The Analects never defines ren. Asked directly what it means, Confucius gives different answers to different students, loving others to one, mastering oneself and returning to ritual propriety to another, careful and slow to speak to a third, a method the text itself frames as tailoring the teaching to the student's own shortcomings rather than withholding a single correct definition. Li receives more concrete treatment: the specific ritual forms of mourning, sacrifice and social address, performed with genuine feeling rather than mechanically, since the Analects insists that ritual without the right inner attitude is empty.
Confucius's two most influential successors read inner disposition and outer form very differently. Mencius argued that ren, with the other constant virtues, is already present in every person as an innate moral sense, visible in the instinctive alarm anyone feels on seeing a child about to fall into a well; moral cultivation on his account draws out what is already there. Xunzi took the opposite position, arguing that human nature left to itself tends toward disorder, so li, ritual and the wisdom of past sages, must actively reshape character rather than simply uncover it.
Han dynasty scholarship, associated with Dong Zhongshu, organized ren, yi, li, zhi and xin into the Five Constant Virtues, a pentad correlated with the five phases of cosmological theory, giving Confucian ethics a systematic vocabulary the Analects never supplies. Centuries later, Song dynasty Neo-Confucian thinkers built a fresh metaphysics of principle and vital force onto this same ethical core, a later development the atlas records separately rather than folding backward into the classical framework described here.