What are the stages that make up the recognition scene?

Recognition is an Aristotelian concept in which a character suddenly realizes something he did not before, reinterprets things as they are based on that realization, and gains new insight into an antagonistic character. Also known as anagnorisis, recognition plays an important role in Shakespeare’s Othello.
The first stage of recognition in the play comes when Emilia reveals the truth about Desdemona’s handkerchief. After killing Desdemona, Othello argues with Emilia over whether his wife was unfaithful to him. Once Iago admits to Emilia that he did tell Othello that Desdemona cheated, she confesses:

O thou dull Moor! That handkerchief thou speak’st of
I found by fortune and did give my husband.
For often, with a solemn earnestness—
More than indeed belonged to such a trifle—
He begged me to steal it. (5.2.238-42)

In this moment, Othello discovers that Desdemona never gave Cassio the handkerchief, which was the only definitive proof Othello had of her infidelity.
Immediately, Othello exclaims in horror at having killed his wife based on false pretenses. He screams, “Are there no stones in heaven/ But what serve for the thunder?” (5.2.247-48). This represents the second stage of recognition. This causes a lot of grief for Othello.
The final stage comes when Othello is able to confront Iago, a man who manipulated Othello into murder. Othello demands that Iago explain his motives for what he did, but Iago refuses. Othello realizes that someone he once trusted was nothing but evil incarnate. He calls Iago a devil and a “pernicious caitiff” (5.2.334), which shows his newfound understanding of Iago’s true character.
The final part of Aristotle’s recognition is a deep insight into the self. Just prior to stabbing himself, Othello delivers a lengthy speech explaining how he wants to be remembered as:

one that loved not wisely, but too well.
Of one not easily jealous, but being wrought,
Perplexed in the extreme. (5.2.360-62)

This shows that Othello accepts blame for killing Desdemona, recognizing that Iago exploited Othello’s weaknesses in order to destroy him.