4 For if he is considered in terms of each of his essential constituent
parts, that is soul and body, man is corruptible; if he is considered only
in terms of one, his soul, he is incorruptible. Hence the appositeness of
Aristotle's remark when he said of the soul, as being incorruptible, in the
second book of the De anima [On the Soul]: "And it alone, being immortal, can be separated
from the corruptible."
5 Thus if man is a kind of link between corruptible and incorruptible
things, since every such link shares something of the nature of the extremes
it unites, man must necessarily have something of both natures.
10 It is for this reason that man had need of two guides corresponding to
his twofold goal: that is to say the supreme Pontiff, to lead mankind to
eternal life in conformity with revealed truth, and the Emperor, to guide
mankind to temporal happiness in conformity with the teachings of
philosophy.
11 And since none can reach this harbour (or few, and these few with
great difficulty) unless the waves of seductive greed are calmed and the
human race rests free in the tranquillity of peace, this is the goal which
the protector of the world, who is called the Roman Prince, must strive with
all his might to bring about: i.e. that life on this threshing-floor of
mortals may be lived freely and in peace.
