A PHILOSOPHICAL APPROACH TO UPPER-LEVEL ONTOLOGIES A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF SOCIAL SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY DİLEK SATIOĞLU IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS IN THE DEPARTMENT OF PHILOSOPHY SEPTEMBER 2015 Approval of the Graduate School of Social Sciences Prof. Dr. Meliha Altunışık Director I certify that this thesis satisfies all the requirements as a thesis for the degree of Master of Arts. Prof. Dr. Şeref Halil Turan Head of Department This is to certify that we have read this thesis and that in our opinion it is fully adequate, in scope and quality, as a thesis for the degree of Master of Arts. Assoc. Prof. Dr. Aziz Fevzi Zambak Supervisor Examining Committee Members Assoc. Prof. Dr. Hilmi Demir (Bilkent Uni., Phil) Assoc. Prof. Dr. Aziz Fevzi Zambak (METU, Phil) Assoc. Prof. Dr. Elif Çırakman (METU, Phil) I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last name : Dilek Satıoğlu Signature : iii ABSTRACT A PHILOSOPHICAL APPROACH TO UPPER-LEVEL ONTOLOGIES Satıoğlu, Dilek M.A., Department of Philosophy Supervisor: Assoc. Prof. Dr. Aziz Fevzi Zambak September 2015, 101 pages The aim of this thesis is to provide a philosophical approach to upper-level ontologies. The ontologies and/or categorical system of Aristotle, Kant, Husserl, and Quine are evaluated in order to give a philosophical understanding of ontologies. After an explanation of the developments in ontology as a new interdisciplinary study, the most well known upper-level ontologies, BFO, DOLCE, SUMO, and Cyc, are analysed technically. In the light of philosophical ontologies and categorical systems, these upper-level ontologies are criticised in terms of the fundamental constituents of upper-level ontologies. Keywords: ontology, upper-level ontologies, philosophical approach iv ÖZ ÜST DÜZEY ONTOLOJİLERE FELSEFİ YAKLAŞIM Satıoğlu, Dilek Yüksek Lisans, Felsefe Bölümü Tez Yöneticisi: Doç. Dr. Aziz Fevzi Zambak Eylül 2015, 101 sayfa Bu tezde üst düzey ontolojiler felsefi bir bakışla analiz edilmiştir. Ontolojinin felsefi olarak nasıl ele alındığını göstermek için Aristoteles, Kant, Husserl ve Quine’nın ontolojileri ve/veya kategori sistemleri incelenmiştir. Disiplinlerarası bir bilim olarak karşımıza çıkan ontolojinin gelişmesi anlatıldıktan sonra, en çok tanınan üst düzey ontolojilerden BFO, DOLCE, SUMO ve Cyc teknik özellikleri bakımından analiz edilmiştir. Felsefi ontolojilerin ve kategori sistemlerinin ışığı altında, bu üst düzey ontolojiler, üst düzey ontolojilerin temel yapıtaşlarına göre araştırılmıştır. Anahtar Kelimeler: ontoloji, üst düzey ontoloji, felsefi yaklaşım v To Truth and Beauty, and to the those who partake of the both vi ACKNOWLEDGMENTS In spite of many difficulties, this thesis has been completed. I owe my gratitude to all lovely people who made this work possible. My deepest gratitude is to my supervisor, Aziz Fevzi Zambak, without whose patience, encouragement, and faith, this thesis could not have been started, continued, or finished. I would like to thank my colleagues in the Laboratory for Computational Ontology for their various forms of support. Special thanks to my friends, especially Onur Eylül Kara and Berk Yaylım who have always encouraged me during my master studies; and Refet Şaban who has always been a dearest friend that reminds the truths. I would like to express my heartfelt gratitude to Başar Yargan, who experienced all the difficult and glorious moments with me throughout this endeavor. Lastly, I would like to express my deep love and gratitude to my family, especially Yavrukuş and Bobi, without whom something is always missing. vii TABLE OF CONTENTS PLAGIARISM . iii ABSTRACT . iv ÖZ . v DEDICATION . vi ACKNOWLEDGMENTS . vii TABLE OF CONTENTS . viii LIST OF TABLES . x LIST OF FIGURES . xi LIST OF ABBREVIATIONS . xii CHAPTER 1. INTRODUCTION . 1 2. ANALYSES OF PHILOSOPHICAL ONTOLOGIES 2.1. Philosophical Ontologies . 9 2.1.1. Aristotle’s Ontology . 10 2.1.2. Husserl’s Ontology . 17 2.1.3. Quine’s Ontology . 24 2.2. Categories . 28 2.2.1. Category System of Aristotle . 29 2.2.2. Category System of Kant . 31 2.2.3. Category System of Husserl . 34 2.2.4. Category System of Quine . 35 3. ANALYSES OF UPPER-LEVEL ONTOLOGIES . 37 3.1. Basic Formal Ontology . 41 3.2. The Descriptive Ontology for Linguistics and Cognitive Engineering . 48 3.3. The Suggested Upper Merged Ontology . 52 viii 3.4. Cyc and OpenCyc . 57 3.5. Some Upper-Level Ontologies . 61 4. ANALYSES . 65 5. CONCLUSION . 78 REFERENCES . 82 APPENDICES APPENDIX A. TURKISH SUMMARY . 89 APPENDIX B. TEZ FOTOKOPİSİ İZİN FORMU . 101 ix LIST OF TABLES TABLES Table 1.1 “The Four Phases of Philosophy” from ancient times to today . 4 Table 2.1 The Selected Philosophers in the Four Phases of Philosophy . 