Ontology in Philosophy

Aristotle was a Greek philosopher, living from 384BC-322BC. He wrote a number of books that were called the Physics. His works were organized in such a way, that there was another set of books right after the Physics. The content of those books was a basic, fundamental area of philosophical inquiry, and did not have a name at this time. Some of Aristotle's scholars gave those books the name ``ta meta ta physika'', meaning ``the (books) after the physics''. Therefore the name ``metaphysics'' has been created.

Nowadays, metaphysics is the name of a branch of philosophy, concerned with the study of the most fundamental concepts, like being, relation, space, time, causation or existence. Ontology is the most fundamental branch of metaphysics. It is concerned with the study of being and existence, and the basic categories of them. Aristotle described ontology as ``the science of being qua being'', the science of being respectively being. It determines the categories of ``beings'', and decides whether and in what sense the elements of those categories can be said to ``be''.

Some examples of ontological questions are: What is existence? What are physical objects? Is existence a property? When does an object go out of existence, as opposed to merely changing?

Some of the basic problems of ontology is the problem of substance and the problem of universals.