Now the _other_ kind of intelligible things is this: that which the _Reason_ includes, in virtue of its power of reasoning, when it regards the assumptions of the sciences as (what they are) assumptions only, and uses them as occasions and starting-points, that from these it may ascend to the _Absolute_, which does not depend upon assumption, the origin of scientific truth. _The reason takes hold of this first principle of truth_, and availing itself of all the connections and relations of this principle, it proceeds to the conclusion--using no sensible image in doing this, but contemplates the _idea alone_; and with these ideas the process begins, goes on, and terminates. "I apprehend," said Glaucon, "but not very clearly, for the matter is somewhat abstruse. _You wish to prove that the knowledge which by the reason, in an intuitive manner, we may acquire of real existence and intelligible things is of a higher degree of certainty than the knowledge which belongs to what are commonly called the Sciences_. Such sciences, you say, have certain assumptions for their basis; and these assumptions are by the student of such sciences apprehended not by sense, but by a mental operation--by conception. "But inasmuch as such students ascend no higher than assumptions, and do not go to the first principles of truth, they do not seem to have true knowledge, intellectual insight, intuitive reason, on the subjects of their reasonings, though the subjects are intelligible things. And you call this habit and practice of the geometers and others by the name of JUDGMENT (διάνοια), not reason, or insight, or intuition--taking judgment to be something between opinion, on the one side, and intuitive reason, on the other. "You have explained it well," said I. "And now consider these four kinds of things we have spoken of, as corresponding to four affections (or faculties) of the mind. INTUITIVE REASON (νόησις), the highest; JUDGMENT (διάνοια)(or _discursive reason_), the next; the third, BELIEF (πίστις); and the fourth, CONJECTURE, or _guess_ (εὶκασία); and arrange them in order, so that they may be held to have more or less certainty, as their objects have more or less truth."[532] The completeness, and even accuracy of this classification of all the objects of human cognition, and of the corresponding mental powers, will be seen at once by studying the diagram proposed by Plato, as figured on the opposite page. [Footnote 532: "Republic," bk. vi. ch. xx. and xxi.]