Knowledge about the lives we live and the world around us has always been essential for the development of human societies throughout history. It was important to know what was right and wrong, and what was true and false. For a long time, this knowledge was developed by people living together in groups and small communities, sharing their experiences with one another. It was also passed on by shamans who claimed contact with the gods of the spiritual world and received their guidance. As societies grew larger, more organized and more complex, the task of sharing knowledge was taken over by powerful religious or secular leaders. After many struggles, the secular upper class eventually prevailed, often through force of arms, and structured societies in ways that ensured they themselves held all the power and could rule over everyone else. This elite used its authority to decide what was right and wrong, and to define what was true and false.