Aristotle defined tragedy as an imitation of a serious action that is complete in itself, uses embellished language, and causes catharsis through pity and fear. Dryden defined play as a just and lively representation of human nature, passions, and changes in fortune that delights and instructs mankind. Some key differences are that Aristotle focused on tragedy being serious and ideal, while Dryden focused on plays being a realistic portrayal of human nature for delight. Both aimed to provide human delight, though they conceptualized it differently.