2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220297The physical motivation for the mathematical formalism of quantum mechanics is made clear and compelling by starting from an obvious fact - essentially, the stability of matter - and inquiring into its preconditions: what does it take to make this fact possible?29 pages, 5 figures. v2: revised in response to referee commentsQuantum Physicstext