To say that consciousness does not exist is only to another way of insisting that it not be detached from the first-person perspective. The matters that exist are things in consensus or in third-person perspective, things of which you can say 'it is'. Clearly there is such a dimension to consciousness in which it is distinguished from unconsciousness in a neurophysiological way - it corresponds to clearly defined brain functions which may or may not be correlated with certain behaviours. In this sense dream and deep-sleep are regarded as modalities of consciousness, as distinct from coma, or the state of a brain under a general anaesthetic. But again, in considering your own consciousness from the inside, since you can be aware of being conscious in addition to simply being conscious, and this additional layer seems perfectly under voluntary control (although not so much the deeper recursive layers it implies), it seems that there are objective correlatives of consciousness that are grasped only subjectively. To know you are there you must make an object of yourself, but it is a purely private object, and a fleeting one - but its readiness-to-hand provides a strong confirmation of your presence. This inner self-object, or self-objectifying process, gives rise to existents, the fleeting inner objectivities that arise must be said to exist. You might, like Hume, question whether they prove what they are naively taken as evidence for, but you won't deny their existence, even though they can't be confirmed in consensus reality. As a class they are entirely consistent with that reality, with the kind of conversation that moves seamlessly between say, external objectivities and private qualia, such as in a wine-tasting. The Humean position is essentially correct; just because these inner contents are objects of a sort they can tell us nothing about their corresponding subject. The inference that would attempt to pass to this subject fails because inference can only be between terms of the same general kind. The gap here is far more severe and unbridgeable than it looks, because we can and do know absolutely nothing about what lies on the other side; all metaphors fail including this one.