 Nietzsche and Schopenhauer are mentioned in the second sentence of the novel as the preferred reading of the friend Humphrey van Weyden visited before his shipwreck.The novel also contains references to Herbert Spencer in chapters 8, 10, Charles Darwin in chapters 5, 6, 10, 13, Omar Khayyam in chapters 11, 17, 26, Shakespeare in chapter 5, and John Milton in chapter 26.The plot has some initial similarities to "Captains Courageous" by Rudyard Kipling in that they each have an idle, rich young man rescued from the sea and shanghaied into becoming a working sailor; however, the two stories differ widely in plot and moral tone.