The doctrine here expounded is developed from what has been said above, or from developments given elsewhere in the Philosophy of the Spirit. We shall not therefore enlarge further upon the immanence of values in facts, upon evil as the stimulus and concreteness of the good, on the non-existence of evil in itself, on the practical character of theoretical error, on moral responsibility for such error, on the content of desire exhibited by negative statements accompanying judgments of value, and so on. In an exposition of Logic the genesis of the theoretical error could be set aside as presupposed, for in this didactic sphere any one among the common definitions which present error as a thinking of the false is sufficient. A task in closer connection with Logic is that of enquiring as to the necessary forms of error, the task, that is to say, not of confuting all errors (which is performed by Philosophy as a whole), but of establishing in how many ways the products of the various forms of knowing and of knowledge can be practically combined, and what therefore are the gnoseological possibilities of error. If error is nothing but an _improper combination_ of ideas (as Vico said), we must see the number to which the fundamental forms of these improper combinations can be reduced. In traditional Logic, the theory of error appears as the doctrine of _Sophisms_ or of sophistical refutations: it has the formalist, verbalist, empirical character common to all that Logic. In our Logic, it must have a philosophic character, that is to say, it must depend upon the already distinguished forms of the theoretic spirit, and deduce from them the arbitrary combinations of the errors which are formally possible. The ideas or concepts of the theoretic and theoretic-practical spirit are so many and no more, and so many and no more must be the possible improper combinations of them and the forms of theoretic error. [Sidenote: _Logical nature of all theoretic errors._]