It is not the impossibility of accurately determining this limit to which the nature of the difference between right and wrong, in the sense of Macaulay, is due. It is rather due to the vague thought which believes in an unlimited right, in absolute virtues and faults, which has not risen to the understanding that the terms good, brave, right, and bad are valid always and everywhere only in relation to some concrete individual who reasons, and that they have no validity in themselves. Courage is foolhardiness in the eyes of the cautious, and caution is cowardice in the opinion of the daring. The revolt against existing governments is always right in the eyes of the rebels, always wrong in the opinion of the attacked. No action can be absolutely right or wrong. The same qualities of man are good or bad, according to his needs and their uses, according to time and place. Here trickery, slyness, and bad faith prevail, there loyally, frankness and straightforwardness. Here compassion and charity serve their purpose and promote welfare, there ruthless and bloody severity. The quantity, the more or less beneficial effect of a human quality, determines the difference between virtue and vice. Reason can distinguish between right and wrong, virtue and vice, only to the extent that it can measure the relative quantity of right in any faculty, rule, or action. No categorical imperative, no ethical code, can serve as a basis for the real practical right. On the contrary, ethics finds its justification in the actual righteousness of perceptible objects. For general reason, frankness is not a better quality than slyness. Frankness is preferable to slyness only inasmuch as it is quantitatively, that is to say, more frequently, better, and more generally appreciated than slyness. It follows that a science of right can serve as a guide in practice only to the extent that practice has served as a basis for science. Reason cannot determine the action of man beforehand, because it can only experience, but not anticipate reality, because every man, every situation, is new, original, exists for the first time, and because the possibilities of reason are confined to understanding _a posteriori_. Absolute right, or right in itself, is an imagined right, is a speculative desire. A scientifically universal right requires certain definite and perceptible premises which form the basis of the determination of the general. Science is not a dogmatic infallibility which may say: This or that is right, because it is so understood. Science requires for its perceptions some external object. It can perceive right only if it rightly exists. The universal existence is the material, premise, condition, and cause of science.