Because, first, the Word is the natural organ between the Father and his exterior work, since, with the same utterance, the Father speaks himself and his external works. Secondly, this union is required in order that the external works may draw as near to their typical state as possible. Now, the Word is the living and personal typical state of the cosmos, the intelligible life of the external works; it is necessary, therefore, that _he_ should enter into the finite, and bring into harmony the interior infinite type of the cosmos, with its finite external expression; unite together the ideal intelligible state with the real subjective state of the cosmos. From all we have said, it follows that all the external works reside in the Word; that inasmuch as they reside in the Word in their typical state, they are his very life, and consequently infinite; that the Word is not only the typical but efficient cause of the cosmos; that the external act tends to express exteriorly the typical state of the cosmos as perfectly as it is uttered interiorly; that this supreme expression could not be substantial and ontological; and that, consequently, the only means of effecting it was an incorporation of the infinite into the finite, to be executed by the Word as the natural organ between God and his external works. Now, this is the answer which Catholicity affords to the problem, What is the union by which the finite attains its highest possible perfection? It answers in the sublime expressions of the Eagle among the Evangelists, and which resume, in a few words, all we have hitherto said. "In the beginning (the Father) was the Word. "And the Word was with God. "And the Word was God. The same was in the beginning with God. All things were made _by him_, and without him was made nothing. "That which was made in him was _life_. "And the Word was made _flesh_, and dwelt among us."[31] The Word of God, the subsisting ideality of the Father, the living type of his external works, united himself to human nature, the micro-cosmos, or abridgment of the cosmos, in such a close and intimate union as to be himself the subsistence of human nature, and thus exalted the cosmos to its highest possible perfection. This union of the Word with human nature is called hypostatic or personal union. We must now study its nature and properties, draw the consequences which flow from it, and point out how well it answers all the requisites and conditions of the problem. And in the first place, we remark that the subsistence of finite beings is also contingent and variable. We have before given an idea of subsistence and personality; but we beg leave to recall a few ideas about these most important notions of ideology, that the reader may better perceive in what the nature of the hypostatic union really consists. We shall explain the following notions: possibility, actuality, nature, substance, subsistence, and personality.