Certainly, if such writers and professors were to proceed in an altogether empirical manner, corresponding with their declarations, nothing could be said against their labours, beyond advising them not to discuss them philosophically in order that they may not waste time in misunderstandings, and to recognize their slight utility. But, as a fact, none of them contains himself within empirical limits, but each gives some philosophic and rational basis to the classification which he proposes. Thus there appear bipartitions of the sciences into _concrete_ and _abstract,_ into _historical_ and _theoromatic_(or nomotechnical), into sciences of the _successive_ and sciences of the _coexistent,_ or into _real_ and _formal;_ or _tripartitions,_ into sciences of _fact,_ of _law_ and of _value_; into _phenomenalist, genetic_ and _systematic_ sciences; and into similar partitions and groups, of which some are old acquaintances and correspond to functions of the spirit that we have already distinguished, while others, on the contrary, must be held to be false, because they confuse under the same name functions that are different and divide functions that are unique. But all of them, true or false, leave the empirical and direct themselves to the problem of Logic and of theoretic Philosophy. This is not the place to criticize them, because substantially it has already been done in the course of the exposition of our theories; and what is left would reduce itself to a criticism of minute errors, which finds a more suitable place in reviews dealing with books of the day than in philosophic treatises. So true is it that those classificatory systems pass with the day that witnessed their birth. [Sidenote: _Coincidence of that problem with the search for the categories, when understood in a strictly philosophic sense._]