Final answer:
Liu argues that civilization is not unthinkable without writing because there are examples of societies that developed complex civilizations without a written language.
Step-by-step explanation:
Liu argues that civilization is not unthinkable without writing because there are several examples throughout history where societies existed without a written language but still developed complex civilizations. For instance, oral traditions and storytelling played a crucial role in preserving and transmitting knowledge in many ancient societies such as the Inca Empire and the Aboriginal cultures of Australia. These civilizations were able to develop advanced systems of governance, agriculture, trade, and cultural practices without relying on a written language. Writing is a powerful tool for communication and record-keeping, but it is not the sole determinant of civilization.