Doug Quail changes his personal characteristics, but his perceptions and mental ideas make him the same person. A person's identity is based on the way in which he or she perceives self- impressions or encounters certain experiences. For example, a person might interpret an impression of something completely different from someone else. David Hume believes that nobody has a personal identity. Instead, he believes that each person is made up of his or her own self-impressions. Hume believes a person's self-impression is acquired either by someone else or by that person's own idea of his or herself. If you were to ask a random person who he or she is, you would most likely get an answer that would involve some kind of impression or idea that the person has grown up hearing or believing. Furthermore, it is the way that a certain person perceives these self-inflicted impressions that makes him who he or she is. It is these perceptions and mental thought processes that make Doug Quail the same person he was in the beginning of the story.
             The main character of the story, Doug Quail, starts out in life as a secret agent/assassin who works undercover for the government on Mars. After he has completed his mission and carried out the duty of killing some person on Mars, Doug
             Quail returns home to Earth and has his memory erased so that no information of his mission can be released. After his mind has been cleared, and he no longer has the memories of Mars, the government replaces his thoughts and, subsequently, Quail becomes an office worker. Married to his wife and working at his boring desk job, Quail begins to desire and dream of going to Mars. However, he has no idea that he has ever been there before. Because Doug Quail is poor, in order for him to obtain his desire to go to Mars he must undergo a form of futuristic surgery. When the surgery is completed it will make him honestly
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