At the beginning of the story, Tom Joad and his family, are concerned about their family, meaning their immediate family consisting of Grandpa, Granma, Ma, Pa, Uncle John, Noah, Rose of Sharon, Al, Ruthie, Winfield, and Tom. They are, in chapter 17, on the road to California along with thousands of other families doing the same thing - heading for what they hope are greener pastures and brighter futures. The philosophy the Joads have is that they will worry about their own and let others worry about their own. Slowly, this mindset changes however. The first major sign of change comes with the Joads helping out Ivy and Sarah Wilson. The Joads help the Wilsons with their car problems and the Wilsons help lighten the Joad's load. Soon, the thoughts begin to change from "I" to "we". The process isn't really complete though until Tom leaves the family in chapter 28. He finally understands what Casy was trying to tell him about how they had to concern themselves with more than just their immediate families and themselves. They had to concern themselves with the family of mankind, even if that meant sacrificing themselves. This was part of Steinbeck's message to the readers. He wanted people to be more selfless and more caring of their fellow people. He wanted people to see others as part of one big family. He used some of Emerson's "oversoul" idea to get this point across; that is, the idea that everyone is a part of one big soul, each person unique and necessary. As part of this one big soul, each person needed to help out any other person in need of help.