Philosophy of medicine

The philosophy of medicine is a branch of philosophy that includes the epistemology, ontology/metaphysics, and ethics of medicine. Perhaps the most well known area is medical ethics, which overlaps with bioethics. It can be distinguished from the philosophy of healthcare, which is mostly concerned with ethical and political issues arising from healthcare research and practice. There are a variety of University courses, journals,   books    and conferences dedicated to the Philosophy of Medicine.

Epistemology of medicine
Epistemology is the study of knowledge. In the context of the philosophy of medicine it is the study of how we come to know about the effects of medical interventions, the accuracy of diagnostic tests, and the predictive value of prognostic markers.

Evidence Based Medicine
In particular the phenomenon of Evidence Based Medicine (EBM) (or Evidence-Based Practice (EBP)) has attracted attention. EBM provides an account of how medical knowledge should be applied to clinical care. It not only provides clinicians with a strategy for best practice, but also, underlying that, a philosophy of evidence.

Interest in the EBM philosophy of evidence has led philosophers to consider the nature of EBM’s Hierarchy of evidence, which rank different kinds of research methodology, ostensibly, by the relative evidential weight they provide. Key questions asked about hierarchies of evidence concern the legitimacy of ranking methodologies in terms of the strength of support that they supply; how instances of particular methods may move up and down a hierarchy;  as well as how different types of evidence, from different levels in the hierarchies, should be combined.

Additionally the epistemological virtues of particular aspects of clinical trial methodology have been examined, mostly notably the special place that is given to randomisation,  the notion of a blind experiment and the use of a placebo control.

Ontology of medicine
There is a large body of work on the ontology of biomedicine, including ontological studies of all aspects of medicine. Ontologies of specific interest to the philosophy of medicine include, for instance: (1) the ontological revolution which made modern science, in general, possible, (2) Cartesian dualism which makes modern medicine, in particular, possible, (3) the monogenenic conception of disease which has informed clinical medicine for a century or so and also the chemical and biological pathways which underlie the phenomena of health and disease in all organisms, (4) the conceptualization of entities such as ‘placebos’ and ‘placebo effects’.

The Ontology of General Medical Science (OGMS)
The Ontology of General Medical Science], which includes a set of logical definitions of very general terms that are used across medical disciplines, including: 'disease', 'disorder', 'disease course', 'diagnosis', and 'patient'. The scope of OGMS is restricted to humans, but many terms can be applied also to other organisms. OGMS provides a formal theory of disease that is elaborated further by specific disease ontologies which extend it, including the Infectious Disease Ontology (IDO) and the Mental Disease Ontology.

The ontological revolution
By this is meant the emergence of what may be called a dramatic change in worldview from the organismic to the mechanistic. Nature, increasingly from the seventeenth century onwards in Western Europe, began to be perceived as machine, the watch being the usual prototype of machine. The change concerned not only abiotic Nature but also biotic Nature. This then constitutes a spectacular ontological volte-face – the world is to be investigated and understood by modern science as machines. Physics studied the motions of material bodies; biology which used to study organisms (including the human organism) as organisms (following Aristotle) began to be investigated no longer as organism but as machine.

Cartesian dualism
René Descartes made ontological space for modern medicine by separating body from mind – while mind is superior to body as it constitutes the uniqueness of the human soul (the province of theology), body is inferior to mind as it is mere matter. Medicine simply investigated(s) the body as machine.

Nosology and the monogenic conception of disease
Modern medicine, unlike Galenic medicine (which dealt with humours), is mechanistic. For example, when a bit of solid matter such as a poison or a worm impacts upon another bit of matter (when it enters the human body), this sets off a chain of motions, giving rise to disease, just as when one billiard ball knocks into another billiard, the latter is set in motion. When the human body is exposed to the solid pathogen, it falls ill, giving rise to the notion of a disease entity. Later in the history of modern medicine, particularly by the late nineteenth and twentieth centuries, in nosology (which is the classification of disease), the most powerful is the etiogically-defined approach as can be found in the monogenic conception of disease which covers not only infectious agents (bacteria, viruses. fungi, parasites, prions) but also genetics, poisons. It constitutes, since Pasteur and Koch, the dominant paradigm of disease and its causation in clinical medicine, side-lining in the main its competing paradigm found in epidemiology. While clinical medicine is concerned with the ill health of the individual patient when s/he has succumbed to disease, epidemiology is concerned with the pattern of diseases in populations in order to study their causes as well as how to manage, control, ameliorate the problems identified under study.

