  Recall the rough idea of the similarity analysis sketched in §2.1: worlds can be ordered by their similarity to the actual world, and counterfactuals say that the most similar—or least different—worlds where the antecedent is true are worlds where the consequent is also true. This idea is commonly attributed to David Lewis and Robert Stalnaker, but the actual history is a bit more nuanced. Although publication dates do not tell the full story, the approach was developed roughly contemporaneously by Stalnaker (1968), Stalnaker and Thomason (1970), D. Lewis (1973b), Nute (1975b), and Sprigge (1970).[29] And, there is an even earlier statement of the view: