We are concerned only to demonstrate more clearly that the demand inherent in such attempts is identical with that which leads to the establishing of a doctrine of the categories or a philosophic system. It is indeed possible to discover now and then in the demands for a classification of the sciences, two demands, the one limited, the other wider. The first takes the form of a demand for a classification of the forms of knowledge, as in the Baconian system, and in the others which repeat the type. Here the sciences are divided according to the three faculties, memory (natural and civil history), imagination (narrative, dramatic and parabolical poetry), and reason (theology, philosophy of nature and philosophy of man). The other tends to a classification not according to gnoseological forms alone, but according to objects, according to all the real principles of being, as in the system of Comte and in those derived from it. Now a classification of the first kind coincides with researches relating to the forms of the theoretic spirit, and the problems that it exposes cannot be solved save by penetrating into the problems of these forms. Otherwise it is not possible to say if, for example, the Baconian classification be exact or no, and if not, where it should be corrected. But in passing to the other form of classification, according to objects or to the real principles of being, we pass from the sea to the ocean, because that coincides with the entire philosophic system. The classification of Comte, for example, is his positivism itself, and it is not possible to accept or refute or evaluate the one, without accepting or refuting or submitting to examination the other. There are people who ingenuously believe that they can understand things by representing them on a sheet of paper, in the form of a genealogical tree or of a table rich in graphic signs of inclusion and exclusion. But when we seriously engage upon the work, we perceive that in order to draw up the tree and construct the table, it is above all things needful to have understood them. The pen falls from the hand and the head is obliged to bend itself in meditation, when it does not prefer to abandon the dangerous game and amuse itself in other ways. [Sidenote: _Forms of knowledge and literary-didactic forms._]