Understanding the character and justifications of James Legge’s (理雅各, 1815-1897) translations, interpretations and assessments of Master Mèng’s 孟子account of human nature is a more complex matter than has been normally assumed or claimed. It involves hermeneutic, comparative philosophical and comparative religious elements which are rarely addressed by those who evaluate Legge’s translation. This article explains the multi-dimensional layers of Legge’s interpretation of the “goodness of human nature” with The Mencius (first edition 1861, second edition 1893) within his Chinese Classics. These include his various translations of shàn 善as well as his extensive introductory essays and translations. Details found in these places help to explain why Legge chose to render the phrase xìng shàn 性善as “the tendency of [human] nature to good.” It also provides a summary of his conclusions from a comparative philosophical analysis of Joseph Butler’s and Master Mèng’s accounts of human nature. Another insight reveals why Legge supported this interpretation of Master Mèng’s teaching on human nature from his own Protestant Dissenter theological studies. Added to this are comparative philosophical and religious questions raised by Legge regarding certain related aspects of the character and teachings of Master Mèng, indicating shy he preferred the character and teachings of Master Kǒng 孔子over Master Mèng in these realms.