It is not at all necessary, however, that the net outcome shall make itself apparent as a mechanical equivalent of the forces at work. The soul, Leibniz says, may use its skill in the formation of parties, so as to make this or that side the victor. How is this to be done, and still disallow the possibility of arbitrary choice? This problem is solved through action becoming deliberate. Deliberate action is impossible unless the soul has formed the habit of looking ahead and of arranging for modes of action which do not present themselves as immediate necessities. Only in this way can one look at the matter impartially and coolly; "at the moment of combat there is no time for discussion. Everything which then occurs throws its full force on the balance, and contributes to an outcome made up in the same way as in mechanics." The formation of certain habits beforehand, therefore, is the secret of translating impulsive action into the deliberate sphere. Of these habits the simplest consists in thinking only occasionally and incidentally of certain things. Imagination is the mother of desire. If we do not allow the imagination to dwell upon certain lines of thought, the probability of such thoughts acquiring sufficient force to become motives of weight is small. A still more effective method of regulating action is "to accustom ourselves to forming a train of thoughts of which reason, and not chance (that is, association), is the basis. We must get out of the tumult of present impressions, beyond our immediate surroundings, and ask: _Dic cur hic? respice finem!_" In other words, we must cross-question our impulses and desires, we must ask whence they come, that we may see how valid are the credentials which they offer. We must ask whither they tend, that we may measure them, not by their immediate interest, but by their relation to an end. The desires are not to be taken at their face-value, but are to be weighed and compared.