Some ‘naturalist’ accounts of disease employ a biostatistical account of dysfunction, whilst others use a ‘selected effect’ account. Several recent authors have argued that the biostatistical account offers the best hope for a naturalist account of disease. We show that the selected effect account survives the criticisms levelled by these authors relatively unscathed, and has significant advantages over the BST. Moreover, unlike the BST, it has a strong theoretical rationale and can provide substantive reasons to decide difficult cases. This is (...) illustrated by showing how life-history theory clarifies the status of so-called diseases of old age. The selected effect account of function deserves a more prominent place in the philosophy of medicine than it currently occupies. _1_ Introduction _2_ Biostatistical and Selected Effect Accounts of Function _3_ Objections to the Selected Effect Account _3.1_ Boorse _3.2_ Kingma _3.3_ Hausman _3.4_ Murphy and Woolfolk _4_ Problems for the Biostatistical Account _4.1_ Schwartz _5_ Analysis versus Explication _6_ Explicating Dysfunction: Life History Theory and Senescence _7_ Conclusion. (shrink)

Conceptual analysis of health and disease is portrayed as consisting in the confrontation of a set of criteria—a “definition”—with a set of cases, called instances of either “health” or “ disease.” Apart from logical counter-arguments, there is no other way to refute an opponent’s definition than by providing counter-cases. As resorting to intensional stipulation is not forbidden, several contenders can therefore be deemed to have succeeded. This implies that conceptual analysis alone is not likely to decide between naturalism and normativism. (...) An alternative to this approach would be to examine whether the concept of disease can be naturalized. (shrink)

Disability studies have been successfully focusing on individuals' lived experiences, the personalization of goals, and the constitution of the individual in defining disease and restructuring public understandings of disability. Although they had a strong influence in the policy making and medical modeling of disease, their framework has not been translated to traditional naturalistic accounts of disease. I will argue that, using new developments in evolutionary biology (Extended Evolutionary Synthesis [EES] about questions of proper function) and behavioral ecology (Niche conformance and (...) construction about the questions of reference classes in biostatistics accounts), the main elements of the framework of disability studies can be used to represent life histories at the conceptual level of the two main “non-normative” accounts of disease. I chose these accounts since they are related to medicine in a more descriptive way. The success of the practical aspects of disability studies this way will be communicated without causing injustice to the individual since they will represent the individuality of the patient in two main naturalistic accounts of disease: the biostatistical account and the evolutionary functional account. Although most accounts criticizing the concept of disease as value-laden do not supply a positive element, disability studies can supply a good point for descriptive extension of the concept through inclusion of epistemic agency. (shrink)

In their paper “Is psychopathy a mental disease?”, Thomas Nadelhoffer and Walter Sinnott-Armstrong argue that according to any plausible account of mental disorder, neural and psychological abnormalities correlated with psychopathy should be regarded as signs of a mental disorder. I oppose this conclusion by arguing that at least on a naturalistically grounded account, such as Wakefield’s ‘Harmful Dysfunction’ view, currently available empirical data and evolutionary considerations indicate that psychopathy is not a mental disorder.

In a recent article in this journal, Zachary Ardern criticizes our view that the most promising candidate for a naturalized criterion of disease is the "selected effects" account of biological function and dysfunction. Here we reply to Ardern’s criticisms and, more generally, clarify the relationship between adaptation and dysfunction in the evolution of health and disease.

The vagueness or imprecision of ‘the normal’ allows it to be exploited for various purposes and political ends. It is conspicuous in both medicine and athletics; I am going to try to say something about the normal in each of these areas. In medicine the idea of the normal is often deployed in understanding what constitutes disease and hence, as some see it, in determining the role of physicians, in determining what is or ought to be covered by insurance, and (...) in underwriting certain views on social justice. In athletics the use of performance enhancing substances raises different sorts of questions about the normal, especially when it comes to deciding what constitutes an enhancement and which enhancements, if any, are acceptable. (shrink)

