Ontology 89 Philosophy 63 Metaphysics 14 Knowledge, Theory of 13 Aesthetics 12 Existentialism 9 Methodology 7 Natural language processing (Computer science) 7 History 6 Information organization 6 Language and languages 6 Phenomenology 6 Social sciences 6 Computational linguistics 5 Epistemology 5 Logic 5 Ontologies (Information retrieval) 5 Postmodernism 5 Quantum theory 5 Semantic Web 5 Social Sciences 5 Truth 5 Classification 4 First philosophy 4 God 4 International relations 4 Political science 4 Realism 4 Religion 4 Space and time 4