The meaning of the term Logic is explained by Kant with his usual clearness. Logic is the science of the laws of thought. Logic may be considered from two points of view, as General or Special. General logic comprehends only the necessary laws of thought, without which there can be no exercise of the Understanding, and it has no reference to any difference in the objects to which it is applied. Special logic comprehends the rules of thinking rightly on any given subject. General logic again is either Pure or Applied logic. In the former we abstract from all empirical conditions under which our understanding is exercised, as for instance, the influence of the senses, imagination, memory, &c. A General and Pure Logic has consequently only to deal with pure d priori principles, and is a canon of the Understanding and of the Reason, but only in respect to the formal part of its use ; the matter which is its object may be either empirical or transcen dental. A General Logic is called Applied when it has reference to the rules of the exercise of the Understanding under the subjective empirical conditions, which we learn from psychology. It has con-• sequently empirical principles, though it is so far General that it has reference to the exercise of the understanding without any distinction of objects. In General Logic consequently, the part which compre hends the pure doctrine of the Reason must be absolutely separated from that which is Applied, though still General Logic. The first part only is properly a science, though brief and dry, as the regular exhibition of an elementary view of the Understanding must be. In this science then logicians must always bear two rules in mind : 1. As General Logic, it abstracts from everything which the under standing contains as knowledge, and from all differences in its objects, and it has only to do with the pure form of thought.
2. As Pure Logic, it has no empirical principles, and consequently derives nothing (as has been sometimes supposed) from psychology, which therefore has no influence at all on the canon of the under standing. It is a demonstrated science, and everything in it must be absolutely d priori true. (Kant, Critik der Heinen Vernunft; p. 55, &c., ed. 1828.) By Applied Logic, Kant understands an exhibition of the under standing and the rules of its necessary exercise in concrete, namely, under those accidental conditions of the subject which may assist or impede its exercise, and all which are only empirical data. It treats of attention, its impediments and consequences, the origin of error, the state of doubt, conviction, &c.
General logic then abstracts from all our knowledge, that is, from all relation of our knowledge to an object, and contemplates only the logical form in the relation of the parts of our knowledge to one another, that is, the form of thought generally. So far as truth is concerned, since logic is conversant only about the general and neces sary rules of thought, the criterion of its truth must lie in these rules ; and whatever contradicts them is false, for logic would then con tradict itself. Yet though a logic may be consistent, that is, nut self-contradictory, yet it may be contradictory to the object ; con sequently the bare logical criterion of truth, namely, the conformity of knowledge with the general and formal laws of thought and of the reason, is the conditio eine qua 71071, and consequently the negative condition of all truth. Further however logic cannot go, and any error which affects not the form, but the matter, logic has no means of detecting.
A recent German writer has viewed logic in a somewhat different light, and given it a wider range. The difficulty of presenting any thing like an adequate view of the principles of Hegel by a few extracts must be the apology for this imperfect attempt; the obscurity of the exposition, if such it shall appear, may bo partly though not entirely due to ourselves.
" That which is generally understood by the term logic, is viewed altogether independent of any metaphysical signification. In its present condition this science has no subject.matter (inhalt) in the sense in which subjeet-matter is considered as a reality and as a truth in the ordinary acceptation of the term. But it is not for this reason a
formal science which is devoid of truth. The region of truth however insist not be sought for in that material which people expect to find in logic, and to the want of which its unsatisfactory nature is usually attributed; but the emptiness of logical forms rather lies in the way in which they are considered and handled. So far as logical forms, considered as determinate notions, are disjointed from one another, and not bound together in organic unity, they are dead forms, and have not in them the spirit which is their living concrete unity. Thus viewed, they have no solid subject-matter (inhalt)—no matter which of itself would be a real substance (gehalt). The subject-matter which is looked for in logical forms is nothing else than a firm founda tion and concretion of these abstract determinations ; and such a substantial essence is usually sought for beyond the bonds of the science. But the logical reason is itself the Substantial or Real matter, which unites in itself all abstract determinations, and is their solid absolute concrete unity. There was no need then to look far for a subject-matter, as it is usually called ; it is not the fault of logic if it appears empty, but it is the fault of the way of considering it." "In forming judgments and conclusions, when the operations are especially referred to and grounded on the quantity of the notions, everything rests in an external difference, in a mere comparison, and becomes a pure analytical process and calculation void of all ideas. The deduction of the so-called rules and laws of conclusions in par ticular, is not much better than a handling of sticks of different lengths in order to sort them out and tie them up according to their magnitude —nothing else than the child's game of selecting and putting together the pieces of a picture which is composed of parts. This exercise of thought has accordingly not unaptly been compared with arithmetic, and arithmetic has been compared with it. In arithmetic, numbers are considered independent of any notions, as something which, in dependent of their equality or inequality, that is, independent of their absolute external relation, have no signification, as something which neither in themselves nor in their relations express a thought. When it is mechanically ascertained that multiplied by make 4, this operation 'contains just; as much' and just as little thought as the ascertainment whether in a given figure this or that conclusion can bo made." Hegel remarks, that with respect to the formation of an individual mind, logic may be compared with grammar. Both logic and grammar are something different for him who first approaches them and science in general, and for him who comes back from the sciences to them. Ile who begins to learn grammatical forms and rules, sees in them nothing but themselves : he who has mastered a language, and com pares it with other languages, is in a capacity to understand the full force of these rules and forms. Through the grammar he can reach the expression of the mind, the logic. The ease is the same with a man's first introduction to logic : its signification is limited to itself. Logic must be first learned as something which 6 man comprehends and understands, hut in which extent, depth, and further meaning are not discovered. It is not till we have a deeper acquaintance with the other sciences that the logical becomes for the mind, subjectively, not a mere abstract universal, but a universal which comprehends within it the abundance of the particular : just as the same moral maxim in the month of a youth, even if he understands it correctly, has not the signification and the comprehensive meaning which it has in the mind of a man of long experience, to whom the words convey the full force of the expression. Thus the logical cannot be fully estimated until it is made the result of experience in the sciences : it then presents itself to the mind as the universal truth, not as a particular knowledge co existent with other matter and realities, but as the essence of all other knowledge.