瑜伽論記 2.284

2.284

第五難中，誰復於彼制其功能者，誰於極微制有情功力不令生之，比量可知，若言不因有情是則無用而外物生者，用謂由也，於有情無用，不由有情故而外物生，不應道理，量云：汝等外物應不得生，於有情無用故，如龜毛等。

In the fifth challenge, regarding "who again curbs their functional efficacy?": Who curbs the effort and power of sentient beings upon the atoms so that they do not produce [effects]? This can be known by inference. Regarding "if it is said to be not due to sentient beings, then external things would arise without purpose": "Purpose" (yong) means "due to"; external things arising without purpose for sentient beings, not due to sentient beings, is unreasonable. The formal inference is: Your external things should not be produced, because they are without purpose for sentient beings, like a tortoise's hair.