eng Science and Education Publishing International Journal of Physics 2333-4576 2024-06-20 12 4 106 125 10.12691/ijp-12-4-1 IJP20241241 article Emmanuil Manousos emanoussos@phys.uoa.gr 1 APM Institute for the Advancement of Physics and Mathematics, Athens, Greece We present the principles and main consequences of Self-Variation Theory. The Theory is based on three principles, the principle of self-variation, principle of conservation of energy-momentum and a definition of the rest mass of a fundamental particle. The main conclusions of the Theory are the following; it predicts a structure of the particles, predicts and justifies the particle interactions, predicts and justifies the cosmological data and it shows that quantum phenomena are implicit in the Self-Variation Theory. The Self-Variation Theory provides a mathematically consistent paradigm for nature. The origin, evolution and current form of the universe are consistent with the theoretical prediction. At all distance scales, from the microcosm to observations billions of light years away, the Theory is remarkably consistent with experimental and observational data. https://pubs.sciepub.com/ijp/12/4/1/ijp-12-4-1.pdf electromagnetism gravity particle interactions origin of universe evolution of universe structure of matter quantum phenomena