Consciousness occupies a central place in contemporary Anglophone philosophy of mind. One reason why this is so – and we shall expand upon this later – is that consciousness poses a problem for naturalist theories of mind. Most Anglophone philosophers of mind are committed to the view that social, linguistic and psychological facts supervene upon and are determined by facts about the objective, non-mental, causal world, a world studied and explained by physics, chemistry, biology and other "natural" sciences. Whilst most philosophers agree that consciousness poses a problem for this naturalistic conception of the world, there is considerable disagreement about what consciousness is. This is, perhaps, not surprising. It has long been recognised that "consciousness' is an ambiguous, polysemic notion.