Themes

This is an image of a sculpture by Mary Edmonia Lewis, a 19th century black female artist. The sculpture is called Forever Free and was created in 1867 as a response to the Emancipation proclamation.

Having read further in the novel, I can now reflect on the words at the beginning on the novel, and understand Hurston's stance.
Hurston equates ships, far off on the horizon, with men's dreams. She says that sometimes the ships come to the men, and their dreams come true, and other times, they stay in their minds, never approaching reality, until those men give up. By using such imagery, Hurston establishes that these dreams are unrealistic, even unattainable, while, as she goes on to say, for women, our dreams are down to earth, they are "the truth," and are readily attained.
As in any instance where blanket generalizations are made concerning the sexes, I immediately looked for the sexism in that statement, and while every time you say "men are A women are B," it is always, ultimately, sexist, the statement is not a typical sexist depiction. It characterises women as sensible and efficient, rather than the typical sexist rhetoric that displays them us as flighty and emotional. And yet, it didn't deride men for being dreamers. I couldn't quite make sense of Hurston's motivations for such a statement, so I let it be, for a time.
In chapter 2, Nanny helps us to understand the state of life for the women Janie knew. She says:

"...de white man throw down his burden and tell de
nigger man to pick it up. he pick it up because he have
to, but he don't tote it. He hand it to his womenfolks. De
nigger women is de mule uh de world..."

Here, Nanny establishes that while all black people are disadvantaged and forced into subservience, women bare the brunt of the load and the burden. While it is difficult for a black man to have high hopes and dreams, as a slave, or the son of a slave, it is unthinkable for women to dream beyond their lot in life. Such is true, especially in this time, for all women. While men had the means and the advantages that allowed them to be unrealistic and hopeful, women were destined for the thankless task of keeping the world going, in the fields, in the kitchens, in the shops, and so only dreamed "the truth", only dreamed for what they could take the according steps to achieve.

"Ah wanted to preach a great sermon about colored women
sittin' on high but they wasn't no pulpit for me."

Here, Hurston clearly establishes, that though women, like all people, would like to dream, they do not have any such opportunity.

Janie, in chapter 2, as she becomes aware of her new found womanhood, begins to dream. She searches for answers, and feels a magical blossoming. She is "looking, waiting, breathing short with impatience. Waiting for the world to be made." She is not sensible or realistic; she is day dreaming; she is sensual, emotional, and free to imagine, to think, to hope, to feel. It is in this state that she experiments, kissing a boy she had no previous attraction to, who she has no expectation of a life with. Her free expression of maturity and sexuality is condemned and stifled by Nanny, who paints a different picture. Nanny shows how every women's sexuality is stolen from her, by white slave owners, by school teachers, and by necessity and the need for protection, which forces her into marriage (like Janie's with Logan) which does not satisfy or fulfill her.
Huston develops this theme, showing that instead of female sexuality being an expression of personal pleasure, choice, and freedom, it is a means of subjugation and survival. Likewise, the female mind and soul cannot be used for free thought and dreams, as it can be for men, but instead, for practicalities. Men may be able to express themselves how they wish, or dream unrealistically, but women, shouldering the burden of mankind, do not have that luxury.

Having established the difficulties and restraints that women face, Hurston can now show how miraculous it is that Janie is able to rise above what her peers thought possible, to disregard the standard way of things, in order to be her own person.