How is the first part of Life of Pi essential for understanding the second part?

There is a sense in which the entire narrative of this
excellent and incredibly creative novel is based around Pi's struggle to define himself
and to establish his own identity. Whilst of course the major narrative of his time at
sea plays a crucial role in this, one of the purposes of the beginning chapters, that
describe his life before this section, is to show the way that Pi struggles with his
identity and has to re-fashion it. Focus on how chapter 5 begins, when Pi tells
us:

My name
isn't the end of the story about my
name.

This of course
highlights the importance of naming and how Pi, tired of being made fun of because of
the resemblance of his name to "pissing," "finds refuge" in the name of Pi and through
this name change is able to be himself. The way that Pi reinvents himself, which allows
him to tell different stories about who he is and his place in the world, is key to the
overall theme of identity in the novel. Note the way that one of Pi's problems with
Christianity is that there is but one story. Pi of course re-tells the story of what is
happening to him at sea to try and understand it better. As we see at the end of the
tale, these stories were radically different. Above all, the text therefore, taken in
its entirety seems to represent the struggle of one man trying to make sense of himself
and his place in the confusing world of which he is a part. Whilst this struggle of
course is heightened by the main narrative, the beginning chapters are valuable in
establishing this theme through Pi's self-transformation from Piscine into
Pi.