因明入正理論疏 1.149

1.149

問：「如立無常，龜毛無彼常住之相，亦名無常；於一切時性常無故，亦得名常。何故不立非同異品？」答：「聲言無常，性是滅義；所作性者，體是生義。龜毛非滅，亦非有生。既無所立，即入異品，故喻唯二，更無雙非。若常宗有，亦入異品。若非有品，便入同中。」

Question: 'As in establishing impermanence, the hair of a tortoise lacks that permanent characteristic, so it is also called impermanent; and because its nature is permanently non-existent at all times, it can also be called permanent. Why not establish a class that is neither homologous nor heterologous?' Answer: 'The word impermanence has the nature of cessation; being produced has the essence of arising. The hair of a tortoise is neither cessation nor does it have arising. Since it lacks that which is to be established, it enters into the heterologous class; therefore, the examples are only two, and there is no negation of both. If what is permanent exists in the thesis, it also enters into the heterologous class. If it is a class without existence, it then enters into the homologous.'