How does methodological individualism explain social events through individual actions?

In the philosophy of social science, methodological individualism is the principle that any explanation of social facts—such as group behaviors, social processes, or large-scale historical events—must ultimately be grounded in facts about individuals.1

According to this view, social phenomena are not treated as independent forces; rather, they are explained by appealing to the beliefs, desires, and actions of the people involved. Proponents of this approach, such as the philosopher Karl Popper, argue that explanations relying on social factors that cannot themselves be reduced to individualistic terms are insufficient.1

This perspective stands in contrast to accounts that treat institutions, states, or social structures as autonomous agents that constrain or enable behavior independently of the individuals who compose them. Methodological individualism essentially posits that social reality is a complex of individual actions, and therefore, a rigorous scientific explanation must trace these macro-level outcomes back to the micro-level motivations and decisions of individual actors.1