Quiddity
Quiddity is the essential whatness of a thing — what makes it that thing and not another. It also carries an older, drier sense: a trifling point or quibble, left over from scholastic hair-splitting.
Full definition of Quiddity →:: COMPARE ::
QuiddityvsHaecceity
The short answer
Quiddity is what KIND of thing it is — the essence it shares with everything else of its type. Haecceity is that it is THIS one and no other — the thisness that no duplicate could copy. Two medieval terms for two genuinely different questions.
Side by side
| Aspect | Quiddity | Haecceity |
|---|---|---|
| Answers | What is it? | Which one is it? |
| Shared with others | Yes | No |
| Latin root | quid, 'what' | haec, 'this' |
| Survives a copy | Yes | No |
What each one means
Haecceity
The contrast above sets out how Haecceity differs from Quiddity on the points that actually matter.