Chapters 21 and 22 of Yann Martel's novel The Life of Pi are at the core of the novel because they grapple with and seek to answer the core theme, which is the existence or absence of God.
In his author's note at the beginning of the novel, Yann Martel explains his process for writing a novel. He has completed most of the work to his satisfaction but then realizes that something is wrong—there is an element of it that won't work. While he was exploring in the South of India, he met an elderly man who claimed he had a story that would "make him believe in God." Intrigued, he travels to Pondicherry and meets Mr. Piscine Patel, who is the main character and narrator of the novel. The novel tells the story of a shipwreck in which Piscine (Pi), a Bengal tiger, a hyena, an orangutan, and a wounded zebra are the only survivors. When the shipwreck investigators hear Pi's story, they feel it is completely unbelievable, and he tells another version of events in which the animal survivors are actually people. In its ambiguity, the novel leaves the conclusion of which version of events is real to the reader.
Chapters 21 and 22 come after Pi is revealing his quest to find God, and the spiritual experiences that ensued after he explored Islam, Christianity, and had an encounter with the Virgin Mary. He says, "The presence of God is the finest of rewards." Chapter 21 and 22 are written from Martel's point of view. Pi has been talking to Martel about "the better story." Martel writes:
Words of divine consciousness: moral exaltation; lasting feelings of elevation, elation, joy; a quickening of the moral sense, which strikes one a more important than an intellectual understanding of things; an alignment of the universe along moral lines, not intellectual ones; a realization that the founding principle of existence is what we call love, which works itself out sometimes not clearly, not cleanly, not immediately, but nonetheless, ineluctably.
The realization that all of existence is founded on the principle of love is proof of the existence of God, for love does not originate in the intellect. It is found in the divine, the unexplainable, and manifests itself in joy.
Chapter 22 is short enough to quote here, narrated by Pi:
I can well imagine an atheist's last words: "White, white! L-L-Love! My God!" and the deathbed leap of faith. Whereas the agnostic, if he stays true to his reasonable self, if he stays beholden to dry, yeastless factuality, might try to explain the warm light bathing him by saying "P-possibly a f-failing oxygenation of the b-b-brain," and to the very end, lack imagination and miss the better story.
In many ways, this chapter parallels the two versions of the shipwreck Pi tells. The atheist may not believe in God but is capable of apprehending the incredible, the miraculous, when encountering it. An agnostic is defined by Merriam-Webster as "a person who holds the view that any ultimate reality (such as God) is unknown and probably unknowable." They don't believe in anything that is beyond material phenomena. Therefore, they will use reason to explain anything they don't understand, as in the example of the white light from chapter 22.
The agnostic would not have believed the version of the shipwreck that included the animals because it doesn't fit within the boundaries of logic and reasoning. An atheist, while not a person who believes in or seeks God, would still be capable of apprehending the miraculous events of the story because they are not necessarily confined to the bonds of reason alone. Here is a quote from the ship's investigator's notes written on the last page of the novel:
As an aside, story of sole survivor, Mr. Piscine Molitor Patel, Indian citizen, is an astounding story of courage and endurance in the face of extraordinarily difficult and tragic circumstances. In the experience of this investigator, his story is unparalleled in the history of shipwrecks. Very few castaways can claim to have survived so long at sea as Mr. Patel, and none in the company of an adult Bengal tiger.
This is the choice readers have in the novel, as well: will they believe the version conceived only in human reasoning or the version of events that contains the miraculous?
Chapters 21 and 22 are best understood after reading the whole novel because they not only outline what the author is in the progress of learning through Pi's story, but mention "the better story," which is later referred to by Pi at the end of the book. These chapters connect the end of the book to the essence of what is learned by Pi. They also discuss God and the difference between the beliefs of an Agnostic person to those of an Athiest's. In the end, each person must decide what s/he will believe about the story of life. One person may choose to view his/her life's story as positive, negative, or purely scientific, as drawn by the difference between an Atheist's and an Agnostic's death. In Martel's analogy, the Atheist switches at the very end to believe that the light he sees at death is God; whereas, the Agnostic could cling to his belief that the white lite of death is merely the brain's failure to endure--a scientific effect, if you will. The connection between this analogy and Pi's two endings to his story seem to be the same. A reader can choose to believe the animal story or the human story, it's up to him/her.