Ontologie is die tak van filosofie wat vra: “Wat bestaan?” en “Wat beteken dit om te wees?” Dit ondersoek die verskillende tipes bestaan (soos fisiese, morele of geestelike dinge) en hul onderlinge verhoudings. Wanneer ons byvoorbeeld onderskei tussen iets wat werklik is (soos God of die natuur) en wat slegs denkbeeldig is (soos ‘n fantasiefiguur), beoefen ons ontologie. In teologie is ontologie belangrik om te verstaan wat dit beteken dat God “is” en dat Hy die grond van alle ander wees is.
Ontology is the branch of philosophy that asks: “What exists?” and “What does it mean to be?” It investigates the different types of existence (such as physical, moral, or spiritual things) and their interrelationships. When we distinguish, for example, between something that is real (such as God or nature) and what is merely imaginary (such as a fantasy figure), we are practising ontology. In theology ontology is important for understanding what it means that God “is” and that He is the ground of all other being.