Hedda Hassel Morch in Nautilus:
The nature of consciousness seems to be unique among scientific puzzles. Not only do neuroscientists have no fundamental explanation for how it arises from physical states of the brain, we are not even sure whether we ever will. Astronomers wonder what dark matter is, geologists seek the origins of life, and biologists try to understand cancer—all difficult problems, of course, yet at least we have some idea of how to go about investigating them and rough conceptions of what their solutions could look like. Our first-person experience, on the other hand, lies beyond the traditional methods of science. Following the philosopher David Chalmers, we call it the hard problem of consciousness. But perhaps consciousness is not uniquely troublesome. Going back to Gottfried Leibniz and Immanuel Kant, philosophers of science have struggled with a lesser known, but equally hard, problem of matter. What is physical matter in and of itself, behind the mathematical structure described by physics? This problem, too, seems to lie beyond the traditional methods of science, because all we can observe is what matter does, not what it is in itself—the “software” of the universe but not its ultimate “hardware.” On the surface, these problems seem entirely separate. But a closer look reveals that they might be deeply connected.
Consciousness is a multifaceted phenomenon, but subjective experience is its most puzzling aspect. Our brains do not merely seem to gather and process information. They do not merely undergo biochemical processes. Rather, they create a vivid series of feelings and experiences, such as seeing red, feeling hungry, or being baffled about philosophy. There is something that it’s like to be you, and no one else can ever know that as directly as you do. Our own consciousness involves a complex array of sensations, emotions, desires, and thoughts. But, in principle, conscious experiences may be very simple. An animal that feels an immediate pain or an instinctive urge or desire, even without reflecting on it, would also be conscious. Our own consciousness is also usually consciousness of something—it involves awareness or contemplation of things in the world, abstract ideas, or the self. But someone who is dreaming an incoherent dream or hallucinating wildly would still be conscious in the sense of having some kind of subjective experience, even though they are not conscious of anything in particular.