e is like the desire of the moth for the light, and the man
who, with constant yearning and joyful expectancy, awaits the new
spring and the new summer, and every new month and the new year, and
thinks that what he longs for is ever too late in coming, and does not
perceive that he is longing for his own destruction. But this desire
is the quintessence, the spirit, of the elements, which, finding itself
captive in the soul of the human body, desires always to return to its
giver. And I would have you know that this same desire is the
quintessence which is inseparable from nature, and that man is the
model of the world. And such is the supreme folly of man that he
labours so as to labour no more, and life flies from him while he
forever hopes to enjoy the goods which he has acquired at the price of
great labour.

[Sidenote: The Senses and the Soul]

69.

The soul seems to dwell in the intellect, and the intellect appears to
dwell in that part where all {26} the senses meet which is called the
brain, and the brain does not pervade the whole body, as many have
thought; on the contrary, it dwells entirely in one part, because if it
were all in all and the same in every part, it would not have been
necessary for the instruments of the senses to combine among themselves
in one single spot; but rather, it would have been sufficient for the
eye to fulfil the function of its sensation on the surface without
transmitting, by means of the optic nerves, the likeness of its vision
to the brain, so that the soul, for the reason given above, might
perceive it in the surface of the eye. Likewise, with regard to the
sense of hearing, it would have been sufficient if the voice had
sounded only in the porous cavity of the indurated bone which lies
within the ear, without making any further transit from this bone to
the brain, which is its destination and where it discourses with common
judgement. The sense of smell, too, is likewise compelled by necessity
to proceed to the intellect; the sense of touch passes through the
nerves and is conveyed to the brain, and these nerves diverge with
infinite ramification in the skin, which encloses the limbs of the body
and the entrails. The nerves convey volition and sensation to the
muscles, and these nerves and the tendons which lie between the muscles
and the sinews give movement to them; the muscles and sinews obey, and
this obedience takes effect by the decrease {27} of their thicknes