Megan Erickson in Big Think:
The simplest description of a black hole is a region of space-time from which no light is reflected and nothing escapes. The simplest description of consciousness is a mind that absorbs many things and attends to a few of them. Neither of these concepts can be captured quantitatively. Together they suggest the appealing possibility that endlessness surrounds us and infinity is within.
But our inability to grasp the immaterial means we’re stuck making inferences, free-associating, if we want any insight into the unknown. Which is why we talk obscurely and metaphorically about “pinning down” perception and “hunting for dark matter” (possibly a sort of primordial black hole). The existence of black holes was first hypothesized a decade after Einstein laid the theoretical groundwork for them in the theory of relativity, and the phrase “black hole” was not coined until 1968.
Likewise, consciousness is still such an elusive concept that, in spite of the recent invention of functional imaging – which has allowed scientists to visualize the different areas of the brain – we may not understand it any better now than we ever have before. “We approach [consciousness] now perhaps differently than we have in the past with our new tools,” says neuroscientist Joy Hirsch.
“The questions [we ask] have become a little bit more sophisticated and we’ve become more sophisticated in how we ask the question,” she adds – but we're still far from being able to explain how the regions of the brain interact to produce thought, dreams, and self-awareness. “In terms of understanding, the awareness that comes from binding remote activities of the brain together, still remains what philosophers call, ‘The hard problem.'”