Ideas, and Perceptions or Sensations, being regarded as the two elements of our knowledge, Locke, or at least the successors of Locke, had rejected the former element, Ideas, and professed to resolve all our knowledge into Sensation. After this philosophy had prevailed for a time, Kant exposed, to the entire conviction of the great body of German speculators, the untenable nature of this account of our knowledge. He taught (one of the first sentences of the above statement) that (2) _Our knowledge derives from our Ideas its form and character as knowledge; our Ideas of space and time being, for instance, the necessary forms of our geometrical and arithmetical knowledge_. Fichte carried still further this view of our knowledge, as derived from our Ideas, or from its nature as knowledge; and held that (3) _all our knowledge is a development of the ideal conditions of knowledge existing in our minds_ (one of our next following sentences). But when the ideal element of our knowledge was thus exclusively dwelt upon, it was soon seen that this ideal system no more gave a complete explanation of the real nature of knowledge, than the old sensational doctrine had done. Both elements, Ideas and Sensations, must be taken into account. And this was attempted by Schelling, who, in his earlier works, taught (as we have also stated above) that (4) _Ideas and Facts are different aspects of the same thing_:--this thing, the central basis of truth in which both elements are involved and identified, being, in Schelling's language, the _Absolute_, while each of the separate elements is subjected to _conditions_ arising from their union. But this Absolute, being a point inaccessible to us, and inconceivable by us, as _our_ philosophy teaches (as above), cannot to any purpose be made the basis of our philosophy: and accordingly this _Philosophy of the Absolute_ has not been more permanent than its predecessors. Yet the philosophy of Hegel, which still has a wide and powerful sway in Germany, is, in the main, a development of the same principle as that of Schelling;--the identity of the idea and the fact; and Hegel's _Identity-System_, is rather a more methodical and technical exposition of Schelling's Philosophy of the Absolute than a new system. But Hegel traces the manifestation of the identity of the idea and fact in the _progress_ of human knowledge; and thus in some measure approaches to our doctrine (above stated), that (5) _the way in which we approach to truth is by gradually and successively, in one instance after another_, that is, _historically, advancing from the perception to the idea, from the fact to the theory_: while at the same time Hegel has not carried out this view in any comprehensive or complete manner, so as to show that (6) _this process constitutes the history of science_: and as with Schelling, his system shows an entire want of the conviction (above expressed as part of our doctrine),