Rebellion Against Authority and Conformism
The psychiatric ward where the novel takes place can be seen as a microcosm of society. Society is presented as a ruthlessly efficient machine (the Combine) that makes everyone conform to its narrow rules. All individuality is squeezed out of people, and the natural, joyful expressions of life are suppressed. In the hospital ward, the representative of society is the Big Nurse. She embodies order, efficiency, repression (including sexual repression), slavery and tyranny. She fulfills the need of society to somehow “repair” those who do not fit into its model so they can be sent back to take their places as cogs in the great machine. If they refuse or resist, they are destroyed by invasive, abusive treatments such as electro-shock therapy and brain surgery.

Against the Big Nurse, who serves the will of the collective, is set McMurphy, who embodies spontaneity, instinct, sexuality, individuality, and freedom. This is the central conflict of the novel. McMurphy, who has moved around a lot during his life, taking many jobs, never marrying, and living by his wits, has managed to escape the corroding influence of the Combine. He is ideally suited to get the men in the ward to see what they have lost, and to help them recover it. McMurphy’s efforts to encourage freedom and spontaneity in the men and to defeat the Big Nurse and all she stands for, reaches two grand climaxes in the novel. The first of these is the fishing trip, in which the men rediscover their own power in a natural environment. The second is the Bacchanalian revel at night in the ward, when all the repressive rules of the Combine are flouted in a drunken orgy.

Chief Bromden plays an important role in this theme of repression and freedom. His life story is told in more detail than the others. He was born into an Indian tribe that lived in close touch with nature. He recalls hunting in the woods and fishing for salmon as a boy. But the Indians’ independent way of life was destroyed by the greed of white society, that took their land and used it to install a hydroelectric dam where the best fishing grounds had been. After a technological work force had been trained to manage the new facilities, the men lost all their individuality. They all had to conform to the same standardized model and became in Bromden’s view only half alive. The fact that in the hospital the Chief pretends to be deaf and dumb indicates the total suppression of a more natural, individualized way of life. It is fitting therefore that at the end of the novel Bromden escapes, and there are hints that perhaps some of the way of life that he remembers from his boyhood can be recaptured.

Importance of Sexual Freedom
The world portrayed in the hospital ward is one of sexual repression and inhibition. This is exemplified in the Big Nurse as well as in Nurse Pilbow, who is frightened of the patients’ sexuality. It is frequently emphasized that the Big Nurse has large breasts, the mark of her femininity, but she tries to conceal them. Everything about her and the ward is sterile, cold, and lifeless, from the Big Nurse’s manner down to the white starched uniforms of the staff.
The first thing that McMurphy notices about the ward is that the Big Nurse emasculates and weakens the men. He calls her a “ball-cutter” (p. 58), and Harding agrees. In other words, the ward is like a matriarchal society which castrates men. This is graphically symbolized by the death of Rawler, who commits suicide by castrating himself and bleeding to death. In a less literal manner, this is what is happening to all the patients.

In contrast, McMurphy is totally open about sex and enjoys his masculine sexual power. He frequently makes sexual remarks to the Big Nurse. He tells the doctor about the statutory rape charge against him without any shame, claiming that the girl lied about her age and was as much the instigator of the act as he was. When he and the men return from the fishing trip he tells a fond story of how he first had sex when he was less than ten years old, with a 9-year-old girl named Judy. Her dress is still caught up high in the branches of a tree, and all the men see it as they drive past the house. For McMurphy, this is almost a badge of honor.

When he tells the Chief that he can restore him to his original size, he tries to encourage the Indian by visualizing women clamoring for his sexual attentions. McMurphy thinks that Billy Bibbit, instead of being cooped up in a psychiatric ward, should really be out pursuing girls, and he clearly believes that Billy can conquer his stutter by having sex with Candy.

Finally, when McMurphy attacks the Big Nurse, rips her clothes and exposes her breasts, he defuses her power by showing her sexual identity as a woman. This is part of the reason that her power over the men is broken. The visible sight of her femininity frees them to be more like men.