Final answer:
Aristotle's definition of comedy is quoted to explain its intention to invoke laughter by highlighting human follies and its role in cultural expression, different from the educational value he ascribed to tragedy.
Step-by-step explanation:
The author quotes Aristotle's definition of comedy because Aristotle's perspective offers a foundational understanding in the evolution of dramatic arts and specifically how comedy and tragedy are differentiated. Aristotle believed that while tragedy was an elevated form that could educate by eliciting pity and fear (catharsis), comedy was meant to invoke laughter through mockery and the highlighting of human follies. In doing so, comedy challenged societal norms, political ideas, and personal behaviors, which though not held in high regard by Aristotle as educational, became an integral element of cultural expression and reflection of societal issues, as evidenced by the works of comic playwright Aristophanes. This comparison allows an understanding of how these dramatic forms have distinct purposes while still providing outlets for societal self-examination and commentary.