HANDBOOK OF ANALYTIC PHILOSOPHY OF MEDICINE

Philosophy and Medicine

VOLUME 113

Founding Co-EditorStuart F. Spicker

Senior Editor

H. Tristram Engelhardt, Jr., Department of Philosophy, Rice University,and Baylor College of Medicine, Houston, Texas

Associate Editor

Lisa M. Rasmussen, Department of Philosophy, University of North Carolinaat Charlotte, Charlotte, North Carolina

Assistant Editor

Jeffrey P. Bishop, Gnaegi Center for Health Care Ethics, Saint Louis University,St. Louis, Missouri

Editorial Board

George J. Agich, Department of Philosophy, Bowling Green State University,Bowling Green, Ohio

Nicholas Capaldi, College of Business Administration, Loyola University,New Orleans, New Orleans, Louisiana

Edmund Erde, University of Medicine and Dentistry of New Jersey, Stratford,New Jersey

Christopher Tollefsen, Department of Philosophy, University of South Carolina,Columbia, South Carolina

Kevin Wm. Wildes, S.J., President Loyola University, New Orleans,New Orleans, Louisiana

For further volumes:

http://www.springer.com/series/6414

HANDBOOK OF ANALYTICPHILOSOPHY OF MEDICINE

byKAZEM SADEGH-ZADEH

University of Münster, Münster, Germany

123

Kazem Sadegh-ZadehUniversity of MünsterTheory of Medicine Department48149 MünsterGermany

ISSN 0376-7418ISBN 978-94-007-2259-0 e-ISBN 978-94-007-2260-6DOI 10.1007/978-94-007-2260-6Springer Dordrecht Heidelberg London New York

Library of Congress Control Number: 2011936738

c© Springer Science+Business Media B.V. 2012No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or byany means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without writtenpermission from the Publisher, with the exception of any material supplied specifically for the purposeof being entered and executed on a computer system, for exclusive use by the purchaser of the work.

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kazem@sadegh-zadeh.de

To

Maria, David, and Manuel

Foreword

This work will shape the philosophy of medicine for years to come. There arevery few scholarly endeavors that truly encompass a field while also havingthe promise of shaping and changing that field. Kazem Sadegh-Zadeh hasproduced such a volume for the philosophy of medicine. This is a founda-tional work of amazing depth and scope, which is also user-friendly. No oneengaged in the philosophy of medicine will in the future be able to proceed,save in the light of and in response to the analyses, arguments, and reflectionsSadegh-Zadeh has compassed in this extraordinarily rich and important study.He has succeeded in bringing together in an integrated vision an explorationof the epistemological, practical, and logical frameworks that sustain the en-gagement of physicians, as well as define the place of patients in medicine.This opus magnum provides remarkably careful explorations of the conceptof disease, as well as of the diagnosis and treatment of patients in the acts ofmedical knowing and treatment. It situates the intertwining of diagnoses, theappreciation of therapy warrants, and the engagement of physicians in treat-ing patients within the complex phenomenon of medicine. This work evenhas what is tantamount to an appendix that shows the bearing of logic onmedicine.

The work begins with a careful exploration of the language of medicine,attending to its epistemic impact, its syntax, semantics, and pragmatics, in-cluding the various ways in which medical concepts are framed and engaged.Sadegh-Zadeh then examines medicine’s encounter with the patient as a bio-psycho-social reality caught up in the drama of health, illness, and disease. Inthis study of medical practice, Sadegh-Zadeh creatively attends to the inter-action of patient and physician in clinical practice. His analysis of the inter-connection of anamnesis, diagnosis, prognosis, therapy, and prevention in theclinical context is innovative, displaying a remarkable depth of understandingthat constitutes not just a foundational contribution to the literature, but areframing of the field. It offers a comprehensive perspective, which is a tourde force. Drawing on a nuanced and subtle appreciation of epistemology ingeneral and an account of the character of medicine in particular, Sadegh-

VIII Foreword

Zadeh explores the semantics and pragmatics of medical knowledge. He thenrelates these reflections to the intertwining of moral concerns, the characterof logic in medicine, and a consideration of medical ontology within which,among other things, he provides a careful analysis of medical reality and thecharacter of medical truth. He ties all of this to what can only be describedas a powerful vision of the conceptual fundamentals that constitute the scopeof the philosophy of medicine. Sadegh-Zadeh offers what will without doubtfor the foreseeable future be the most widely influential and comprehensiveaccount of the philosophy of medicine.

This impressively nuanced work bears the mark of a lifetime of research,reflections, and publications on the philosophy of medicine. While others wereengaged in the birth of bioethics, Sadegh-Zadeh was focusing with critical en-ergy on the philosophy of medicine. As a result, he became one of the centralfigures driving the re-emergence of the philosophy of medicine as a scholarlyfield. Early on, he helped to establish and then expand the scope and depthof philosophical medicine. One must note in particular that he aided in sup-porting scholarship in the philosophy of medicine through his pioneering workwith his journal Metamed which was established in 1977, and which then latertook the name Metamedicine and which finally became Theoretical Medicine.He has also been involved from the early years in The Journal of Medicine andPhilosophy. Both through his own scholarly articles, as well as through creat-ing vehicles for the publication of scholarly articles, his work in the philosophyof medicine has helped locate bioethics within the broader geography of thefoundational explanation and therapeutic concerns that define medicine. Asa physician and philosopher, Sadegh-Zadeh has without flinching addressedthe conceptually challenging issues that lie at the basis of a philosophical ap-preciation of contemporary medicine. The result is that Kazem Sadegh-Zadehhas come to have a command of the philosophy of medicine possessed by noother scholar.

Drawing on a rich lifetime of scholarship, Sadegh-Zadeh has been able tointegrate recent work in epistemology, the philosophy of science, and logicin a work in the philosophy of medicine. Because of his disciplined and in-novative eye, this volume sheds a bright analytic light on the character ofcontemporary medicine and charts the future of the philosophy of medicine.It is marked both by creativity and an encyclopedic scope, and will establishitself as the standard for the field. It is likely that no one could have accom-plished such a substantial exploration of the nature of medicine, other thanKazem Sadegh-Zadeh. He has produced an indispensable resource for schol-ars in the philosophy of medicine, including those working in bioethics. Thiswork surely secures Kazem Sadegh-Zadeh’s place as a cardinal founder of thecontemporary field of the philosophy of medicine.

