" Logic has been defined (by Hegel) as the science of the pure thought, which has for its principium (princip) the pure knowledge (wisten); not an abstract, but a concrete living unity ; and concrete in this way, that in it there are undeniably opposed to one another the consciousness of a subjective self-existence, and a second such existence, an objective ; and that existence is known as a pure Notion in itself, and the pure Notion is known as the real existence. These then are the two momenta which are contained in the logical. But they are only known as existing inseparably, and not each in the consciousness as existing by itself ; but it is only by virtue of their being also known as different (yet not self-existing) that their unity is not abstract, empty, and inactive, but concrete.
"This unity constitutes the logical principium (princip) as its element, so that the development of this difference, which is always in it, takes place within this element. Thus the entire notion is to be considered in the one case as existing Notion, in the other as Notion simply : in the former case it is notion by itself of reality or existence ; in the latter it is notion as such, self-existing notion.
" Logic will therefore be divided into the logic of the notion as existence, and of the notion as notion ; or, to make userof the common though very indefinite and ambiguous expressions, into the objective and subjective logic.
" Consistently with the fundamental element of tho unity of the notion in itself, and the connected inseparability of its momenta, these momenta must be viewed also in their mutual relations, so far as they are different, and so far as the notion is considered with respect to a difference. Hence arises a sphere of Mediation (vermittlung), or of the notion as a system of reflective determinations, that is, of the existence 'aiming into the internal existence of the notion, which, in this way, is not viewed as such by itself, but is affected by the immediate existence as by a thing properly external to itself." This is the doctrine of the essence (wcsen), which stands between the doctrine of existence and of the notion ; but in the general division of Hegel's work it is placed under the objective logic, inasmuch as, though the essence is certainly the Internal, yet the character of the subject is expressly appropriated to the Notion.
Hegel's division, therefore, is into the objective and subjective, or, more distinctly, into : I. The Logic of Existence (Die Logik des Seyns).
2. The Logic of Essence (Die Logik des ll'esens).
3. The Logic of the Notion (Die Logik des Begriffs).
(‘Wissenschaft der Logik,' enter band, 1832.) It may be useful to show in a general way what the Organon of Aristotle, as we now have it, contains. The name Organon, or Instru
ment, was not given by Aristotle, but is of a date posterior to him.
The following synopsis is given by Giulio Paci, in his edition of the Organon With this tabular view, the following general description of the contents of the Organon of Aristotle, by an able writer, will be intel ligible. " The incorrect notions which have prevailed, and still con tinue to prevail, in regard to the nature and province of logic,' are, without detraction from his merits, mainly to be attributed to tho example and authority of the philosopher himself. The books of Categories, as containing an objective classification of real things, is metaphysical, not logical. The two books of Posterior Analytics, as solely conversant about demonstrative or necessary matter, transcend the limits of the formal science ; and the same is true of the eight books of Topics, as wholly occupied with probable matter, its accidents and applications. Even the two books of the Prior Analytics, in which the pure syllogism is considered, are swelled with extralogical dis cussions. Such for example, is the whole doctrine of modality of syllogisms, as founded on the distinction of pure, necessary, and con tingent matter ; the consideration of the real truth or falsehood of propositions, and the power so irrelevantly attributed to the syllogism of inferring a true conclusion from false premises; the distinction of the enthymeme through the extra formal character of its premises, as a reasoning from signs and probabilities ; the physioguomic syllogism, &c. &c. The same is true of the book on Interpretation (wepl'Epunvetas); and matters are even worse with that on Fallacies (Sophistic Elcnchi). If Aristotle, therefore, did more than any other philosopher for the progress of the science, he also did more than any other to overlay it with extraneous lumber, and to impede its development under a precise and elegant form. Many of his successors had the correetest views of the object and scope of logic ; and even among the schoolmen there were minds who could have purified the science from its adventitious sediment, had they not been prevented from applying their principles to details by the implicit deference then exacted to the precept and practice of Aristotle." (` Edinburgh Review,' April, 1833.) It may indeed be strongly suspected that the various treatises which compose the Organon contain interpolations. Further, what we now have are only a part of the logical works of Aristotle ; and even this part does not exhibit simply a logical system, properly so called, but rather a system of argumentative discourse.