Pi is an incredibly wise character, and reading about his life and religion philosophies is a highlight of the book for many readers. It is always interesting to read about how Pi personally mixed Christianity, Islam, and Hinduism to form his own personal faith and belief system. At one point in the book, we learn about a conversation that Pi has with Mr. Kumar. Mr. Kumar is a strong atheist. Science, experimentation, logic, reason, and experience make up his personal faith and belief system.
"There are no grounds for going beyond a scientific explanation of reality and no sound reason for believing anything but our sense experience. A clear intellect, close attention to detail and a little scientific knowledge will expose religion as superstitious bosh. God does not exist."
Mr. Kumar believes that there is no need for religions that worship a god of any kind. Pi does not agree with this, but he respects Mr. Kumar's stance because Mr. Kumar has taken a stance. Mr. Kumar has put his faith in something. Agnostics, on the other hand, really bother Pi because they don't put their faith in anything. They allow for the possibility of anything while simultaneously doubting everything. Pi doesn't like agnostics because he thinks that they haven't chosen to believe in anything.
I'll be honest about it. It is not atheists who get stuck in my craw, but agnostics. Doubt is useful for a while. We must all pass through the garden of Gethsemane. If Christ played with doubt, so must we. If Christ spent an anguished night in prayer, if He burst out from the Cross, "My God, my God, why have you forsaken me?" then surely we are also permitted doubt. But we must move on. To choose doubt as a philosophy of life is akin to choosing immobility as a means of transportation.