Poetics (11.4-11.8)

A discovery, as the term itself implies, is a change from ignorance to knowledge, producing either friendship or hatred in those who are destined for good fortune or ill.

A discovery is most effective when it coincides with reversals, such as that involved by the discovery in the Oedipus.

There are also other forms of discovery, for what we have described may in a sense occur in relation to inanimate and trivial objects, or one may discover whether some one has done something or not.

But the discovery which is most essentially part of the plot and part of the action is of the kind described above, for such a discovery and reversal of fortune will involve either pity or fear,

Now since the discovery is somebody’s discovery, in some scenes one character only is discovered to another, the identity of the other being obvious; but sometimes each must discover the other. Thus Iphigeneia was discovered to Orestes through the sending of the letter, but a separate discovery was needed to make him known to Iphigeneia.[*]