There is a moment, in fact, when the instinct of life, not yet opposed to the instinct of form, acts as nature and as necessity; when the sensuous is a power because man has not begun; for even in man there can be no other power than his will. But when man shall have attained to the power of thought, reason, on the contrary, will be a power, and moral or logical necessity will take the place of physical necessity. Sensuous power must then be annihilated before the law which must govern it can be established. It is not enough that something shall begin which as yet was not; previously something must end which had begun. Man cannot pass immediately from sensuousness to thought. He must step backwards, for it is only when one determination is suppressed that the contrary determination can take place. Consequently, in order to exchange passive against active liberty, a passive determination against an active, he must be momentarily free from all determination, and must traverse a state of pure determinability. He has then to return in some degree to that state of pure negative indetermination in which he was before his senses were affected by anything. But this state was absolutely empty of all contents, and now the question is to reconcile an equal determination and a determinability equally without limit, with the greatest possible fulness, because from this situation something positive must immediately follow. The determination which man received by sensation must be preserved, because he should not lose the reality; but at the same time, in so far as finite, it should be suppressed, because a determinability without limit would take place. The problem consists then in annihilating the determination of the mode of existence, and yet at the same time in preserving it, which is only possible in one way: in opposing to it another. The two sides of a balance are in equilibrium when empty; they are also in equilibrium when their contents are of equal weight. Thus, to pass from sensation to thought, the soul traverses a medium position, in which sensibility and reason are at the same time active, and thus they mutually destroy their determinant power, and by their antagonism produce a negation. This medium situation in which the soul is neither physically nor morally constrained, and yet is in both ways active, merits essentially the name of a free situation; and if we call the state of sensuous determination physical, and the state of rational determination logical or moral, that state of real and active determination should be called the aesthetic. LETTER XXI. I have remarked in the beginning of the foregoing letter that there is a twofold condition of determinableness and a twofold condition of determination. And now I can clear up this proposition.