do rainbows
assume different forms at different times? A philosopher, I suppose,
will think of some reason; for he will consider it a disgrace not to
be able to assign a reason for all things. But indeed, he will never
persuade me to believe that he speaks the truth.

59. The only consistent and incontrovertable view to take is that all
these phenomena are either works of God or of evil spirits. I have no
doubt that the dancing goats (stars), the flying serpents, fiery
lances, and the like, are produced by evil spirits, which thus gambol
in the air, either to terrify or to deceive men. The flames which
appear on board of ships were thought by the heathen to be Castor and
Pollux. Sometimes the image of a moon appears above the ears of
horses. It is certain that all these things are due to the antics of
evil spirits in the air, though Aristotle believes them to be luminous
air, just as he also declares that a comet is shining vapor.

60. To me it appears that we shall move with greater security and
certainty, when, arguing from cause to effect, we conclude that the
comet blazes, when it pleases God, as a sign of calamity, just as the
rainbow glows, when it pleases God as a sign of mercy. Who can compute
all the causes which produce the appearance of the rainbow in such
diversity of beautiful color, and in the form of an arch of perfect
curvature? The arrangement of the clouds alone surely does not produce
this perfection. Hence it is by the will and the promise of God, and
fulfilling his pleasure, that the rainbow is a sign to man and beast
that there will nevermore at any time be a flood.

61. In recognition of this token we ought to give thanks to God. As
often as the rainbow appears, it proclaims to the world with a loud
voice, as it were, the story of the wrath of God, which once destroyed
the world by a flood. And it proclaims solace for us, so that we may
conclude that God is propitious to us henceforth and will never again
visit upon us so fearful a punishment. It teaches both the love and
the fear of God, the highest virtues, of which philosophy knows
nothing. Philosophy only disputes about material and formal causes. It
does not know the final cause of this most beautiful creation. But
theology does explain it.

62. In this connection also the question has received much attention
whether the rainbow existed from the beginning. And in this
controversy much force has been displayed. Since it is written above