Renouvier admits that this is _a priori_ reasoning, and speedily _a posteriori_ arguments can be brought up as mighty battering-rams against the fortress of immortal life, but although they mav shake its walls, they are unable to destroy the citadel. Nothing can demonstrate the impossibility of future existence, whereas the whole weight of the moral law and the teleological elements at work in the universe are, according to Renouvier, in favour of such a belief. Morality, like every other science, is entitled to, nay obliged to, employ the hypothesis of harmony. Now in this connection the hypothesis of harmony (or, as Kant styled it, the concurrence of happiness and virtue necessary to a conception of order) finds reinforcement from the consideration of the meaning and significance of freedom. For the actual end or purpose of freedom is not simply the attainment of perfection, but rather the possibility of progress. Immortality becomes a necessary postulate, reinforced by instinct, reason, morality, by the fact of freedom, and the notion of progress. Further, Renouvier feels that if we posit death as the end of all we thereby give an absolute victory to physical evil in the universe. The postulate of Immortality has a certain dignity and worth. The discussion of future life must, however, be kept within the possibilities of law and phenomena. Religious views, such as those of Priestley, by their appeal to the miraculous debase the notion of Immortality itself. Talk of an immortal essence, and a mortal essence is meaningless, for unless the same identical person, with his unique character and memory, persists, then our conception of immortality is of little or no value. The idea of an indestructible spiritual substance is not any better or more acceptable. Our notion of a future life must be based upon the inherent and inalienable rights of the moral person to persistence and to chances of further development or progress. Although we must beware of losing ourselves in vain speculations, which really empty our thought of all its content, Renouvier claims that we are quite entitled to lay down hypotheses.