I am very interested in the concept of the Philosophical Zombie, though after
Try this. Suppose everything that is explained is explained by facts about the physical world - that's physicalism. If zombies were possible and existed, we would be physically indistinguishable from them. But they would have no consciousness. So whatever explains our consciousness cannot be physical. If it were, it would also make consciousness for the zombies. That's the point of the physical indistinguishability between us and the zombies. There is a very good article in the Stanford Encyclopedia of Philosophy called "Zombies", by Robert Kirk, by the way, which will clear everything up for you.