What's the difference between i.e. and e.g.?
c.1800, from Latin, from Greek anagnorisis "recognition," from anagnorizein "to recognize."
(Greek: "recognition"), in a literary work, the startling discovery that produces a change from ignorance to knowledge. It is discussed by Aristotle in the Poetics as an essential part of the plot of a tragedy, although anagnorisis occurs in comedy, epic, and, at a later date, the novel as well. Anagnorisis usually involves revelation of the true identity of persons previously unknown, as when a father recognizes a stranger as his son, or vice versa. One of the finest occurs in Sophocles' Oedipus Rex when a messenger reveals to Oedipus his true birth, and Oedipus recognizes his wife Jocasta as his mother, the man he slew at the crossroads as his father, and himself as the unnatural sinner who brought misfortune on Thebes. This recognition is the more artistically satisfying because it is accompanied by a peripeteia ("reversal"), the shift in fortune from good to bad that moves on to the tragic catastrophe. An anagnorisis is not always accompanied by a peripeteia, as in the Odyssey, when Alcinous, ruler of Phaeacia, has his minstrel entertain a shipwrecked stranger with songs of the Trojan War, and the stranger begins to weep and reveals himself as none other than Odysseus. Aristotle discusses several kinds of anagnorisis employed by dramatists. The simplest kind, used, as he says, "from poverty of wit," is recognition by scars, birthmarks, or tokens. More interesting are those that arise naturally from incidents of the plot.