, disagreeing primarily on the comparative contribution of the two elements and the policy relevance of their contributions. As noted in the last section, dissenters mainly focused on the characterization of one or both elements, as, e.g., on the first as social vs. biological, rather than on the “anatomy” itself. More recently, however, there has been some movement away from reliance on these two-part approaches to defining disability (e.g., Barnes 2016, and much of the literature responding). One reason may be that in most settings, we do not think of or refer to disabilities as relationships or interactions, but as individual somatic or psychic traits, states or conditions (including absences and deficiencies). These commonsense referents are hard to find in, for example, the multifactorial charts by which the ICF illustrates its definition of disability as a complex interaction of health conditions with environmental, social, and personal factors.
Some might argue that ordinary usage is ideological, shaped by false failure to be conscious of the insights of social and interactionist models. But defining “disability” in rough conformity to ordinary usage hardly implies that its referents are selected by biomedical criteria, let alone that the traits selected cause the disadvantages faced by their bearers or dictate the appropriate social response to those disadvantages. Rather, this view on what “disability” and “people with disabilities” refer to is compatible with a wide variety of positions on how those referents are picked out: e.g., by biomedical criteria; by the rules of a civil-rights movement; by the assumptions of the dominant ideology about bodily dysfunction; or by the demands of justice. The extent to which what counts as a disability, or a person with a disability, varies with context will depend on the account adopted; on biomedical accounts, the extension of “disability” will be as stable as human biology; on other accounts, it will change with changing social norms, economic needs, or political developments. Further, on some accounts, the referents will have common features, identifiable by inspection; on others, what they have in common can only be understood in terms of an ideology or a theory of justice.
After discussing several types of accounts, we will address the claim, inspired by the diversity of traits and conditions they pick out, that “disability” has no core meaning, and that it may be futile and distracting to search for one.