" Just as a concept becomes a unit when integrated with others into a wider concept, so a genus becomes a single unit, a species, when integrated with others into a wider genus. For instance, “table” is a species of the genus “furniture,” which is a species of the genus “household goods,” which is a species of the genus “man-made objects.” “Man” is a species of the genus “animal,” which is a species of the genus “organism,” which is a species of the genus “entity. "

― Ayn Rand , The Ayn Rand Lexicon: Objectivism from A to Z