prayogaḥ yadyadākārasaṃvedanaṃ na bhavati na tat tadviṣayaṃ yathā cakṣurjñānaṃ na śabdaviṣayaṃ
The argument is: Whatever does not apprehend the form of something cannot have that thing as its object, just as visual cognition cannot have sound as its object.