evaṃ tarhi yadarthakriyāsamarthaṃ tadekaṃ vastu, yaccāsamarthaṃ taddvitīyam iti vastudvayam eva kevalaṃ bhavatā pratipāditam, natvekasyobhayātmatvam //
In that case, what is capable of producing an effect is one thing, and what is incapable is a second thing - thus you have merely established [the existence of] two things, not the dual nature of one [thing].