Legacy of Slavery
Although the novel is set in the Jim Crow era, slavery and its legacies still haunt every single piece of the text. The Southern landscape is filled with the songs, memories, and blood of slaves who labored and died under the hot sun. Slavery reduced human beings to animals and mere chattel; it stunted the opportunities of African Americans for centuries to come. It featured the grossest excesses of oppression, sexual abuse, violence, and assertions of power and hegemony. The characters in Cane feel the weight of slavery in a myriad of ways. They have to negotiate racial violence and racially motivated legislation in the South, along with the pressures of racism and integrating into white society in the North. They strive to form identities and create art and meaning in a world where merely surviving can be difficult. Their bodies bear scars, as does their collective unconscious.
The Body
Racism is writ on the body. The bodies of slaves were raped, mutilated, and killed. In Jim Crow, the black body is controlled heavily by the racial structure put in place; black people can only assert themselves bodily to an extent before whites push back. In the North the black body tries to assimilate and blend in; this proves difficult, stripping away autonomy and racial pride. The bodies of women are subject to the male gaze (not only in the characters depicted, but also by the narrator himself) and to the male grasp. Women give men sex (or it is taken from them), bear children, work, carry burdens. Their physicality and energy are subject to male control as well as white control. Internal and external conflicts play out on the body.
North and South
Both the North and the South were shaped by slavery. Slaves lived, worked, and died primarily in the South, while the North was a white man's land. After slavery ended, some blacks moved North, but most remained in the South until the early 1900s when thousands migrated looking for jobs and freedom from the oppressive Jim Crow laws and its concomitant racial violence. Toomer's views on both regions are complex, but essentially the South is the homeland. It is a place deeply rooted in the past. Its violence is offset by the incredible beauty of the natural landscape, and many blacks find it soul-crushing to be parted from it. The South is often depicted as more spiritually rich and more authentic in terms of bodily expression and cultural production. Despite the horrors of slavery, there is a link between black people and the Southern land. The North is a much more alien place, however. There black men and women grapple with the formation of self-identity in a place that does not belong to them. There is a push and pull between the white and black worlds, between intellectualism and visceral, lived bodily experience. The streets and lights are artificial, as are the social conventions and constructs.
Men and Women
Whereas many of the women in Cane have a degree of power owing to their sensuality (Karintha), beauty (Fern, Avey), mystique (Karintha), virtue (Carrie K), or even physical strength (Carma), they are still ultimately subjugated by a patriarchal system that prvileges the male gaze and the male narrative. The narrator often misunderstands or trivializes the women he discusses. He does not see them for who they truly are; he does not know their soul. Men lay claim to women's bodies and war over them. Especially in the pieces in Part 2, they are contemptuous of them, more willing to indulge in their quest for intellectual and social survival and progress rather than emotional connection.
Racial heritage/pride
Many of the characters, particularly those in Part 2 and "Kabnis," grapple with their racial identity (although the white Becky's ostracism due to her black children and mixed-race Esther's obsession with the blackness of Barlo also serve as apposite examples from Part 1). In the North, black people tend to surrender a part, if not all, of their blackness to assimilate into society. Whereas black culture is energizing, fecund, and vital, black people are not considered valuable. They must quell their racial pride and conform to the white mores. In "Kabnis" the titular character ultimately rejects identifying with his blackness and remains alienated and self-absorbed.
Unity
Toomer called Cane a circle, and indeed the blank pages between each part have the intimations of a circle. Importantly, though, that circle never comes together. In a macro sense, the work is fragmented. It has been called a collage, a montage, and a loose grouping of related pieces only haphazardly linked by a theme. In a micro sense, many of the characters never achieve wholeness or unity. Many of the women in Part 1 never get to fully develop their soul or live meaningful lives. In Part 2, Northern blacks struggle against the monolith of white society. And in Part 3, Kabnis rejects his blackness and the past. Characters remained alienated and estranged; this is the effect of centuries of slavery and racism, and Toomer reflects this, both in his characters and overarching structure of the book.
Music and Song
In both the North and the South, music and song permeate the lives of black people. In the South, slave spirituals provide both catharsis and impetus to action. Songs are sung to express fears, hopes, dreams, prayers, and desires. Music fills the air of Georgia, whether it comes from the church, the field, or the lone wanderer. Music is interwoven into the very fabric of life in the South. Blacks who migrated North brought their music and song, filling theaters with jazz and blues. Toomer even mimics the syncopation of jazz in his prose and verse here, improvising and experimenting. Those musical forms may be much beloved by the white audiences in the North even as they are an authentic expression of black culture, but jazz cannot alleviate the racial tensions that exist. Music again becomes a means of catharsis.