 Philip Goff (2010) suggests that this loophole for Russellian versions of physicalism weakens the zombie argument. He recommends instead an argument from ghosts: pure subjects of experience without any physical nature. He argues that such ghosts are conceivable and possible, and that they provide an argument against physicalism which leaves no loophole for Russellian monism. (Physicalists are likely to object that arguments against the conceivability of zombies can also be mobilized against ghosts.) 