Definitions HQ

Existence (n.) has ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠its purpose fulfilled by the man who is happy, as Dostoevsky said.

Existence (n.) is ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠for physics to say, not logic, and whether there are infinitely many things experience cannot decide.

Existence (n.) has, ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠in mathematics, no concept independent of the concept of an existence proof.

Existence (n.) of ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠books and armchairs is not a lesson children receive — they learn to fetch books and sit in armchairs, and a question about unicorns is possible only because as a rule no such question arises.

Existence (n.) in ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠mathematics is simply defined when a proof is required to contain a construction; it is not like proving a man is in the room by looking.