Abstract

The term “genus” has evolved over time. This paper traces development of the word from the common usage of Ancient Greece, through the pre-Socratic philosophers and Plato, and up to the more technical use in Aristotle. It began in common use to mean a class or race of people, most specifically referring to people with a common parentage. The pre-Socratics applied the term to refer to things that were generated. Plato used the term to refer to groups of people generated by a common interest or aim. Aristotle employed it in different ways based on his predecessors. This paper makes comparisons between these usages and the philosophy of Thomas Aquinas. It argues that understanding the development of “genus” facilitates understanding how Thomas Aquinas used it.