Clinical medicine, as presented above, is part of a reductionist approach to disease, based ultimately on Cartesian dualism which says that the proper study of medicine is an investigation of the body when the latter is viewed as machine. A machine can exhaustively be broken down into its component parts and their respective functions; in the same way, the human body can be broken down/analysed in terms of its component parts and their respective functions, such as its internal and external organs, the tissues and bones of which they are composed, the cells which make up the tissues, the molecules which constitute the cell, down to the atoms (the DNA sequences) which make up the cell in the body. According to this ontology, a whole is no more than the sum of its parts – once you have grasped the parts, you have grasped the whole. In other words, ontologically as well as logically, methodologically and semantically, to maintain that wholes can exist over and above their parts and their respective functions is to maintain something unintelligible or ‘metaphysical’ in the abusive sense of the term.

In contrast, epidemiology in terms of ontology makes sense only within a framework which is holistic, as it recognises that the pattern of disease forms part of a system, whose components are complexly interrelated. (See notion of causality.)

Placebo
Placebos and placebo effects have generated years of conceptual confusion about what kinds of thing they are. Example definitions of a placebo may refer to their inertness or pharmacological inactivity in relation to the condition they are given for. Similarly, example definitions of placebo effects may refer to the subjectivity or the non-specificity of those effects. These type of definition suggest the view that when given a placebo treatment, one may merely feel better while not being ‘really’ better.

The distinctions at work in these types of definition: between active and inactive/inert, specific and non-specific, and subjective and objective, have been problematized. For instance, if placebos are inactive or inert, then how do they cause placebo effects? More generally, there is scientific evidence from research investigating placebo phenomena which demonstrates that, for certain conditions (such as pain), placebo effects can be both specific and objective in the conventional sense.

Other attempts to define placebos and placebo effects therefore shift focus away from these distinctions and onto therapeutic effects that are caused or modulated by the context in which a treatment is delivered and the meaning that different aspects of treatments have for patients. The problems arising over the definition of placebos and their effects may be said to be the heritage of Cartesian dualism, under which mind and matter are understood as two different substances. Furthermore, Cartesian dualism endorses a form of materialism which permits matter to have an effect on matter, or even matter to work on mind (epiphenomenalism, which is the raison d’être of psycho-pharmacology), but does not permit mind to have any effect on matter. This then means that medical science has difficulty in entertaining even the possibility that placebo effects are real, exist and may be objectively determinable and finding such reports difficult if not impossible to comprehend and/or accept. Yet such reports which appear to be genuine pose a threat to Cartesian dualism which provides the ontological underpinning for biomedicine especially in its clinical domain.

Metaphysics
Although most areas of study within the Philosophy of Medicine are concerned with matters of epistemology, there is a growing interest in the metaphysics of medicine, particularly the idea of causality. Philosophers of medicine might not only be interested in how medical knowledge is generated, but also in the nature of such phenomena. Causation is of interest because the purpose of much medical research is to establish causal relationships, e.g. what causes disease, or what causes people to get better. Thus the idea of cause is central to this philosophy. The scientific processes used to generate causal knowledge give clues to the metaphysics of causation. For example, the defining feature of randomised controlled trials (RCTs) is that they are thought to establish causal relationships, whereas observational studies do not. Therefore, metaphysically, the nature of causation has something to do with the nature of the RCT. It is not just a question of how RCTs generate the knowledge. In this instance, causation can be considered as something which is counterfactually dependent, i.e. the way RCTs differ from observational studies is that they have a comparison group in which the intervention of interest is not given. This aligns to a Humean notion of causation where a cause is considered when one event repeatedly follows another, and in a situation where the first event did not occur neither would the second. The only things observed are in-fact, one event following another. The actual cause itself is unobservable, thus it is a metaphysical notion. Metaphysicians wonder if there are alternative notions for the nature of causation. At least two different causal paradigms in biomedicine have been identified – the Humean, linear, mono-factorial paradigm championed mainly in clinical medicine, the non-linear, reciprocal, multi-factorial paradigm invoked in epidemiology. The former is part of reductionist ontology, the latter a holist one. This, if correct, argues for a strong link between ontology/metaphysics on the one hand and causality/methodology on the other; indeed one might argue that every ontology entails its own methodology.

Major philosophers of medicine

 * Rachel Ankeny
 * Christopher Boorse
 * Nancy Cartwright
 * H. Tristram Engelhardt, Jr.
 * Fred Gifford
 * Donald A. Gillies
 * Jeremy Howick
 * Hilde Lindemann
 * Ingvar Johansson
 * Keekok Lee
 * Michael Loughlin
 * Frederica Russo
 * Kazem Sadegh-Zadeh
 * Kenneth F. Schaffner
 * Miriam Solomon
 * David Papineau
 * Edmund Pellegrino
 * John Worrall