system
Given the following post, respond as if you're commenting on Reddit:
human
Any literature/guidance on writing a purely theoretical master's thesis?

I'm currently a master student of sociology and decided with my mentor to write a purely theoretical thesis. However, I couldn't find any good guidance besides Umberto Eko's "How to Write a Thesis", everything I found was research-based  (theoretical framework, method, results, discussion).

Any help would be welcome, even your own advice.
gpt
Rather than books - which may be entirely unapplicable to your specific situation - ask your advisor for examples from their past students, and find relevant examples for yourself.  

Pretty much every university out there puts masters theses online, usually through the university library.  Go find some examples of the kind of thesis you're doing, in similar fields, for the same type of degree, and from whatever country you're in (since the standards/expectation for masters thesis vary a *lot* by country and type of degree).  Skim through several.  Look at how they're structured, how the work is introduced, how much depth there is, how the different sections are related to one another, etc etc, and go from there.