Poems and lyrics arise from genuine feelings, which, however, should not be excessive but be controlled by ritual propriety and righteousness, so as to be tactfully persuasive. This term was first used when commenting on The Book of Songs and then developed into a guiding principle for literary creation in general. It not only acknowledges people's instinctive desires and the need to express and describe such desires, but also emphasizes that Confucian ethics should be employed to contain and guide feelings, which should neither be improperly vented nor transgress the boundaries of society, politics and ethics. Thus, feelings expressed via poetry are both individual and social.