The Catcher in the Rye and Life of Pi do have many themes and plot points in common. They both center on a young male protagonist who struggles on his own to overcome obstacles.

The Catcher in the Rye is about a young man named Holden Caulfield who has been expelled from his boarding school and is now wandering the city, somewhat lost and disillusioned. Holden longs for the innocence of a child, but he cannot unsee the "phoniness" (superficiality) of the adult world. Holden certainly does not know the meaning of life, but if you asked him, he might tell you that life is meaningless and it's only worth living if you have the innocence of a child.

Here are some quotes that illustrate Holden's disillusionment, isolation, and longing for the innocence of childhood:

• "My brother Allie had this left-handed fielder's mitt. He was left handed. The thing that was descriptive about it though, was that he had poems written all over the fingers and the pocket and everywhere. In green ink. He wrote them on it so that he'd have something to read when he was in the field and nobody was up to bat. He's dead now."
• "Every time I came to the end of a block and stepped off the goddam curb, I had this feeling that I'd never get to the other side of the street. I thought I'd just go down, down, down, and nobody'd ever see me again. Boy, did it scare me. You can't imagine. I started sweating like a bastard—my whole shirt and underwear and everything."
• "Anyway, I keep picturing all these little kids playing some game in this big field of rye and all. Thousands of little kids, and nobody's around—nobody big, I mean—except me. And I'm standing on the edge of some crazy cliff. What I have to do, I have to catch everybody if they start to go over the cliff—I mean if they're running and they don't look where they're going I have to come out from somewhere and catch them. That's all I do all day. I'd just be the catcher in the rye and all. I know it's crazy, but that's the only thing I'd really like to be."

Life of Pi is about a young man named Pi Patel who, after losing his family in a shipwreck, is trapped alone with a tiger on a raft on the ocean. He and the tiger have to learn to live with each other in order to survive their journey. It becomes unclear at the end whether the tiger is real or simply a metaphor, but in any case, Pi's journey to work with the tiger and survive on the raft shows that he overcomes fear and relies on himself to get through the difficult voyage.

Here are some quotes that illustrate the themes of grief, loss, and faith in Life of Pi:

• "It's important in life to conclude things properly. Only then can you let go. Otherwise you are left with words you should have said but never did, and your heart is heavy with remorse."
• "If you stumble about believability, what are you living for? Love is hard to believe, ask any lover. Life is hard to believe, ask any scientist. God is hard to believe, ask any believer. What is your problem with hard to believe?"
• "I must say a word about fear. It is life's only true opponent. Only fear can defeat life."
• "To lose a brother is to lose someone with whom you can share the experience of growing old, who is supposed to bring you a sister-in-law and nieces and nephews, creatures who people the tree of your life and give it new branches. To lose your father is to lose the one whose guidance and help you seek, who supports you like a tree trunk supports its branches. To lose your mother, well, that is like losing the sun above you. It is like losing—I'm sorry, I would rather not go on."

Some comparisons you could draw between the two novels include the following.

1. Loss of Loved Ones. Holden and Pi both lose people dear to them, and this loss shapes both of them tremendously. Holden lost his younger brother to cancer when they were young boys, and Pi loses his family when the ship goes down in the storm. For both of them, the story is about overcoming the grief and trauma of these losses, and it's unclear if either of them ever do really recover from that trauma.
2. Isolation. Holden is isolated from the world inside his own head. He feels alone, and in his depression and angst, he has cut himself off from anyone who could support him, such as teachers, family, and friends. Besides, those teachers, family, and friends weren't the best support to him in the first place. He ends up wandering the streets mostly by himself throughout the story. Similarly, Pi is the only human being on the raft, and he's left alone with the tiger. He had a loving family but lost them when the ship went down, so he was isolated from any support and had to complete the journey without help from anyone else. As this relates to the meaning of life, you could argue that life can't be lived to its full meaning when you're isolated; these two characters show that life is very difficult when you don't have anyone to support you.
3. Questioning Faith. Holden says outright that he doesn't have faith; he wants to pray and says he "likes Jesus and all" but he doesn't "care too much for most of the other stuff in the Bible." Pi struggles with a similar desire to believe in God while also not understanding why God would put him through the trauma he went through at sea. In both stories, the characters struggle with the idea that life may not have a religious "meaning" or that life's meaning might just be for God or the universe to put us through torture for no good reason.
4. Overcoming Obstacles. Holden and Pi both have to overcome obstacles in their path, although they do so in different ways. Holden needs to overcome his loss of his younger brother and expulsion from school, while Pi needs to overcome the loss of his family and the fear of the tiger on the boat. You could argue that these two stories show that life is about overcoming difficult things and becoming stronger as a result.
5. Loss of Innocence. Both Holden and Pi go through trauma that takes away their childhood innocence. With this in mind, you could argue that the meaning of life is to lose one's innocence and really see the pain and complexity of the adult world.