All these are to be reckoned among the second and co-operative
causes which God, carrying into execution the idea of the best as
far as possible, uses as his ministers. They are thought by most
men not to be the second, but the prime causes of all things,
because they freeze and heat, and contract and dilate, and the
like. But they are not so, for they are incapable of reason or
intellect; the only being which can properly have mind is the
invisible soul, whereas fire and water, and earth and air, are
all of them visible bodies. The lover of intellect and knowledge
ought to explore causes of intelligent nature first of all, and,
secondly, of those things which, being moved by others, are
compelled to move others. And this is what we too must do. Both
kinds of causes should be acknowledged by us, but a distinction
should be made between those which are endowed with mind and are
the workers of things fair and good, and those which are deprived
of intelligence and always produce chance effects without order
or design. Of the second or co-operative causes of sight, which
help to give to the eyes the power which they now possess, enough
has been said. I will therefore now proceed to speak of the
higher use and purpose for which God has given them to us. The
sight in my opinion is the source of the greatest benefit to us,
for had we never seen the stars, and the sun, and the heaven,
none of the words which we have spoken about the universe would
ever have been uttered. But now the sight of day and night, and
the months and the revolutions of the years, have created number,
and have given us a conception of time, and the power of
enquiring about the nature of the universe; and from this source
we have derived philosophy, than which no greater good ever was
or will be given by the gods to mortal man. This is the greatest
boon of sight: and of the lesser benefits why should I speak?
even the ordinary man if he were deprived of them would bewail
his loss, but in vain. Thus much let me say however: God invented
and gave us sight to the end that we might behold the courses of
intelligence in the heaven, and apply them to the courses of our
own intelligence which are akin to them, the unperturbed to the
perturbed; and that we, learning them and partaking of the
natural truth of reason, might imitate the absolutely unerring
courses of God and regulate our own vagaries. The same may be
affirmed of speech and hearing: they have been given by the gods
to the same end and for a like reason. For this is the principal
end of speech, whereto it most contributes. Moreover, so much of
music as is adapted to the sound of the voice and to the sense of
hearing is granted to us for the sake of harmony; and harmony,