There is a cup. We think we see it but we don't. We think we know it but we don't. Its nature is totally unknown.....
.....This cup cannot be negated, but remember it is still impermanent.
There is the cup of perception......
.....that tells me just about nothing about the nature of whatever it is that is causing these perceptions.
Then there is the cup of the mind......
.....Plus, again they tell us nothing about the cause of all these perceptions.
Finally there is the other cup of the mind.....
There's a lot to a cup.
All of your cups are not different, and have the same source- mind.
In your first case, you say you can't see it or otherwise know it, but you still affirm there is a cup.... based on what?
All of your cups, in every case, point to the same thing. But you keep saying they tell us nothing about the cause of the perceptions.
This is simply because you are focusing too much on the object of perception. If you follow it back, perception is a mental aggregate. It is mind. It's cause is delusion and habitual karma.
But as the Heart Sutra tells us, in emptiness "there is no perception". If even perception is false, that mind of the aggregates is false, and subject and object both disappear. So based on what do you still maintain that there is a cup and there is you who perceives it?
True dependent origination points to true mind. No matter how real a cup seems, it is only due to our karma. But we shouldn't doubt it's origin.
Shurangama Sutra, Chapter 9 wrote:"Ananda, you should know that as a cultivator sits in the Bodhimanda, he is doing away with all thoughts. When his thoughts come to an end, there will be nothing on his mind. This state of pure clarity will stay the same whether in movement or stillness, in remembrance or forgetfulness. When he dwells in this place and enters Samadhi, he is like a person with clear vision who finds himself in total darkness. Although his nature is wonderfully pure, his mind is not yet illuminated. This is the region of the form skandha. If his eyes become clear, he will then experience the ten directions as an open expanse, and the darkness will be gone. This is the end of the form skandha. He will then be able to transcend the turbidity of time. Contemplating the cause of the form skandha, one sees that false thoughts of solidity are its source."