On the one hand, suddenly very near to all these empiricaldomains, questions arise which before had seemed very distant from them: these questions concern a general formalization of thought and knowledge; and at a time when they were still thought to be dedicated solely to the relation between logic and mathematics, they suddenly open up the possibility, and the task, of purifying the old empirical reason by constituting formal languages, and of applying a second critique of pure reason on the basis of new forms of the mathematical a priori.