Haecceity

Haecceity, a term from philosophy, refers to the unique "thisness" that distinguishes an individual object from all others. It is the specific quality that makes a particular thing one-of-a-kind, beyond its general features or qualities. For example, while many chairs share common characteristics, the haecceity of a specific chair is what makes it the particular chair you recognize and cannot be replaced by any other. Haecceity helps explain how individual entities maintain their distinct identity over time, emphasizing the importance of uniqueness in understanding existence.