German-Iranian philosopher of medicine
Kazem Sadegh-Zadeh (; ; 23 April 1942 – 6 March 2023) was a German analytic philosopher of medicine of Iranian descent. He was the first ever professor of philosophy of medicine at a German university and has made significant contributions to the philosophy, methodology, and logic of medicine since 1970.
Life and career.
Sadegh-Zadeh was born on 23 April 1942 in Tabriz, Iran. The fourth of eight children, he grew up in Tabriz and attended school from 1947 to 1959. His father was a craftsman and manufacturer and ran a minor terrycloth weaving mill. In the wake of severe political and economic crisis in the country caused by the U.S. and British coup d'état against the democratically elected government of Iran's Prime Minister Mohammad Mosaddegh in 1953, he went bankrupt and never recovered. At eleven years of age when entering the high school shortly after his father's bankruptcy, Sadegh-Zadeh told his parents he would become a professor of medicine in the future and provoked laughter from them. Upon finishing school education at the prestigious Ferdowsi High School in Tabriz, Sadegh-Zadeh came to Germany in March 1960 to pursue his goal as a working student and studied medicine and philosophy at the universities of Münster, Berlin, and Göttingen from 1960 to 1971 with Internship and residency 1967–1971. He earned a doctorate of medicine, Dr. med., from the University of Göttingen in November 1971. But after these five years of doing practical medicine he left clinical practice to conduct theoretical research on clinical theory and reasoning, for during his work in the hospital he had got the impression that in the foundations of clinical decision-making something was going wrong to produce about 38% errors of diagnosis and treatment. In an autodidactic way he specialized in the philosophy of medicine and was assistant professor and lecturer 1972–1982 and full professor of philosophy of medicine 1982–2004 at the University of Münster located in the city of Münster in the state of North Rhine-Westphalia in northwest Germany. He was married since 1970 and has two sons.
Sadegh-Zadeh was the founder of analytic philosophy of medicine. He inaugurated this new direction in the philosophy of medicine, which he based, like analytic philosophy, on the application of formal logic to distinguish it from the traditional philosophy of medicine for he did not consider this latter, traditional style of philosophizing on medicine a scientific endeavor, but "belles lettres". His international recognition came especially through his work on the logic and methodology of clinical reasoning, including artificial intelligence and fuzzy logic application in the theory of medical decision-making, in the theory of medical knowledge and in medical ethics. He was the founding editor of two international journals, first "Metamed" founded in 1977 (renamed "Metamedicine" later. Current title: "Theoretical Medicine and Bioethics", published by Springer Verlag), and second, "Artificial Intelligence in Medicine" founded in 1989 (published by Elsevier). His extensive work includes the following innovative theories: a comprehensive theory of medicine presented in his monumental "Handbook," theory of fuzzy biopolymers, the prototype resemblance theory of disease, the palimpsest theory of mind, and the theory of technoevolution and Machina sapiens.
Work.
Analytic philosophy of medicine.
Sadegh-Zadeh conceived "analytic philosophy of medicine" as philosophy of medicine in the analytic tradition of philosophizing, i.e., "philosophy of medicine by means of logical and conceptual analysis" with its primary fields of inquiry being:
Philosophy of medical language.
Sadegh-Zadeh considered medical language an ill-structured and ill-kept extension of everyday language by adding technical terms such as "angina pectoris", "appendicitis", etc. Sadegh-Zadeh claims that most of its terms are imprecise and ambiguous because they are either undefined or ill-defined. Since it has a significant impact both on medical knowledge and medical decision-making, he devotes himself extensively to the analysis of its nature and of its syntax, semantics, and pragmatics. He demonstrates and analyzes what he claims to be the inherent vagueness of medical terms and constructs techniques for dealing with this principally ineliminable feature by means of fuzzy logic. To this end, he introduces a comprehensive methodology of medical, including fuzzy, concept formation. Inspired by Patrick Suppes's and Carl Gustav Hempel's works, he bases this methodology on an explication and formalization of all methods of definition known today.
