Great posts , I don't have much time but I want to stay involved in such an interesting conversation. So, here some more fodder that (maybe incorrectly) comes to my mind on these topics…
Perhaps, this is due to my somewhat limited knowledge, but isn't there a difference btw the Prasangika and Svatantrika interpretation with regards to the object of negation?
It is the false object of comprehension posited by the mistaken consciousness that is the object of negation not something from the side of the object.
Also, for Gelug prasangika the object of negation includes both the conception of inherent existence and also the appearance of inherent existence that has to be eliminated.
When it comes to understanding Tsongkhapa's presentation of the object of negation or inherent existence I think his interpretation of chapter 15 of Nagarjuna's MMK is particularly insightful. In particular verses one and two.
In the prasnnapadā Candrakirti preposes that these verses give Nagarjuna's definition of inherent existence (svabhāva). He gives the definition of svabhāva then as not fabricated and not dependent on anything else.
For Tsongkhapa it is a little more tricky because he interprets Chandra as posting this type of svabhāva as emptiness rather than the object of negation. This is a massive distinction!!!
Khedrup Je explains further how to understand emptiness as not fabricated and not dependent. For the definition to apply to emptiness rather that just the gross view of selflessness we should understanding unfabrication as meaning not just uncaused but also not mentally fabricated. Since, it is only emptiness that is not mentally fabricated, meaning appear truly. Also, he says we have to qualify dependent here meaning not dependent in terms of comparison.
So, Tsongkhapa says that this is not a complete description of the object of negation and would leads to negating too much. Therefore, Tsongkhapa adds to the above definition of svabhāva two more qualifications so that it might qualify as the object of negation. That it is established from its own side and that it is natural and not learned.
And, this is how the object in terms of the conventional truth is not negated and nihilism is averted from the Prasangika POV?
I think the unique perspective of Gelug prasangika have for not falling into nihilism is that they understand the wisdom perceiving emptiness has limits so to speak - in that since it is an examination of the ultimate it cannot refute the conventional. This is why Tsongkhapa counter-intuitively claims that it is the understanding of emptiness that protects is from nihilism.
The Svatantrika identify this differently and I used to have a little bit of a clue how, but the details have evaporated as my studies have
Gelug presentation of svatantrika has them making a distinction between inherent existence and true existence that prasangkia do not make. This is why they attach to the definition of a prasnagika, "that they do not assert true existence even conventionally". Geshe Tashi's explanation was excellent - thanks for posting.