A closer statement of the Aristotelian logic would be familiar to every one, since the formal representations of this science ordinarily given, employ for the most part only the material furnished by Aristotle. Kant has remarked, that since the time of the Grecian sage, logic has made neither progress nor retrogression. Only in two points has the formal logic of our time advanced beyond that of Aristotle; first, in adding to the categorical conclusion which was the only one Aristotle had in mind, the hypothetical and disjunctive, and second, in adding the fourth to the first three figures of conclusion. But the incompleteness of the Aristotelian logic, which might be pardoned in the founder of this science, yet abides, and its thoroughly empirical method not only still continues, but has even been exalted to a principle by making the antithesis, which Aristotle did not, between the form of a thought and the content. Aristotle, in reality, only attempted to collect the logical facts in reference to the formation of propositions, and the method of conclusions; he has given in his logic only the natural history of finite thinking. However highly now we may rate the correctness of his abstraction, and the clearness with which he brings into consciousness the logical operation of the understanding, we must make equally conspicuous with this the want of all scientific derivation and foundation. The ten categories which he, as already remarked, has discussed in a separate treatise, he simply mentions, without furnishing any ground or principle for this enumeration; that there are this number of categories is only a matter of fact to him, and he even cites them differently in different writings. In the same way also he takes up the figures of the conclusion empirically; he considers them only as forms and determinations of relation of the formal thinking, and continues thus, although he allows the conclusion to stand for the only form of science within the province of the logic of the understanding. Neither in his Metaphysics nor in his Physics does he cite the rules of the formal methods of conclusion which he develops in the Organon, clearly proving that he has nowhere in his system properly elaborated either his categories or his analytic; his logical investigations do not influence generally the development of his philosophical thought, but have for the most part only the value of a preliminary scrutiny.