Often termed as wenjian zhizhi 聞見之知 (knowing from hearing and seeing), sensory knowing was a prominent topic in Song (960–1279) writings. Zhang Zai 張載 (1020–1077) developed a systematic critique of sense perception in the broad context of learning. While endorsing its utility, Zhang considered this way of knowing to be partial, superficial, and prone to error. He located the source of sensory errors inside the human body, arguing that the sense organs’ vulnerability to pathological changes constituted the cause for perceptual fallibility. This line of argument had solid corroborating evidence in contemporaneous medical knowledge, a field of study Zhang was interested in pursuing. In sum, Zhang's critique demonstrated the importance of the senses and the different ways in which middle-period Chinese literati conceptualized the problem of perception in comparison with Western epistemological traditions.
