A tragic character is a highborn individual, at least in classic theater. Like the comic hero, she must have some admirable qualities so the audience cheers her on. She is pitted against another person, her environment or even herself; she may have a tragic flaw that brings about her downfall or, in Hegelian tragic theory, two values or goals that oppose each other -- one of which must be sacrificed for the other.
A comedy's main character, the comic hero, has at least some sort of charm or sympathetic quality. The character may an underdog -- a lower-class citizen, such as a servant or rogue, with some redeeming and even admirable qualities. At times, a higher-class but pompous or arrogant character may appear, one who may either subversively question and challenge his society or environment or who may be party to it and a tool to satirize an idea, like the main character in the "The Sarah Silverman Program."
Comedy and tragedy can have modes of thought that differ from each other. John Morreall of Dallas Baptist University states that tragedies prefer black-and-white or clear-cut solutions to problems, whereas comedy relies on ambiguity and some degree of disarray. Tragedy tends to put the human spirit in a high place, because tragic heroes long to reach a higher level; comedy, though, concerns itself with physical, concrete ideas such as bodily functions or sexual desires. These conventions are often reversed and melded in 21st-century drama.
Classical tragedies and comedies tend to center around specific social worlds. Tragedies such as the story of Oedipus and the protagonist in the film "Gladiator" focus on larger-than-life characters. Though Maximus in "Gladiator" was of a low caste, he was depicted as having almost superhuman strength, dignity and virtue. Some works defy this convention, such as "Death of a Salesman" or "American Beauty," which revolve around an anti-hero who is absolutely ordinary. Tragedies tend to highlight a social hierarchy, whereas comedies stress equality despite class. Comedy may give an author more "room" to question authority, since it can be worked into jokes. Tragedy features heroes who respect tradition or fight for their deeply held beliefs.