2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89759The conventionalistic aspects of physical world perception are reviewed with an emphasis on the constancy of the speed of light in relativity theory and the irreversibility of measurements in quantum mechanics. An appendix contains a complete proof of Alexandrov's theorem using mainly methods of affine geometry.27 pagesQuantum Physicstext