Thus, having shown how there cannot be consciousness without external objects, in order to reject the position that it simply must exist, it is said:

And if detached from subject-object there could be
Dependent nature, empty of duality,
Then who would know of its existence? Just to say,
‘It’s there but not perceived,’ is quite unreasonable. (6.72)

If a dependent nature empty of so-called apprehended and apprehender exists, through what cognition do you apprehend its existence? It is untenable that it apprehends itself, since it is contradictory for something to direct its act upon itself: the blade of a sword cannot cut itself; the tip of a finger cannot touch itself; even the strongest and most dextrous athlete isn’t able to climb onto his own shoulders; fire cannot burn itself; and an eye cannot look at itself. Another cognition cannot be apprehending it since that would conflict with your own tenets; if cognition was the object of another cognition, one could then say that this undermines the sense of cognition only. Hence there is no way whatsoever that there can be an apprehender of it; and that which cannot be apprehended cannot exist.