Kazem Sadegh-Zadeh

Since the advent of the natural sciences, natural scientists have spread the idea that the pursuit of truth about the facts of the world is the main drive of scientific research. The aim, they say, is to acquire knowledge and to provide explanations and predictions of phenomena and events. Surprisingly, even in our contemporary world in which scientific research is strongly involved in seeking solutions to practical problems pertaining to the pursuit of food, water, energy, health, labor, peace, war, nuclear weapons, money, and the like, the pursuit-of-truth postulate nevertheless enjoys vigorous advocacy, especially in philosophy. In this chapter, the role that truth actually plays in medicine will be examined. Our discussion of this issue divides into the following four sections: 24.1 Truth in Medical Sciences; 24.2 Truth in Clinical Practice; 24.3 Misdiagnoses; 24.4 Truth Made in Medicine. In summary, it is shown that medical knowledge does not contain much truth because it mainly consists of hypotheses, theories, and deontic rules. The truth values of the former are unknown, while theories and deontic rules do not assume truth values. Likewise, in clinical practice true diagnoses and prognoses are not always attainable because (i) medical knowledge is inevitably vague, uncertain, and unreliable and is therefore scarcely truth-conducive; (ii) this also applies to most parts of patient data; (iii) physicians are not trained in viable and efficient methodology of clinical reasoning; and (iv) neither clinical decision support systems nor the automation of clinical decision-making will be able to compensate for the first two shortcomings. So, misdiagnoses will remain inevitable forever, although their frequency may be reduced by improving the techniques of clinical judgment. Since medical theories are artifactual structures and medical languages are artifactual systems, the truth of diagnoses and prognoses, and of any other judgment based thereon is made in medicine.

Due to the intricate nature of its subject matter, medicine is always threatened by speculations and disagreements about which among its entities exist, e.g., any specific biological structures, substructures or substances, pathogenic agents, pathophysiological processes, diseases, psychosomatic relationships, therapeutic effects, and other possible and impossible things. To avoid confusion, and to determine what entities an item of medical knowledge presupposes to exist if it is to be true, we need medical ontology. The term “medical ontology” we understand to mean the study that seeks to ascertain what entities exist in the world of medicine, which formal relations hold between them, and whether there are any relatioships between types of medical research and practice, on the one hand; and the new worlds they create, on the other.

Linguistics, in general, is the basic science of all language studies. It is concerned with the nature and structure of language and with the role it plays in human communication. Medical linguistics uses some methods of general linguistics and also creates additional ones. This is motivated by the following practical needs: Computer-aided data record, storage, and retrieval in medical practice and research require that medical data be stored in such a manner that enables their computational processing. However, databases written in natural medical language cannot be easily processed. To enable efficient natural language processing, medical terms and sentences used in them must be made amenable to syntactic and semantic operations by computer programs. Medical linguistics is an ill-defined, interdisciplinary branch of medical informatics and medical information and library sciences concerned with methods and problems of natural language processing in medicine.

Clinical judgment, also called clinical reasoning, clinical decision-making, and diagnostic-therapeutic decision-making, lies at the heart of clinical practice and thus medicine. In thepast, clinical judgment was considered the expert task of the physician. But the advent of computers in the 1940s and their use in medicine as of the late 1950s gradually changed this situation. In the 1960s, a new discipline emerged that has come to be termed medical computer science or medical informatics, including clinical informatics. Clinical informatics is concerned with all aspects of the application of computing machinery in clinical research and practice. As one of its accomplishments in clinical practice, the physician’s capacity for clinical judgment is in the process of being turned over to computers. We are told that computers will be responsible for making diagnoses and treatment decisions in a not-too-distant future. This prospect, its historical, methodological and philosophical background, and its impact on health care will be discussed in the present Part VI which divides into these three chapters: 19 Medical Decision-Making 20 Clinical Decision Support Systems 21 Artificial Intelligence in Medicine?

Medical practice is practiced morality, and clinical research belongs to normative ethics. The present book elucidates and advances this thesis by: 1. analyzing the structure of medical language, knowledge, and theories; 2. inquiring into the foundations of the clinical encounter; 3. introducing the logic and methodology of clinical decision-making, including artificial intelligence in medicine; 4. suggesting comprehensive theories of organism, life, and psyche; of health, illness, and disease; of etiology, diagnosis, prognosis, prevention, and therapy; and 5. investigating the moral and metaphysical issues central to medical practice and research. Many systems of (classical, modal, non-classical, probability, and fuzzy) logic are introduced and applied. Fuzzy medical deontics, fuzzy medical ontology, fuzzy medical concept formation, fuzzy medical decision-making and biomedicine and many other techniques of fuzzification in medicine are introduced for the first time.

The language of medicine is an extension of everyday language by adding technical terms such as "appendicitis", "angina pectoris", "blood pressure" and the like. It is therefore characterized by semantic chaos. Most of its terms are either not defined or ill-defined. The chaos would not deserve any attention, however, if it were not practically detrimental in research and practice. The best way to prevent the damage it causes is to learn in medicine something about methods of scientific concept formation. The present chapter provides a concise and unrivalled introduction to such a methodology. We shall discuss the main methods of scientific concept formation known today, that is, all methods of definition and explication. Our discussion divides into the following four sections and is based on, and extends, the most valuable pioneering studies by Carl Gustav Hempel and, especially, Patrick Suppes (Hempel, 1952; Suppes, 1957, 151–173, 246–260): 6.1 What a Definition is; 6.2 What Role a Definition Plays; 6.3 Methods of Definition; 6.4 What an Explication is.

Medical knowledge as well as clinical practice are characterized by inescapable uncertainty. There are many reasons this is the case, but foremost among them is that almost everything in medicine is inevitably vague, be it something linguistic such as the term “illness”, or something extra-linguistic such as the condition referred to as illness. If we ask ourselves, then, what the term “illness” means exactly, on the one hand; and how we may precisely delimit the condition illness, on the other; we shall realize that to answer these and similar questions requires specific methods that enable us to adequately cope with vagueness. As we shall see below, fuzzy logic provides us with just such methods

Clinical practice is where the clinical encounter and decision-making occur. Thus, it constitutes the focus of medicine. Since the time of Hippocrates, it has been composed of five activities that have come to be known as anamnesis, i.e., history taking or clinical interview, diagnosis, prognosis, therapy, and prevention. These five activities are fundamental features of the healing relationship. The present chapter is devoted to the analysis and discussion of their logical, methodological, and philosophical problems. Usually, the patient expects the physician to be an expert of her specialty devoid of a bad reputation. This constitutes what may be called a good doctor, i.e., one whose clinical decisions are right and good in most cases, at least in as many cases as another expert in the same area also achieves. In what follows, we shall analyze the characteristics and presuppositions of such right and good clinical decisions. To this end, we shall undertake a conceptual analysis of the clinical encounter and its outcomes, in order to develop a theory of clinical practice. Our analysis consists of the following five parts: 9.1 The Clinical Encounter; 9.2 Anamnesis and Diagnosis; 9.3 Prognosis; 9.4 Therapy; 9.5 Prevention.