Yogācārabhūmi-śāstra, Volume 34 (38)

Original text:如是比度作意力故。由灭坏行。于彼诸行刹那生灭。灭坏无常而得决定。于如是事得决定已。复于他世非所现见。诸行生起。应正比度。云何比度。谓诸有情现有种种差别可得。或好形色。或恶形色。或上族姓。或下族姓。或富族姓。或贫族姓。或大宗叶。或小宗叶。或长寿命。或短寿命。言或威肃。或不威肃。或性利根。或性钝根。如是一切有情差别。定由作业。有其差别方可成立。非无作业。如是有情色类差别。定由先世善不善业。造作增长种种品类。

Explanation: Because of the power of intensified mental engagement (adhimātramanaskārabala) in inference, through contemplation of destruction and ceasing, one observes that all formations arise and cease moment by moment, being destroyed and impermanent, and thereby reaches a definite conclusion: all formations are mutable and impermanent. After arriving at certainty regarding these matters, one should then correctly infer, by means of inference, the arising of formations in past and future lives, which cannot be directly perceived. How does one infer? The various kinds of differences presently observable among sentient beings can be seen: some have fine physical features, some have ugly physical features; some are of noble lineage and caste, some are of lowly lineage and caste; some come from great clans, some come from small clans; some are long-lived, some are short-lived; some speak with dignity and sternness, some speak without dignity or sternness; some have sharp spiritual faculties, some have dull spiritual faculties.

All such differences among sentient beings can only be established on the basis of differences in the karmic actions they have performed, not in the absence of karmic actions. These differences in the physical types of sentient beings are certainly due to the wholesome and unwholesome karma created and cultivated in past lives, which has produced and increased the various kinds of differences among them.

Correct inference is deliberation (manana) by comparison based on what has been directly perceived and upon which the mind has already reached certainty. If it is not based on direct perception, then the comparison and deliberation is incorrect inference; incorrect inference is not encompassed by wisdom, whereas correct inference yields wisdom.