The explanatory gap
First articulated by Levine [], the idea of the explanatory gap is that no matter how much we learn about the functioning of the brain and how that connects with behaviour, there is still no explanation of why particular experiences feel the way they do, and not in some other way. Moreover, although we can consider science leading to a greater and greater knowledge and understanding of physical Nature, there is no handle on how that new knowledge could lead to an answer to the “hard problem” of phenomenal consciousness.
This gap is specific to phenomenal consciousness. In other areas of science, reductions do not lead to such a puzzle. So the reduction of temperature to mean kinetic energy does not prompt the question, “why” does mean kinetic energy yield temperature. Such an explanation is readily available. So this implies that there is something different about phenomenal consciousness compared with other things.
Papineau [] attempts to answer this difficulty by comparing the situation with one person having two names. For instance, nobody can say why Mark Twain is the same as Samuel Clemens. However, the two cases can be considered as disanalogous, as Papineau acknowledges. Nevertheless he maintains that the argument stands and it is only an instinct of distinctiveness which makes people reluctant to accept that. He then proceeds to dispense with the term “explanatory” thus completely missing the point.
“If we are not thinking of pain as something with certain physical causes and effects, but as something that feels a certain way, then we find ourselves quite unable to offer any explanation of why brains yield pains.”
Some believe that this is simply a gap in our understanding of Nature, others believe that it represents a gap in Nature itself, and therefore that there is more to Nature than the physical.