 We admit as legitimate mathematics certain reflections on the grammar of a language that concerns the empirical. If one seeks to formalize such a mathematics, then with each formalization there are problems, which one can understand and express in ordinary language, but cannot express in the given formalized language. It follows (Brouwer) that mathematics is inexhaustible: one must always again draw afresh from the “fountain of intuition”. There is, therefore, no characteristica universalis for the whole mathematics, and no decision procedure for the whole mathematics. In each and every closed language there are only countably many expressions. The continuum appears only in “the whole of mathematics” … If we have only one language, and can only make “elucidations” about it, then these elucidations are inexhaustible, they always require some new intuition again. (As quoted, in translation, in Wang 1987: 50)