“For if Fortune ordains that a powerful and enlightened people should form a republic—which by its very nature is inclined to perpetual peace—this would serve as a centre of federal union for other states wishing to join, and thus secure conditions of freedom among the states in accordance with the idea of the law of nations. Gradually, through different unions of this kind, the federation would extend further and further.” Readers who are acquainted with the general philosophy of Kant will find many traces of its influence in the essay on _Perpetual Peace_. Those who have no knowledge of his philosophy may find some of his forms of statement rather difficult to understand, and it may therefore not be out of place for me to indicate very briefly the meaning of some terms which he frequently uses, especially in the Supplements and Appendices. Thus at the beginning of the First Supplement, Kant draws a distinction between the mechanical and the teleological view of things, between “nature” and “Providence”, which depends upon his main philosophical position. According to Kant, pure reason has two aspects, theoretical and practical. As concerning knowledge, strictly so called, the _a priori_ principles of reason (_e.g._ substance and attribute, cause and effect etc.) are valid only within the realm of possible sense-experience. Such ideas, for instance, cannot be extended to God, since He is not a possible object of sense-experience. They are limited to the world of phenomena. This world of phenomena (“nature” or the world of sense-experience) is a purely mechanical system. But in order to understand fully the phenomenal world, the pure theoretical reason must postulate certain ideas (the ideas of the soul, the world and God), the objects of which transcend sense-experience. These ideas are not theoretically valid, but their validity is practically established by the pure practical reason, which does not yield speculative truth, but prescribes its principles “dogmatically” in the form of imperatives to the will. The will is itself practical reason, and thus it imposes its imperatives upon itself. The fundamental imperative of the practical reason is stated by Kant in Appendix I. (p. 175):—“Act so that thou canst will that thy maxim should be a universal law, be the end of thy action what it will.” If the end of perpetual peace is a duty, it must be necessarily deduced from this general law. And Kant does regard it as a duty. “We must desire perpetual peace not only as a material good, but also as a state of things resulting from our recognition of the precepts of duty” (_loc. cit._). This is further expressed in the maxim (p. 177):—“Seek ye first the kingdom of pure practical reason and its righteousness, and the object of your endeavour, the blessing of perpetual peace, will be added unto you.” The distinction between the moral politician and the political moralist, which is developed in Appendix I., is an application of the general distinction