In Life of Pi, our protagonist (Pi) is interested in science and multiple religions because he finds meaning in all these disciplines. When Pi is stranded on the lifeboat, he struggles with maintaining those intellectual pursuits and he struggles with maintaining his values in practice. For instance, he must eventually eat meat (including human flesh) although he had been a vegetarian. While on the lifeboat, basic human needs become is primary pursuit and at desperate times they become his sole interest. Because survival (securing these basic needs) occupies his thoughts and practices, they also become the way he finds meaning (just as he did with religion and science prior to the lifeboat).
One of the things the author is trying to do is to show the link between nature and spirituality. He establishes this link with Pi's interest in religion and science. He completes this message by showing how Pi gives greater narrative and spiritual significance to events during his ordeal. This is how Pi deals with his ordeal: by giving it more meaning. Martel plants this question in the reader's mind: Does tragedy or acquiring a basic necessity of life have meaning beyond the event itself? Do humans impose meaning on the events of life or are those meanings potentially there, waiting for us to notice and/or help manifest them? This is a large philosophical question and Martel does well to pose the question without giving the reader a simple answer.
Some examples of the ways Martel expresses how Pi attributes greater significance to tragedy and to daily tasks of acquiring basic human needs are as follows. In Chapter 47, Pi sees Orange Juice as a "simian Christ on the Cross," thus giving her suffering meaning and supposing that she dies for him. In Chapter 60, Pi notes:
For the first time I noticed-as I would notice repeatedly during my ordeal, between one throe of agony and the next-that my suffering was taking place in a grand setting.
In Chapter 99, Pi asks Mr. Chiba and Mr. Okamoto which story they like better. It is here that Pi shows a surprising similarity to a scientific description and a description of the same events in the form of a narrative or parable.
So tell me, since it makes no factual difference to you and you can't prove the question either way, which story do you prefer? Which is the better story, the story with animals or the story without animals?
To which, they reply that they prefer the story with the animals. The author tries to show how we attribute or discover meaning in all life's events: from solemn religious beliefs to scientific data to tragedy to essential human needs.