of sight imply a faculty of sight which is the most complex and costly of our senses, requiring not only objects of sense, but also a medium, which is light; without which the sight will not distinguish between colours and all will be a blank? For light is the noble bond between the perceiving faculty and the thing perceived, and the god who gives us light is the sun, who is the eye of the day, but is not to be confounded with the eye of man. This eye of the day or sun is what I call the child of the good, standing in the same relation to the visible world as the good to the intellectual. When the sun shines the eye sees, and in the intellectual world where truth is, there is sight and light. Now that which is the sun of intelligent natures, is the idea of good, the cause of knowledge and truth, yet other and fairer than they are, and standing in the same relation to them in which the sun stands to light. O inconceivable height of beauty, which is above knowledge and above truth! (“You cannot surely mean pleasure,” he said. Peace, I replied.) And this idea of good, like the sun, is also the cause of growth, and the author not of knowledge only, but of being, yet greater far than either in dignity and power. “That is a reach of thought more than human; but, pray, go on with the image, for I suspect that there is more behind.” There is, I said; and bearing in mind our two suns or principles, imagine further their corresponding worlds—one of the visible, the other of the intelligible; you may assist your fancy by figuring the distinction under the image of a line divided into two unequal parts, and may again subdivide each part into two lesser segments representative of the stages of knowledge in either sphere. The lower portion of the lower or visible sphere will consist of shadows and reflections, and its upper and smaller portion will contain real objects in the world of nature or of art. The sphere of the intelligible will also have two divisions—one of mathematics, in which there is no ascent but all is descent; no inquiring into premises, but only drawing of inferences. In this division the mind works with figures and numbers, the images of which are taken not from the shadows, but from the objects, although the truth of them is seen only with the mind’s eye; and they are used as hypotheses without being analysed. Whereas in the other division reason uses the hypotheses as stages or steps in the ascent to the idea of good, to which she fastens them, and then again descends, walking firmly in the region of ideas, and of ideas only, in her ascent as well as descent, and finally resting in them. “I partly understand,” he replied; “you mean that the ideas of science are superior to the hypothetical, metaphorical conceptions of geometry and the other arts or sciences, whichever is to be the name of them; and the latter conceptions you refuse to make subjects of pure intellect, because they have no first principle, although when resting on a first principle, they pass into the higher sphere.” You understand me very well, I said. And now to those four divisions of knowledge you may assign four corresponding faculties—pure intelligence to the highest sphere; active intelligence to the second; to the third, faith; to the fourth, the perception of shadows—and the clearness of the several faculties will be in the same ratio as the truth of the objects to which they are related. …
Like Socrates, we may recapitulate the virtues of the philosopher. In language which seems to reach beyond the horizon of that age and country, he is described as “the spectator of all time and all existence.” He has the noblest gifts of nature, and makes the highest use of them. All his desires are absorbed in the love of wisdom, which is the love of truth. None of the graces of a beautiful soul are wanting in him; neither can he fear death, or think much of human life. The ideal of modern times hardly retains the simplicity of the antique; there is not the same originality either in truth or error which characterized the Greeks. The philosopher is no longer living in the unseen, nor is he sent by an oracle to convince mankind of ignorance; nor does he regard knowledge as a system of ideas leading upwards by regular stages to the idea of good. The eagerness of the pursuit has abated; there is more division of labour and less of comprehensive reflection upon nature and human life as a whole; more of exact observation and less of anticipation and inspiration. Still, in the altered conditions of knowledge, the parallel is not wholly lost; and there may be a use in translating the conception of Plato into the language of our own age. The philosopher in modern times is one who fixes his mind on the laws of nature in their sequence and connection, not on fragments or pictures of nature; on history, not on controversy; on the truths which are acknowledged by the few, not on the opinions of the many. He is aware of the importance of “classifying according to nature,” and will try to “separate the limbs of science without breaking them” (“Phaedrus” 265 E). There is no part of truth, whether great or small, which he will dishonour; and in the least things he will discern the greatest (“Parmenides” 130 C). Like the ancient philosopher he sees the world pervaded by analogies, but he can also tell “why in some cases a single instance is sufficient for an induction” (Mill’s Logic, 3, 3, 3), while in other cases a thousand examples would prove nothing. He inquires into a portion of knowledge only, because the whole