O Regan, Goneril,
Your old kind father, whose frank heart gave all—
Oh, that way madness lies. Let me shun that.
No more of that. (3.4.20-23)
King Lear is trying to justify his action for disregarding Cordelia by controlling himself to not go mad on his two treacherous daughters. When he basically relegates Cordelia to King of France by not giving her share, he is blinded to see the true, faithful love of his youngest daughter. He, also, rants to Kent when he displays his distress to the king. Although it is reasonable for the king to feel enraged against a servant’s rude remarks, the king only shows this to anyone who scold him of his illogical action towards Cordelia.
In both Act II and III, he tries to get his mind together when he encounters Duke of Cornwall’s punishment towards Kent. Unlike his outrage against Kent’s criticism, the king at least shows some effort to be reasonable when his daughter and Duke of Cornwall doesn’t show up: “O, how this mother swells up toward my heart!/Hysterica passio, down, thou climbing sorrow./Thy element’s below.—Where is this daughter?” (2.4.49-51) or “To suffer with the body. I’ll forbear,” (2.4.102). Also, even if he curses his two daughters, he doesn’t degrade them completely. The inconsistency in the display of his fury assists him to justify his irrational response to Cordelia. It seems as if he is trying to make up for his unjustifiable behavior by being a weak, senile father to his two daughters in front of them, and he loses his mind when they are not around. He, himself, is confused at why he treated Cordelia brutally.