3. (It might however be objected) that the body of the world could not contribute to the immortality of the world, since the body itself fluctuates perpetually. But this fluctuation does not take place in an outward direction, while the body (of the world) remains ever the same because this fluctuation occurs so entirely within the world that nothing issues therefrom. The world therefore could neither increase nor diminish, nor further grow old. (As proof of this we may) consider how, from all eternity, the earth constantly preserves the same shape and mass; similarly, the air never diminishes, any more than the water. The changes within them do not affect the universal living Organism. Even we human beings subsist a long while, in spite of the perpetual change of our constituent parts, and though some of these parts even issue from the body. So much the more will the world's nature, from which nothing issues, sufficiently harmonize with the nature of the universal Soul to form along with her an organism which ever remains the same, and subsists for ever. FIRE, THOUGH AN APPARENT EXCEPTION, STILL CONFORMS TO THIS PROCEDURE. For example, fire (as the principal element of the heaven), is both lively and swift, and cannot remain in the inferior regions, any more than the earth can abide in the superior regions. When it has reached these regions where it is to remain, it becomes established in the most suitable place. But even so, like all other bodies, it still seeks to extend in all directions. However, it cannot ascend, since there is no place higher than the one it occupies; nor can it descend, because of the opposition of its own nature. The only thing left for it to do is to yield to the guidance and natural impulsion of the life-imparting universal Soul, that is, to move into the most beautiful place, in the universal Soul. Its falling from here is prevented by the universal Soul's circular movement which dominates and supports it, as well as by its innate indisposition to descend, so that its continuance in the higher regions is unopposed. (The fire has no similarity with) the constitutive parts of our body which are forced to derive their suitable form from elsewhere. If unaided, they are not even capable of preserving their organization. Merely to subsist, they are forced to borrow parts from other objects. The case is entirely different with the fire of the heaven, which needs no food because it loses nothing. If indeed it allowed anything to escape, we might indeed be forced to state that when in the heaven a fire is extinguished, a substitute must be lit. But in such a case the universal living Organism would no more remain identical. THE IMMORTALITY OF THE HEAVEN IS DUE TO RESIDENCE THERE OF THE UNIVERSAL SOUL.