What Is Consciousness?

Consciousness is what we can know best and explain least. It is the inner subjective experience of what it feels like to see red or smell garlic or hear Beethoven. Consciousness has intrigued and baffled philosophers. To begin, we must define and describe consciousness. What to include in a complete definition and description of consciousness.

The hard problem of consciousness is the problem of explaining why any physical state is conscious rather than nonconscious. It is the problem of explaining why there is 'something it is like' for a subject in conscious experience, why conscious mental states 'light up' and directly appear to the subject.  The usual methods of science involve explanation of functional, dynamical, and structural properties—explanation of what a thing does, how it changes over time, and how it is put together. But even after we have explained the functional, dynamical, and structural properties of the conscious mind, we can still meaningfully ask the question, Why is it conscious? This suggests that an explanation of consciousness will have to go beyond the usual methods of science. Consciousness therefore presents a hard problem for science, or perhaps it marks the limits of what science can explain.  Explaining why consciousness occurs at all can be contrasted with so-called 'easy problems' of consciousness: the problems of explaining the function, dynamics, and structure of consciousness.  These features can be explained using the usual methods of science. But that leaves the question of why there is something it is like for the subject when these functions, dynamics, and structures are present. This is the hard problem.

In more detail, the challenge arises because it does not seem that the qualitative and subjective aspects of conscious experience—how consciousness 'feels' and the fact that it is directly 'for me'—fit into a physicalist ontology, one consisting of just the basic elements of physics plus structural, dynamical, and functional combinations of those basic elements. It appears that even a complete specification of a creature in physical terms leaves unanswered the question of whether or not the creature is conscious. And it seems that we can easily conceive of creatures just like us physically and functionally that nonetheless lack consciousness. This indicates that a physical explanation of consciousness is fundamentally incomplete: it leaves out what it is like to be the subject, for the subject. There seems to be an unbridgeable explanatory gap between the physical world and consciousness. All these factors make the hard problem hard.

David Chalmers is an Australian philosopher specializing in the area of philosophy of mind and philosophy of language. He is Professor of Philosophy and co-director of the Center for Mind, Brain, and Consciousness at New York University.

https://drive.google.com/file/consciousness.mp4