Plural of haecceity; the unique, individual essence or 'thisness' of a thing that makes it specifically itself, a philosophical concept.
From Medieval Latin haecceitas, coined by philosopher John Duns Scotus from haec ('this') to express the idea that each individual thing has its own special essence beyond its general properties.
Haecceities is what makes you specifically YOU rather than just 'a human'—it's the philosophical name for your irreplaceable uniqueness, and medieval monks invented the term to solve theological puzzles.
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