Of the particles coming from other bodies which fall upon the
sight, some are smaller and some are larger, and some are equal
to the parts of the sight itself. Those which are equal are
imperceptible, and we call them transparent. The larger produce
contraction, the smaller dilation, in the sight, exercising a
power akin to that of hot and cold bodies on the flesh, or of
astringent bodies on the tongue, or of those heating bodies which
we termed pungent. White and black are similar effects of
contraction and dilation in another sphere, and for this reason
have a different appearance. Wherefore, we ought to term white
that which dilates the visual ray, and the opposite of this is
black. There is also a swifter motion of a different sort of fire
which strikes and dilates the ray of sight until it reaches the
eyes, forcing a way through their passages and melting them, and
eliciting from them a union of fire and water which we call
tears, being itself an opposite fire which comes to them from an
opposite direction-the inner fire flashes forth like lightning,
and the outer finds a way in and is extinguished in the moisture,
and all sorts of colours are generated by the mixture. This
affection is termed dazzling, and the object which produces it is
called bright and flashing. There is another sort of fire which
is intermediate, and which reaches and mingles with the moisture
of the eye without flashing; and in this, the fire mingling with
the ray of the moisture, produces a colour like blood, to which
we give the name of red. A bright hue mingled with red and white
gives the colour called auburn. The law of proportion, however,
according to which the several colours are formed, even if a man
knew he would be foolish in telling, for he could not give any
necessary reason, nor indeed any tolerable or probable
explanation of them. Again, red, when mingled with black and
white, becomes purple, but it becomes umber when the colours are
burnt as well as mingled and the black is more thoroughly mixed
with them. Flame colour is produced by a union of auburn and dun,
and dun by an admixture of black and white; pale yellow, by an
admixture of white and auburn. White and bright meeting, and
falling upon a full black, become dark blue, and when dark blue
mingles with white, a light blue colour is formed, as flame-colour
with black makes leek green. There will be no difficulty in
seeing how and by what mixtures the colours derived from these
are made according to the rules of probability. He, however, who
should attempt to verify all this by experiment, would forget the
difference of the human and divine nature. For God only has the
knowledge and also the power which are able to combine many
things into one and again resolve the one into many. But no man
either is or ever will be able to accomplish either the one or
the other operation.
These are the elements, thus of necessity then subsisting,
which the creator of the fairest and best of created things
associated with himself, when he made the self-sufficing and most
perfect God, using the necessary causes as his ministers in the
accomplishment of his work, but himself contriving the good in
all his creations. Wherefore we may distinguish two sorts of
causes, the one divine and the other necessary, and may seek for
the divine in all things, as far as our nature admits, with a
view to the blessed life; but the necessary kind only for the
sake of the divine, considering that without them and when
isolated from them, these higher things for which we look cannot
be apprehended or received or in any way shared by us.
Seeing, then, that we have now prepared for our use the
various classes of causes which are the material out of which the
remainder of our discourse must be woven, just as wood is the
material of the carpenter, let us revert in a few words to the
point at which we began, and then endeavour to add on a suitable
ending to the beginning of our tale.
As I said at first, when all things were in disorder God
created in each thing in relation to itself, and in all things in
relation to each other, all the measures and harmonies which they
could possibly receive. For in those days nothing had any
proportion except by accident; nor did any of the things which
now have names deserve to be named at all-as, for example, fire,
water, and the rest of the elements.
