What are the motifs in The Light Fantastic by Terry Pratchett?

Finding oneself is a recurring idea. The main character in this novel is Rincewind. Unlike the other characters, Rincewind lacks an identity. Cohen is a hero coming to the end of his career; Twoflower is a tourist, but with an enough money and self-confidence to suggest he copes well enough in his own world, and Bethan seems to have little ambition other than to get married. Even Luggage is happy serving his master. In contrast, Rincewind is a failed wizard, who has sunk to new depths when he became a tourist guide.