Pancallism is the belief that everything is beautiful, or at least everything that exists, which is quite a lot of things.
The idea, occurred to some medieval scholastic philosophers. Their reasoning went roughly like this.
God exists.
Existence is one of the features of God.
All the features of God are beautiful.
Hence existence is a kind of beauty.
I exist.
Therefore, I must be beautiful.
This is the sort of positive thinking that makes Medieval philosophy such fun; I expect it’s also an extremely effective argument to put on your internet dating profile.
I came across the word pancallistic (the adjective) while reading Art and Beauty in the Middle Ages by Umberto Eco. The book’s a little dry, but it’s beautifully short.
The etymology, by the way is Greek. Pan means everything, as in a pandemic which is a disease that has spread to all the people. The demic there is the same as democracy, which is government by the people.
The callism bit comes from kalos, which meant beautiful and is the same root that you get when looking a pretty things in a kaleidoscope, or admiring somebody who is callipygian.
Since you ask, callipygian means possessing a beautiful bottom, and is also a very useful word to use on first dates, I expect.