Luhmann wrote:

On what basis does it make this connection? I personally would worry
that such a system would make a lot of useless connections. I would
prefer to have some degree of manual control over it.

Based on the record name/filename. That is, if I have a file called Plato, every occurrence of the word "Plato" elsewhere is a link to this file.

I personally would worry
that such a system would make a lot of useless connections. I would
prefer to have some degree of manual control over it.

It can actually be quite useful. Here is a use case to illustrate: https://discourse.devontechnologies.com/t/how-i-use-wiki-links-and-aliases/47846