itself towards republicanism. Both Saint-Pierre and Rousseau favoured an international federation with coercive authority; Kant’s approach is different (see chapter 8). Saint-Pierre and Rousseau used the past to justify their projects. They referred to Henri IV, Sully and the Holy Roman Empire. Kant, on the other hand, is the philosopher of pure reason. Reason, not history tells us what we should do: ‘reason, as the highest legislative moral power, absolutely condemns war as a test of rights and sets up peace as an immediate duty’ (VIII, 356, 2–4). All three thinkers defend idealism in ethics and rights: the primacy of normative ideals over facts and figures. In addition, Kant sees his peace concept as part of a system of rights. He provides basic juridical principles, leaves out utilitarian considerations and tries to present a coherent system. Kant goes beyond international legal theories of Vattel’s type. It has been claimed that Vattel lacks a legal philosophy.33 Kant offers a complex and convincing one. Vattel stays too close to eighteenth-century political realities. Kant develops ideas to transform existing conditions.
An outline of Kant’s doctrine of international right
Kant’s doctrine of international right is part of his doctrine of rights, which is in turn part of the metaphysics of morals; the most comprehensive account of this doctrine of international right is found in The Metaphysics of Morals. Kant’s principle of justice forms its basis, and it is a special version of the categorical imperative.34 ‘Right is … the sum total of those conditions within which the will of one person can be reconciled with the will of another in accordance with a universal law of freedom’ (VI, 230, 24–6). One’s use of external freedom may violate the freedom of others. In this case, the use of coercion is justified to remove this ‘hindrance to freedom’. Therefore ‘right entails the authority to apply coercion’ (VI, 231, 30–4). From this, Pogge’s consistency principle follows: ‘rational persons ought to coexist under a system of constraints ensuring mutually consistent domains of external freedom’.35 A full juridical condition guarantees this. The universality principle is subordinate to the first one. It claims that the system of constraints ‘ought to limit everyone’s external freedom equally – the constraints should be general and universal’.
The universal principle of justice or rights is specified in the six preliminary and three definitive articles. Kant’s ‘philosophical sketch’ (VIII, 341) has the function ‘to constitute the rules and the basis of legitimation for internal and external State activity’.36
The preliminary articles specify what states should not do if they want to set up the conditions for a true peace treaty among them. These articles do not exclude war; it may still be necessary for a state to defend its independence or territory by military means.37 The preliminary treaty excludes actions that would make a peace treaty impossible and which contradict the idea of a peaceful society of nations. The preliminary articles offer six requirements.38
1. A conditional peace treaty and ‘secret reservations’ are forbidden (VIII, 343, 20–1). All parties agree mutually and unconditionally to recognize the status quo.
2. States identify each other as ‘moral personalities’ (VIII, 344, 22) with full external and internal sovereignty.
3. States are willing to reduce the readiness for war, stop the arms race and gradually abolish ‘standing armies’ (VIII, 345, 1).
4. National debt ‘in connection with the external affairs of the state’ (VIII, 345, 20–1) should be avoided. This provision is supposed to reduce the readiness for war.
5. If states are sovereign moral personalities (see article no. 2), then military intervention must be forbidden.
6. As wars can still be fought, they should be conducted in such a way that any future peace treaty is not made impossible.
Systematically speaking, each state has three perfect duties towards oneself and others, according to the Ulpian formula honeste vivere, neminem laedere and suum cuique (VI, 236–7).39 In international relations, the first axiom means that a state must not be commanded or disposed of by others (VIII, 344, 19), is not allowed to use itself as a mere means or dissolve itself as a moral personality, and should refrain from hostilities during war that would make mutual trust impossible (VIII, 346, 23–5). If there is a duty to sustain oneself as a moral personality, then this implies the duty not to destroy oneself as a physical entity, since the moral, noumenal entity is in need of, and actualized by, a physical one (VI, 422, 31–423, 6). Both the second and the third principle refer to others; Kant admits that there is no difference between the two in terms of content (XXVII, 1, 144, 14–15). They can be distinguished if we assume that the second refers to the state of nature, whereas the third postulates to leave it. Neminem laedere asks moral persons not to injure others, or violate their natural rights (VI, 236, 31–2). In terms of international right, it prohibits war and intervention for reasons of principle.40 The third principle asks individuals or states to leave the state of nature and enter a civil condition (Rechtszustand; VI, 237, 1–8; XXVII, 2, 1, 528, 12–15). In the state of nature, provisional property rights do exist, and this state must be left to secure them, and turn them into peremptory rights (VI, 256).41 The state of nature is, above all, characterized by a certain mode of resolving disputes, namely by private force. One’s own perceived rights and personal judgement is defended with one’s own sword.42 This mode is changed in a juridical condition: modus ius suum persequendi in republica est per actiones non per vim privatum (XIX, refl. 7693).
Kant distinguishes between an active injury (laesio), or violation of a right (VI, 249, 1–3) in a juridical condition and an injury per statum (XIX, refl. 7647). In the state of nature, individuals (or countries) injure each other by this very state in which they coexist, by its ‘very lawlessness’ (Gesetzlosigkeit; VIII, 349, 19), characterized by permanent threats to each other. Anyone is entitled to see neighbours as enemies. Consequently, the state of nature is a state of war, even if there might be a period of tranquillity. As space on earth is limited and often densely populated, humans cannot avoid getting into contact with and influencing each other.43 As a consequence, a state of public right should be instituted. The three definitive articles are based on the postulate that ‘all humans who can at all influence one another must adhere to some kind of civil constitution’ (VIII, 349, 23–4).
The definitive articles institute this juridical condition on three levels: domestic, international and cosmopolitan. These layers are termed civil right, international right (right of nations), and cosmopolitan right. Kant’s classification is indeed logically ‘necessary’ (VIII, 349, 34) and follows from his system of rights. Kant’s reasoning includes only one non-juridical, empirical element. He refers to the earth’s shape and human interaction. ‘Since the earth is a globe’, the third definitive article runs, people ‘cannot disperse over an infinite area’ (VIII, 358, 10–11). This minimalist assumption is plausible, not controversial and does not carry the weight of the argument.44
Some interpreters have spotted a tension between the preliminary and the definitive articles. A reading of the first ‘leads to a realist or statist interpretation that gives primacy to states and governments over individuals’, whereas the definitive articles, above all the third, emphasize the priority of human rights.45 Like similar tensions in Kant’s writings, we can solve this fundamental one by arguing that Kant’s sketch is evolutionary. The preliminary articles are norms for a semi-juridical condition, a condition after the state of nature has been left, but a juridical condition has not yet been fully achieved. Kant is a realist in the sense that he offers a step-by-step-model of how to go beyond the state of nature. He is an idealist because he is not satisfied with the first step(s).
Does Kant expect people to overcome wars and, if he does, what would the future state of affairs be like? Would there be complete harmony, no conflict of interest? Realists will argue that this cannot be achieved, and social Darwinists might add that this goal is not desirable. Humankind would rot to pieces. Kant distinguishes between antagonism and contest on the one hand and war on the other. Contest is the conflict of two or more parties who share a common final end or goal (Endzweck).