Despite the effort on DSM-5 and ICD-11, few appear satisfied with these classification systems. We suggest that the core reason for dissatisfaction is expecting too much from them; they do not provide discrete categories that map to specific causes of disease, they describe clinical syndromes intended to guide treatment choices. Here we review work on anxiety and anxiety disorders to argue that while clinicians draw a pragmatic distinction between normal and abnormal emotions based on considerations such as severity and duration, (...) understanding the evolutionary origins and utility of the emotions, including the adaptive value of adverse emotions, is key for formulating comprehensive assessments of an individual patient’s symptoms and for providing a conceptual foundation for pharmacotherapy, psychotherapy, and public health. (shrink)

Two decades ago, the eminent evolutionary biologist George C. Williams and his physician coauthor, Randolph Nesse, formulated the evolutionary medicine research program. Williams and Nesse explicitly made adaptationism a core component of the new program, which has served to undermine the program ever since, distorting its practitioners’ perceptions of evidentiary burdens and in extreme cases has served to warp practitioner’s understandings of the relationship between evolutionary benefits/detriments and medical ones. I show that the Williams and Nesse program more particularly embraces (...) the panselectionist variety of adaptationism (the empirical assumption that non-adaptive evolutionary processes are causally unimportant compared to natural selection), and argue that this has harmed the field. Panselectionism serves to conceal the enormous evidentiary hurdles that evolutionary medicine hypotheses face, making them appear stronger than they are. I use two examples of evolutionary medicine texts, on neonatal jaundice and on asthma, to show that some evolutionary medicine practitioners have allowed their fervent panselectionism to directly shape their recommendations for clinical practice. I argue that this escalation of panselectionism’s influence is inappropriate under Williams’ and Nesse original stated standards, despite being inspired by their program. I also show that the examples’ conflation of clinical and evolutionary considerations is inappropriate even under Christopher Boorse’s controversial evolution-rooted concepts of disease and health. (shrink)

In this article, I argue that distinguishing ‘evolutionary’ from ‘Darwinian’ medicine will help us assess the variety of roles that evolutionary explanations can play in a number of medical contexts. Because the boundaries of evolutionary and Darwinian medicine overlap to some extent, however, they are best described as distinct ‘research traditions’ rather than as competing paradigms. But while evolu- tionary medicine does not stand out as a new scientific field of its own, Darwinian medicine is united by a number of (...) distinctive theoretical and methodological claims. For example, evolutionary medicine and Darwinian medicine can be distinguished with respect to the styles of evolutionary explanations they employ. While the former primarily involves ‘forward looking’ explanations, the latter depends mostly on ‘backward looking’ explanations. A forward looking explanation tries to predict the effects of ongoing evolutionary processes on human health and disease in contem- porary environments (e.g., hospitals). In contrast, a backward looking explanation typically applies evolutionary principles from the vantage point of humans’ distant biological past in order to assess present states of health and disease. Both approaches, however, are concerned with the prevention and control of human diseases. In con- clusion, I raise some concerns about the claim that ‘nothing in medicine makes sense except in the light of evolution’. (shrink)

Although natural selection might be expected to reduce the incidence and severity of disease, disease persists. Natural selection leads to increases in the mean fitness of populations and so will reduce the frequency of disease-associated alleles, but other evolutionary processes, such as mutation and gene flow, may introduce or increase the frequency of these deleterious alleles. The pleiotropic actions of genes and the epistatic interactions between them complicate the relationship between genotype and phenotype, and may result in the preservation of (...) disease-associated alleles. Deleterious alleles may also be maintained because of linkage to beneficial alleles. The inability of natural selection to eliminate diseases of aging is a reminder that fitness – success in producing progeny, or in contributing genes to the population gene pool – is not equivalent to the absence of disease. Nutritional or psychosocial cues may lead to life history strategies that maximize survival to reproductive maturity at the expense of disease later in life. Natural selection acts on genes, cells, and groups, as well as on organisms; the outcome of evolution reflects selection at different levels of biological organization. Finally, the human environment is constantly changing, largely because of the evolution of our parasites and because of changes in cultural beliefs and practices; genetic evolution is comparatively slow and lags behind environmental change. An evolutionary nosology complements traditional medical nosologies and enhances our understanding of the persistence of disease and the meaning of human variation. (shrink)