In man five outer powers exist, which are the agents of perception, that
is to say, through these five powers man perceives material beings. These
are sight, which perceives visible forms; hearing, which perceives audible
sounds; smell, which perceives odors; taste, which perceives foods; and
feeling, which is in all parts of the body, and perceives tangible things.
These five powers perceive outward existences.
Man has also spiritual powers: imagination, which conceives things;
thought, which reflects upon realities; comprehension, which comprehends
realities, memory, which retains whatever man imagines, thinks, and
comprehends. The intermediary between the five outward powers and the
inward powers, is the sense which they possess in common, that is to say,
the sense which acts between the outer and inner powers, conveys to the
inward powers whatever the outer powers discern. It is termed the common
faculty, because it communicates between the outward and inward powers,
and thus is common to the outward and inward powers.
For instance, sight is one of the outer powers; it sees and perceives this
flower, and conveys this perception to the inner power--the common
faculty--which transmits this perception to the power of imagination, which
in its turn conceives and forms this image and transmits it to the power
of thought; the power of thought reflects, and having grasped the reality,
conveys it to the power of comprehension; the comprehension, when it has
comprehended it, delivers the image of the object perceived to the memory,
and the memory keeps it in its repository.
The outward powers are five: the power of sight, of hearing, of taste, of
smell, and of feeling.
The inner powers are also five: the common faculty, and the powers of
imagination, thought, comprehension, and memory.