I start with some quotes, to show how I got to two specific questions about Buddhism, then a question that is more philosophical and general.
Batchelor's translation of Nagajuna's MMK:
I bow down to the most sublime of speakers, the completely awakened one who taught contingency (no cessation, no birth, no annihilation, no permanence, no coming, no going, no difference, no identity) to ease fixations.
Looking at the section on birth, 7.4 (I'm more or less choosing interesting parts at random to get to my particular point, below)
The birth of birth gives birth to the root birth alone. The root birth also is that which gives birth to the birth of birth
That seems like an infinite regress of births, suggesting birth is caused (7.19)
If another [thing] that has been born gives birth [to it], this would be endless. If it is born without [another] which has been born [OR if it is born without being born], everything would be born like that [i.e. causelessly].
which may be why he concludes (7.34)
Like a dream, like a magician’s illusion, like a city of gandharvas, likewise birth and likewise remaining, likewise perishing are taught.
perhaps via support from 1.3
The essence of things does not exist in conditions and so on. If an own thing does not exist, an other thing does not exist.
birth is not an other thing, its essence is not in others, and in conjunction with the argument in 1.5
Since something is born in dependence upon them, then they are known as “conditions”. As long as it is not born, why are they not non-conditions?
we're back to birth being an infinite regress, but the apparent way out, it being caused, makes no difference, because cause too is a birth: birth is no birth.
We can pile up adjectives as long as we want. The red of the rose is a red that is red, and so on. Whereas actions, verbs, take up time, and suggest an infinite number of tasks, births, need to occur for one to.
Is there, in Nagarjua's Sanskrit (different grammars teach different rules), an adjective for the past tense of born?
Even if we do use an adjective for birth does this offer any problems? Does the meaning of "born" always involve an incomplete infinite regress of actions, or can that be avoided if it itself is not an action?
I suspect that we can get out of the infinite regress only through the claim that the born thing exists to have such and such aspects. Am I right?
Does my presentation of the idea that born things must exist because they are caused, unlike nirvana, makes sense to yogacarin theories of trisvabhava?