November Axioms and Non-Euclidean Geometry Posted to LDL on 20. No, they need to be perceptually self-evident, too.
Existence exists is perceptually self-evident.
Just look at all of the things around you. What I said about arbitrariness and the stolen concept applies to this as well. To say that something could have been otherwise is to speak of it as a product of someone's choice. But POC just doesn't work. There has to be existence first for anyone to be conscious of it.