PurposeThis paper seeks to present a hypothesis that is based not only on theoretical considerations, but also on experimental and clinical data. The hypothesis concerns the holographic principle as the main principle that ensures formation and functioning of any complex adaptive system (CAS).Design/methodology/approachThe submitted paper represents the continuation of an article published in 2005 in Kybernetes. It substantiates the crucial role of holo‐diffraction in system‐genesis and system‐functioning. New experimental results are discussed and some parallels are also drawn between natural systems of various scales.FindingsA new physical phenomenon of holo‐diffraction is considered as the general principle of CAS organization.Research limitations/implicationsBiological holograms, emitted by various minor parts of the human body in specified conditions, allow in vivo and harmless imaging of various internal disorders. New approach to the study of complex adaptive (living) systems would help researchers to reveal some general laws and regulations of natural systems formation.Practical implicationsA new approach to the study of living systems that is based on parametric and visual analysis of emitted holograms is already used for medical purposes. Recently developed analytical software is being tested.Originality/valueThe paper contributes to the understanding of those principles which enable any CAS to integrate, control and organize its components while functioning.