Much has been made about the disappearance of the Fool in King Lear. He is an almost constant presence in the first half of the play, then speaks his last line in Act III, scene vi, and is never seen again. No reason is given. Some productions interpolate a scene between III.vi and III.vii where Gloucester is carried away before he’s brought to “trial” before Cornwall, and have the Fool carried off as well.
Others point to the fact that Cordelia and the Fool never appear together, and the could be played by the same actor. Modern productions have been staged this way, but we know that in Shakespeare’s day, Robert Armin took the roles of Shakespeare’s fools and that Cordelia would have been played by an adolescent boy. In addition, Cordelia isn’t on stage again until IV.vii and so the Fool could have been present significantly longer.
I have another explanation. Act III, scene iv is where Edgar, disguised as Tom o’ Bedlam encounters the king, and Lear is in the process of losing his mind. The “rational” fool is therefore replaced by the “mad” fool as well.
During the Renaissance, these two different kinds of fools were recognized. There was the joker or jester, whose wit was given license to entertain, parody, and speak truth to power. This is the character we see in Lear’s Fool. But there was also the “natural fool”, the village idiot or crazy man. These people would be used for entertainment, their confused or misguided actions a source for mocking and laughter. Though Tom o’ Bedlam is really Edgar in disguise, he represents that kind of fool, appropriate for a king who’s wits could no longer comprehend the gibes (and wisdom) of his court jester.
At the end of the play, when Lear mourns his dead daughter, holding Cordelia in his arms, he says, “my poor fool is hanged.” In this, he equates Cordelia with his jester, in that she, like the Fool, was willing to speak plainly. Unfortunately, he didn’t heed either of them.