Imagine two people arguing over whether Plato was taller than Aristotle. They explore old texts, compare them, and go round and round arguing about it. Now imagine two people arguing over whether Don Quixote was taller than Hamlet. They explore old texts, compare them, and go round and round arguing about it. Someone might say that these two arguments are different because there is a fact about whether Plato was taller than Aristotle, but there is no such fact about Hamlet and Don Quixote. What would a phenomenalist say?
Can two people experience the same hallucination? Is there a difference between saying they experience the same hallucination and saying they experience identical hallucinations? What about two people having the same idea or the same concept?
Suppose some characters in a video game became conscious and you can talk to them. Suppose further that you explain to them the GDD, and they become skeptical of their knowledge of their world. You read this chapter to them—or send them a copy of it—and as a result some of them become phenomenalists. Does this make any sense? Can they become phenomenalists if the objects they thought they were experiencing were only virtual to begin with?