Lewis' Modal Realism

Lewis' Modal Realism is the philosophical idea that possible worlds are as real as our actual world. According to this view, every way a situation could possibly be is represented by a distinct world—so, for instance, in some worlds, you made different life choices, or dinosaurs never went extinct. These worlds exist independently of our own, and they help us understand possibilities and counterfactual statements (what could have happened). So, when we talk about possibility, we're referring to the existence of these many real worlds, not just imaginary or hypothetical ideas.