Overall, this masterful poem seeks to exert the coexistence of past, present and future as well as contradictory values, such as being rooted to one spot and motion and rest and action. These themes are developed as the speaker watches people crossing the Brooklyn ferry. He then thinks of the ways in which he is bound to the future; people will be crossing the ferry in a hundred years and will be looking at the same sunset and the same tides endlessly going in and out. The speaker then fixes his attention very firmly to the present, describing what he can see. Much of this description captures the contradictory values of stasis and motion and rest and action, such as the seagulls that are "with motionless wings, oscillating their bodies" and the people who stand still by the rail of the ferry "yet hurry with the swift current."
As the speaker develops his thoughts, he maintains that time and space do not separate. The speaker feels a tremendous sense of oneness with those in the future, those in the present and those in the past. This is something that is made more explicit in Stanza 9, when the speaker addresses the reader of the future:
Who knows, for all the distance, but I am as good as looking at you now, for all you cannot see me?
Such statements infer that each individual human is part of a much larger, connected and integrated self which is eternal and is not subject, like humans are, to the limitations of time and space. This is something that is again developed in the final stanza, where, throguh this mystical union suggested by the symbolic river, the speaker and the future reader are no longer separate people, but are joined together, the "We" the speaker addresses in the final verse.