Ch 18, Sh 48 continued-3, Bhagawad Gita, Shankar Bhashya

Vaisesika: Is it not that relationship of a non-existent thing is not at all established by the Vaisesikas? Indeed, what is said by them is that only existent entities like dvyanuka etc. have the relationship in the form of samavaya with their own causes.
Vedantin: No, for it is not admitted (by them) that anything has existence before the (samavaya) relationship (occurs). It is surely not held by the Vaisesikas that a pot etc. have any existence before the potter, (his) stick, wheel, etc. start functioning. Nor do they admit that clay itself takes the shape of a pot etc. As a result, it has to be admitted (by them) as the last alternative that non-existence itself has some relationship!
Vaisesika: Well, it is not contradictory even for a non-existent thing to have the relationship in the form of inherence.
Vedantin: No, because this is not seen in the case of a son of a barren woman etc. If the antecedent non-existence (prag-abhava) of the pot etc. alone comes into a relationship with its own (material) cause, but not so the non-existence of the son of a barren woman etc. though as non-existence both are the same, then the distinction between the (two) non-existences has to be explained. Through such descriptions ( of abhava, non-existence) as non-existence of one, non-existence of two, non-existence of all, antecedent non-existence, non-existence after destruction, mutual non-existence and absolute non-existence, nobody can show any distinction (as regards non-existence itself)! There being no distinction, (therefore, to say that:) 'it is only the "antecedent non-existence" of the pot which takes the form of the pot through the (action of) the potter and others, and comes into a relationship with the existing pot-halves which are its own (material) causes and becomes fit for all empirical processes [Such as production, destruction, etc.] but the "non-existence after destruction" of that very pot does not do so, though it, too, is non-existence. Hence, the "non-existence after destruction", etc. [Etc. stands for 'mutual non-existence (anyonya-abhava)' and 'absolute non-existence (atyanta-abhava)'.] are not fit for any empirical processes, whereas only the "antecedent non-existence" of things called dvyanuka etc. is fit for such empirical processes as origination etc.' all this is incongruous, since as non-existence it is indistinguishable, as are 'absolute non-existence' and 'non-existence after destruction'.
Vaisesika: Well, it is not at all said by us that the 'antecedent non-existence' becomes existent.
Vedantin: In that case, the existent itself becomes existent , as for instance, a pot's becoming a pot, or a cloth's becoming a cloth. This, too, like non-existence becoming existent, goes against valid evidence.