I've started to sort of rethink my definition of science fiction. I know there are books considered hard sf, though I haven't had the pleasure of reading them yet. But I've wondered increasingly whether the definitions of fantasy and science fiction is fact completely arbitrary? When I think of science fiction, my first thought it phaser guns, blown up spaceships, and high tech; low life. And then when I think of fantasy, I generally think of magic, fairies, and elves.
Reading the Mary Poppins books in particular is causing me to rethink my definitions a little bit. Those books at an angle could be thought as a social science fiction. They are a study of the social dynamics of people -- how they work together, how they behave. While it may be true that the characters are symbolic in nature, it doesn't take away from the fact that they are people within the book.
It just a different sort of SF.