In creating spirits, God could endow them with self-conscious personality only by their restriction in an envelope, so to centralise their action and by restriction save it from being lost. When the soul separates from the body it changes environment of necessity, since it changes the envelope.[74] It goes forth clothed only in the astral form, or vehicle of light, ascending in virtue of its nature above the atmosphere, as air rises from the water in escaping from a broken vessel. We say that the soul ascends because the vehicle ascends and because action and consciousness are both attached thereto.[75] The atmospheric air becomes solid for luciform bodies which are infinitely rarer than itself, and they could only come down by assuming a grosser vehicle. Where would they obtain this in the region above our atmosphere? They could only return to earth by means of another incarnation, and such return would be a lapse, for they would be renouncing the state of free spirit and renewing their novitiate. The possibility of such a return is not admitted, moreover, by the catholic religion. The doctrine here set forth is formulated by the Kabalists in a single axiom: The spirit clothes itself to come down and unclothes itself to go up. The life of intelligence is ascensional. In the body of its mother, the child has a vegetative life and draws nourishment through a cord to which it is attached, as the tree is attached to the earth by its root and is also nourished thereby. When the child passes from vegetative to instinctive and animal life, the cord breaks and henceforth he has free motion. When the child becomes man, he escapes from the trammels of instinct and can act as a reasonable being. When the man dies, he is liberated from the law of gravitation, by which he has been previously bound to earth. When the soul has expiated its offences, it grows strong enough to emerge from the exterior darkness of the terrestrial atmosphere and mount towards the sun.[76] The unending ascent of the sacred ladder begins therein, for the eternity of the elect cannot be a state of idleness; they pass from virtue to virtue, from bliss to bliss, from victory to victory, from glory to glory. There is no break in the chain, and those of the superior degrees can still exercise an influence on those who are below, but it is in harmony with the hierarchic order and after the same way that a king who rules wisely does good to the humblest of his subjects. From stage to stage, the prayers arise and the graces pour down, never mistaking the path. But spirits who have once gone up cannot again come down, for in proportion to their ascent the zones solidify below them. The great gulf is fixed, says Abraham, in the parable of the rich man, so that they which would pass from hence to you cannot.[77]