Modern theorists often use Immanuel Kant's work to defend the normative primacy of human rights and the necessity of institutionally autonomous forms of global governance. However, properly understood, his law of nations describes a loose and noncoercive confederation of republican states. In this way, Kant steers a course between earlier natural lawyers such as Grotius, who defended just-war theory, and visions of a global unitary or federal state. This substantively mundane claim should not obscure a more profound contribution to the science of international law. Kant demonstrates that his concept of law forms part of a logical framework by which to ascertain the necessary institutional characteristics of the international legal order. Specifically, his view is that the international legal order can only take a noncoercive confederated form as its subjects become republican states and that in these circumstances law can exist without a global state. Put another way, Kant argues that if we get state-building right, the law of nations follows.

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 plaintiff's damage would not have occurred,” I suggest the more explicit “if the defendant had acted lawfully, the plaintiff would have met a better fate.” An explicitly contrastive approach can thus potentially help the lawyer phrase her causal question in a more explicit way, while shedding light on our conception of causation.