10 Table 2.2 Kant’s System of Categories . 33 Table 2.3 Husserl’s System of Categories . 34 Table 3.1 Basic Primitive Relations in DOLCE . 51 Table 4.1 Philosophical Assumptions of ULOs . 77 x LIST OF FIGURES FIGURES Figure 2.1 Brentano’s Tree of Aristotle’s Categories . 31 Figure 3.1 The BFO 2.0 is_a Hierarchy . 43 Figure 3.2 The Top Level Categories in DOLCE . 50 Figure 3.3 The Top Level Categories in SUMO . 55 Figure 3.4 The Hierarchy of SUMO Theories . 56 Figure 3.5 The Top Level Categories in Cyc . 59 xi LIST OF ABBREVIATIONS In this work, while citing from Aristotle, I use Bekker numbers without mentioning the names of books of the corpus. Similarly, citations from Kant include both Kant’s first (A) and second (B) editions. Further, the belief that citing Husserl’s Logical Investigations as “LI” may confuse readers because of the usage of Roman numerals, which are used for indicating the chapters, make me use the German name of the book, Logischen Untersuchen, when citations are made. xii CHAPTER 1 INTRODUCTION Ἀρχή, in a philosophical sense, means the first principle that is the ultimate cause of everything there is; and the history of philosophy, if it finds its roots in Ancient Greek, starts with questioning what ἀρχή is. In the course of investigation, this question is modified to “What is there?”, hence; obviously the first inquiry of philosophy is boiled down to ontology, the science of being.1 Throughout the history of philosophy, the answer to what there is has taken various versions according to philosophers’ doctrines. The versions can be derived by formulation, rejection, interpretation, or construction.2 Ontology, moreover, has been given many names during centuries. At the very early phrase of philosophy, as mentioned before, ontology is the science of ἀρχή. Aristotle calls it the first philosophy, and then it is also called metaphysics after him; and in the doctrines of Plotinus, and Al-Farabi, for instance, it is nothing but theology. Today, understandably, it has a different guise. Whether it is called the first philosophy, metaphysics or theology, ontology is the science of the things that exist in reality and the hierarchical relations between them.3 Therefore, the difference lies between different ontologies on that what has to be taken as reality and how the relations between these realities have to be mapped. The developments of philosophical ideas and/or concepts have been classified even from the ancient times; moreover, classifications depart from one 1 Etymologically, ontology comes from the Greek word ὄν, meaning “being”, that is the present participle of εἰμί, meaning “to be”. When λογία is added to ὄν, the word ontology is constructed as the study of being. 2 Formulation, e.g. Thales’ statement that everything is ultimately water; rejection, e.g. Anaximenes’ statement that everything is not water but ultimately air; interpretation, e.g. statements of Zeno of Elea who is a passionate advocate of Parmenides; construction, e.g. the works of St. Thomas Aquinas who adapted Aristotelian ontology to Christian theology. 3 Any debate about the distinction between “that there is” and “that there exists” is ruled out. 1 another according to understanding of a thinker. Among the many readings of history of philosophy, I appeal to Brentano’s theory of history of philosophy for the following reasons.4 The first reason is based on Brentano’s attitude to philosophy as a scientific effort, which holds also for ontology. As it will be explained in the following lines, ontology today is taken as a new science, so Brentano’s reflection to history of philosophy can provide an appropriate approach to today’s ontology. Thereby, the second reason is that Brentano’s theory can help us to interpret the current situation of ontology, so that predictions can be done in order to flourish this new science. Hence, before the explanation of the current situation of ontology, Brentano’s theory of history of philosophy has to be shown. Philosophy, according to Brentano, has always had two phases, of which the first phase covers ascending development, and the second phase covers decadence.5 These two phases of development and decline in the history of philosophy have recursive feature, and can be observed “in the periods of antiquity, in the Middle Ages, and in the modern period up to the collapse of the Hegelian school”. Brentano explains these two phases in the part three of his essay. The development in the first phase is gained either through “a lively and pure theoretical interest” or through the support of scientific methodologies, such as perfecting hypotheses, enlarging the scope of the inquiry, challenging new questions. The second phase, which is the decline of the first phase, is “in fact the first stage of decline”.