Why did the Ming dynasty reduce contact with the outside world?

Whether or not a given study has the possibility of causing harm to participants:

Aresearcher conducting behavioral research collects individually identifiable sensitive information about illicit drug use and other illegal behaviors by surveying college students. the data are stored on a laptop computer without encryption, and the laptop computer is stolen from the researcher’s car on the way home from work. this is an unanticipated problem that must be reported because the incident was (a) unexpected (i.e., the researchers did not anticipate the theft); (b) related to participation in the research; and (c) placed the subjects at a greater risk of psychological and social harm from the breach in confidentiality of the study data than was previously known or recognized. according to ohrp, this unanticipated problem must be reported to the irb in which timeframe? promptlywithin 48 hourswithin 24 hourswithin two weeks

Match the philosopher with his ideas, achievement, or events in his life. aristotle