What is the fifth foundation?

The Fifth Foundation is a concept in the "Foundation" series by Isaac Asimov. It refers to a hypothetical future development of a new foundation that could arise after the decline of the previous four. This new foundation would be based on the principles of psychohistory and would aim to guide humanity through a new era of stability and prosperity. The idea emphasizes the cyclical nature of civilizations and the importance of adapting to changing circumstances.