Hatred: This theme is found in the story because the real William Wilson hated his mimic because he would always stop him to completing his crimes, and this had been going on for a long time. It even got to the point where the real William assasinated the mimic.
Mystery: This theme is found in the story because the real William Wilson was confused about why he couldn't control the other William Wilson in the school he was in. Also one day the other William Wilson started imitating every movement and expression that he made.