H. Tristram Engelhardt, Jr.Houston, TX Professor, Rice UniversityApril 23, 2011 Professor Emeritus, Baylor College of Medicine

Preface

Medicine is a science and practice of intervention, manipulation, and controlconcerned with curing sick people, caring for sick people, preventing maladies,and promoting health. What necessitates this task, is the human suffering thatresults from maladies, and the desire for remedy and relief. Medicine servesthis human need by attempting to lessen suffering that human beings evaluateas bad, and to restore and augment well-being that human beings evaluate asgood. On this account, medicine as health care is practiced morality insofaras it acts against what is bad, and promotes what is good, for human beings.And insofar as it seeks rules of action toward achieving those goals and strivescontinually to improve the quality and efficacy of these rules, i.e., as clinicalresearch, it belongs to normative ethics. Medicine is not human biology, bio-physics, biochemistry, or biopathology. Nor is it any sum of these and similarbiomedical and natural sciences. To view it as such, would shift medicinetoward bio- and anthropotechnology where morality and ethics would losetheir meaning and significance. As an aid in preventing such an autolysis ofmedicine, the present book elucidates and advances the view sketched aboveby:

• analyzing the structure of medical language, knowledge, and theories,• inquiring into the foundations of the clinical encounter,• introducing the logic and methodology of clinical decision-making,• suggesting comprehensive theories of organism, life, and psyche; of

health, illness, and disease; and of etiology, diagnosis, prognosis, pre-vention, and therapy,

• investigating the moral and metaphysical issues central to medical prac-tice and research.

To this end, the book offers in its final Part VIII, as an appendix so to speak,a concise introduction to some focal systems and methods of logic that areneeded and used throughout. Each line, paragraph, and page of its remainingseven parts relies upon what precedes it and what has been said in Part VIII.

X Preface

The readers, therefore, should study the book systematically following theinstructions given in Figure 1 on page 8. In that case, it will prove absolutelyself-contained. It does not require any special knowledge and is easily acces-sible to all interested students. By virtue of its didactic style, the book is alsousable in graduate courses in the philosophy of medicine, bioethics, medicalethics, philosophy, medical artificial intelligence, and clinical decision-making.

My thanks are due to H. Tristram Engelhardt, Jr., from whom I havelearned, among many other things, that the concept of disease says whatought not to be (Engelhardt, 1975, 127). It is thus a deontic concept (fromthe Greek δεoν, deon, for “what is binding”, “duty”) which obliges us to act.Since this normative aspect is dismissed by most physicians and philosophersof medicine alike, initially I wanted to analyze and demonstrate it in whateventually became the present handbook, HAPM, by means of deontic logic.In the process of writing, however, my thoughts extended beyond the conceptof disease to the entire field of medicine when I fully recognized the deonticityof the field as a whole in the early 1980s (Sadegh-Zadeh, 1983). Although it is afascinating feature of medicine that places the institution of health care in thesame category as charity, it seems to have been overlooked by philosophers ofmedicine and medical ethicists until now. I hope they will concern themselveswith this issue and discover additional facts about it when they read HAPM.

Also, my intellectual debt is to four scholars whose works greatly impactedmy way of thinking and my life: Karl Eduard Rothschuh (1908–1984), one ofmy teachers at the University of Munster in Germany, ignited my love for thephilosophy of medicine in 1964 when I was a graduate student of medicine andphilosophy; Patrick Suppes’s precision in philosophizing taught me analyticphilosophy in the late 1960s; Newton C.A. da Costa’s paraconsistent logicchanged my view of logic and my Weltanschauung in the late 1970s; and LotfiA. Zadeh’s fuzzy logic changed everything anew and inspired me to initiatefuzzy analytic philosophy and methodology of medicine in the early 1980s.

I am particularly grateful to my wife, Maria, for surrounding me with somuch love and support over the long period of creating HAPM; and to mysons, David and Manuel, for their assistance. Manuel drew the figures. Daviddid extensive LATEX work (references, indexes) and produced, with the aid ofMatlab R©, the 3D representation of high blood pressure on page 672.

I would also like to extend special thanks to the editors of the Philosophyand Medicine for including HAPM in their highly respectable book series,and for excellent supervision, advice, and support; to Mr. Richard Preville inCharlotte, North Carolina, for carefully transforming my imperfect ‘GermanEnglish’ into well-readable English; and to Springer for their outstanding pro-duction process management. But without the patient and competent work ofthree anonymous reviewers, none of us would be reading this line right now. Iwholeheartedly thank all of them for their thoughtful comments and valuablesuggestions.

Some of the ideas in this handbook present a further development of theirseeds and preliminary forms that have appeared in my previous publications.

Preface XI

Specifically, my theories of health and disease in Section 6.3, of etiology inSection 6.5, and of diagnosis in Section 8.2 are based on my “Fundamentalsof clinical methodology”, 1-4, in Artificial Intelligence in Medicine (1994-2000); on my theory of fuzzy health, illness, and disease in The Journal ofMedicine and Philosophy (2000, 2008); and on my “The logic of diagnosis” inHandbook of the Philosophy of Science, Vol. 16 (2011). Section 16.5.4 relies onmy previous articles “Fuzzy genomes” and “The fuzzy polynucleotide spacerevisited” in Artificial Intelligence in Medicine (2000, 2007). Although duringthe process of writing the handbook, I have drawn on this previously publishedwork, most of this material has been substantially revised, rewritten, andsupplemented.

One of the reviewers proposed that I create a companion website forHAPM, which could provide a glossary and additional resources online. I wel-comed the proposal, as I have already been offering a website on philosophy ofmedicine in German for many years. This website has now been internation-alized to facilitate studies in the analytic philosophy of medicine, includingHAPM. You may take a look at it here ⇒ http://www.philmed-online.net

Tecklenburg, Kazem Sadegh-ZadehGermany 49545 Emeritus Professor of Philosophy of MedicineSummer 2010 University of Munster, Germany

Contents

0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 A Fresh Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 The Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.3 The Subject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.4 Methods of Inquiry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70.5 How to Read this Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Part I The Language of Medicine

1 The Epistemic Impact of Medical Language . . . . . . . . . . . . . . . 111.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111.1 Types of Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131.2 Propositional Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.3 Propositions and Facts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171.4 Medical Sentences and Statements . . . . . . . . . . . . . . . . . . . . . . . . . 191.5 Medical Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231.6 How to Care About our Medical Concepts? . . . . . . . . . . . . . . . . . 261.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

2 The Syntax and Semantics of Medical Language . . . . . . . . . . . 292.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292.1 Medical Language is an Extended Natural Language . . . . . . . . . 302.2 What a Medical Term Means . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312.3 Ambiguity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342.4 Vagueness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.4.1 The Nature of Vagueness . . . . . . . . . . . . . . . . . . . . . . . . . . . 352.4.2 The Sorites Paradox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402.4.3 Varieties of Vagueness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2.5 Clarity and Precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452.6 Semantic Nihilism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

XIV Contents

3 The Pragmatics of Medical Language . . . . . . . . . . . . . . . . . . . . . . 513.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513.1 The So-Called Language Games . . . . . . . . . . . . . . . . . . . . . . . . . . . 513.2 Assertion, Acceptance, and Rejection . . . . . . . . . . . . . . . . . . . . . . 523.3 Speech Acts in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4 Varieties of Medical Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574.1 Qualitative, Comparative, and Quantitative Concepts . . . . . . . . 58

4.1.1 Individual Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584.1.2 Qualitative Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594.1.3 Comparative Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654.1.4 Quantitative Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

4.2 Dispositional Terms in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . 764.3 Linguistic and Numerical Variables in Medicine . . . . . . . . . . . . . 784.4 Non-Classical vs. Classical Concepts . . . . . . . . . . . . . . . . . . . . . . . 794.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

5 Fundamentals of Medical Concept Formation . . . . . . . . . . . . . . 815.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 815.1 What a Definition is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 825.2 What Role a Definition Plays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845.3 Methods of Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

5.3.1 Explicit Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 875.3.2 Conditional Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895.3.3 Operational Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 915.3.4 Definition by Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 945.3.5 Recursive Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 965.3.6 Set-Theoretical Definition . . . . . . . . . . . . . . . . . . . . . . . . . . 1005.3.7 Ostensive Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

5.4 What an Explication is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1035.4.1 What: Quod vs. Quid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1045.4.2 Is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

5.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Part II Medical Praxiology

6 The Patient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1096.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1096.1 The Suffering Individual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116.2 The Bio-Psycho-Social Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

6.2.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1126.2.1 The Living Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Contents XV

6.2.2 The Psyche . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1316.2.3 The Social Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1426.2.4 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

6.3 Health, Illness, and Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1496.3.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1496.3.1 Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1516.3.2 Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1846.3.3 Illness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1866.3.4 Disease, Health, and Illness Violate Classical Logic . . . . 1926.3.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

6.4 Systems of Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1956.4.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1956.4.1 Symptomatology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1956.4.2 Nosological Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2016.4.3 Pathology vs. Nosology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2026.4.4 Nosological Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2076.4.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

6.5 Etiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2196.5.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2206.5.1 Cause and Causation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2216.5.2 Deterministic Etiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2266.5.3 Probabilistic Etiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2336.5.4 Fuzzy Etiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2646.5.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

7 The Physician . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

8 Clinical Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2758.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2758.1 The Clinical Encounter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

8.1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2758.1.1 The Patient Elroy Fox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2798.1.2 Dynamic, Branching Clinical Questionnaires . . . . . . . . . . 2838.1.3 Clinical Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2948.1.4 The Clinical Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2968.1.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

8.2 Anamnesis and Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2998.2.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2998.2.1 The Clinical Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2998.2.2 The Logical Structure of Medical Statements . . . . . . . . . 3068.2.3 Action Indication and Contra-Indication . . . . . . . . . . . . . 3088.2.4 Differential Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3108.2.5 The Computability of Differential Indication . . . . . . . . . . 3168.2.6 The Logical Structure of Diagnosis . . . . . . . . . . . . . . . . . . 3198.2.7 The Syntax of Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 325

XVI Contents

8.2.8 The Semantics of Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . 3288.2.9 The Pragmatics of Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . 3358.2.10 The Methodology of Diagnostics . . . . . . . . . . . . . . . . . . . . 3398.2.11 The Logic of Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . 3418.2.12 The Epistemology of Diagnostics . . . . . . . . . . . . . . . . . . . . 3418.2.13 The Relativity of Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . 3468.2.14 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.3 Prognosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3488.3.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3488.3.1 The Clinical Role of Prognosis . . . . . . . . . . . . . . . . . . . . . . 3498.3.2 The Structure of Prognosis . . . . . . . . . . . . . . . . . . . . . . . . . 3508.3.3 The Uncertainty of Prognosis . . . . . . . . . . . . . . . . . . . . . . . 3518.3.4 Prognosis is a Social Act . . . . . . . . . . . . . . . . . . . . . . . . . . . 3528.3.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

8.4 Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3538.4.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3538.4.1 Therapeutic Decisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3538.4.2 Expected Value Therapeutic Decision-Making . . . . . . . . . 3558.4.3 Treatment Threshold Probability . . . . . . . . . . . . . . . . . . . . 3588.4.4 Treatments are Social Acts . . . . . . . . . . . . . . . . . . . . . . . . . 3598.4.5 Therapeutic Efficacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3598.4.6 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371

8.5 Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3718.5.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3718.5.1 What is a Risk Factor? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3728.5.2 Prevention is Goal-Driven Practice . . . . . . . . . . . . . . . . . . 3798.5.3 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

Part III Medical Epistemology

9 The Architecture of Medical Knowledge . . . . . . . . . . . . . . . . . . . 3839.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3839.1 Detachment of Medical Knowledge from the Knower . . . . . . . . . 3849.2 The Syntax of Medical Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . 387

9.2.1 Problematic Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3889.2.2 First-Order Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3899.2.3 Modal Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3909.2.4 Probabilistic Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3909.2.5 Fuzzy Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

9.3 Medical Hypotheses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3959.4 Theories in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399

9.4.1 The Statement View of Theories . . . . . . . . . . . . . . . . . . . . 4009.4.2 The Non-Statement View of Theories . . . . . . . . . . . . . . . . 4039.4.3 The Semantic View of Theories . . . . . . . . . . . . . . . . . . . . . 429

Contents XVII

9.4.4 Theory-Nets and Intertheoretic Relations . . . . . . . . . . . . . 4299.4.5 Untestability of Theories . . . . . . . . . . . . . . . . . . . . . . . . . . . 4389.4.6 Theories Fuzzified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439

9.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441

10 Types of Medical Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44310.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44310.1 Shallow and Deep Medical Knowledge . . . . . . . . . . . . . . . . . . . . . . 44410.2 Classificatory Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44410.3 Causal Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44510.4 Experimental Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44710.5 Theoretical Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45010.6 Practical Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45010.7 Clinical Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45510.8 Medical Metaknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45710.9 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458

11 The Semantics and Pragmatics of Medical Knowledge . . . . . 45911.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45911.1 Justified True Belief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460

11.1.1 Truth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46011.1.2 Justification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46711.1.3 Are There Justified True Beliefs in Medicine? . . . . . . . . . 486

11.2 Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48811.2.1 Metaphysical Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48811.2.2 Semantic Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48911.2.3 Epistemic Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48911.2.4 Medical Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490

11.3 Anti-Realism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49211.3.1 Metaphysical Anti-Realism . . . . . . . . . . . . . . . . . . . . . . . . . 49211.3.2 Semantic Anti-Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49311.3.3 Epistemic Anti-Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49411.3.4 Medical Anti-Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494

