I suddenly realized something yesterday. Hopefully, people will find this illuminating.
I've heard many times that phenomena do not come or go. I didn't understand this. Yesterday I was thinking about what Ra Lotsawa and duckfiasco have said about thoughts. They are empty appearances that neither come nor go. Then in a flash of insight, I realized that thoughts appear because of causes (past events, mental objects, etc) and conditions (the mind itself) but if the thought existed it would have to be a continuum. But, a fresh thought arises from nowhere and fades to nowhere.
Then in a second flash I realized that physical phenomena are the same. They neither come nor go, but due to causes and conditions, appear and function.
This also ties into what Tsongkhapa said about Dependent Origination (causes and conditions) eliminating eternalism. If phenomena have causes and condition then they do not belong to a continuum, therefore they are merely appearances.
I'm struggling with my obscurations to maintain my understanding of this, so I'm going to write it down before the 'heat' fades.
My 2 cents - stay with the "flash" - don't sweat the "understanding."
"Although Tsonkhapa argued in favour of Yogacara views early in his career his later understanding is derived from Candrakirti, who states that conventionally there are entities with distinguishing characteristics, but ultimately those qualities are not independent essences. But since this emptiness is true for everything that exists, this emptiness may also be regarded as an essence, though not in the sense of an independent essence. Candrakirti formulates a final negation by stating that even the denial of svabhava implies ...
...that either oneself or one's audience is not entirely free from the belief in svabhava. Therefore, ultimate truth, truth as it is for those who are free from misknowledge, cannot be expressed by asserting either the existence or nonexistence of svahbava"http://en.wikipedia.org/wiki/Madhyamaka ... .B9.85gika
Sooooooooooooo - Try relaxing into the flash / heat and just gently guide your attention back to this when thoughts of it is, it is not, neither or both arise.