Medical praxiology.
"Medical", or clinical, "praxiology" is an old term introduced by Sadegh-Zadeh in 1977–1981 already to denote a wide-ranging inquiry into the foundations of clinical practice, particularly of clinical judgment and decision-making, with the aim of reducing diagnostic-therapeutic errors and of improving physician performance. In the latter article referred to, he has defined the term explicitly as "analysis of clinical practice", "inquiry into clinical practice", and "theory of clinical practice", i.e., "the philosophy, methodology, and logic of medical doing and acting". Central topics include everything related to concepts and theories that are basic to clinical practice, i.e., the concepts and theories of patient, suffering, health, illness, disease, diagnosis, etiology, prognosis, therapy, and prevention. This perspective, Sadegh-Zadeh claims, creates a fertile scientific field with a host of tasks ranging from conceptual analyses (like "what is "disease?"", "what is a diagnosis?", "what is differential diagnosis?", etc.) to logical analyses – such as "is clinical decision-making computable or does it require human intelligence and intuition?" – to epistemology, ethics, and metaphysics of clinical decision-making and so forth. Over the past decades, Sadegh-Zadeh's clinical praxiology has developed further with increasing sophistication. One example of his theories is the "prototype resemblance theory of disease" presenting a fuzzy-logical explication of the vague concept of disease:
 ;templatestyles src="Template:Blockquote/styles.css" / ;It demonstrates what it means to say that the concept of disease is a non-classical one and, therefore, not amenable to traditional methods of inquiry. The theory undertakes a reconstruction of disease as a category that in contradistinction to traditional views is not based on a set of common features of its members, that is individual diseases, but on a few best examples of the category, called its prototypes, and a similarity relationship such that a human condition is considered a disease if it resembles a prototype. It enables new approaches to resolving many of the stubborn problems associated with the concept of disease.
Medical epistemology.
Medical epistemology is the philosophy of medical knowledge or simply "theory of medical knowledge". Sadegh-Zadeh conceived it as a task or branch of the philosophy of medicine already in 1982 deploring that "The contemporary philosophy of medicine movement is mainly concerned with medical-ethical problems while unduly neglecting medical-epistemological ones".
The category "medical knowledge" consists of statements of spatio-temporally localized facts, general hypotheses, and theories. Sadegh-Zadeh has proposed an elaborate systematics of all types of medical hypotheses and knowledge the latter ones including classificatory knowledge, causal knowledge, experimental knowledge, theoretical knowledge, practical knowledge, clinical knowledge, and medical metaknowledge. Most important among them is what is called "practical knowledge" or "know-how" in medicine. By a formally precise explication of this knowledge type he shows that medical-practical knowledge actually consists of conditional norms, i.e., deontic conditionals, mainly conditional obligations. This is one of the reasons why Sadegh-Zadeh considers medicine a deontic discipline. Specifically, he views clinical practice as "practiced morality" because clinical decision-making is nothing but the application of conditional obligations of which diagnostic-therapeutic rules of action primarily consist. And since clinical research pursues such rules of action and tries to improve the available ones, it constitutes "explorative and normative ethics" based on empirical research and experience.
A central role in Sadegh-Zadeh's medical epistemology play medical theories. He analyzes the concept of "medical theory" in line with the so-called structuralist view of theories to represent their structure and content, according to Patrick Suppes and Joseph D. Sneed's approach, as set-theoretic predicates. This enables him to show that a theory in medicine cannot be confirmed, supported, disconfirmed, verified or falsified simply because it is merely a "conceptual structure" and no "epistemic entity" to be true, probable or false. It does not make any empirical claims about the world. Such claims are made "using the theory" as a tool. The claims themselves, as empirical hypotheses, are something different than the theory.
