  (a) The ‘ectoplasm’ account: The view that immaterial substance is a kind of immaterial stuff. There are two problems with this approach. First, in so far as this ‘ectoplasm’ has any characterisation as a ‘stuff’ – that is, a structure of its own over and above the explicitly mental properties that it sustains – it leaves it as much a mystery why this kind of stuff should support consciousness as it is why ordinary matter should. Second, and connectedly, it is not clear in what sense such stuff is immaterial, except in the sense that it cannot be integrated into the normal scientific account of the physical world. Why is it not just an aberrant kind of physical stuff?