Beauty

There is one thing you gotta remember. When we see others, we see the way we see our faces in plain mirror, but not in concave mirror.

The former experience is seen as, as you say it, constant. More real than others.

This 'we' is some set of people, because all people in this group borrow some knowledge, info, beliefs from the same stock i.e biological. In the sense that our way of seeing the way in plain mirror is evolutionary.

Beauty is a relational property, as any experience is!