2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/17419A set of general physical principles is proposed as the structural basis for the theory of complex systems. First the concept of harmony is analyzed and its different aspects are uncovered. Then the concept of reflection is defined and illustrated by suggestive examples. Later we propose the principle of (random) projection of symmetrically expanded prereality as the main description method of complex systems.4 pages, minor corrections in modality principleDisordered Systems and Neural NetworksStatistical Mechanicstext