俱舍論記 17.158

17.158

「若有人害至心境劣故」者，簡差別。若有人害非人父、母，不成逆罪，由心劣故、由境劣故。又《正理》云「若有人害非人父、母，亦不成逆罪，少恩、羞恥故。謂彼於子無如人恩，子於彼無如人慚、愧（已上論文）。」由此准釋，若有非人害人父、母亦不成逆，人境雖勝，由心劣故。又解：父母於彼少恩，彼於父母慚愧心微。

Regarding "If a human kills ... because of the inferiority of mind and object": this distinguishes the differences. If a human kills non-human parents, it does not constitute a mortal offense, because the mind is inferior and because the object is inferior. Furthermore, the *Nyāyānusāra* says: "If a human kills non-human parents, it also does not constitute a mortal offense, because of slight kindness and shame. That is, those [parents] have no kindness toward the offspring comparable to that of humans, and the offspring have no shame or conscience toward them comparable to that of humans (end of quotation from the treatise)." Analogously explained based on this: if a non-human kills human parents, it also does not constitute a mortal offense; although the human object is superior, the mind is inferior. Another explanation says: the parents had little kindness toward them, and they had feeble shame and conscience toward their parents.