This prop is not found in the natural character of man, who, being selfish and violent, directs his energies rather to the destruction than to the preservation of society. Nor is it found in his moral character, which has to be formed, which can never be worked upon or calculated on by the lawgiver, because it is free and never appears. It would seem therefore that another measure must be adopted. It would seem that the physical character of the arbitrary must be separated from moral freedom; that it is incumbent to make the former harmonise with the laws and the latter dependent on impressions; it would be expedient to remove the former still farther from matter and to bring the latter somewhat more near to it; in short to produce a third character related to both the others--the physical and the moral--paving the way to a transition from the sway of mere force to that of law, without preventing the proper development of the moral character, but serving rather as a pledge in the sensuous sphere of a morality in the unseen. LETTER IV. Thus much is certain. It is only when a third character, as previously suggested, has preponderance that a revolution in a state according to moral principles can be free from injurious consequences; nor can anything else secure its endurance. In proposing or setting up a moral state, the moral law is relied upon as a real power, and free will is drawn into the realm of causes, where all hangs together, mutually with stringent necessity and rigidity. But we know that the condition of the human will always remains contingent, and that only in the Absolute Being physical coexists with moral necessity. Accordingly if it is wished to depend on the moral conduct of man as on natural results, this conduct must become nature, and he must be led by natural impulse to such a course of action as can only and invariably have moral results. But the will of man is perfectly free between inclination and duty, and no physical necessity ought to enter as a sharer in this magisterial personality. If therefore he is to retain this power of solution, and yet become a reliable link in the causal concatenation of forces, this can only be effected when the operations of both these impulses are presented quite equally in the world of appearances. It is only possible when, with every difference of form, the matter of man's volition remains the same, when all his impulses agreeing with his reason are sufficient to have the value of a universal legislation.