Mencius (Romanization; 孟子, pinyin: Mèng Zǐ; Wade-Giles: Meng Tzu; most accepted dates: 372 – 289 BCE; other possible dates: 385 – 303/302 BCE) was a Chinese philosopher who was arguably the most famous Confucian after Confucius himself.

Mencius, also known by his birth name Meng Ke or Ko, was born in the State of Zhou (周朝; pinyin: zhōu cháo; Wade-Giles: chou ch`ao; 372BC to 289BC), now forming the territory of the county-level city of Zoucheng (邹城; originally Zouxian), Shandong province, only thirty kilometres (eighteen miles) south of Qufu, Confucius' birthplace.

He was an itinerant Chinese philosopher and sage, and one of the principal interpreters of Confucianism. Supposedly, he was a pupil of Confucius' grandson, Zisi. Like Confucius, according to legend, he travelled China for forty years to offer advice to rulers for reform. He served as an official during the Warring States Period (403–221 BCE) in the State of Qi (齊; pinyin: qí; 1046 BC to 221 BC) from 319 to 312 BCE. He expressed his filial devotion when he took an absence of three years from his official duties for Qi to mourn his mother's death. Disappointed at his failure to effect changes in his contemporary world, he retired from public life.

Mencius' interpretation of Confucianism has generally been considered the orthodox version by subsequent Chinese philosophers, especially the Neo-Confucians of the Song dynasty. The Mencius (also spelled Mengzi or Meng-tzu), a book of his conversations with kings of the time, is one of the Four Books that Zhu Xi grouped as the core of orthodox Neo-Confucian thought. In contrast to the sayings of Confucius which are short and self-contained, the Mencius consists of long dialogues, including arguments, with extensive prose.

While Confucius himself did not explicitly focus on the subject of human nature, Mencius asserted the innate goodness of the individual, believing that it was society's influence – its lack of a positive cultivating influence – that caused bad moral character. "He who exerts his mind to the utmost knows his nature" and "the way of learning is none other than finding the lost mind".

His translator James Legge finds a close similarity between Mencius' views on human nature and those in Bishop Butler's Sermons on Human Nature.

To show innate goodness, Mencius used the example of a child falling down a well. Witnesses of this event immediately feel

alarm and distress, not to gain friendship with the child's parents, nor to seek the praise of their neighbors and friends, nor because they dislike the reputation [of lack of humanity if they did not rescue the child]...

The feeling of commiseration is the beginning of humanity; the feeling of shame and dislike is the beginning of righteousness; the feeling of deference and compliance is the beginning of propriety; and the feeling of right and wrong is the beginning of wisdom.

Men have these Four Beginnings just as they have their four limbs. Having these Four Beginnings, but saying that they cannot develop them is to destroy themselves.<ref>The Mencius 2A:6 in Chan 1963: 65. Formatting has been applied to ease readability.</ref>

Mencius spoke frequently and highly of the well-field system.

Mencius emphasized the significance of the common citizens in the state. While Confucianism generally regards rulers highly, he argued that it is acceptable for the subjects to overthrow or even kill a ruler who ignores the people's needs and rules harshly. This is because a ruler who does not rule justly is no longer a true ruler. Speaking of the assassination of the wicked King Jie of Xia, Mencius said, "I have heard of killing a mere fellow Chou, but I have not heard of murdering [him as] the ruler.".

He said during the Spring and Autumn Period, there's no Just war.

His alleged years make him contemporary with Xun Zi, Zhuangzi, Gaozi, and Plato.

Xun Zi was a Confucian who believed that human nature is originally evil, and the purpose of moral cultivation is to develop our nature into goodness. Obviously, Mencius was at odds with him. His views were declared as unorthodox by Chu Hsi.

Mencius is often compared to Plato for their theories on human nature. Both were idealists in that they believed in the innate moral goodness of all human beings.

Mencius' argument that unjust rulers may be overthrown is reminiscent of Socrates' argument in Book I of Plato's Republic.

*Chan, Wing-tsit (translated and compiled). A Source Book in Chinese Philosophy. Princeton, NJ: Princeton University Press, 1963. *Graham, A.C., Disputers of the TAO: Philosophical Argument in Ancient China (Open Court 1993). ISBN 0-8126-9087-7

<div class="infobox sisterproject"> <div style="margin-left: 60px;">Original works by Mencius in Chinese at Chinese Wikisource (維基文庫) : <div style="margin-left: 10px;">孟子</div> </div> </div>

*English translation of the Mencius by Charles Muller *English Translation of the Mencius with comments by James Legge *Mengzi (Chinese-English bilingual version) *Stanford Encyclopedia of Philosophy entry *