 This is the famous “explanatory gap” for qualia (Levine 1983, 2000). Some say that the explanatory gap is unbridgeable and that the proper conclusion to draw from it is that there is a corresponding gap in the world. Experiences and feelings have irreducibly subjective, non-physical qualities (Jackson 1993; Chalmers 1996, 2005). Others take essentially the same position on the gap while insisting that this does not detract from a purely physicalist view of experiences and feelings. What it shows rather is that some physical qualities or states are irreducibly subjective entities (Searle 1992). Others hold that the explanatory gap may one day be bridged but we currently lack the concepts to bring the subjective and objective perspectives together. On this view, it may turn out that qualia are physical, but we currently have no clear conception as to how they could be (Nagel 1974). Still others adamantly insist that the explanatory gap is, in principle, bridgeable but not by us or by any creatures like us. Experiences and feelings are as much a part of the physical, natural world as life, digestion, DNA, or lightning. It is just that with the concepts we have and the concepts we are capable of forming, we are cognitively closed to a full, bridging explanation by the very structure of our minds (McGinn 1991).