What conception of causation is at work in the law? I argue that the law implicitly relies on a contrastive conception. In a liability case where the defendant’s breach of duty must be shown to have caused the plaintiff’s damages, it is not enough to consider what would have happened if the cause had not occurred—the law instructs us to look to a specific replacement for the cause, which in this case is the hypothetical scenario in which the defendant acted lawfully. And it is not enough to ask if the effect would still have occurred—the law requires us to look to a specific replacement for the effect, which in this case is the hypothetical outcome in which the plaintiff came off better. In place of “but for the defendant’s breach, the plai...