Sarvadarshanasangraha 2.13

2.13

And those Buddhists proclaim the highest aim of human existence by means of a fourfold contemplative cultivation. And these Buddhists, famous by the names Mādhyamika, Yogācāra, Sautrāntika, and Vaibhāṣika, maintain respectively the doctrines of the emptiness of all things, the emptiness of external objects, the inferability of external objects, and the perceptibility of external objects. Although the blessed Buddha was only one teacher, nevertheless, owing to the difference in intellect of those to be taught, there is a fourfold division. Just as when it is said, "the sun has set," paramours, thieves, Vedic scholars, and others understand [thereby] the time for their assignation, stealing another's property, performing proper conduct, and so forth, according to their own desires.