Not only medical theories, as non-epistemic entities, do not deserve the ascription of truth or falsehood. Regarding any other piece of general medical knowledge, Sadegh-Zadeh shows that apart from the Gettier problem, it does not fulfill the classical definition of knowledge as "justified true belief". According to his detailed analysis, there are no justified true beliefs in medicine. Statements, hypotheses and theories in medicine and other fields are usually viewed as knowledge only because the ascription "this is knowledge", for example, "that AIDS is caused by HIV is knowledge", is a performative conducted or affirmed by a scientific or professional community as a "social group". This communitarian and social epistemology that goes back to the Polish physician and epistemologist Ludwik Fleck (1896–1961), is profitably utilized and extended by Sadegh-Zadeh.
Medical deontics.
Apart from the deontic nature of medical-practical knowledge referred to above, a second reason why Sadegh-Zadeh classifies medicine as a deontic field is his view that according to his prototype resemblance theory of disease, the concept of disease is inherently value-laden. This is so because prototype diseases upon which nosology is based are, as phenomena, "disvalued" by human beings and are therefore considered to be something "that ought not to be". That means that they are, and consequently all other diseases as their resemblants are, deontic entities.
The deonticity of medicine and of disease as its basic concept necessitates, according to Sadegh-Zadeh, a specific inquiry by means of suitable tools and methods, i.e., deontic logic. This research field he terms "medical deontics". It also includes medical ethics, medical metaethics, and medical law.
Medical logic.
Publications entitled "The Logic of Medicine" give rise to the question whether medicine has its own logic like quantum logic is argued to be "the logic of" quantum mechanics. To answer the question, Sadegh-Zadeh distinguishes between "logic in medicine" and "logic of medicine". "Logic in medicine" means the class of all logics that are, or may be, applied in medicine to solve theoretical or practical problems. Examples are classical two-valued logic, many-valued logic, paraconsistent logic, deontic logic, temporal logic, probability logic, fuzzy logic, and so on. Their number is unlimited. But none of them is specifically made for medical use. This "logical pluralism" in medicine parallels the mathematical pluralism in that innumerable mathematical theories are used in medicine as well without any of them being "the mathematics of medicine". So, there is no "logic of medicine", Sadegh-Zadeh concludes, a logic that could be viewed or used as a specifically medical logic.
Medical metaphysics.
Medical metaphysics is primarily concerned with (i) medical ontology, (ii) medical truth, and (iii) the nature of medicine.
(i) Medical ontology. Sadegh-Zadeh devotes himself extensively to pure, formal, and applied ontology to use them in his logical analysis of medical-ontological issues of medical knowledge, clinical practice, nosology, psychiatry, psychosomatics, and biomedicine such as, for example, whether diseases exist or are fictitious entities invented by nosologists and physicians, and whether particular other things such as genes, psyche, and schizophrenia exist or are mere myths. To settle these enduring controversies and similar ones in medicine, he first distinguishes between ontology "de re" and ontology "de dicto". The distinction is based on a syntactic criterion similar to Barcan formula and enables differentiation between fictional entities such as Sherlock Holmes and real ones. Second, he inaugurates an intriguing fuzzy ontology by introducing a many-place existence operator and fuzzyfying this operator to obtain a quantitative concept of existence that he calls the "Heraclitean operator". The Heraclitean operator ranges over the domain of all imaginable entities, including existent, non-existent, and fictitious ones, and over all possible frames of reference, a frame of reference being a particular language and a particular logic. As a result, an entity exists, does not exist, or is fictitious only to a particular extent in the unit interval [0, 1] with respect to a particular language and a particular logic. In this way, ontological stances such as realism, anti-realism, and fictionalism regarding whether something exists or not, become obsolete. For example, schizophrenia may exist with respect to Eugen Bleuler (1857–1939) and his followers' language and logic, while Thomas Szasz and his followers may view it as a myth with respect to their language and logic. The only remedy for irreconcilable ontological controversies of this and similar type is to care about one's unkempt language and logic, and to reach an agreement about which language and conceptual