[
546a]
“How?” “Somewhat in this fashion. Hard in
truth
1 it is for a state thus constituted to be shaken and disturbed; but
since for everything that has come into being destruction is appointed,
2 not even such a fabric as this will abide
for all time, but it shall surely be dissolved, and this is the manner of
its dissolution. Not only for plants that grow from the earth but also for
animals that live upon it there is a cycle of bearing and barrenness
3 for soul and body as often as the revolutions of
their orbs come full circle, in brief courses for the short-lived and
oppositely for the opposite; but the laws of prosperous birth or infertility
for your race,
[
546b]
the men you have bred to
be your rulers will not for all their wisdom ascertain by reasoning combined
with sensation,
4 but
they will escape them, and there will be a time when they will beget
children out of season. Now for divine begettings there is a period
comprehended by a perfect number,
5 and for
mortal by the first in which augmentations dominating and dominated when
they have attained to three distances and four limits of the assimilating
and the dissimilating, the waxing and the waning, render all things
conversable
6 and
commensurable
[
546c]
with one another, whereof
a basal four-thirds wedded to the pempad yields two harmonies at the third
augmentation, the one the product of equal factors taken one hundred times,
the other of equal length one way but oblong,—one dimension of a
hundred numbers determined by the rational diameters of the pempad lacking
one in each case, or of the irrational
7 lacking two; the other dimension of a hundred
cubes of the triad. And this entire geometrical number is determinative of
this thing, of better and inferior births.
[
546d]
And when your guardians, missing this, bring together
brides and bridegrooms unseasonably,
8 the offspring will not be well-born or fortunate. Of such
offspring the previous generation will establish the best, to be sure, in
office, but still these, being unworthy, and having entered in turn
9 into the powers of their fathers, will
first as guardians begin to neglect us, paying too little heed to music
10 and then to
gymnastics, so that our young men will deteriorate in their culture; and the
rulers selected from them
[
546e]
will not
approve themselves very efficient guardians for testing