How do you know computers don't experience their existence? We assume because they behave predictably that this indicates they are unaware automata, but assume I asked you if you would like me to put a gun to your head and pull the trigger. You would answer no with extremely high probability. Just because your answer is predictable doesn't indicate that there is no awareness behind it. In fact, there is almost certainly something that it is "like" to be a tightly coupled system of transistors. Of course, that experience is undoubtedly very different from ours.

Part of the problem is that consciousness is a nebulous term that conflates awareness, self-awareness and intelligence. Specifically, I'm only speaking of awareness here.

Also, when sand undergoes chemical reactions, how do you know that isn't a simple form of information processing?