Perception

Perception This word refers to our reception of knowledge through the senses, an operation which to the common understanding seems simple enough; but, viewed philosophically, is attended with much difficulty. Perception, considered as a source of knowledge, refers exclusively to the outer, or the object world — the world of extended matter and its properties. The names for the act of knowing one's own mind — the feelings and thoughts of the individual are self-consciousness and self-introspection. The word "consciousness" is sometimes improperly limited to this signification. Locke used the term "reflection" for the same meaning; but this is ambiguous, and is now disused. All our knowledge is thus said (by those that deny innate ideas) to spring from two sources — perception and self- consciousness.

Sir William Hamilton (Intel. Pow. essay i, ch. i) notices the following meanings of perception, as applied to different faculties, acts, and objects

1. Perceptio, in its primary philosophical signification, as in the mouths of Cicero and Quintilian, is vaguely equivalent to comprehension, notion, cognition in general.