Schopenhauer was a bitter enemy of Hegel and his followers. He dismissed their philosophical writings as brain-numbing nonsense, and he disparaged them personally as lackeys of the state religion. Kant had wrenched philosophy away from its subservience to religion, the hallmark of the scholastic philosophy. He demonstrated that it is impossible to prove on metaphysical grounds the existence of God or the immortality of the soul. But in so doing, he wrote at times in an obscure manner, which gave license to his successors. "The public had been forced to see that what is obscure is not always without meaning; what is senseless and without meaning at once took refuge in obscure exposition in language" (The World as Will and Representation, Appendix).
Hegel, whom he regarded as the worst of the abusers of language. "The greatest effrontery in serving up sheer nonsense, in scrabbling together senseless and maddening webs of words, such as had previously been heard only in madhouses, finally appearad in Hege. It became the instrument of the most ponderous and general mystification that has ever existed, with a result that will seem incredible to posterity, and be a lasting monument to German stupidity (The World as Will and Representation, Appendix). Schopenhauer's invective toward Hegel was surely a reason that he was not awarded a prize in an essay contest in which he was the only entrant!
Anyone who has read Hegel must agree that they are difficult to comprehend. Hegel's own explanation was that language was an expression of an entirely new mode of philosophical expression. The reader must judge for himself whether they are meaningful. As far as religion is concerned, it has from the start been debated whether the religions trappings of Hegel's system were mere window dressing (similar questions have been raised about Descartes, among others). Still, Hegel stated in no uncertain terms that the fundamental conception of his system, the "absolute," refers to God.
Hegel was not modest in his claim to have produced a metaphysical system which yields "absolute knowledge" of all reality, and which incorporates the essential insights of all his predecessors. The entire history of philosophy could be shown as leading to his own work as its culmination. The reconciliation of opposing points of view in a higher standpoint was the heart of Hegel's methodology. Philosophical strife was diagnosed as the inevitable product of "one-sided" perspectives.
Hegel maintained that the clue to his discovery had been given by Kant, who portrayed reason as in dialectical conflict with itself. Human reason wishes to grasp the unconditioned, to know the ultimate nature of things (which for Hegel becomes the absolute). In its search for the unconditioned, reason attempts to extend the categories of the understanding beyond appearances and apply them to things in themselves. But in ripping itself loose from the constraints of experience, reason finds itself unable to find stable footing. Opposing views become equally plausible because they cannot be falsified by experience. Kant's solution to this undesirable situation was skepticism: we should give up pretensions to knowledge of things in themselves.
Philosophers after Kant, including Hegel, attempted to overcome the restraints he had placed on metaphysics. As might be expected, Hegel attacked the dichotomy between appearances and things in themselves. Any limitation, he argued, requires a recognition of what stands beyond the limit: :to call a thing finite or limited proves by implication the very presence of the infinite and unlimited, and that our knowledge of a limit can only be when the unlimited is on this side in consciousness" (Encyclopedia of Philosophical Sciences: The Science of Logic, Section 60). Hegel maintained that Kant's categories of the understanding are indeed limited, but that this limitation is seen from the standpoint of reason, which can comprehend the absolute.
The elevation of reason over the understanding is crucial to Hegel's methodology. The understanding operates with fixed, "either/or" categories. Kant was correct in his recognition that attempting to extend these categories to the unconditioned is futile. But he failed to grasp the real lesson: that reason's function is not to extend the reach of the understanding, but rather to comprehend reality on its own terms, using its own kind of concepts. The science of logic is the development of the "notion" or system of concepts of reason which together describe reality absolutely. (In fact, they ultimately not only describe the absolute, but constitute it!)
What differentiates reason from understanding is that reason overcomes oppositions that the understanding finds to be fixed. Perhaps the most fundamental opposition is that between identity and difference: everything is what it is and is not what it is not. Hegel proposed that there is literally "identity in difference": things are not what they are and are what they are not. Taken at this abstract level, it seems impossible even to understand what Hegel was trying to say: his system has seemed to many to be based fundamentally on a contradiction. Of course, the Hegelian retort is that such a criticism comes from the standpoint of the fixed categories of the understanding, which has not attained the higher standpoint of reason.
To make things a bit more concrete, I shall turn to two philosophical conceptions: thought and being. In Hegel's view, the project of philosophy historically has been to discover the relationship between the two. The two chief approaches are these:
Rationalism claims that there is a conformity between thought and being because reality has a form which is suitable for comprehension by thought.
Empiricism holds that thought has no form of its own but is shaped by an external being.
Both these approaches are one-sided, which Kant recognized. Against rationalism, he argued that the human mind does not find its objects ready-made; rather its objects are in part the contribution of the mind itself. Against empiricism, he claimed that the order found in objects cannot be abstracted from the objects themselves, but must be contributed by the mind. Note that Schopenhauer was in agreement with both these points, where the "objects" to which the subject contributes are appearances.
But Hegel chastized Kant for not going far enough, for not recognizing that even the realities which do not come before the senses are in part a product of the mind. Thought and being are united in that being is the activity of thought, and thought finds itself when it investigates reality. Thus Hegel's idealism is not restricted like the idealisms of Kant and Schopenhauer. It is an absolute idealism, which claims absolute knowledge of absolute reality, which in turn is nothing but thought itself.
Opposition has been reconciled through the identification of what had been set up originally as distinct from each other. Thought and being are originally construed as being opposed to each other or as one being one subservient to the other. The two are reconciled by taking a higher view of the activity of thought. This is chronicled in Hegel's Phenomenology of Spirit, in which the opposition between thought and being is finally overcome through thought's recognition of itself in the reality it has attempted to comprehend.