The more things change, the more they stay the same. That's pretty much the message of "Crossing Brooklyn Ferry" as it relates to time. Walt Whitman takes comfort in the idea that all people have the same basic needs and desires, and always will. Though the details of the scenery might change, he doesn't think the world will look substantially different in 50, 100, even 500 years. He projects himself into the future to tell us, his future-readers, about the view from the Brooklyn Ferry.
Questions About Time
What does speaker mean when he says he "projects himself and returns"? Is the person that projects himself the "real" Whitman?
What does Whitman mean when he says that his readers "look back" on him because he "looked forward" to us?
In what ways will the world be the same in five hundred years, and in what ways will the world be different?
Does the speaker care if humanity survives into the distant future or not?
Chew on This
The speaker of "Crossing Brooklyn Ferry" cares more about the continuity between physical things than about the future of humanity. His emphasis on things over people implies a belief that humans won't be around forever.