Mencius is the Confucian thinker traditionally associated with the text called the Mencius.
Mencius, also known by the name Mengzi, lived during the Warring States period, several centuries after Confucius. He developed Confucian ideas about human nature, moral cultivation, benevolent government, and the ruler’s obligation to care for the people.
The Mencius is structured as conversations and episodes involving the philosopher and rulers or students. It includes the influential claim that human beings have natural beginnings of goodness, often illustrated through the instinctive compassion a person feels on seeing a child in danger.
The book was especially influential in later Neo-Confucianism. It became one of the Four Books selected for study in the Song period, alongside the Analects, the Great Learning, and the Doctrine of the Mean. Mencius is therefore both a historical thinker and the name of his associated classic.