section_path: Definition
section_name: Definition
paragraph_text: Definition
  
  Ontology is the study of being. It is the branch of philosophy that investigates the nature of existence, the features all entities have in common, and how they are divided into basic categories of being. It aims to discover the foundational building blocks of the world and characterize reality as a whole in its most general aspects. In this regard, ontology contrasts with individual sciences like biology and astronomy, which restrict themselves to a limited domain of entities, such as living entities and celestial phenomena. In some contexts, the term ontology refers not to the general study of being but to a specific ontological theory within this discipline. It can also mean a conceptual scheme or inventory of a particular domain.
  
  Ontology is closely related to metaphysics but the exact relation of these two disciplines is disputed. According to a traditionally influential characterization, metaphysics is the study of fundamental reality in the widest sense while ontology is the subdiscipline of metaphysics that restricts itself to the most general features of reality. This view sees ontology as general metaphysics, which is to be distinguished from special metaphysics focused on more specific subject matters, like God, mind, and value. A different conception understands ontology as a preliminary discipline that provides a complete inventory of reality while metaphysics examines the features and structure of the entities in this inventory. Another conception says that metaphysics is about real being while ontology examines possible being or the concept of being. It is not universally accepted that there is a clear boundary between metaphysics and ontology. Some philosophers use both terms as synonyms.
  
  The word ontology has its roots in the ancient Greek terms ὄντως (ontos, meaning ' being ') and λογία (logia, meaning ' study of '), literally, ' the study of being '. The ancient Greeks did not use the term ontology, which was coined by philosophers in the 17th century.