 The disputes about whether attention is sufficient for consciousness, necessary for consciousness, or both, are related to questions about attention’s metaphysics. The claim that attention is not sufficient for consciousness is typically made as part of a defence of the idea that attention and consciousness are underpinned by two distinct brain processes, which can occur independently (see, e.g., Koch and Tsuchiya, 2007). The claim that the things to which we attend are a proper subset of the things that appear in our consciousness is required by those who, like Locke (see Section  1.3),  think that there is a process of conscious thinking, and that this constitutes attention when it happens in a certain way.   And the claim that attention is both necessary and sufficient for consciousness is required by those who think that the process by which things come to consciousness is identical to the process by which attention is allocated (Prinz, 2005, 2011). Some scientific theories of consciousness also carry strong commitments concerning its relationship to attention: Taylor Webb and Michael Graziano emphasize these commitments in making the empirical case for their ‘Attention-Schema’ theory, according to which consciousness emerges from processes in which the control of attention requires a schematic representation of the way in which attention is being allocated (Graziano and Webb, 2014; Webb and Graziano, 2015).