I'm not completely sure who invented the zombie concept. Let me know if you find out.

David Chalmers believes in the concept of philosophical zombies. He defines a philosophical zombie as: "Zombies are physically and behaviorally identical to a conscious human, but lack any conscious experience". Essentially, they lack qualia. Chalmers argues that the idea of zombies is logically consistent, he says the existence of zombies is entirely plausible.

Chalmers argues that since our zombie counterparts can exist, and they are physically identical to ourselves and somehow lack res cogitens, then res extensa must not give rise to res cogitens. (For if res extensa gave rise to res cogitens, then identical sets of res extensa would give rise to identical sets of res cogitens, and our physically identical zombies would otherwise have minds. Since they lack qualia but are physically identical, qualia must be independant of the physical world). To him, this thought-experiment destroys materialism.

The argument is decent, except it depends on believing in dualism to swallow the presupposition of "imagine that something physically identical can be somehow intrinsically different".

The argument actually goes back and forth quite a lot. It's pretty much the good old dualism vs monism fight.

Daniel C. Dennett fights for monism. He claims that physical indistinguishability is all there is. I agree with him.

The individual cells that compose you are alive, but we now understand life well enough to appreciate that each cell is a mindless mechanism, a largely autonomous micro-robot, no more conscious than a yeast cell. [...] it has been tempting over the ages to imagine that [the mind] must be due to the special features of some extra thing--a soul--installed somehow in the bodily headquarters.
Until fairly recently, this idea of a rather magical extra ingredient was the only candidate for an explanation of consciousness that even seemed to make sense. For many people, this idea (dualism) is still the only vision of consciousness that makes any sense to them, but there is now widespread agreement among scientists and philosophers that dualism is–-must be–-simply false: we are each made of mindless robots and nothing else, no non-physical, non-robotic ingredients at all.

In fact, Chalmers makes the same logical flaw that Plato made, way back in the day. Plato assumed that because he could imagine his mind existing without his body, that therefore minds can always exist without bodies, and therefore res extensa is separate from res cogitens. The flaw is this: just because you can imagine something (such as zombies, or a body-independant mind) doesn't make it possible.

Now for a bit of my own personal philosophy. If zombies were possible, and you asked one of them "do you feel qualia?" he would respond in the affirmative, the same way his conscious counterpart would. In fact, he would believe (as much as zombies can believe anything) that he is conscious, he believes that he has an active mental life.

So if we were zombies, we would have no way of knowing it. So maybe qualia is an illusion. This point is made by a story by Raymond Smullyan (sorry I don't know the title) about a soul-less man who isn't aware he's soul-less.