In other histories we have a clear conception of their subjects, at least so far as their principal points are concerned; we know whether they concern a particular land, people or race, or whether their subject is the science of mathematics, physics, &c., or an art, such as painting. The science of Philosophy has, however, this distinguishing feature, and, if you will, this disadvantage as compared with other sciences, that we find the most varied points of view as regards its Notion, and regarding that which it ought to and can accomplish. If this first assumption, the conception of the subject of the history, is not established, the history itself is necessarily made vacillating, and it only obtains consistency when it sets forth a definite conception: but then in view of the various ways of regarding its subject, it easily draws upon itself the reproach of one-sidedness. That drawback relates, however, only to an external consideration of this narrative; there is another and greater disadvantage allied to it. If there are different Notions of the science of Philosophy, it is the true Notion alone that puts us in a position to understand the writings of philosophers who have worked in the knowledge of it. For in thought, and particularly in speculative thought, comprehension means something quite different from understanding the grammatical sense of the words alone, and also from understanding them in the region of ordinary conception only. Hence we may possess a knowledge of the assertions, propositions, or of the opinions of philosophers; we may have occupied ourselves largely with the grounds of and deductions from these opinions, and the main point in all that we have done may be wanting—the comprehension of the propositions. There is hence no lack of voluminous and even learned histories of Philosophy in which the knowledge of the matter itself about which so much ado has been made, is absent. The authors of such histories may be compared to animals which have listened to all the tones in some music, but to whose senses the unison, the harmony of their tones, has not penetrated.