If the economic actions of man be considered, in their uncontaminated and undiminished reality, with an eye free from all prejudice, it is never possible to establish even a _single one_ of the concepts and laws of economic science. Every individual is different at every moment of his life: he wills always in a new and different way, not comparable with the other modes of his or of others' willing. If A spent seven soldi to buy a loaf of bread yesterday, and to-day he spend the same amount in making the same purchase, the seven soldi of to-day are not for this reason those of yesterday, nor is the bread the same as that of yesterday, nor the want that A satisfies to-day the same as that of yesterday, nor is the effort that his action costs him identical with that of yesterday. If the individual B also spend seven soldi for a loaf of bread, the action of B is different from that of A, as that of the A of to-day was different from that of yesterday. If we lead the economist on to this ground of reality (or rather to the side of this Heraclitean river, in which it is not possible to dip the same hands twice in the same water), he will feel himself impotent, for he will not find any point of support for the edification of any of his theories.--The value of a piece of goods (says a theorem of Economy) depends upon the quantity of it and of all the other goods that are upon the market.--But what does "goods" mean? Bread, for example, or wine? In reality, abstract bread and wine do not exist, but a given piece of bread, a given glass of wine, with a given individual who will give a treasure or nothing in order to eat the one or to drink the other, according to the conditions in which he finds himself.--Any sort of enjoyment, when protracted, decreases and finally becomes extinguished.--That is the law of Gossen, one of the foundation--stones of economic theory. But what are these enjoyments that are protracted, decrease, and end by becoming extinguished? In reality there exist only actions, which assume different positions at every moment, owing to the continual changing of surrounding reality, in which the volitional individual operates. The difference is qualitative, not quantitative: if the individual A eat the bread that he has bought for seven soldi, when swallowing the second or the tenth or the last mouthful, he has a pleasure, not inferior to that which he had when swallowing the first, but different: the last was not less necessary for him, in its way, than the first; otherwise he would have remained unsatisfied in his normal want, in his habit, or in his caprice.--The economic man seeks the maximum of satisfaction with the least effort.--That is the very principle of Economy, but neither does this principle correspond with reality, most simple and general though it be. The individual A disputes for an-hour, in order to save two soldi in the purchase of an object, for which he has been asked