因明入正理論疏 2.49

2.49

問：「何故但名異喻，不名異宗、因耶？」答：「喻合兩法，宗、因各一，說異喻以總苞，言異二而為失。若言異宗異因，謂更別成他義，非是離前返成能立。故總名異喻，合異宗因，不別說異宗異因之號。」

Question: 'Why is it only called a negative example (vaidharmya-dṛṣṭānta) and not called a negative thesis or negative reason?' Answer: 'The example combines the two properties, whereas the thesis and reason are each one; speaking of a negative example subsumes them generally, whereas speaking of negative thesis and reason would be a fault. If one spoke of a negative thesis and a negative reason, one would think it separately establishes another meaning, rather than departing from the preceding to turn around and establish the proof. Therefore it is generally called a negative example, combining the negation of thesis and reason, without separately stating the designations of negative thesis and negative reason.'