DEFINE Index

At this point Ayn Rand adopts the Greek philosopher Aristotle's formal invention of the definition. This gives the concept identity.

• Determine the genus. The larger concept in which this is a sub-concept.
• State the differentia. Essential characteristics that identify these examples within the genus.

Ayn Rand warns that a definition is NOT a concept. A concept stands for the totality of the actual existents in reality. A definition connects the existent to your other knowledge.