11.4 Beyond Realism and Anti-Realism in Medicine . . . . . . . . . . . . . . 49611.4.1 Fuzzy Epistemology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49611.4.2 Constructivism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497

11.5 Social Epistemology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49811.5.1 Logical Empiricism and Critical Rationalism . . . . . . . . . . 49911.5.2 The Rise of Social Epistemology . . . . . . . . . . . . . . . . . . . . . 50211.5.3 Medical Knowledge is a Social Status . . . . . . . . . . . . . . . . 51211.5.4 Social Constructivism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523

11.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530

XVIII Contents

12 Technoconstructivism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53112.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53112.1 Experiments as Epistemic Assembly Lines . . . . . . . . . . . . . . . . . . 53212.2 Epistemic Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535

12.2.1 An Experiment is a Production System . . . . . . . . . . . . . . 53612.2.2 An Experiment is an Epistemic Machine . . . . . . . . . . . . . 538

12.3 Epistemic Factories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54212.3.1 The Engineering of Materials . . . . . . . . . . . . . . . . . . . . . . . 54312.3.2 The Engineering of Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 54412.3.3 The Engineering of Knowledge . . . . . . . . . . . . . . . . . . . . . . 545

12.4 The Global Knowledge-Making Engine . . . . . . . . . . . . . . . . . . . . . 54712.5 The Industrialization of Knowledge . . . . . . . . . . . . . . . . . . . . . . . . 54812.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550

Part IV Medical Deontics

13 Morality, Ethics, and Deontics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55513.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55513.1 Morality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55613.2 Ethics and Metaethics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55813.3 Deontics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55913.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565

14 Disease as a Deontic Construct . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56714.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56714.1 Common Morality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56714.2 Common Morality as a Deontic-Social Institution . . . . . . . . . . . . 56814.3 Deontic Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56914.4 The Deontic Construction of Prototype Diseases . . . . . . . . . . . . . 57214.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574

15 Medicine is a Deontic Discipline . . . . . . . . . . . . . . . . . . . . . . . . . . . 57715.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57715.1 Deonticity in Clinical Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57815.2 Deonticity in Medical Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58115.3 Deontic Things in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58215.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 582

Part V Medical Logic

16 Logic in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58716.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58716.1 Classical Logic in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58916.2 Paraconsistent Logic in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . 593

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16.3 Modal Logics in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59416.4 Probability Logic in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596

16.4.1 Uncertainty and Randomness . . . . . . . . . . . . . . . . . . . . . . . 59616.4.2 Probabilistic-Causal Analysis . . . . . . . . . . . . . . . . . . . . . . . 59816.4.3 Probabilistic-Causal Factors . . . . . . . . . . . . . . . . . . . . . . . . 60216.4.4 Bayesian Reasoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603

16.5 Fuzzy Logic in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60316.5.1 Fuzzy Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60516.5.2 Fuzzy Clinical Decision-Making . . . . . . . . . . . . . . . . . . . . . 61616.5.3 Similaristic Reasoning in Medicine . . . . . . . . . . . . . . . . . . . 63916.5.4 Fuzzy Logic in Biomedicine . . . . . . . . . . . . . . . . . . . . . . . . . 64116.5.5 Fuzzy Deontics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65916.5.6 Fuzzy Concept Formation in Medicine . . . . . . . . . . . . . . . 664

16.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673

17 The Logic of Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67517.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67517.1 What is Logic? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67517.2 Implication Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67717.3 On the Logic of Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67817.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 681

Part VI Medical Metaphysics

18 On What There Are . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68518.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68518.1 Ordinary Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687

18.1.1 Pure Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68818.1.2 Applied Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69718.1.3 Formal Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 698

18.2 Fuzzy Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69818.3 Vague, Fictional, and Non-Existent Entities . . . . . . . . . . . . . . . . . 704

18.3.1 Vague Entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70518.3.2 Fictional Entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70618.3.3 Non-Existent Entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708

18.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710

19 Medical Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71119.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71119.1 The Ontology of Medical Knowledge . . . . . . . . . . . . . . . . . . . . . . . 712

19.1.1 Ontological Commitments of Medical Knowledge . . . . . . 71219.1.2 Medically Relevant Ontological Categories . . . . . . . . . . . . 71419.1.3 Models for Medical Knowledge . . . . . . . . . . . . . . . . . . . . . . 715

XX Contents

19.2 Clinical Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71619.2.1 Disease Nominalism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71819.2.2 Disease Platonism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72019.2.3 Disease Tropism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72219.2.4 Disease Realism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 723

19.3 The Ontology of Psychiatry and Psychosomatics . . . . . . . . . . . . 72419.3.1 The Mind-Body Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . 72419.3.2 Mental States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72919.3.3 The Ontology of Mental Diseases . . . . . . . . . . . . . . . . . . . . 73019.3.4 The Ontology of Psychosomatic Diseases . . . . . . . . . . . . . 733

19.4 Biomedical Ontology Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . 73519.5 Formal Medical Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 738

19.5.1 Mereology and Mereotopology . . . . . . . . . . . . . . . . . . . . . . 73919.5.2 Fuzzy Formal Ontology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741

19.6 Medical Ontology de re and de dicto . . . . . . . . . . . . . . . . . . . . . . . 75319.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755

20 On Medical Truth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75720.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75720.1 Truth in Medical Sciences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75720.2 Truth in Clinical Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75820.3 Misdiagnoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75920.4 Truth Made in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76120.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762

21 On the Nature of Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76321.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76321.1 The Subject and Goal of Medicine . . . . . . . . . . . . . . . . . . . . . . . . . 76421.2 Is Medicine a Natural Science? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76621.3 Is Medicine an Applied Science? . . . . . . . . . . . . . . . . . . . . . . . . . . . 76721.4 Does Medicine Belong to the Humanities? . . . . . . . . . . . . . . . . . . 76821.5 Is Medicine a Practical Science? . . . . . . . . . . . . . . . . . . . . . . . . . . . 768

21.5.1 Practical vs. Theoretical Sciences . . . . . . . . . . . . . . . . . . . . 76821.5.2 Means-End Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76921.5.3 Clinical Research is a Practical Science . . . . . . . . . . . . . . . 77021.5.4 Relationships Between Biomedicine and Clinical Medicine 776

21.6 Medicine is Practiced Morality as well as Ethics . . . . . . . . . . . . . 77721.6.1 Clinical Practice is Practiced Morality . . . . . . . . . . . . . . . 77721.6.2 Clinical Research is Normative Ethics . . . . . . . . . . . . . . . . 778

21.7 Quo Vadis Medicina? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77921.7.1 Medicine as an Engineering Science . . . . . . . . . . . . . . . . . . 78021.7.2 Medicine Toward Anthropotechnology and

Posthumanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78521.7.3 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786

Contents XXI

Part VII Epilog

22 Science, Medicine, and Rationality . . . . . . . . . . . . . . . . . . . . . . . . . 78922.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78922.1 On the Concept of Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789

22.1.1 Research Institutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79022.1.2 Scientific Research Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . 79422.1.3 Science in General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79522.1.4 Types of Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798

22.2 On the Scientific Status of Medicine . . . . . . . . . . . . . . . . . . . . . . . 79922.3 On Rationality in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799

22.3.1 Theoretical and Practical Rationality . . . . . . . . . . . . . . . . 80022.3.2 Rationality in Medical Sciences . . . . . . . . . . . . . . . . . . . . . 80122.3.3 Rationality in Clinical Practice . . . . . . . . . . . . . . . . . . . . . . 803

22.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806

23 Perspectivism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80723.1 Relativism, Contextualism, Perspectivism . . . . . . . . . . . . . . . . . . 80723.2 Perspectivism de re and Perspectivism de dicto . . . . . . . . . . . . . 810

24 The Doubter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 815

Part VIII Logical Fundamentals

25 Classical Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82125.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82125.1 Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82425.2 Operations on Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 826

25.2.1 Intersection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82625.2.2 Union . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82725.2.3 Subset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82825.2.4 Complement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82925.2.5 Powerset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82925.2.6 Two Basic Laws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 830

25.3 Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83125.3.1 Ordered Tuples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83125.3.2 Cartesian Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83325.3.3 n-ary Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 834

25.4 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83625.4.1 Functions are Single-Valued Relations . . . . . . . . . . . . . . . . 83625.4.2 Composition of Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 84125.4.3 Restriction of a Function . . . . . . . . . . . . . . . . . . . . . . . . . . . 84325.4.4 Point and Set Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 843

25.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844

XXII Contents

26 Classical Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84526.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84526.1 Basic Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 847

26.1.1 Reasoning, Argumentation, and Proof . . . . . . . . . . . . . . . . 84726.1.2 The Classical Concept of Inference . . . . . . . . . . . . . . . . . . 84926.1.3 Object Language and Metalanguage . . . . . . . . . . . . . . . . . 85226.1.4 Syntax, Semantics, and Pragmatics . . . . . . . . . . . . . . . . . . 85326.1.5 Material and Formal Truth . . . . . . . . . . . . . . . . . . . . . . . . . 85526.1.6 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 856

26.2 Classical First-Order Predicate Logic with Identity . . . . . . . . . . 85726.2.1 The Syntax of the Language L1 . . . . . . . . . . . . . . . . . . . . . 85726.2.2 The Semantics of the Language L1 . . . . . . . . . . . . . . . . . . 87326.2.3 A Predicate-Logical Calculus . . . . . . . . . . . . . . . . . . . . . . . 89026.2.4 Metalogic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89826.2.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904

27 Modal Extensions of Classical Logic . . . . . . . . . . . . . . . . . . . . . . . 90727.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90727.1 Alethic Modal Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 913

27.1.1 Alethic Modalities and Operators . . . . . . . . . . . . . . . . . . . . 91327.1.2 A First-Order Alethic Modal Logic . . . . . . . . . . . . . . . . . . 91527.1.3 Metalogic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92227.1.4 Necessary vs. Contingent Identity . . . . . . . . . . . . . . . . . . . 92227.1.5 De re and de dicto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92527.1.6 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 927

27.2 Deontic Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92727.2.1 Deontic Modalities and Operators . . . . . . . . . . . . . . . . . . . 92827.2.2 The Standard System of Deontic Logic . . . . . . . . . . . . . . . 92927.2.3 Metalogic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93327.2.4 Deontic Conditionals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93527.2.5 De re and de dicto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93627.2.6 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 937

27.3 Epistemic Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93727.3.1 Epistemic Modalities and Operators . . . . . . . . . . . . . . . . . 93827.3.2 A First-Order Epistemic Logic . . . . . . . . . . . . . . . . . . . . . . 94027.3.3 Metalogic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94327.3.4 Opaque Epistemic Contexts . . . . . . . . . . . . . . . . . . . . . . . . 94427.3.5 De re and de dicto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94727.3.6 Dynamic Epistemic Logic . . . . . . . . . . . . . . . . . . . . . . . . . . 94727.3.7 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 949

27.4 Temporal Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94927.4.1 Temporal Modalities and Operators . . . . . . . . . . . . . . . . . 95027.4.2 A Minimal System of Temporal Logic . . . . . . . . . . . . . . . . 95127.4.3 Metalogic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95427.4.4 Since and Until . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 955

Contents XXIII

27.4.5 Metric Temporal Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95727.4.6 Alternative Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95827.4.7 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 958

28 Non-Classical Logics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95928.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95928.1 Relevance Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96028.2 Intuitionistic Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96128.3 Paraconsistent Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96128.4 Non-Monotonic Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96328.5 Many-Valued Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96428.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 968

29 Probability Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96929.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96929.1 Probability Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 970

29.1.1 Probability Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97329.1.2 Probability Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97629.1.3 Probabilistic Independence . . . . . . . . . . . . . . . . . . . . . . . . . 97829.1.4 Conditional Probability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97829.1.5 Bayes’s Theorem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98029.1.6 What Does “Probability” Mean? . . . . . . . . . . . . . . . . . . . . 982

29.2 Inductive Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98429.3 Bayesian Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98829.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 991

30 Fuzzy Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99330.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99330.1 Fuzzy Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99530.2 Operations on Fuzzy Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1005

30.2.1 Fuzzy Complement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100530.2.2 Fuzzy Intersection and Union . . . . . . . . . . . . . . . . . . . . . . . 100630.2.3 Empty Fuzzy Set and Fuzzy Powerset . . . . . . . . . . . . . . . . 100730.2.4 Degrees of Fuzziness and Clarity . . . . . . . . . . . . . . . . . . . . 100730.2.5 Fuzzy Logic is a Non-Classical System . . . . . . . . . . . . . . . 1010

30.3 Fuzzy Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101130.3.1 The Concept of a Fuzzy Relation . . . . . . . . . . . . . . . . . . . . 101130.3.2 Composition of Fuzzy Relations . . . . . . . . . . . . . . . . . . . . . 1014

30.4 Fuzzy Logic Proper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101730.4.1 Linguistic and Numerical Variables . . . . . . . . . . . . . . . . . . 101830.4.2 Fuzzy Quantifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103530.4.3 Fuzzy Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103530.4.4 Fuzzy Reasoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1038

30.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1041

XXIV Contents

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1043

Index of Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1089

Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1099

0

Introduction

In a pain there is always more knowledgeabout the truth than in all wise men’s seren-ity. All I know I have learned from the unfor-tunates, and what I recognized I saw throughthe look of the pained (Stefan Zweig, 1993,56, translated by the present author).

