Mencius was the philosopher whose influence upon ancient Chinese thought was second only to that of Confucius, whose teachings Mencius defended and expanded. The Mencius, in which he recounts his dialogues with kings, dukes, and military men, as well as other philosophers, is one of the four books that make up the essential Confucian corpus. It takes up Confucius’s theories of jen, or goodness, and yi, righteousness, explaining that the individual can achieve harmony with mankind and the universe by perfecting his innate moral nature and acting with benevolence and justice. Mencius’s remarkably modern views on the duties of subjects and their rulers and on the evils of war created a Confucian orthodoxy that has remained intact since the third century BCE.