There have been some recent notable attempts in the literature to clarify Kant’s project of perpetual peace and the related idea of a guarantee for perpetual peace. In this paper, I pursue critically the same project with a view to a further clarification and defence of Kant’s guarantee. I rely on an assumption argued for elsewhere, according to which an interpretation of perpetual peace as a highest (complete) good leads to a misleading view of the guarantee by analogy with the postulates of pure practical reason. By contrast, I claim that perpetual peace is a juridical condition, which can legitimately be realised without a need for ethical motivation. Consequently, I claim that the function the guarantee is supposed to perform is that of enforcing the rules of peace treaties and of giving in this way reassurance about the continuation of peace. I demonstrate further that the argument in support of the guarantee cannot be a moral one, cannot invoke the possibility of an ethical duty, and cannot go beyond the limits of reason. By an examination of Kant’s discussion, in the Canon of Pure Reason, of the distinction between opinion, belief and knowledge, I conclude that the guarantee can be defended as the object of doctrinal belief, a form of assent that can generate conviction about the enforcement of peace treaties by the “great artist nature”. In its turn, this is a genuine guarantee that head of states will play by the rules of peace; still, I claim, this is not so much a game directly enforced, but an indirectly influenced performance.
