The Categories is a text from Aristotle's Organon that enumerates all the possible kinds of things that can be the subject or the predicate of a proposition. They are "perhaps the single most heavily discussed of all Aristotelian notions". The work is brief enough to be divided, not into books as is usual with Aristotle's works, but into fifteen chapters. The Categories places every object of human apprehension under one of ten categories (known to medieval writers as the Latin term praedicamenta). Aristotle intended them to enumerate everything that can be expressed without composition or structure, thus anything that can be either the subject or the predicate of a proposition.
Aristotle, 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Lyceum, the Peripatetic school of philosophy, and the Aristotelian tradition. His writings cover many subjects including physics, biology, zoology, metaphysics, logic, ethics, aesthetics, poetry, theatre, music, rhetoric, psychology, linguistics, economics, politics, and government. Aristotle provided a complex synthesis of the various philosophies existing prior to him. It was above all from his teachings that the West inherited its intellectual lexicon, as well as problems and methods of inquiry. As a result, his philosophy has exerted a unique influence on almost every form of knowledge in the West and it continues to be a subject of contemporary philosophical discussion.