The Etymologies of Isidore of Seville - Pot-pourri

You make this number into a square, and 6 six times
makes 36. Youaddtogether the low and high numbers
that you first took, 6 and 12, andtogether they make
18. Youdivide 36 by 18, anditmakes 2. Youaddthis to
the low number, that is, 6, andit comes to 8. 8 is the
mean between 6 and 12. Wherefore8 exceeds 6 by two
units, that is, a third of 6, and 8 is exceeded by 12 by
four units, a third of 12.Thus, the high number exceeds
xxiv. The name of astronomy (De astronomiae
nomine) Astronomy (astronomia)isthelaw (cf. ,
“law”) of the stars (aster), which, by investigative reasoning,
touches on the courses of the constellations, and the
figures and positions of the stars relative to each other
and to the earth.
xxv. The inventors of astronomy (De inventoribus
eius) 1. The Egyptians were the first to discover
astronomy. However, the Chaldeans were the first to
teach astrology (astrologia)andobservations concerning
nativities. But the author Josephus asserts that Abraham
instructed the Egyptians in astrology. The Greeks say
that this art was earlier conceived by Atlas, and that is
why he was said to have held up the sky. 2. Yetwhoever
the inventor was, he was stirred by the movement of the
heavens and prompted by the reasoning of his mind, and
through the changing of the seasons, through the fixed
and defined courses of the stars, through the measured
expanses of their distances apart, he made observations
of certain dimensions and numbers. By defining and discerning
these things, and weaving them into a system,
he invented astrology.
xxvi. Those who established astronomy (De institutoribus
eius) In both languages, there are indeed volumes
that have been written by diverse writers about
astronomy. Among these writers, Ptolemy, the king of
Alexandria, 25 is thought to excel among the Greeks, for
he established the canons whereby the courses of the
stars are discovered.
25 Isidore is confusing Claudius Ptolemy (second century ce)with
the Ptolemys who ruled Egypt.
26 An illustration may have been planned at this point.
The Etymologies III.xxiii.2–xxx 99
Astronomy (De astronomia)
the mean by the same proportion as the low number is
exceeded by the mean. 2. Butjust as this proportion in
the universe derives from the revolution of the spheres,
so even in the microcosm it has such power beyond
mere voice that no-one exists without its perfection
and lacking harmony. Indeed, by the perfection of
this same art of Music, meters are composed of
arsis and thesis, that is, by rising up and setting down.
xxvii. The difference between astronomy and astrology
(De differentia astronomiae et astrologiae) 1.
There is some difference between astronomy and astrology.
Astronomy concerns itself with the turning of the
heavens, the rising, setting, and motion of the stars, and
where the constellations get their names. But astrology
is partly natural, and partly superstitious. 2. Itisnatural
as longasitinvestigatesthe courses of the sun and
the moon, or the specific positions of the stars according
to the seasons; but it is a superstitious belief that
the astrologers (mathematicus) follow when they practice
augury by the stars, or when they associate the twelve
signs of the zodiac with specific parts of the soul or body,
or when they attempt to predict the nativities and characters
of people by the motion of the stars.
xxviii. Astronomical reckoning (De astronomiae
ratione) There are several kinds of astronomical reckoning.
Indeed, it defines what the world is; what the heavens
are; what is the position and course of the sphere;
what is the axis of the heavens and the pole; what are the
zones oftheheavens; what are the courses of the sun and
the moon and the stars, and so on.
xxix. The world and its name (De mundo et eius
nomine) The world (mundus) isthat which consists
of the heavens, the earth, the seas, and all of the stars.
The world is so named, because is it always in motion
(motus), for no rest is granted to its elements.
xxx. The shape of the world (De forma mundi) The
shape of the world is shown in this way. 26 Just as the world
is raised up toward the northern region, so it declines
toward the south. Its head and its face, as it were, is