0.1 A Fresh Start

Errors of diagnosis and treatment are major problems in health care, despiterecent advances in biomedical and clinical sciences and technology. They aredue to physician fallibility, on the one hand; and medical imperfection, on theother, raising the question of how the failures emerge and whether it is possibleto prevent them. To evaluate this question and to understand its far-reachingimplications, we may first briefly consider the following five examples:1

A 42-year-old female teacher consulted her family physician because ofdiarrhea that had lasted for five days. The doctor diagnosed enteritis andadministered antibiotics. The patient died the next week. An autopsy revealedthat she had a stomach cancer.

A 49-year-old male physiologist had been suffering from some malaise forseveral weeks. Based on his own expert knowledge, he convinced himself thathe had exocrine pancreatic insufficiency, i.e., lowered production of digestiveenzymes by pancreas. He visited an internist to have his suspicion examined.The doctor took some blood tests. A few days later, she calmed the patientdown assuring him he did not have an exocrine pancreatic insufficiency. Sincehis health didn’t improve, in the years that followed he successively consultedfive additional doctors, to receive additional, conflicting diagnoses. It was onlythe last, sixth, doctor who was able to confirm his own, initial suspicion ofsuffering from exocrine pancreatic insufficiency, and to help him.

A 56-year-old housewife complained of being poisoned by her neighbors,and was hospitalized in a psychiatric institution. Paranoid schizophrenia wasdiagnosed. In the third year of her hospital life, a new, young doctor at theward discovered that the patient had cancer of the esophagus. He concludedthe cancer had certainly existed, at least as a precancer, prior to the patient’shospitalization three years earlier, and had caused her gastro-esophageal dis-1 Two of these examples, the second and third one, are real patient histories en-

countered by the author himself. The other three are based on (Cutler, 1998).

2 0 Introduction

tress that she had interpreted as a symptom of being poisoned by her neigh-bors. But it was now too late to correct the past. She died shortly after thediagnosis was made.

A 22-year-old female student was diagnosed of having multiple sclerosisbecause of her complaints of permanent, unbearable headaches, and of somesensory and muscular problems. She was treated for multiple sclerosis overthe next eight years. After she moved to another city and changed her apart-ment, her health problems disappeared immediately. No further treatmentwas needed. She was able to continue her university studies. Her new doctorspeculated that effluents from the furniture in her previous apartment mighthave been the cause of her health problems.

A 39-year-old male engineer had several episodes of sharp, stabbing leftchest pain. The pain lasted only a few minutes each time, did not radiate, andwas not related to physical activity. The physician whom he visited, foundthat his ECG was normal and all blood parameters, including blood lipids,were also normal. No risk factors were present. The patient had no history ofany disease. X-rays of thoracic organs displayed no abnormalities. The doctordiagnosed Tietze’s syndrome and sent the patient home, assuring him thathe had no serious health problem. He was asked to return in six weeks. Twoweeks later the physician read his obituary notice in the local newspaper. Hehad not survived a second heart attack.

There are still many more misdiagnoses, wrong treatments, and physician-caused misfortunes, pains, and deaths. Why and how do they arise? I havetried to understand this phenomenon since my clinical training at the endof the 1960s. Living in West Berlin then, i.e., the free sector of then dividedBerlin, Germany, I regularly witnessed at clinical rounds the debates betweenour chief and senior officers about their conflicting bedside diagnoses andtreatment recommendations. It was surprising and even disturbing to me as ayoung physician to encounter such differences among their clinical judgments.This observation made me aware of an issue for the first time that our teach-ers had not taught us during our medical education, i.e., methods of clinicalreasoning. Clinical reasoning, also called clinical decision-making, diagnostic-therapeutic decision-making, and clinical judgment, lies at the heart of clinicalpractice and thus medicine. Although as students of medicine we had learnedlarge parts of natural sciences, anatomy, physiology, biochemistry, pathology,pathophysiology, and many clinical disciplines, diseases, therapies, and meth-ods of diagnosing and treating individual, specific diseases such as gastritis,leukemia, schizophrenia, etc., we had learned nothing about how to search for adiagnosis and treatment in general, i.e., how to arrive at a clinical judgment.I asked myself whether there was a scientific methodology of clinical judg-ment that our teachers had withheld from us, and if so, what did it look like?My extensive search was disappointing. It revealed that there was no suchmethodology. I have since been concerned with this topic, and have foundthat a variety of highly intriguing logical, linguistic, methodological, episte-mological, moral, and metaphysical issues and problems are involved. The

0.3 The Subject 3

present book addresses these issues and problems, many of which have eitherbeen overlooked or neglected until now by both medicine and its philosophers.Their analysis will not only enrich medical practice, research, and philosophy,but may also stimulate interest in the other areas involved.

0.2 The Objective

Medicine constitutes one of the major and most influential social institutions,including religion, law, education, and government, that interpret, rule, andshape our lives. It is therefore desirable to examine the adequacy and qualityof its methods, means, practices, and perspectives. The present book under-takes such an examination by inquiring into the structure, nature, and goalsof medicine. Our aim is to clarify the conceptual, methodological, epistemo-logical, moral, logical, and metaphysical foundations of medicine in order tounderstand what occurs in the doctor-patient clinical encounter; what factors,forces, and sciences determine the dynamics and products of this interactionsystem; and how to best organize it.

0.3 The Subject

To attain our above-mentioned goals, we shall do analytic philosophy ofmedicine. But what is analytic philosophy of medicine?

Analytic philosophy that has emerged at the turn of the 20th century, is awell-established method of philosophical inquiry by means of logical and con-ceptual analysis. It was founded by the German mathematician and logicianFriedrich Ludwig Gottlob Frege (1848–1925), and the British mathematicianand logician Bertrand Arthur William Russell (1872–1970).2 It attempts toclarify the structure and meaning of concepts, conceptual systems, knowledge,and action, and to analyze and improve methods of scientific investigationand reasoning. Accordingly, analytic philosophy of medicine is philosophy ofmedicine by means of logical and conceptual analysis (Sadegh-Zadeh, 1970a–c,1977c).

My basic motive for analyzing medicine logically is my long-standing inter-est in the sources and conundrums of physician fallibility and medical imper-fection; my desire to contribute to enhanced physician performance; and my2 It is sometimes maintained in the literature that analytic philosophy was founded

by the British philosopher George Edward Moore (1873–1958) and the Austrian-British philosopher Ludwig Wittgenstein (1889–1951). However, it began earlierin Gottlob Frege’s works on the philosophy of mathematics and language (Frege,1884, 1891, 1892a, 1892b, 1893, 1904; Kenny, 2000), which caused Bertrand Rus-sell to change his previous, Hegelian perspective (Russell, 1969) and initiate thelogical phase of his philosophical inquiries as of 1900 (Russell, 1903, 1905, 1914,1919; Whitehead and Russell, 1910).

