These means are of two kinds. In the first place, what evils must we set about removing? What are the negative conditions? And, secondly, what are the general positive conditions which will make the realisation of this idea possible and guarantee the permanence of an international peace once attained? These negative and positive conditions Kant calls Preliminary and Definitive Articles respectively, the whole essay being carefully thrown into the form of a treaty. The Preliminary Articles of a treaty for perpetual peace are based on the principle that anything that hinders or threatens the peaceful co-existence of nations must be abolished. These conditions have been classified by Kuno Fischer. Kant, he points out,[62] examines the principles of right governing the different sets of circumstances in which nations find themselves—namely, (_a_) while they are actually at war; (_b_) when the time comes to conclude a treaty of peace; (_c_) when they are living in a state of peace. The six Preliminary Articles fall naturally into these groups. War must not be conducted in such a manner as to increase national hatred and embitter a future peace. (Art. 6.)[63] The treaty which brings hostilities to an end must be concluded in an honest desire for peace. (Art. 1.)[64] Again a nation, when in a state of peace, must do nothing to threaten the political independence of another nation or endanger its existence, thereby giving the strongest of all motives for a fresh war. A nation may commit this injury in two ways: (1) indirectly, by causing danger to others through the growth of its standing army (Art. 3)[65]—always a menace to the state of peace—or by any unusual war preparations: and (2) through too great a supremacy of another kind, by amassing money, the most powerful of all weapons in warfare. The National Debt (Art. 4)[66] is another standing danger to the peaceful co-existence of nations. But, besides, we have the danger of actual attack. There is no right of intervention between nations. (Art. 5.)[67] Nor can states be inherited or conquered (Art. 2),[68] or in any way treated in a manner subversive of their independence and sovereignty as individuals. For a similar reason, armed troops cannot be hired and sold as things. [62] _Geschichte der neueren Philosophie_, (4th ed., 1899), Vol. V., I. Ch. 12, p. 168 _seq._ [63] See p. 114. [64] See p. 107. [65] See p. 110. [66] See p. 111. [67] See p. 112. [68] See p. 108. These then are the negative conditions of peace.[69] There are, besides, three positive conditions: