You are reading these words right now. You are not just processing information. You are experiencing something. There is "something it is like" to be you, right now, reading this sentence. That fact - the existence of subjective, conscious experience - is one of the deepest unsolved problems in all of philosophy and science. And it may be the most powerful argument against materialism ever discovered.
Philosopher David Chalmers drew a distinction in 1995 that changed the field. He identified what he called the "easy problems" and the "hard problem" of consciousness.
The easy problems (easy in principle, not in practice) are questions about how the brain processes information:
These are "easy" because they are, at least in principle, solvable by finding the right neural mechanism. You explain the function, and you have explained the phenomenon.
The hard problem is different: Why is there subjective experience at all? Why does all that information processing feel like something from the inside? When you see red, neurons fire in your visual cortex. A neuroscientist could map every single one of them. But none of that explains why you experience redness. Why isn't the brain just a sophisticated information-processing machine operating in the dark, with no inner experience whatsoever?
The hard problem is not a gap in our current knowledge that more neuroscience will fill. It is a gap in the kind of explanation that physical science can provide. Physics deals with objective, third-person, quantitative properties: mass, charge, position, momentum. Consciousness is subjective, first-person, and qualitative. No arrangement of objective properties seems to logically entail the existence of subjective experience. And that is the problem.
If materialism (the view that only physical matter exists) is true, then consciousness should be fully explainable in terms of physics and chemistry. If it is not - if subjective experience cannot be reduced to brain states - then materialism is incomplete as a worldview. And if materialism is incomplete, the door is open to the possibility that mind is fundamental to reality rather than an accidental byproduct of it. A worldview in which a conscious God creates conscious beings has explanatory resources that materialism lacks.
Philosopher Frank Jackson proposed a thought experiment in 1982 that crystallized the problem:
Mary is a brilliant color scientist who has lived her entire life in a black-and-white room. She has studied everything there is to know about the physics and neuroscience of color: wavelengths, photon absorption, retinal cone responses, neural processing, every measurable fact about what happens when a human sees red. Her physical knowledge is complete.
One day, Mary is released from the room and sees a red rose for the first time.
Does she learn something new?
Almost everyone's intuition says yes. She learns what it is like to see red. She knew every physical fact, but she did not know the subjective experience of redness. If she learns something new, then physical facts do not exhaust all facts. There are facts about conscious experience that cannot be captured by physics.
If physical facts do not exhaust all facts, then materialism is false. There is more to reality than matter and energy.
Thomas Nagel is an atheist philosopher at New York University. His 2012 book Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False sent shockwaves through the academic world - not because a theist wrote it, but because a committed atheist did.
Nagel's argument proceeds in stages:
The significance of Nagel's argument is that it comes from within the secular philosophical tradition. He is not arguing for Christianity. He is arguing that the dominant materialist worldview cannot account for the most obvious feature of reality: that there is something it is like to be a conscious being.
Materialist philosophers have proposed several strategies for dealing with the hard problem. None has succeeded:
Philosophers use the term qualia (singular: quale) for the subjective, experiential properties of conscious states. The redness of red. The painfulness of pain. The taste of coffee. The warmth of sunlight on your skin.
Qualia have properties that physical objects do not:
These properties are unlike anything in the physical world as described by physics. Physics deals with relational, quantitative, structural properties. Qualia are intrinsic, qualitative, and subjective. If qualia are real (and your experience right now confirms they are), then the physical world as described by physics is not the whole of reality.
If consciousness cannot be reduced to matter, what follows?
There are several options. Nagel proposes a kind of "natural teleology" - that the universe is oriented toward the production of consciousness without any designer. Panpsychism proposes that consciousness is a fundamental feature of all matter. Theism proposes that consciousness originates from a conscious God who created conscious beings.
The theistic explanation has several advantages:
The next lesson examines Bell's inequality and quantum non-locality. The connection to consciousness is direct: if quantum mechanics shows that reality at its most fundamental level is non-local, contextual, and observer-dependent, then the materialist picture of a universe made of tiny billiard balls bouncing around in empty space is incomplete. Some physicists and philosophers have argued that consciousness may be fundamental to the structure of reality itself - not an add-on produced by brains, but the ontological ground from which physical reality emerges.
The hard problem of consciousness, examined in this lesson, provides the philosophical foundation. Bell's theorem, examined in the next, provides the physical evidence. Together, they constitute one of the most powerful challenges to materialism in the history of thought.
"Neuroscience will eventually explain consciousness. We just need more data."
More neuroscience will undoubtedly teach us more about the neural correlates of consciousness - which brain states correspond to which experiences. But correlation is not explanation. Knowing that C-fibers fire when you feel pain does not explain why C-fiber firing feels like anything. The hard problem is not about missing data. It is about a conceptual gap between objective, third-person physical descriptions and subjective, first-person experience. No amount of third-person data can bridge a first-person gap.
"Consciousness is an emergent property, like wetness emerges from water molecules."
Wetness is not actually a good analogy. Wetness is fully explainable in terms of molecular interactions: hydrogen bonds, surface tension, and molecular behavior. Once you understand the molecules, you understand the wetness. There is no "hard problem of wetness." But consciousness is different. Once you understand every neuron, every synapse, every chemical interaction, you still have not explained why any of it feels like something from the inside. The emergence of wetness from molecules is a straightforward case of macro-level properties arising from micro-level interactions. The emergence of subjective experience from objective matter is a different kind of claim altogether, one for which we have no model and no mechanism.
"Even if consciousness is mysterious, that does not prove God exists."
Correct. The hard problem of consciousness does not, by itself, prove God exists. What it does is demonstrate that materialism is incomplete. If matter is not all there is, then the door is open to explanations that include mind as a fundamental feature of reality. The theistic hypothesis - that a conscious God is the foundation of reality - explains consciousness more naturally than materialism does. Combined with the cosmological, fine-tuning, moral, and historical arguments examined elsewhere in this curriculum, the consciousness argument adds another convergent line of evidence pointing toward a personal Creator.
What is the "hard problem" of consciousness, and why is it different from the "easy problems"?
Why does the hard problem of consciousness pose a challenge to materialism specifically?
The hard problem of consciousness is not a gap in our current scientific knowledge. It is a gap in the kind of explanation that physical science can provide. Subjective experience is real, irreducible, and unlike anything in the physical world as described by physics. Materialist attempts to explain it away (eliminativism, identity theory, functionalism, emergentism) have all failed. Even atheist philosopher Thomas Nagel concludes that materialism is "almost certainly false." If consciousness cannot be reduced to matter, then the materialist worldview is incomplete, and the door opens to explanations in which mind is fundamental to reality. The next lesson examines what quantum physics has to say about that possibility.