Alastair Macaulay for The New York Times

How many layers are there to human thought? Sometimes in art, just as in people’s conversations, we’re aware of only one at a time. On other occasions, though, we realize just how many layers can be in simultaneous action, and we’re given a sense of both revelation and mystery. When a choreographer responds to music — when one artist reacts in detail to another — the sensation of multilayering can affect us as an insight not just into dance but into the regions of the mind.