Logical, Generative
Borges' narrator proceeds according to a very logical agenda. His description of the universe is accompanied by the introduction of a few basic rules, or "axioms," describing how things work. After that, his narrative unfolds kind of like a logic puzzle, imitating the ordered structure of the Library. His thought experiments and research allow him to develop logical "corollaries" and to thereby arrive at conclusions about, you know, life and stuff.
The narrator's logical style means he's pretty good about keeping his treatise on life, the universe, and everything relatively concise. But his narrative does raise a ton of questions and ideas, and his references to other texts send us running to the Internet to figure out what he's talking about. (See our discussion of "intertextuality" in the section "What's Up With the Title?") In other words, his thoughts generate lots and lots of other thoughts. That's why we're calling his style "generative," but we suppose you could also call it "stimulating" or "inspiring."