The situation has not changed much since the Dark Ages. Truth is still sought because it has value, and the scientific method remains the most systematic way of pursuing it. The method starts with a problem. Once the problem is well defined, information that might have an effect on it is gathered. The information is sorted and analyzed, and that which is useful is kept—to be used as a basis for general principles. In the social sciences, the principles are often used to help formulate policies. The policies ultimately are aimed at removing the problem and improving people's lives.
In economics (and in other social sciences), the pursuit of truth is slowed because human behavior. cannot be subjected to the kinds of controlled experiments that are possible with white rats and guinea pigs. The economist must follow the steps in a search for new truths about economic behavior, but following them is frustrating and often leads up blind alleys. Nevertheless, problems, facts, principles, and policies must be considered in a systematic way.
What can we infer from the fact that the world was perceived as flat？

A. Most people during the Dark Ages were illiterate.
B. People during the Dark Ages were lacking in social knowledge.
C. People today were more knowledgeable than those during the Dark Ages.
D. People's cognition of the world was related to the scientific development.