The character of Robert Cohn in Ernest Hemingway's The Sun Also Rises, is a compelling one for a host of reasons. Although Cohn is a central character in the novel, it is impossible for the reader to gain an unbiased depiction of his personality. Therefore, although his actions speak loudly for some of his feelings, Cohn is never fully understood. He is presented to the reader through the slanted eyes of the novel's main character and narrator, Jake. As such, Robert's true personality is never lucid or fully developed for the reader.
There are two significant explanations for why Jake is unable to construct an objective depiction of Robert Cohn. Regardless of his inability to satiate his hunger for her, Jake's everlasting love for Brett is perhaps the biggest factor skewing his perception of Cohn. While Jake is and always will be unable to consummate his love for Brett, Robert was able to do so on a rendezvous with her in San Sebastian. Although Brett was to blame for leading him on, Cohn took the brunt of the blame in Jake's mind. In addition, Jake along with the other central characters in the novel have a predetermined perception of Jews. Whether or not their attitudes are anti-Semitic in nature is questionable; however, it is certain that this perception coupled with his feelings for Brett cause Jake to gauge and therefore depict Cohn in a warped manner.
Surely Robert Cohn is overconfident in many instances as Jake describes. He believes he can win Brett over, become a success through his novels and make a living when necessary at Bridge. Certainly Jake has just cause to perceive Robert as a tag-along. After all, the reader can attest to Cohn waiting for Jake to get off work to hang out, as well as being an obvious third wheel to Brett and Michael on the trip to Pamplona. Still, it is certain that many aspect of his personality remained unanswered and undeveloped. Therefore, the reader is left feeling unfulfilled in its account of Robert's true emotions and aspirations.