Blindness is defined, according to dictionaries, as "unable to see and without the sense of sight", but in King Lear, written by William Shakespeare, it has a relatively new definition. Blindness, as Shakespeare describes, is not only a physical inability to see, but also a mental defect that some characters present in this tragic comedy. King Lear and the Earl of Gloucester are the two characters who make up the parallel "double plot" of the tragedy caused by their lack of sight, by mental blindness. They both suffer a very similar plot and suffer for their false decisions, ones they will later greatly regret. In other words, such blindness is the root of false decisions that lead to disaster. The interaction between physical blindness and mental blindness was dramatically depicted in the play. To clarify, since their blurred vision was not cleared until the end, the realization of the statement in the middle of the play, "I am a man who has more sin than sinner" (3.4.60-61), is not reasonably energetic. Lear's lack of sight was the most important theme and he is the blindest of all the characters. Due to his social situation, the king of the English is believed to be the one who possesses extraordinary wisdom and ability to make sensible choices and rationally manage his power. However, his mental blindness prevents him from doing so. First of all, as king, he must be responsible for his kingdom and remain king until death, not ignoring the order of the chain of being and giving up his monarchical power and handing it over to his daughters. In Act 1, he plans to offer one of three parts of his kingdom to each of his daughters. According to the idea of ​​“The Great Chain of Being”, “the structure of… in the center of the card… is seeing things with the eyes. However, this solution comes too late to prevent tragedy from happening, the once supreme king has fallen into a heartbreaking and eyeless state, but the recovering Gloucester is considering himself to be as mad as the king so that he does not have to face this depressing situation which has as it says: “The king is mad. How rigid is my base sense, that I get up and have an ingenious feeling of my enormous pains! Better if I were distracted." (4.6.305-307) This fall is devastating for both Lear and Gloucester, and mental blindness is the cause. Consequently, they cannot blame the fact that "I am a man who has sinned more what a sinner,” because the origin comes from themselves. It is an impressive lesson for all who live in this physical world that our eyes can only see the surface of objects and our hearts can see through the essence of objects..