[grumpopotamus]

You could in theory behave in exactly the same way without inner subjective experience. The argument goes like your brain gets exactly the same signals and processes them in exactly the same way, and initiates exactly the same actions, except you are not experiencing anything. Imagine a robot that gets sensory inputs from the world and processes them in some giant neural network brain and behaves very similarly to a human, and even claims that it is feeling things. Is it really feeling anything? So far we have absolutely no way of answering that question.