Comment by cmrdporcupine

Relational algebraic model (which SQL is a debased form of) is literally based on propositional logic. Or at least that's the claim. Propositional & predicate logic is evidently part of human language, grammar, and present in human thinking systems. Though it would be -- as you are intimating -- insane hubris to make one singular claim about how the brain represents knowledge.

Commenter is self-promoting their "graph DB" related product.