The main themes in Dickens' first full novel, 'The Pickwick Papers', are quite diverse. Social satire is a big one. Dickens uses humor to poke fun at the absurdities of English society, especially in relation to the legal system and the behavior of the upper classes. There's also the theme of naivete, as Mr. Pickwick often finds himself in tricky situations due to his overly trusting nature. And of course, the theme of discovery, both of the self and of the wider world, as the characters travel and experience new things.
In 'The Pickwick Papers', one of the main themes is friendship. Mr. Pickwick and his friends' relationships are central to the story. Another theme is the exploration of different social classes in England at that time. Dickens shows the differences between the upper - class and the lower - class through their various encounters. Also, there is a sense of adventure as they travel around, which is a theme that keeps the story moving forward.