§ 165. But the besetting problem is in fact not solved, and is one of the chief incentives to that other philosophy of absolutism which defines an absolute spirit or mind. Both Aristotle and Leibniz undertake to make the perfection which determines the order of the hierarchy of substances, at the same time the responsible author of the whole hierarchy. In this case the dilemma is plain. If the divine form or the divine monad be other than the stages that lead up to it, these latter cannot be essential to it, for God is by definition absolutely self-sufficient. If, on the other hand, God is identical with the development in its entirety, then two quite incommensurable standards of perfection determine the supremacy of the divine nature, that of the whole and that of the highest parts of the whole. The union of these two and the definition of a perfection which may be at once the development and its goal, is the task of absolute idealism. [Sidenote: Absolute Realism in Epistemology. Rationalism.] § 166. Of the two fundamental questions of epistemology, absolute realism answers the one explicitly, the other implicitly. As respects _the source of the most valid knowledge_, Parmenides, Plato, Aristotle, Spinoza are all agreed: true knowledge is the work of reason, of pure intellection. Plato is the great exponent of dialectic, or the reciprocal affinities and necessities of ideas. Aristotle is the founder of deductive logic. Spinoza proposes to consider even "human actions and desires" as though he were "concerned with lines, planes, and solids." Empirical data may be the occasion, but cannot be the ground of the highest knowledge. According to Leibniz, "it seems that necessary truths, such as we find in pure mathematics, and especially in arithmetic and geometry, must have principles whose proof does not depend upon instances, nor, consequently, upon the witness of the senses, although without the senses it would never have come into our heads to think of them."[340:12] [Sidenote: The Relation of Thought and its Object in Absolute Realism.] § 167. The answers which these philosophies give to the question of _the relation between the state of knowledge and its object_, divide them into two groups. Among the ancients reason is regarded as the means of emancipation from the limitations of the private mind. "The sleeping turn aside each into a world of his own," but "the waking"--the wise men--"have one and the same world." What the individual knows belongs to himself only in so far as it is inadequate. Hence for Plato the ideas are not the attributes of a mind, but that self-subsistent truth to which, in its moments of insight, a mind may have access. Opinion is "my own," the truth is being. The position of Aristotle is equally clear. "Actual knowledge," he maintains, "is identical with its object."