Sentence:  The practice of topos theory quickly spawned an associated philosophy—jocularly known as “<WSD>toposophy</WSD>”— whose chief tenet is the idea that, like a model of set theory, any topos may be taken as a taken as an autonomous universe of discourse or “world” in which mathematical  concepts can be interpreted and constructions performed. 
Meaning of the word marked with <WSD> tags:  The idea that any intellectual subject can be treated as an independent topos which can be described and understood in purely mathematical terms.