This chapter shows that conditioned existence is given in three different ways-as internal phenomenon, as external phenomenon, and as possible existence, or all objects of thought in general. After showing the Reason applied to the different forms of conditioned existence in external phenomena must give rise to Ideas of the unconditioned or the Idea of the Totality of the Universe in space and time. The four Cosmological Ideas, corresponding to the four classes of the categories, thus relate to: absolute completeness of composition or quantity; absolute completeness of division; absolute completeness of origination; and absolute completeness of dependence of existence. In all the doctrines of Rational Cosmology it is possible to prove from pure reason that their affirmation is as true as their negation. The antinomies have crossed philosophers throughout the ages, and in his criticism of Rational Cosmology Immanuel Kant has some things to do in order to clear up the problem.