Understanding cannot intuite, and the sensuous faculty cannot think. in no other way than from the united operation of both, can knowledge arise. We therefore distinguish the science of the laws of sensibility, that is, aesthetic, from the science of the laws of the understanding, that is, logic. Now, logic in its turn may be considered as twofold- namely, as logic of the general, or of the particular use of the understanding. The first contains the absolutely necessary laws of thought, without which no use whatsoever of the understanding is possible, and gives laws therefore to the understanding, without regard to the difference of objects on which it may be employed. The logic of the particular use of the understanding contains the laws of correct thinking upon a particular class of objects.
General logic is again either pure or applied.
Pure general logic has to do, therefore, merely with pure a priori principles, and is a canon of understanding and reason, but only in respect of the formal part of their use, be the content what it may, empirical or transcendental. General logic is called applied, when it is directed to the laws of the use of the understanding, under the subjective empirical conditions which psychology teaches us. It has therefore empirical principles, although, at the same time, it is in so far general, that it applies to the exercise of the understanding, without regard to the difference of objects. On this account, moreover, it is neither a canon of the understanding in general, nor an organon of a particular science, but merely a cathartic of the human understanding. The former alone is properly science, although short and dry, as the methodical exposition of an elemental doctrine of the understanding ought to be.