There is an especial similarity between El túnel and Dostoevsky's Notes from the Underground. The deranged murderer of Sábato's novel, Castel, clearly seems to be a twentieth-century version of Dostoevsky's underground man. Castel's role can be more fully understood in the light of the Dostoevskian protagonist. Although living almost a century apart, both characters suffer from hyperconsciousness, loss of identity, and extreme inability to communicate with other human beings. Their reactions to the situations in which they find themselves are surprisingly similar. They are constantly immersed in extraordinarily detailed rationalizations, but their logic leads them nowhere; they become rebels against society and even themselves, and in the end they bring harm to the only person with whom they could have established a successful human relationship. In the two novels the suffering of both protagonists finds its literary expression in a central metaphor of existential isolation, the underground and the tunnel. The fact that these two metaphors, derived from terms denoting subterranean separation from life, are interchangeable is the most obvious similarity of the two works. The most significant parallel, however, is their philosophical affinity. (p. 440)

Sábato, like Dostoevsky, shows that man's behavior is contradictory and illogical, that the reasoner is incapable of following his own rational plan. The more logically he proceeds the more chance conspires to lead him to the opposite extreme—to the very antithesis of his rationally conceived goal. Herein lies the paradox of his existence.

The Dostoevskian premise that every act of reason is a covert act of will helps to explain Castel's capricious nature and his incapacity to adjust to others. His relationship with María, which represents perhaps his only opportunity to escape the extreme isolation of his life, is gradually destroyed by his tyrannical attitude toward her. The more analytical he becomes, the less easy it is for him to appreciate her individuality…. She never becomes a person in her own right, but remains a projection of his powerful and distorted will….

The natures of the woman protagonists in both novels are completely passive. María never protests against the physical and mental torture Castel inflicts upon her. She even accepts death calmly when her mad lover finally stabs her. (p. 442)

Liza, the prostitute in Notes from the Underground, has been retrieved from apathy and indifference with a moral lecture on conjugal love delivered by the underground man. His seeming concern and sympathy for her plight arouse in her the desire to abandon her dissolute way of life. She comes to the underground man for help, but he tells her that he had not been sincere, that he was only laughing at her…. Liza, humiliated and insulted, leaves him.

Although Liza and María must bear the affronts and cruelties of their respective lovers, the men are the true sufferers. Both novels abound in examples which illustrate this point. (p. 443)

Both the underground man and the tunnel man have failed to find an Archimedian point in the outside world and have turned inward only to find that the self is bottomless…. In Dostoevsky's novel as well as in Sábato's individualism is upheld in spite of all the suffering it causes. At the end of Notes from the Underground its protagonist threatened by separation, loneliness, isolation, and at the same time recognizing his dependency on humanity, chooses to defend the validity of the individual. He admonishes the reader for not having dared to attain true consciousness whereby he might have avoided losing the meaning of life and the sense of his individuality….

The tunnel man has all the symptoms of extreme individualism. His monomania exasperates him…. Sábato has symbolically endowed Castel with special consciousness of his individuality by making him an artist. Consequently his hero detests all social groups…. However, as he desperately attacks society in the defense of his individuality, he is, at the same time, fully aware of his need for human contact. (p. 444)

Besides these areas of philosophical coincidence, there are additional points of comparison between El túnel and Notes from the Underground. Both novels are written in the form of a confession. However, the protagonists remain unrepentent throughout because of the pride and the feeling of superiority inherent in their nature. In both works the image of the window is used as an essential symbol of the psychological struggle. (pp. 444-45)

The chief points of comparison between El túnel and Notes from the Underground lie, however, in their philosophical affinity. The protagonists of both novels are anguished individuals living in bitter conflict with reality. By bringing pain and hurt to others and to themselves they develop their consciousness as an expression of their individuality in confrontation with the world. Reason fails them and their culpability is brought about by the freedom and the terror of the will. From Dostoevsky's other works we know that his final solution is a Christian one…. In Dostoevsky's view, man must have faith and believe in Christ if he is to achieve peace of mind and salvation. Liza through her love and pity can be saved; the underground man has only reason to rely upon and it cuts him off from life and condemns him. By contrast, Ernesto Sábato, writing three quarters of a century later, offers no solution whatsoever to man's estrangement from his fellows. To his protagonist, Christ has only historical existence, God is an empty exclamation, and the world does not seem to make any sense at all…. (p. 445)