Concept, related to various theories and interpretations of human behavior. Basically this is the idea that anything you gain is Bad for me. Any gain for others is a loss for me and mine. No good can occur for others without diminishing my existence. For some theorists, This is where envy comes from.
In this world I cannot tolerate or appreciate the success of others, because its not mine, and is thereforeinherently bad.
Simple math idea: If someone gains something off the board I must have lost something. The only way there can be equilibrium is to postulate that gains are always offset by losses.
This "logical view of the world" was created long ago and far away. Similar theories at the time: The world is flat and the earth is the center of the universe.
PS This is a great recipe to make yourself miserable.