Looks like you won’t be switching to the Sarvāstivāda on us, venerable! ![:laughing: :laughing:](https://discourse.suttacentral.net/images/emoji/twitter/laughing.png?v=12)
Because it is the assertion that one side of sense-contact (the object side) is real and independent. If they don’t assert that this is the case, then they cannot assert that the cup is real. Does that make sense?
Basically, they have to believe that their perception of the cup is an actual, real cup independent of/beyond that perception. If they don’t think that, they can’t actually claim that there is a real, independent cup there.
Now, once they assert (or assume—as most people do) that the object of sense-contact is substantial, real, independent, etc. That means that the subject (by this I mean the senses–the eye, ear, nose, etc.; the knower) is also independent of those objects. Because it encounters different objects in the world. So it means it is independently roaming around in space and time. The “subject” becomes one of the “objects” in an existent external world. And the objects are assumed to be independent entities, or substantial things.
If the subject is an independent entity, it is either permanent (eternal) or impermanent (annihilated). If they think that the substance making up reality is matter-energy (modern physicalists), then they think that the subject (the senses, the knower) will be annihilated. If the person thinks that the substance making up reality is some kind of Idealist Mind, they will probably be an eternalist, because the substance of the senses/knower will also be made of that eternal substance. The belief in substance alone is enough for annihilationism/eternalism. They do not need to form a specific belief in a “self,” and some of them may even deny that there is a self. But by positing substantial entities, it is the same thing as a self.
This is the assumption Rohitassa made, BTW. The dependent arising of contact resolves this issue. At which point, the arising/ceasing of contact itself can be the area of focus. Not selves or substances.
Dependent arising does not make a new assertion about the cup. It simply refutes the assertion of substantial objects. By refuting the substance of objects, “subjects” (the senses) too cannot be reified into independently existing entities. Which means they cannot be eternal or annihilated.
Yay! ![:laughing: :laughing:](https://discourse.suttacentral.net/images/emoji/twitter/laughing.png?v=12)