The Republic - pg. 213

"Then it will be acceptable, " I said, "just as before, to call
the first part knowledge, the second thought, the third
trust, and the fourth imagination; and the latter two taken
together, opinion, and the former two, intellection. And
opinion has to do with coming into being and intellection
with being; and as being is to coming into being, so is intellection
to opinion; and as intellection is to opinion, so is knowledge to
trust and thought to imagination. But as for the proportion
between the things over which these are set and the division
into two parts of each - the opinable and the intelligible - let's
let that go, Glaucon, so as not to run afoul of arguments many
times longer than those that have been gone through."