(urth) Why so much synchronicity?

[junk06 at amalar.com]

I'm rereading (started with BOTNS this time, then back to Shadow).

I've read many theories on Severian's genealogy. Assuming all (or even 
most) of those theories are true, why does Severian end up meeting 
practically every single relative he has? He almost can't walk down a 
street without running into one.

It's not just relatives. Even as the narrator keeps mentioning how 
incomprehensibly populated Nessus is, he keeps running into people he 
knows. He even runs into people he knows out in the wilderness sometimes. 
Synchronicity abounds.

Meets man in library, meets same man years later racing down a street.
Meets man digging a grave, meets same man years later in a boat.
Has childhood friend, meets him again years later in the middle of a vast 
ocean.
Meets man in library, meets him years later in another library across the 
country.
etc etc etc for probably a dozen more examples

Why? It smells of ham handedness, as someone mentioned recently. Anyone 
have theories as to why so many coincidences fill the series?