The human mind has need of being able to know where it is at any moment, surrounded, as it is, by so many roads, running in so many different directions. It ought to account to itself for its progress, its deviations from the right path, and for its mistakes.(20) History alone can throw any light on questions which are not simply intellectual curiosities, but which, rather, are most deeply concerned with the vital interests of society. It confirms the noble teachings of philosophy, by showing how our life is made up of one unchanging tissue of relations, and how man, even if he may vary their colors, and change their design, cannot renew their texture. It teaches us to admire nothing, and to despise nothing, beyond measure. It enlightens us concerning questions of a very complicated nature. Witnessing the evolutions of humanity, following the development of social facts and theories, we better discern principles, and grow wary in relation to the alchemists of thought, who imagine that society may be made to undergo a transformation between the rising and the setting of the sun. As there is a natural law, so, too, there are certain principles of Political Economy which emanate from philosophy, and may be reduced to one supreme principle; that of liberty and responsibility. The domain of Political Economy is the _labor_ of generations. But we reject with all our strength, the materialistic doctrine which, inexplicably confusing matters, endeavors to assimilate ideas so distinct as intelligence and things; and which would descend so low as to employ the dynamometer to measure the creative force of man and its results, and which sees only figures where there is a living soul. Man is an intelligent being, served by organs,(21) by _personal_ organs, with which the Creator has endowed him, by giving him a body provided with marvellous aptitudes, by _external_ organs which he finds in nature subjected to his power. Man was created in the image of God, say the Scriptures, and these words contain a deep meaning. He alone, of all terrestrial beings, possesses a spark of divine intelligence. He alone has been called to pursue the magnificent work of creation, by giving a new face to a world to which he cannot add so much as an atom. _Labor_ is nothing but the action of spirit on itself and on matter.(22) Hence its dignity and grandeur. Hence, also, the difficulties in the way of economic studies; since, to consider them only as concerned with questions of material production, is to forget that the products of industry are made for man, not man for industrial products; to ignore the close relationship between their fruitful investigations and the whole circle of the moral sciences; to debase them and to mutilate them.