Final answer:
Pi builds an additional raft from life jackets and oars tied to the main boat, creating a safe space apart from the tiger.
Step-by-step explanation:
The student has asked about the necessary addition to the raft that the protagonist, Pi, builds in the novel 'Life of Pi' by Yann Martel. In the narrative, the central character Pi finds himself in a survival situation, stranded in the Pacific Ocean on a lifeboat with a Bengal tiger named Richard Parker. To improve his chances of survival and create a separate space away from the tiger, Pi constructs an additional raft from life jackets and oars. This raft is tied to the main boat and serves as a makeshift safe zone for Pi, allowing him to maintain a cautious coexistence with the tiger.
The analogy given in the question regarding the philosophy of life and the crossing of a river with a raft is reflected in Pi's practical decision to build an addition to his raft. Much like the philosophical analogy where each raft represents a different approach to problems, Pi's raft represents his resourcefulness and will to survive in the face of overwhelming odds. The imperfections and variability of rafts mentioned in the philosophy could symbolize the flaws and strengths of Pi's raft and his survival strategy as a whole.