"One goes on. And the time, too, goes on--till one
perceives ahead a shadow-line warning one that
the region of early youth, too, must be left behind."
Before starting the plot, the narrator contemplates the meaning one oneself and of youth. Time doesn't wait for anyone and everyone is bound to come to the shadow-line, where they no longer enjoy the easiness of youth; it has to be left behind at some point.
"The whole thing strengthened in me that
obscure feeling of life being but a waste of days,
which, half-unconsciously, had driven me out of
a comfortable berth, away from men I liked, to
flee from the menace of emptiness . . . and
to find inanity at the first turn."
The narrator is talking to Captain Giles and suddenly comes to doubt the man's sanity. In these lines, he expresses his feeling of pointlessness of life and the pointlessness of his decisions. He escaped the comfortable life on ship because of just that - it being too comfortable and not exciting. He escaped it to find excitement, thrills, but only found himself in another emptiness which leads him to believe in the emptiness of life as a whole.
"You, too!" it seemed to say, "you, too, shall
taste of that peace and that unrest in a searching
intimacy with your own self--obscure as we were
and as supreme in the face of all the winds and all
the seas, in an immensity that receives no impress,
preserves no memories, and keeps no reckoning of
lives."
The narrator got aboard of his ship and looks at the photos of previous captains. He suddenly comes to a realization that they all shared a similar experience and feels as if they are telling him this as well. He realizes that this path will be a self-searching and self-testing experience where he would be finally be able to find his purpose. What the narrator is talking about as well is that every generation shared the similar experience and all are excited to follow the path of their predecessors, but in their own individual ways.
