Home / Theories / The hard problem
The Hard Problem of Consciousness, Explained
Why does it feel like anything to be you? The question David Chalmers named in 1995 still divides philosophers and scientists.
- “Easy” problems ask how the brain performs functions; the “hard” problem asks why those functions come with experience.
- Whether the hard problem is real, or a confusion, is itself debated.
Easy problems and the hard problem
In his 1995 paper “Facing up to the problem of consciousness”, David Chalmers listed “easy problems”: explaining how we discriminate stimuli, integrate information, report mental states, focus attention and control behaviour. They are enormously difficult in practice, but we know what a solution looks like: a mechanism that performs the function. The hard problem is different. Even with a complete account of every mechanism, we could still ask why that processing is accompanied by subjective experience rather than happening “in the dark”.
The explanatory gap and philosophical zombies
The philosopher Joseph Levine called this the explanatory gap (1983). Chalmers sharpened it with the thought experiment of a philosophical zombie: a being physically identical to you, behaving identically, but with no inner experience. If such a being is even conceivable, he argued, physical facts alone do not logically fix facts about experience. Critics reply that conceivability is a poor guide to possibility.
The main responses
| Response | In one line |
|---|---|
| Type-B physicalism | Experience is physical; the gap is in our concepts, not in reality. |
| Illusionism | The sense of an extra, ineffable quality is itself an illusion produced by the brain. |
| “Meta-problem” approach | First explain why we think there is a hard problem (Chalmers, 2018). |
| Panpsychism / Russellian monism | Experience is a fundamental feature of matter. See panpsychism. |
| Dualism | Experience is non-physical and must be added to our picture of reality. |
Why it still matters
The hard problem shapes what scientific theories try to do. Some, like Global Workspace Theory, mostly target the easy problems and hope the hard one dissolves. Others, like IIT, start from experience itself. It also matters practically for questions about animal minds, patients with disorders of consciousness and artificial intelligence.
Sources
- Chalmers, D. (1995). Facing up to the problem of consciousness. Journal of Consciousness Studies, 2(3).
- Levine, J. (1983). Materialism and qualia: the explanatory gap. Pacific Philosophical Quarterly, 64.
- Chalmers, D. (2018). The meta-problem of consciousness. Journal of Consciousness Studies, 25(9–10).
- Stanford Encyclopedia of Philosophy: Consciousness