  Of the two lectures held in Vienna in 1928 — “Mathematics, Science and Language” (1929A) and “The Structure of the Continuum” (1930A) — the first is for the most part of a philosophical nature while the second is more mathematical. In “Mathematics, Science and Language”, Brouwer states his general views on the relations between the three subjects mentioned in the title, following a genetic approach, and stressing the role of the will. A longer version of this lecture was published as “Will, Knowledge and Speech” (1933A2); it contains the first explicit remarks about a notion that had been present from the start, now known as that of the “ideal(ised) mathematician” or “creating subject”.