Much of Life of Pi can be seen as a religious allegory for a young man’s spiritual journey, as portrayed through his literal journey of being stranded at sea. This allegory comes to its head when Pi reaches the algae island. In many ways, Pi has been unquestioning in his faith, even through his hardships, and has relied on his faith to help him survive. However, after Richard Parker kills the French man and Pi begins eating him, Pi feels as if he has lost a part of himself—and perhaps that part of himself is his innocent and unquestioning faith.
The island provides all of Pi’s physical needs, which Pi is grateful to God for. However, the island also leads Pi to become complacent in his journey, foregoing the salvation of a return to civilization for immediate physical comfort. He mirrors the meerkats on the island, who are described as being "ruled" by "meekness"—a reference to the Bible passage “Blessed are the meek, for they shall inherit the earth.” The meerkats are "meek" out of laziness and apathy, though, not spiritual humility.
Pi similarly seeks physical pleasure rather than spiritual revelation, which is what leads him to a fruit tree on the island that symbolizes the "forbidden fruit" of the biblical Book of Genesis. His realization that the fruits are inedible and, in fact, harmful represents a fall from innocence as Pi reckons with his own cannibalism. But it also represents a second chance for Pi to pursue an end to his journey. This is similar to Adam and Eve's expulsion from the Garden of Eden due to their pursuit of knowledge and pleasure beyond what God has ordained. After his encounter with this false Edenic paradise, Pi’s faith is reinvigorated in his ascetic lifestyle at sea, where he has nothing to sustain him but God. As such, his arduous journey is not only a physical struggle but also a spiritual transformation with clear parallels to religious stories.