"Science,
or the knowledge of nature, consists of an internal perception, and
needs the same essentials as the external percep- tion, namely the eye,
an object, and light. If these be given, perception will follow. The
eye of the inner perception is the mind or the understanding, the object
is all that lies within or without our apprehension, while the light
is the necessary attention."
"He,
therefore, who wishes to show anything to another at night must provide
light, and must polish the object so that it shines; and in the same
way a master, if he wishes to illuminate with knowledge, a pupil shrouded
in the darkness of ignorance, must first excite his attention, that
he may drink-in information with a greedy mind."