A counterfactual is a concept used to explore "what if" scenarios by considering alternative outcomes that could have occurred if certain events had happened differently. For example, one might ask, "What if Albert Einstein had never developed the theory of relativity?" This approach helps in understanding causality and the significance of specific events in history. In various fields like philosophy, history, and economics, counterfactuals are used to analyze decisions and their consequences. By imagining different scenarios, researchers can assess the impact of actions and better understand the complexities of human behavior and societal changes.