One such point of view is that currently all existing explanations for qualia - even the ones that try to be materialistic - are actually dualist. For instance, suppose we have a materialist-computational explanation of the brain, which explains how each neuron performs a certain type of computation, and how certain activity patterns in the neurons correspond to specific mental states. We find the model to be good and to accurately predict what people will do. So far, so good.

Yet here we run into a problem - we can now fully explain the brain and one's doings in terms of the computational model, without needing to include actual qualia or subjective feelings in the explanation at all. The model works just as well regardless of whether or not we experience phenomenal consciousness, or are p-zombies. In trying to explain mental states, we have actually explained them away and created a theory that has no need for them.

Therefore, the argument goes, assuming we don't deny the existence of qualia entirely, we must dualists. After all, we now have two models, one physical model which doesn't include qualia, and one which assumes their existence but provides no physical explanation.