src: Isto é, as perguntas que formulamos e as nossas dúvidas dependem do fato de certas proposições estarem isentas de dúvida serem como que dobradiças em volta das quais as dúvidas giram.
tgt: the questions that we raise and our doubts depend on the fact that some propositions are exempt from doubt, are as it were like hinges on which those turn.