What is the main function of the fool in "King Lear"? What is the secondly function?
The fool's original purpose was to be funny. In the beginning of the play, the fool does offer some comic relief. However, in "King Lear" the fool is also a very good assessor of the situation in which Lear finds himself. Over and over again, he reminds Lear of his mistake in banishing Cordelia and he insists that Lear recognize how evil Regan and Goneril really are. When Lear begins to lose his sanity, the Fool is the one who reminds Lear that he has brought his condition on himself by not seeing how ungrateful his daughters have been. Mysteriously, the Fool vanishes from the play once Lear is in the hovel and lies down to rest. The fool says, "I'll go to bed at noon." ( III,vi,85) Then he is never seen again. Lear is left along to suffer the rest of the consequences of his actions alone.
The fool as a character is confusing, but part of this is the difference between the 1600s and today, as well as the difference in place. If somebody made a joke about your local sports team, would people several hundred years from now get it?
Shakespeare also wrote his plays for his group of actors, and the original actor portraying fool was a comedian of sorts, that was the type of character he played. So it can be really hard to understand the fool.
He does serve as a counter to Lear, especially in the Storm scene, a kind of reasonable-ish counterpart to the absolutely insane Lear. The fool's position also gives him the ability to say things that no body else can say, even if they believe them. He is the ultimate character allowed to "speak truth to power."