Ben Gunn is a former member of Flint’s crew who has been marooned on Treasure Island. In Chapter 15, we learn that Ben tried to lead an exhibition to the island in the hopes of discovering Flint’s treasure. However, the mission was unsuccessful and Ben’s shipmates marooned him on the island as punishment. He has been living alone on the island for the past three years. 

Ben’s three years of solitude have left him both wild and unstable. To begin with, Ben has an uncivilized appearance that initially frightens Jim who thinks that he is a cannibal. Jim notes that Ben’s skin is “burnt by the sun; even his lips were black” and remarks that he looked more ragged than any beggar he had ever seen. Ben also has a deranged, roundabout way of speaking that Jim has a hard time following. Ben’s haggard appearance and half-mad ramblings represent the negative impact that greed can have on a person. After all, Ben’s appearance, speech, and mental state have all been compromised in the pursuit of treasure. Stevenson also attributed Ben’s madness to his prolonged removal from the protection of the social structure. His lack of interpersonal connection over the past three years have stripped Ben of his humanity because he is no longer able to conform to law or reason. The degradation of Ben’s spirit is so extreme that Dr. Livesey even asks Jim if Ben is a man or not after he meets him. Even escaping from Treasure Island is not enough to restore Ben to normalcy; in the novel’s final chapter, Jim informs the reader that Ben spent the entirety of his 1,000 pounds in 19 days and was “back begging on the twentieth.” Clearly, his time in isolation has left Ben unable to exist in regular society.