One of the main features of Yogācāra philosophy is the concept of "vijñapti-mātra". According to Lambert Schmithausen, the earliest surviving appearance of this term is in chapter 8 of the "Saṅdhinirmocana Sūtra," which has only survived in Tibetan and Chinese translations that differ in syntax and meaning. The passage is depicted as a response by the Buddha to a question which asks "whether the images or replicas ("*pratibimba") which are the object ("*gocara") of meditative concentration (*"samadhi"), are different/separate ("*bhinna") from the contemplating mind ("*citta") or not." The Buddha says they are not different, "Because these images are "vijñapti-mātra."" The text goes on to affirm that the same is true for objects of ordinary perception.