The final, most evolved stage is the positivist stage, the stage when humans give up on discovering absolute truth, and turn towards discovering, through reasoning and observation, actual laws of phenomena. Humans realize that laws exist, and that the world can be rationally explained through science, rational thought, laws, and observation. Comte was a positivist, believing in the natural rather than the supernatural, and so he claimed that his time period, the 1800s, was in the positivist stage. He believed that within this stage, there is a hierarchy of sciences: mathematics, astronomy, terrestrial physics, chemistry, and physiology. Mathematics, the “science that relates to the measurement of magnitudes”, is the most perfect science of all, and is applied to the most important laws of the universe. Astronomy is the most simple science, and is the first “to be subjected to positive theories". Physics is less satisfactory than astronomy, because it is more complex, having less pure and systemized theories. Physics, as well as chemistry, are the “general laws of the inorganic world”, and are harder to distinguish. Physiology completes the system of natural sciences, and is the most important of all sciences because it is the “only solid basis of the social reorganization that must terminate the crisis in which the most civilized nations have found themselves”. This stage will fix the problems in current nations, allowing progression and peace.