Core Points - The article discusses the concept of dimensional reduction in physics, illustrating how theories evolve from higher dimensions to lower dimensions, ultimately affecting human understanding of the universe [1][2][3] Group 1: Dimensional Reduction Theories - The first layer is M-theory, which operates in 11 dimensions and reduces to string theory through various projections [4] - The second layer is string theory, which exists in 10 dimensions and includes 3D space, 1D time, and 6D Calabi-Yau manifolds, influencing the types of fundamental particles and physical constants in the universe [5][6] - The third layer is General Relativity, which reduces from string theory in low-energy limits and connects to the concept of gravitons [9] Group 2: Further Reductions - General Relativity can further reduce to Special Relativity under conditions of flat spacetime and no gravity [10] - Special Relativity reduces to Newtonian mechanics when objects are moving at speeds much lower than the speed of light [11] - Newtonian mechanics is described in a 3+1 dimensional framework, emphasizing the complexity of truly understanding it [12] Group 3: Quantum Field Theory - Quantum Field Theory, considered a fourth layer, is composed of Quantum Yang-Mills theory, Higgs mechanism, and fermionic field theory [14] - Under certain conditions, Quantum Field Theory can reduce to Quantum Electrodynamics [15] - Quantum Electrodynamics can further reduce to Maxwell's equations in low-energy and non-relativistic limits [16][17] Group 4: Historical Context and Challenges - The article highlights the historical significance of Yang-Mills theory and its revival after being initially dismissed, showcasing the complexity of applying classical theories to quantum contexts [18][19] - It also discusses the contributions of mathematicians like Hilbert and their impact on the development of theories in physics, contrasting them with physicists like Einstein [20][21]