"faculty of the immediate introspection of the soul by itself," 1670s, from self- + perception.
Entries linking to self-perception
self-
word forming element indicating "oneself," also "automatic," from Old English use of self (pron.) in compounds, such as selfbana "suicide," selflice "self-love, pride, vanity, egotism," selfwill "free will." Middle English had self-witte "one's own knowledge and intelligence" (early 15c.).
OED counts 13 such compounds in Old English. Middle English Compendium lists four, counting the self-will group as a whole. It re-emerges as a living word-forming element mid-16c., "probably to a great extent by imitation or reminiscence of Greek compounds in (auto-)," and formed a great many words in the pamphlet disputes of the 17c.
perception n.
late 14c., percepcioun, "understanding, a taking cognizance," from Latin perceptionem (nominative perceptio) "perception, apprehension, a taking," noun of action from past-participle stem of percipere "to perceive" (see perceive). Also used in Middle English in the more literal sense of the Latin word. The meaning "intuitive or direct recognition of some innate quality" is from 1827.