4 0 Introduction

conviction that such enhancement is feasible by employing logic in medicine.A measure of physician performance is provided by the quality of diagnostic-therapeutic decisions. Since these decisions are the obvious outcome of clinicalreasoning, their quality mirrors the quality of that reasoning. It is well known,however, that despite the advances in medical science and technology, manyclinical decisions turn out wrong, leading to malpractice suits. As some statis-tic report, there are 30–38% misdiagnoses (Gross and Loffler, 1997; Sadegh-Zadeh, 1981c). At first glance, these errors call into question the clinical com-petence of the physicians involved. Viewed from a practical perspective, thisdeficiency in physician performance may appear as a failure that in princi-ple is avoidable by improving the diagnostic-therapeutic methodology, sayfor example, using ‘medical expert systems’. However, there are also scholarswho interpret it as an inevitable physician fallibility due to the peculiarity ofclinical practice as “a science of particulars” (Gorovitz and MacIntyre, 1976).

I have been concerned with the issues surrounding clinical reasoning andits imperfection for about forty years. In the present book, some of the mainresults of this endeavor are discussed. They reveal the deeply philosophical-metaphysical character of medicine, the realization of which is likely to ex-ert far-reaching impacts on both medicine and philosophy of medicine. Thediscovery that was briefly mentioned on page IX in the Preface, representsone of them. That is, (i) medicine as health care consists of obligatory well-doings and avoiding prohibited wrong-doings, and is thus practiced morality ;and (ii) as clinical research, it seeks, justifies, and establishes rules of thatpractice, and thus, belongs to normative ethics (Sadegh-Zadeh, 1983). In con-trast to the philosophically and methodologically sterile debate about whethermedicine is a science or an art (Montgomery, 2006; Munson, 1981), the abovethesis asserts that medicine is a deontic, i.e., duty-driven and normative, dis-cipline. (The adjective “deontic” originates from the Greek term δεoν, deon,for “what is binding”, “duty”.) I am convinced that philosophers of medicine,as well as medical professionals, will welcome this surprising finding. As weshall see later, its recognition and understanding requires minutely detailedlogical analyses of medical language, concepts, knowledge, and decisions. Thelogic primer provided in the final part of the book is meant to make suchilluminating analyses possible. Apart from its philosophical-metaphysical fer-tility, the finding will also stimulate medical informaticians and expert systemresearchers to customize their clinical decision-support programs and hospi-tal information systems accordingly, and to base them on deontic logic. (Fordeontic logic, see Section 27.2 on page 927.)

The book is divided into eight parts, Parts I–VIII, which comprise 30chapters. The starting-point is the patient, examined in Part II, since thephilosophy of medicine that I shall develop will be tailored to her/his needsand interests. To this end, in the opening Part I preceding it, the languageof medicine is carefully analyzed and enriched with methods of scientific con-cept formation, to contribute to its improved use in clinical practice, medicalresearch, and philosophy of medicine.

0.3 The Subject 5

In Part II, the patient is interpreted as a bio-psycho-social and moral agentin order to propose a theory of organism, an emergentist theory of psyche,and a concept of sociosomatics that substitutes for psychosomatics. This in-terpretation will help to provide an understanding of what it means to saythat such an agent may feel ill, or be categorized as diseased. In the pursuitof this understanding, the concepts of health, illness, disease, diagnosis, prog-nosis, therapy, and prevention are logically analyzed, and a number of novelconceptual frameworks are advanced. These include the prototype resemblancetheory of disease, according to which a few prototype diseases determine, bysimilarity relationships, the whole category of diseases; a probabilistic the-ory of etiology, which reconstructs medical causality as probabilistic-causalassociations between cause and effect; and a theory of relativity of clinicaljudgment, according to which diagnostic-therapeutic decisions and preventivemeasures are relative to a number of parameters. The aim is to inquire intohow medicine is engaged in shaping the human world, by deciding who is apatient to be subjected to diagnostics and therapy, and who is a non-patient.In this way, nosology, pathology, etiology, diagnostics, prognostics, therapy,and prevention are understood as conceptual and methodological endeavorsthat serve as means of medical worldmaking. All necessary logical tools areprovided in our logic primer in Part VIII.

Part III is devoted to medical knowledge. In it, we analyze the conceptand types of medical knowledge to expose the relationships of this knowl-edge to what it talks about. It is shown that medical knowledge consists ofnorms, hypotheses, and theories. While for syntactic reasons medical normsand most types of medical hypotheses are unverifiable, theories are empir-ically not testable at all because, like norms, they do not consist of state-ments of facts. They are conceptual structures, just like buildings are architec-tural structures. Several example theories are reconstructed according to thisnon-statement view of theories, to discuss its medical-epistemological conse-quences. An important question in this context is from where medical theoriesand knowledge arise. It is shown that, in contrast to our received views, thesources of medical knowledge and theories are medical-scientific communitiesand not individual scientists. Pronouncements such as “Robert Koch discov-ered the bacillus of tuberculosis” are inappropriate because underlying sucha discovery are groups of scientists and technical assistants, research fundingagencies, and a number of social and political-historical factors. This social-constructivist idea was first developed by Ludwik Fleck and adopted later byThomas Kuhn. It is of particular significance in medicine because it impliesthat, by and large, medical-scientific communities determine the nature ofmedical truth and the way how to act. We even go one step further to suggesta theory of technoconstructivism, according to which scientific research todayis in transition to engineering; and scientific knowledge is increasingly beingconstructed as a technical product and commodity by technology.

In Part IV, the concept of medical deontics is introduced to include underthis umbrella term all medical research, on the one hand, whose outcome

6 0 Introduction

is formulated by deontic sentences, namely ought-to-do rules; and all medicalpractices that obey such deontic rules, on the other. Thus, medical deontics notonly covers normative medical ethics and law, but also diagnostic-therapeuticresearch as well as clinical practice. This momentous deonticity of medicinealso includes the concept of disease, that is argued to be a deontic conceptcreated by the minimal common morality in the human society. As was alreadypointed out above, the deontic character of medicine has been ignored untilnow. I hope that philosophers of medicine, and medical ethicists as well, willconcern themselves with this intriguing feature of health care in order to opennew fields of research and to enlarge our understanding of how maladies andhealing are intertwined with morality and charity.

