What would we define as the philosophy of the book? Looking out for your friends is a main theme, especially for the smaller animals, as is hospitality, even for strangers. Rat immediately befriends Mole, Toad loves everyone (if just to show off), Badger is gruff but welcoming, too. There is also a current of “knowing one’s place”. I don’t think it’s just a British class thing, but more about being happy.