Some of the cosmological ideas reflected in Chaucer's writings can be
traced back to systems older than the Ptolemaic. The beautiful fancy that
the universe is governed by harmony had its origin in the philosophy of
the Pythagoreans in the fourth century B. C., and continued to appeal to
men's imagination until the end of the Middle Ages. It was thought that
the distances of the planetary spheres from one another correspond to the
intervals of a musical scale and that each sphere as it revolves sounds
one note of the scale. When asked why men could not hear the celestial
harmony, the Pythagoreans said: A blacksmith is deaf to the continuous,
regular beat of the hammers in his shop; so we are deaf to the music which
the spheres have been sending forth from eternity.
In ancient and mediaeval cosmology it was only the seven spheres of the
planets that were generally supposed to participate in this celestial
music; but the poets have taken liberties with this idea and have given
it to us in forms suiting their own fancies. Milton bids all the celestial
spheres join in the heavenly melody:
"Ring out, ye crystal spheres,
Once bless our human ears,
If ye have power to touch our senses so;
And let your silver chime
Move in melodious time,
And let the base of heaven's deep organ blow;
And with your ninefold harmony,
Make up full consort to the angelic symphony."[17]
Shakespeare lets every orb of the heavens send forth its note as it moves:
"There's not the smallest orb which thou behold'st
But in his motion like an angel sings,
Still quiring to the young-eyed cherubins;"[18]
Chaucer, too, makes all nine spheres participate:
"And after that the melodye herde he
That cometh of thilke speres thryes three,
That welle is of musyke and melodye
In this world heer, and cause of armonye."[19]
Only in unusual circumstances can the music of the spheres be heard by
mortal ears. In the lines just quoted the celestial melody is heard during
a dream or vision. In _Troilus and Criseyde_, after Troilus' death his
spirit is borne aloft to heaven whence he beholds the celestial orbs and
hears the melody sent forth as they revolve:
"And ther he saugh, with ful avysement,
The erratik sterres, herkeninge armonye
With sownes fulle of hevenish melodye."[20]