Over phrases like these the poor gentleman was losing his wits. He lay awake trying to understand them and pull out their meaning, which Aristotle himself could not have extracted or understood, had he risen from the dead for that purpose alone.

Two words for the mind meet here. The prose he reads is all razones, and what he loses is his juicio, his judgment: perder el juicio is the ordinary Spanish for going mad, and the novel’s whole plot hangs on this line. The verb desentrañar is vivid, too. Its root is entrañas, entrails, so he is trying to gut the sentences to find what is inside them. Aristotle was the master of logic in the Spanish universities of 1605, the authority every student of philosophy learned to argue with. Bringing him back from the dead for this one job makes the point by contrast: the greatest reasoner of the ancient world would find nothing in these sentences, because there is nothing there to find.