Part V deals with the roles that systems of logic play in medicine, andwith the question whether there is an inherent logic of medicine. It is shownthat, due to the syntactic richness of medical language, different types oflogic are required to cope with it in medical research and practice, becauseit transcends the scope and capabilities of individual logic systems. In thisplurality of logics in medicine, an exception is provided by fuzzy logic. Fuzzylogic, also briefly introduced in our logic primer in the final Part VIII, isa logic of vagueness, and therefore highly suitable for use in medicine. It isa general enough logic to satisfy almost all logical needs of medicine, andmoreover, to serve as an outstanding methodological tool for constructing in-novative techniques of problem solving in research and practice. This has beendemonstrated by an extensive application of fuzzy logic to clinical, biomedi-cal, conceptual, medical-deontic, and metaphysical issues. By virtue of its wideapplicability, strength, and elegance, it is likely to become the leading logic inmedicine in the not-too-distant future. Besides the logical pluralism referredto above, no other logical peculiarity of medicine is observed that would re-quire a specific medical logic. However, that does not mean that there is norationale behind medical thinking and acting.

Medical metaphysics is the subject of Part VI. It is primarily concernedwith medical ontology, medical truth, and the nature of medicine. Ontologyis divided into pure ontology, applied ontology, and formal ontology. In thesethree areas, novel suggestions have been made by using fuzzy logic. Specifi-cally, we have introduced a fuzzy ontology that seems to be auspicious for bothmedicine and philosophy. It not only determines degrees of being by meansof a fuzzy existence operator, that we have dubbed the Heraclitean operator,but also makes it possible to construct a fuzzy mereology, by means of whichvague part-whole relationships become tractable. Of particular importanceis our distinction between de re and de dicto ontology, that is based on asyntactic criterion, and enables differentiation between fictional entities suchas Sherlock Holmes, and real ones. The salient advantage of this approachis that it allows precise analyses of controversial questions like “are diseasesfictitious or real?”. Using this approach, we have extensively examined the on-tological problems associated with nosology, psychiatry, and psychosomatics,and have also critically explored the so-called biomedical ontology engineer-

0.4 Methods of Inquiry 7

ing that is expanding today. Regarding medical truth, it has been shownthat there is sufficient evidence to support the assertion that medical truthsare system-relative, and are formed within the respective health care systemsthemselves. They do not report scientifically discovered facts ‘in the worldout there’. Particular emphasis has been placed on the analysis of medicineas a scientific field. Abandoning widespread, exclusive mono-categorizationssuch as “medicine is a science” versus “medicine is an art”, we have demon-strated that in declarations of the type “medicine is such and such”, the globalterm “medicine” should be differentiated to recognize that medicine, compris-ing many heterogeneous disciplines, belongs to a large number of categories.For example, without doubt biomedicine is natural science; clinical research,however, is practical science; it is also normative ethics; clinical practice ispracticed morality; and so on. What is worth noting, is that medicine is alsoa poietic science that invents, designs, and produces medical devices in thewidest sense of this term, from drugs to prosthetics to brain chips to artificialorgans to artificial babies. Medicine is thus on its way to become an engineer-ing science, conducted as health engineering and anthropotechnology.

Part VII of the book attempts to clarify some epistemological and meta-physical issues that our preceding analyses of medicine have revealed. First,taking into account the peculiarities of medicine, the concept of science is ex-plicated to demonstrate why the traditional understanding of this concept inthe general philosophy of science is terribly one-sided. The yield is a tripartiteconcept of science that, in contrast to the traditional mono-scientism, suggeststhree different types of science: theoretical science, practical science, and de-ontic science. Medicine comprises all three types of science. Second, it is shownthat rationality cannot be a criterion of the scientificity of medicine, becauserationality is something relative, and depends on the perspective from whichit is judged. Third, it is argued that this dependence on perspective is an in-escapable property of views, rendering perspectivism an interesting approachto epistemology and ontology both in medicine and elsewhere.

To conduct the studies sketched above, we must first assemble the logicaland conceptual tools that we shall use. This task is accomplished in PartVIII of the book as a sort of appendix. It provides the logical fundamentalscomprising a brief outline of the relevant fields from classical set theory andlogic, to modal logics, non-classical logics and probability logic, and furtheron to fuzzy set theory and logic. For readers not acquainted with logic andits terminology, Part VIII is the prerequisite for understanding the medical-philosophical frameworks and theories developed in the book.

0.4 Methods of Inquiry

It is a truism that a tool for analyzing a particular object should be suffi-ciently sensitive to the subtleties of that object. Otherwise, the details andpeculiarities of the analysandum will be lost. For example, it would be fatuous

8 0 Introduction

if someone tried to examine a biological cell by employing a pneumatic ham-mer, since such a brute-force approach only destroys the cell. The ingeniousapparatus of a microscope and thin light waves will be necessary to discernwhat is before one’s eyes. The same holds for analyzing a scientific enterpriseitself. Medicine as a scientific enterprise is too complex an area to be amenableto coarse and crude tools and techniques of inquiry.

VIII required VIII optional

Acquainted with logicand probability

I–VII sequentially

partially wellbarely

VIII recommended

Fig. 1. How to read this book

My interest in the subject addressed inthis book goes back to my youth when, inthe early 1960s, I was a graduate studentof medicine and philosophy at the Uni-versity of Munster in Germany. Initially, Iwas an adherent to phenomenologic andhermeneutic approaches, until analyticphilosophy persuaded me in the late 1960sthat it was a more adequate and supe-rior method of philosophical analysis inmedicine. I had the good fortune to realizeearly on that in philosophizing on topicssuch as diagnostic-therapeutic reasoningor the conceptual structure of medicaltheories, well-developed, sensitive, andprecise tools and techniques such as logicare required. The reason why logic isneeded rather than a pneumatic hammerfor such an inquiry, is simply that bothdiagnostic-therapeutic reasoning and the-ory structures have some logical characteristics, which are not adequatelyanalyzable by tools other than logic. Accordingly, my approach to philosophyof medicine in this book takes an analytic route. It is my conviction thatmedicine will only benefit from logical self-analysis.

0.5 How to Read this Book

As a consequence of using logic as our method of inquiry, the book is not lightreading like a traditional medical-philosophical treatise. Some knowledge oflogic is required to understand the analyses, reconstructions, and construc-tions involved. For those readers who are not acquainted with logic, a logicprimer is provided in the final part of the book, Part VIII, that they mayconsult before or while reading chapters of the book. In that case, the bookwill be self-contained and easily accessible to any interested student. Theauthor recommends that you study the logic primer first, and then proceedsequentially through Parts I–VII and not skip anything. The book has beenorganized systematically and should be read accordingly (Figure 1).