Final answer:
The definition 'A chair is a piece of furniture that you sit on' is broadly appropriate but can be refined to exclude non-designed objects and living beings, aligning with Plato's Theory of the Forms which emphasizes essence and purpose.
Step-by-step explanation:
Assessing whether 'A chair is a piece of furniture that you sit on' is a definition that is too broad, too narrow, or appropriate involves understanding the essence or purpose of a chair. From a philosophical standpoint, a better definition might be: 'A chair is an inanimate object expressly designed and manufactured for the purpose of having humans sit upon it.' This refined definition excludes living entities and other objects that are not specifically designed for seating, aligning with Plato's Theory of the Forms. Indeed, Plato argues that understanding the essence of things, such as a chair, is akin to understanding simple mathematical truths such as 2+3=5.