You know, when I think of a library branch, I think of all knowledge
being divided into branches.

At the twigs would be the most recently attained facts.

At the small branches more basic facts,

At large branches even more basic facts,

Until you get to the trunk, which provides nourishment for all the rest.

Supposedly, each fact fits somewhere in the tree.

At the twigs are the assertions.

They are proven by more basic assertions.

Which are proven by still more basic assertions.

Until you get to the trunk, which supports all the assertions.

The trunk facts are self proving, and need no further premise.

So, some facts need no proving, or the trunk could not exist.

How could we ever encounter such a fact, in this world where
there are no absolutes?