In discussions concerning the possibility of AI consciousness, computational functionalism has been the dominant position. This is the view that consciousness is essentially kind of computation and therefore medium independent (not reliant on any one kind of physical realizer). The opposing position, biological naturalism, has recently been discussed by Block (2025) and Seth (forthcoming). This is the view that consciousness is essentially a property of (some) living organisms and is therefore medium dependent. According to Block, the debate between computational functionalism and biological naturalism is over whether it is the role or the realizer that determine consciousness. Here I argue that biological naturalism is better understood as the thesis that in living, conscious beings, roles and realizers are inextricably related in such a way that the computational functionalist requirement of medium independence cannot obtain. I discuss findings in neuroscience that are relevant to this issue. Although the neuroscience is still not settled, we can make progress on setting the parameters for the debate over the material basis of consciousness as it unfolds.