The intrinsic diffusion concept is an illusion in the diffusion history. By eradicating the illusion, the diffusion problems of N elements system are reasonably solved. An excellent analytical method of diffusion problems is established in the parabolic space. The equation and the diffusion equation yield a universal diffusivity expression applicable to every material in proportion to the Planck constant. Since the results obtained here is thus extremely fundamental and indispensable for the diffusion theory, hereafter they will give a turning point in the diffusion study.