The Guide (Symbol)
The Hitchhiker's Guide to the Galaxy represents that nothing is what it seems to be. Almost every entry in the Guide is completely inaccurate, if not very humorous. The Guide does not uphold a truth claim, meaning that it cannot be held responsible for its misinformation. This shows that although it is known as one of the best guides in the galaxy, it can't tell you the difference between a sperm whale and a bowl of petunias. Entries from the Guide are riddled throughout the book, mostly for comedic purposes, but also to show that nothing can be taken without question, or you can be in for a world of hurt.
The Vogons (Symbol)
In the book, the Vogons represent everything bad: evil, stupidity, and chaos—and a deadly combination of the three. So deadly, in fact, that they end up destroying the entire earth just to finish a construction project. They often are much happier when angry. Many of the Vogons follow blind orders and end up almost killing Arthur and Ford. This race is incredibly ugly, stupid, and evil, and is always an antagonist in the story.
The Improbability Drive (Symbol)
The improbability drive on the Heart of Gold starship is a device that can allow anything to happen, including the last-minute rescue of Arthur and Ford and a fleet of missiles turning into a bowl of petunias and a sperm whale. The drive is a symbol of unpredictability. Literally anything can happen under its influence, and it shows that everything that happens is unlikely—some events are just more unlikely than others.
The President of the Galaxy (Symbol)
The galactic political system in the story is a humorous symbol of how modern politics often function. Zaphod Beeblebrox is named the president of the galaxy, but he has no idea what he wants to do with that title. In fact, it is specified that whoever wants to become the president must undergo a psychological exam that proves that they really don't want to be in power. This shows that often the best people to be in power don't actually want to be in power at all (an old concept that dates at least as far back as Plato's Republic).
Slartibartfast (Symbol)
Slartibartfast, despite his ridiculous name, represents a wise mentorship. He shows Arthur the creation of his planet and why it was created in the first place. This begins Arthur's quest to find out meaning in life and how he will use the information Slartibartfast has given him. Although there is not much going on inside Arthur's head, it is up to old Slarty to fix that and make him into someone meaningful.
