“I think” is therefore the only text of rational psychology, from which it must develop its whole system. It is manifest that this thought, when applied to an object (myself), can contain nothing but transcendental predicates thereof; because the least empirical predicate would destroy the purity of the science and its independence of all experience. But we shall have to follow here the guidance of the categories—only, as in the present case a thing, “I,” as thinking being, is at first given, we shall—not indeed change the order of the categories as it stands in the table—but begin at the category of substance, by which at the a thing in itself is represented and proceeds backwards through the series. The topic of the rational doctrine of the soul, from which everything else it may contain must be deduced, is accordingly as follows: 1 2 The Soul is SUBSTANCE As regards its quality it is SIMPLE 3 As regards the different times in which it exists, it is numerically identical, that is UNITY, not Plurality. 4 It is in relation to possible objects in space[43] [43] The reader, who may not so easily perceive the psychological sense of these expressions, taken here in their transcendental abstraction, and cannot guess why the latter attribute of the soul belongs to the category of existence, will find the expressions sufficiently explained and justified in the sequel. I have, moreover, to apologize for the Latin terms which have been employed, instead of their German synonyms, contrary to the rules of correct writing. But I judged it better to sacrifice elegance to perspicuity. From these elements originate all the conceptions of pure psychology, by combination alone, without the aid of any other principle. This substance, merely as an object of the internal sense, gives the conception of Immateriality; as simple substance, that of Incorruptibility; its identity, as intellectual substance, gives the conception of Personality; all these three together, Spirituality. Its relation to objects in space gives us the conception of connection (commercium) with bodies. Thus it represents thinking substance as the principle of life in matter, that is, as a soul (anima), and as the ground of Animality; and this, limited and determined by the conception of spirituality, gives us that of Immortality.