In the Republic, Republic , VI. pp. 509 D-511 E. he supposes the universe, as one line, to be cut into two unequal sections; again he cuts each of these sections in two after the same proportion, and supposes the two sections first made to constitute the two genera of things sensible and things intelligible in the universe. The first represents the genus of intelligibles, comprehending in the first subdivision the primitive forms or ideas, in the second the mathematics. Of sensibles, the first subdivision comprehends solid bodies, the second comprehends the images and representations of them. Moreover, to every one of these four he has assigned its proper judicatory faculty;—to the first, reason; to the mathematics, the understanding; to sensibles, belief; to images and likenesses, conjecture. BUT WHAT DOES HE MEAN BY DIVIDING THE UNIVERSE INTO UN EQUAL PARTS? AND WHICH OF THE SECTIONS, THE INTELLIGIBLE OR THE SENSIBLE, IS THE GREATER? FOR IN THIS HE HAS NOT EXPLAINED HIMSELF. At first sight it will appear that the sensible is the greater portion. For the essence of intelligibles being indivisible, and in the same respect ever the same, is contracted into a little, and pure; but an essence divisible and pervading bodies constitutes the sensible part. Now what is immaterial is limited; but body in respect of matter is infinite and unlimited, and it becomes sensible only when it is defined by partaking of the intelligible. Besides, as every sensible has many images, shadows, and representations, and from one and the same original several copies may be taken both by nature and art; so the latter must needs exceed the former in number, according to Plato, who makes things intelligible to be patterns or ideas of things sensible, like the originals of images and reflections. Further, Plato derives the knowledge of ideas from body by abstraction and cutting away, leading us by various steps in mathematical discipline from arithmetic to geometry, thence to astronomy, and setting harmony above them all. For things become geometrical by the accession of magnitude to quantity; solid, by the accession of profundity to magnitude; astronomical, by the accession of motion to solidity; harmonical, by the accession of sound to motion. Abstract then sound from moving bodies, motion from solids, profundity from superficies, magnitude from quantity, we are then come to pure intelligible ideas, which have no distinction among themselves in respect of the one single intelligible essence. For unity makes no number, unless joined by the infinite binary; then it makes a number. And thence we proceed to points, thence to lines, from them to superficies, and profundities, and bodies, and to the qualities of the bodies so and so qualified. Now the reason is the only judicatory faculty of intelligibles; and the understanding is the reason in the mathematics, where intelligibles appear as by reflection in mirrors. But as to the knowledge of bodies, because of their multitude, Nature has given us five powers or distinctions of senses; nor are all bodies discerned by them, many escaping sense by reason of their smallness. And though every one of us consists of a body and soul, yet the hegemonic and intellectual faculty is small, being hid in the huge mass of flesh. And the case is the same in the universe, as to sensible and intelligible. For intelligibles are the principles of bodily things, but every thing is greater than the principle whence it came. Yet, on the contrary, some will say that, by comparing sensibles with intelligibles, we match things mortal with divine, in some measure; for God is in intelligibles. Besides, the thing contained is ever less than the containing, and the nature of the universe contains the sensible in the intelligible. For God, having placed the soul in the middle, hath extended it through all, and hath covered it all round with bodies. The soul is invisible, and cannot be perceived by any of the senses, as Plato says in his Book of Laws; therefore every man must die, but the world shall never die. For mortality and dissolution surround every one of our vital faculties. The case is quite otherwise in the world; for the corporeal part, contained in the middle by the more noble and unalterable principle, is ever preserved. And a body is said to be without parts and indivisible for its minuteness; but what is incorporeal and intelligible is so, as being simple and sincere, and void of all firmness and difference. Besides, it were folly to think to judge of incorporeal things by corporeal. The present, or now, is said to be without parts and indivisible, since it is everywhere and no part of the world is void of it. But all affections and actions, and all corruptions and generations in the world, are contained by this now. But the mind is judge only of what is intelligible, as the sight is of light, by reason of its simplicity and similitude. But bodies, having several differences and diversities, are comprehended, some by one judicatory faculty, others by another, as by several organs. Yet they do not well who despise the intelligible and intelligent faculty in us; for being great, it comprehends all sensibles, and attains to things divine. The most important thing he himself teaches in his Banquet, where he shows us how we should use amatorious matters, turning our minds from sensible goods to things discernible only by the reason, that we ought not to be enslaved by the beauty of any body, study, or learning, but laying aside such pusillanimity, should turn to the vast ocean of beauty. See Plato’s Symposium , p. 210 D.