The zombie argument came to be in 1974, in a paper by Robert Kirk, but it was David Chalmers` book, The Conscious Mind (1996) that gave it a prominent place within philosophy of mind. This argument`s main objective, and that of its several different versions, is to refute materialism. In short, it says that, if it is possible to think of a physical zombie, a being physically identical to a human being, but lacking qualitative conscious states - that is, lacking qualia - then such states cannot be physical. If such states were physical, the zombie would have to lack something. This way, all that would be necessary to refute materialism would be to show that such a being is conceivable. However, several critiques arose and the main author of those, Daniel Dennett, has been gaining support in his defense of the view that zombies are logically impossible, that is, are unconceivable.