In Life of Pi, the protagonist has an unusual approach to religion. He manages to adhere to several religions while still referring to atheists as his brothers and sisters. As with most people, however, Pi's first religion is the faith of his family and his culture, which, in his case, is Hinduism. Pi explains what Hinduism means to him at some length in chapter 16:
I am a Hindu because of sculptured cones of red kumkum powder and baskets of yellow turmeric nuggets, because of garlands of flowers and pieces of broken coconut, because of the clanging of bells to announce one's arrival to God, because of the whine of the reedy nadaswaram and the beating of drums, because of the patter of bare feet against stone floors down dark corridors pierced by shafts of sunlight, because of the fragrance of incense, because of flames of arati lamps circling in the darkness, because of bhajans being sweetly sung, because of elephants standing around to bless, because of colourful murals telling colourful stories, because of foreheads carrying, variously signified, the same word-faith. I became loyal to these sense impressions even before I knew what they meant or what they were for.
Two related points emerge from this explanation. The first is that Pi's initial attachment to Hinduism is aesthetic and sensual, coming from the beauty of the Hindu rites of worship. The second point, which he makes himself, is that he became attached to the details of the religious experience long before he knew anything about the central ideas and beliefs of any particular religion.
It is this approach to religious belief that allows Pi to become a Christian and a Muslim as well as a Hindu. Initially, he looks for what is beautiful and harmonious in a religion. Later in the same chapter, he exclaims fiercely, "A plague upon fundamentalists and literalists!" Pi has no interest in working out what tenets of a particular faith might exclude belief in others. Even later, when he is more interested in the intellectual side of religious belief, he seeks out the overarching ideas, such as peace and brotherhood, rather than the tribal elements of a particular religion.