The social philosophy presented by Steinbeck in The Grapes of Wrath is complex and somewhat contradictory. The basic social theory expressed by Jim Casy, acted on by Ma Joad, and eventually realized by Tom Joad, is one that compels the so-called "little people," the impoverished and dispossessed, to come together in order to gain power against capital-minded owners. This social philosophy maintains that human survival is dependent upon the banding together of humans to find strength in group unity and action. The elaboration of this theory in the novel is seen in the education of the oppressed and disadvantaged with the organization of unions and strikes as vehicles of group protest and change.
Theoretically, Steinbeck's philosophy appears to be based upon the socialist theories of Lenin and Marx, although it shows the clear influence of several distinctly American philosophies. The Emersonian concept of the Oversoul is expressed in the earthy folk language of Jim Casy, who believes that all person's souls are really just part of one big soul. The symbolic contrasts between the vitality of the land and the "deadness" of inanimate machines represent the theory of Jeffersonian agrarianism, which holds that the identification of humankind with soil is necessary for the continuation of the life cycle. The pragmatism of Henry James, in which the meaning and truth of all concepts are defined by their practical consequences, is seen in the active approach of Ma and Tom to adversity. Finally, in Casy's assertion that "maybe it's all men an' all women we love," we find the idea of humanism, a love of all persons and the embracing of mass democracy found in the works of Walt Whitman and Carl Sandburg.
