"Cry you mercy, I took you for a joint stool";
Although this is said with a comical tone, it also points out the seriousness of the Lear's madness, as he could mistake a stool for his daughter.
Another function of the fool is to be an apparatus for Lear's good characteristics. This is especially true for the first section of the play, where we see none of Lear's redeeming characteristics through any other source other than the fool. An example of this is when Lear has gone mad, and is out in the storm. When the fool finally persuades the King to take shelter, Lear, for the first time thinks of someone else before himself, saying "Prithee, go in thy self; seek thine own ease"
This venting of a new characteristic through the Fool by Lear, suggests that he may or is at least capable of change. One other way the fool is an apparatus for Lear's good side is the fact that he is the only person in the play that Lear will actually listen to, and may begrudgingly respect. Only the fool dares to confront Lear with the route of his folly and where Kent's quiet demur when criticising the King (about his rash treatment of Cordelia) results in immediate banishment, the fools criticisms are respected by Lear. This shows that Lear has the capability, if not the willingness, to listen and learn from others.
Some critics have also suggested that Shakespeare created the fool to be seen as a profit figure, a wise-man that can foresee the future. There are two main parts of this in the play. The first is the Merlin like prophecy suggesting that when the everything is upside down, the world will be in confusion. This is a parody with the Kings situation "When every case in law is right;
No squire in debt, nor no poor knight;
When slanders do not live in tongues
Nor cutpurses come to throngs; …Then shall the realm of Albion Come to great confusion"
The fool says that it is Merlin's prophecy. This reference suggests the profit figure, as the play was set before Merlin's time. If one believes him to be a profit figure, then his final line is very significant.
"Lear: … We'll go to supper i' the morning. So, so, so
Fool: And I'll go to bed at noon."
With this final quote the Fool suggests the tragedy that will come. Lear is mad, and his thoughts are inverted, he believes supper to be in the morning. This compared with the Merlin Prophecy (about the world being inverted and therefore Britain being in being in great confusion) shows that Lear's world is inverted, and the fools final line shows his belief that it will soon end in tragedy.
A function that is not unique to the Fool (Kent does it as well), is that he shows that the King throughout all, commands loyalty. The Fool, as Kent is, is incredibly loyal to Lear, despite the treatment of Lear. Whereas others desert the now powerless king, the fool stays loyal. This shows two things, firstly the fool's own good character, but also that the King must have had some admirable qualities before he went mad, otherwise the fool would have also deserted him. To add to this admirable loyalty of the fool, he is doing it knowing that it is worthless, for he says to Kent, "All that follow their noses are led by their eyes but blind men;…"
This quotation from the Fool to Kent suggests that Kent is mad to be following this 'fading star'. Ironically the fact they both are only serves to greaten the loyalty that they are showing.:
In conclusion the Fool is far from a fool. He is not responsible for any of the folly in play, nor is he as conceited (Edmund), as evil (Goneril, Regan) or ignorant (Gloucester, Edgar) as other characters. Although his time in the play, is relatively brief, he serves to show us many different dramatic functions of the play, and the play would be less rounded without this very human character.
