In particular Hegel was impressed with the necessity of avoiding the extremes which the philosophy of Fichte and Schelling presented. In correcting the one-sided idealism into which Fichte fell Schelling exaggerated the other side. Therefore, Hegel, though in agreement for a time with Schelling, found it necessary to reaffirm that which both Fichte and Schelling had lost sight of—the absolute unity of the subject, the unity of self-consciousness. The two elements of knowledge which Kant had left unreconciled, and which Fichte and Schelling only succeeded in harmonizing by a suppression of one of the sides, Hegel seeks to bring into a higher synthesis.
What had been regarded as opposites,—mind and matter, spirit and nature, the intelligible and phenomenal world,—must be grasped in a unity of thought, and that not in an external way, but by bringing into distinct consciousness the meaning of their differences as necessary elements of reason. The ultimate principle of all knowledge is the unity of consciousness. In other words, the absolute is not mere substance, but subject, the consciousness to which all beings are to be referred and in which all things are to find their justification and explanation.