What is the significance of the soldier who sees everything twice?

Despite Yossarian’s claim that he has liver pain, the other doctors say he is well and must return to the front.Fortunately, Yossarian is saved when a soldier creates havoc by declaring he sees everything twice. At last, after much squabbling, the doctors diagnose him with meningitis, although they admit they really do not know what is wrong with him. At the hospital, Yossarian has the most rational, pleasant Thanksgiving dinner he has ever had. (Later, Yossarian remembers this Thanksgiving, when the following year he spends it with the eccentric Lieutenant Scheisskopf's wife. They bicker about the pain in life and about why God created pain. Yossarian becomes short-tempered and begins to blaspheme against God, and the wife beats him in anger.)

The doctors' medical ignorance and unjustified arrogance assist Yossarian as he devises plans to remain in the hospital. The English doctor is the one who tells Yossarian that a liver condition is incurable. Similarly, when Yossarian decides to copy the man who feigns a strange illness, the doctors are so afraid of having him die and being exposed that they keep him in the ward. But when one of the doctors threatens to expose Yossarian's liver condition as fake, he decides to take part in the doctor's scheme.