You might say that esotericism is the philosophy, or the science, of the evolutionary process, as it pertains to the human and the subhuman kingdoms. But it is about the evolution of consciousness, not of the physical form. If you want to know about the evolution of the physical form, turn to Darwin - he has pretty well summed up the nature of evolution as regards the form of the animal and the human kingdoms. But in terms of the evolution of consciousness, you have to turn to the esoteric - esoteric only so far; for that which is esoteric gradually becomes exoteric.