What would happen if the entire world practised one common religion of humanity as a way of life ?
If the entire world practised one common religion of humanity as a way of life, still there would not be peace and harmony. Every religion are divided into different sects and one sect tries to impose its views, ideas and values on the other and proves itself as superior. Even , within one religion disagreement would appear. It is not basically the religion but the people who follow the religion creates disunity and disharmony.