Ontology – definition and meaning

Ontology is the study of things in the Universe. In other words, what kind of things exist? What entities are there in our Universe? Ontology is a branch of metaphysics that deals with the nature of being. Metaphysics is a branch of philosophy, not physics – it deals with the first principles of things.

The term sounds like oncology, which is the study and treatment of tumors (cancer). However, it has nothing to do with oncology.

The term also includes the basic categories of being and how they relate to each other.

In other words, ontology deals with questions concerning what exists or may exist, and how we group those entities. We group them ontologically, i.e., according to their similarities and differences.

Put simply; it is the examination of what we mean, in context, by the word ‘thing.’

The Online Etymology Dictionary says that the English term comes from Modern Latin ‘Ontologia’ (c. 1600). However, its roots go back to ancient Greece.

‘Ont’ in Ancient Greek means ‘to be.’ Etymology is the study of the history of words and how their meanings evolved.

Ontology - image explaining what it means
Ontology is the study of the nature of being. For example, it covers questions line “What is a thing?” It is a branch of metaphysics, which is a part of philosophy.

Ontology – principal questions

The principal ontological questions are:

– ‘What exists?’ and ‘What can we say exists?’

– What is a thing?

– Can we sort existing things into categories? And if so, what categories?

– What does ‘being’ mean?

– What modes of being do entities have?

According to BusinessDictionary.com, ontology is:

“[The] study of the nature of being or existence. The assumptions underlying a classification scheme, concept, system, or theory.”

Ontology in computer science

The term is also used in computer science. In computer science, it refers to IT resources that represent previously-agreed domain semantics. ‘IT’ stands for Information Technology.

Webopedia.com has the following definition for the term in computer science:

“In relation to computer science, ontology refers to computer-based resources that represent agreed domain semantics.”

Ontology is in our nature

It is human nature to classify things. In fact, we like doing it. Throughout human history, we have been taking apart the Universe and creating an underlying structure for everything.

Humans love structure. We love structure because it allows us to pigeon-hole knowledge into compartments that we understand more easily. Hence, we have ontology.

Humans have discussed ontological concepts for a long time. In fact, we have been philosophizing over it for thousands of years.

Our first discussions on the ontological categorization of existence date back to Parmenides, circa 500 BCE. Parmenides was a pre-Socratic Greek philosopher.

In modern history, artificial intelligence (AI) research in the 1970s brought about the rebirth of ontological categorization.

Tom Gruber borrowed the term from philosophy as an apt system for categorizing and ordering knowledge systems. Specifically, knowledge systems that AI engineers required.

Tom Gruber is an American computer scientist, inventor, and entrepreneur. He created the Siri intelligent personal assistant, part of the operating systems of Apple Inc. devices.

You can find existing ontologies everywhere. In fact, there are thousands of them in the world today. They exist in virtually every industry, from medical research, e-commerce, to software engineering. Ontologies also exist in banking and linguistic processing.