Plato Epinomis 990

It is, indeed, a rather strange thing to hear; but the name that we, at any rate, give it—one that people would never approve, from inexperience in the matter—is astronomy; people are ignorant that he who is truly an astronomer must be wisest, not he who is an astronomer in the sense understood by Hesiod and all the rest of such writers, the sort of man who has studied settings and risings; but the man who has studied the seven ¹ out of the eight orbits, each travelling over its own circuit in such a manner as 990b could not ever be easily observed by any ordinary nature, that did not partake of a marvellous nature. As to this, we have now told, and shall tell, as we profess, by what means and in what manner it ought to be learnt; and first let us make the following statement.
  The moon travels through its orbit very swiftly, bringing first the month and full-moon; and in the second place we must remark the sun, with his turning motion through the whole of his orbit, and with him his satellites. But to avoid repeating again and again the same things on the same subjects 990c in our discussion, the other courses of these bodies that we have previously described are not easily understood: we must rather prepare our faculties, such as they may possibly be, for these matters; and so one must teach the pupil many things beforehand, and continually strive hard to habituate him in childhood and youth. And therefore there will be need of studies: the most important and first is of numbers in themselves; not of those which are corporeal, but of the whole origin of the odd and the even, and the greatness of their influence on the nature of reality. 990d When he has learnt these things, there comes next after these what they call by the very ridiculous name of geometry, ² when it proves to be a manifest likening ³ of numbers not like one another by nature in respect of the province of planes; and this will be clearly seen by him who is able to understand it to be a marvel not of human, but of divine origin. And then, after that, the numbers thrice increased and like to the solid nature, and those again which have been made unlike, he likens by another art, namely, that which 990e its adepts called stereometry; and a divine and marvellous thing it is to those who envisage it and reflect, how the whole of nature is impressed with species and class according to each analogy, as power and its opposite ⁴ continually turn 991a upon the double.