What Is the Hard Problem vs Easy Problems?

Direct Answer

The distinction between the easy problems and the hard problem of consciousness was formulated by David Chalmers in his 1995 paper "Facing Up to the Problem of Consciousness." The easy problems are the problems of explaining the various cognitive functions that are associated with consciousness: the ability to discriminate stimuli and react to them, to integrate information from different senses, to report mental states verbally, to focus attention, to control behavior, and to access one's own internal states. These problems are "easy" not because they are trivial — they are extremely difficult — but because they are tractable in principle: we have a clear idea of what a solution would look like, namely an explanation of how a physical mechanism performs the function.

The hard problem is different in kind. It is the problem of explaining why and how any physical process is accompanied by subjective experience — why there is something it is like to see red, feel pain, or taste coffee. Even if we explained every function the brain performs — every discrimination, every integration, every report, every act of attention — we would still face the question: why is this activity accompanied by experience at all? Why does the processing not go on "in the dark," as it does in a camera, a thermostat, or a well-designed robot? The easy problems explain what the brain does; the hard problem asks why doing it feels like anything.

The two kinds of problem differ in the kind of explanation they require. For the easy problems, a functional explanation suffices: describe the mechanism, show how it performs the task, and the problem is solved. For the hard problem, no functional explanation seems to work: you can describe every mechanism in complete physical detail, and the question "but why is there experience?" remains. This is the explanatory gap — the gap between a complete physical description and the phenomenal character it is supposed to explain. Chalmers's claim is not that the hard problem is unsolvable but that it cannot be solved by the methods that solve the easy problems; it requires new ideas.

Historical Context

The distinction has precedents. The idea that there is a residual mystery in consciousness that functional science cannot touch runs through philosophy from Leibniz's mill argument (the mind cannot be found by inspecting the machinery of the brain) to the nineteenth-century discussions of the explanatory gap. But the modern debate was set up in the 1970s and 1980s: Thomas Nagel's "What Is It Like to Be a Bat?" (1974) argued that objective, third-person science cannot capture the subjective character of experience; Frank Jackson's knowledge argument (1982) argued that a complete physical description leaves out the phenomenal facts.

Chalmers's 1995 paper and 1996 book The Conscious Mind gave the distinction its canonical form and its name. Chalmers argued that the easy problems can, in principle, be solved by the standard methods of cognitive science, but that the hard problem requires a different approach: consciousness must be treated as a fundamental feature of the world, governed by psychophysical laws, in the way that mass, charge, and spacetime are fundamental features of physics. This "naturalistic dualism" (or property dualism) was a deliberate attempt to take the hard problem seriously while remaining scientifically respectable.

The distinction became the organizing framework of the philosophy and science of consciousness. It was adopted by the scientific community (the Journal of Consciousness Studies ran the famous 1995–1997 debates on the hard problem), and it sharpened the divide between "realists" about the hard problem (Chalmers, Nagel, McGinn, and many others) and "deflationists" who deny there is a hard problem at all (Dennett, the illusionists, and some physicalists).

Key Arguments & Debates

The argument for the distinction is the conceivability argument in its simplest form: for any functional description of the brain, we can conceive of a system that satisfies that description entirely — performs all the functions — yet has no experience. The philosophical zombie is exactly this: a being behaviorally and functionally identical to a human but with no inner life. If the zombie is conceivable, it is (Chalmers argues) metaphysically possible, and if it is possible, then the functions do not entail experience, and the hard problem is real. The argument from Mary's room makes the same point epistemically: Mary knows all the physical and functional facts but learns something new when she first sees red, so the functional facts do not exhaust the phenomenal facts.

The main line of attack is to deny that there is a hard problem. Daniel Dennett argues that the "hard problem" is a philosophical artifact: once you have explained all the functions — discrimination, integration, report, access — there is nothing left over to explain. The apparent "what it is like" is an illusion generated by the way our introspective concepts work. Illusionists (Frankish, Kammerer) follow this line: phenomenal consciousness is a powerful illusion, and the task is to explain why we believe in it, not to explain it. Other physicalists (Churchland, Tye) argue that the hard problem will dissolve as science progresses — just as "vital force" dissolved with the advance of biochemistry. Still others (McGinn) argue the hard problem is real but permanently beyond human cognitive reach ("mysterianism").

The debate is complicated by disagreement about what would count as solving the hard problem, and about whether the conceivability of zombies carries modal weight. Chalmers's response to the deflationists is that the phenomenal facts are the most certain facts we have — you cannot argue someone out of the datum that they experience redness — and that a theory that denies the datum has refuted itself.

Contemporary Relevance

The hard problem/easy problems distinction is now the default frame for consciousness research, from neuroscience to AI. When neuroscientists claim to have "explained consciousness," philosophers ask: have you explained the easy problems (function) or the hard problem (experience)? The distinction disciplines experimental work: paradigms that measure reportable access (the easy problems) must not be conflated with the experience they accompany. It also structures the AI debate: a chatbot that passes every functional test still leaves the hard question — is there something it is like to be the chatbot? For AI ethics, the stakes are direct: if the hard problem is real and unresolved, then we cannot infer from functional competence to experience, and we do not yet know whether sophisticated machines suffer. The distinction thus remains not only the deepest puzzle in philosophy of mind but a practical boundary condition on the ethics of artificial minds.

Related Concepts

• The explanatory gap: the epistemic gap the hard problem names.
• Phenomenal consciousness: the target of the hard problem.
• Qualia: the qualitative characters the hard problem concerns.
• Mary's room: the knowledge argument that supports the distinction.
• What is it like to be a bat: Nagel's argument for the irreducibility of the subjective.
• Illusionism: the denial that there is a hard problem.

Further Learning

• Internet Encyclopedia of Philosophy: The Hard Problem of Consciousness
• Stanford Encyclopedia of Philosophy: Consciousness
• David Chalmers, "Facing Up to the Problem of Consciousness," Journal of Consciousness Studies 2 (1995): full text.
• David Chalmers, The Conscious Mind: In Search of a Fundamental Theory (1996).