Mencius
Chinese Confucian philosopher (c. 372 – c. 289 BC), born in the state of Zou, a third-generation disciple of Confucius through the latter's grandson Zisi, and traditionally regarded as the second sage of Confucianism, after Confucius himself. He lived during the Warring States period, an era of endemic war and political fragmentation, and, like Confucius before him, travelled the courts of various states offering their rulers counsel on virtuous government that was almost never followed with conviction. His thought, collected by his disciples in the Mengzi, is distinguished from early Confucianism by a bold and optimistic thesis: human nature is fundamentally good, and all human beings are born with four innate moral 'sprouts' — compassion, shame, deference and the sense of right and wrong — which, properly cultivated through education and moral exercise, blossom into the four cardinal Confucian virtues (benevolence, righteousness, propriety and wisdom); evil is thus not part of human nature but the result of adverse circumstances that corrupt these original sprouts. He firmly defended the people's right to rebel against a ruler who had lost the 'mandate of Heaven' through tyranny and negligence, maintaining that 'the people are of supreme importance; the altars of soil and grain come next; the ruler counts for the least' — one of the most radically proto-democratic formulations in all of classical Chinese political philosophy. His controversy with Xunzi, who held that human nature is fundamentally bad and needs to be corrected through ritual discipline, structured Confucian debate on human ethics for centuries.