An action is what a concrete object or abstract entity does or undergoes.
Actions are one of the main ways we notice change. A rock falls. A person speaks. A promise binds. An argument supports a conclusion. In each case, something is happening. The entity is not merely described by its attributes; it is doing something, undergoing something, or participating in a process.
Actions apply to both concrete objects and abstract entities. A concrete object can act or be acted upon in the material world. A ball rolls, a body heals, and a river erodes stone. These actions map to empirical ideas. An abstract entity can also have actions within a rational framework. A rule restricts behavior. An equation balances two sides. A contradiction undermines an argument. These actions map to rational ideas.
Actions are also a type of universal when they repeat across entities. Falling, growing, proving, and organizing are not limited to one moment. They are repeatable patterns. A single apple falls once, but falling is a pattern that can appear across many concrete objects. A single argument supports one conclusion, but supporting is a pattern that can appear across many abstract entities. This is how actions help us recognize what things do across time, frameworks, and situations.
Action also helps clarify state. A state is a current configuration; an action is movement, process, or change. A door may be closed, which is a state. The door closing is an action. A belief may be uncertain, which is a state. A belief changing is an action. This distinction matters because the world is not static. Concrete objects and abstract entities both participate in patterns of change, and those patterns shape how we understand them.
